EPA-670/4-75-006
June 1975
Environmental Monitoring Series
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REVIEW NOTICE
The National Environmental Research Center—Cincinnati
has reviewed this report and approved its publication.
Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
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FOREWORD
Man and his environment must be protected from the
adverse effects of pesticides, radiation, noise, and other
forms of pollution, and the unwise management of solid
waste. Efforts to protect the environment require a focus
that recognizes the interplay between the components of our
physical environment—air, water, and land. The National
Environmental Research Centers provide this
multidisciplinary focus through programs engaged in
• studies on the effects of environmental
contaminants on man and biosphere,
• the development of efficient means of
monitoring these contaminants, and
• a search for ways to prevent contamination
and to recycle valuable resources.
The current and projected increase in the number of
nuclear power stations requires expanded monitoring
programs at the state and federal level to assure that
radiation exposures of persons in the environment remain at
an acceptably low level. The Environmental Protection
Agency is therefore engaged in a spectrum of activities to
assure that the monitoring programs are reliable. These
include distributing calibrated radioactivity solutions,
undertaking laboratory intercomparisons, and preparing
manuals of radiochemical analyses. As part of these
activities, the Environmental Protection Agency
participated in this symposium arranged by the Subcommittee
on the Use of Radioactivity Standards, Committee on Nuclear
Science, NAS-NRC, and is publishing the proceedings.
A. W. Breidenbach, Ph.D.
Director
National Environmental Research Center
Cincinnati
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ABSTRACT
A symposium was held to discuss the needs for
radioactivity standards in environmental monitoring
programs concerned with population radiation exposure.
Papers were presented on "Status of Decay Schemes," "Some
Activities and Needs for AEC Regulatory in the Use of
Radioactivity Standards," "Standards for Environmental
Studies," "Program and Activities of the Quality Assurance
Branch, NERC-Las Vegas," "Activities of commercial
Radionuclide Producers," and "Radionuclide Metrology and
Quality Assurance." The presentations indicated that
numerous radioactivity standards and aids for correctly
utilizing them were available. New needs, however, had
arisen recently because lower levels of ambient
radioactivity must be measured by many more groups due to
requirements that population radiation exposure from
nuclear power production be as low as practicable. Based
on the presentations and resulting discussions, the
following actions were recommended: 1) Establish a focal
point for systematically planning activities to meet cited
needs for decay schemes, specific standards, analytical
methods, and quality assurance programs; 2) Develop a clear
chain of traceability to the National Bureau of Standards;
3) Prepare guides for standardizing radiation detection and
maintaining quality control; and 1) Train qualified
analysts to obtain satisfactory analytical results.
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CONTENTS
Page
Introduction and Recommendations . . . Bernd Kahn, EPA .... 1
Status of Decay Schemes Daniel J. Horen, ORNL . 4
Some Activities and Needs for AEC Regulatory in the
Use of Radioactivity Standards . . . Bernard H. Weiss, AEC . 9
Standards for Environmental Studies. . John H. Harley, HASL. .20
Program and Activities of the Quality
Assurance Branch, NERC-Las Vegas . . Arthur N. Jarvis, EPA .28
Activities of Commercial Radionuclide
Producers Carl W. Seidel, NENC. .39'
Radionuclide Metrology and Quality
Assurance Wilfrid B. Mann, NBS. .47
Appendix: Participants 55
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INTRODUCTION AND RECOMMENDATIONS
Bernd Kahn
Radiochemistry and Nuclear Engineering Facility
U. S. Environmental Protection Agency
National Environmental Research Center
Cincinnati, Ohio 45268
Considerable efforts currently are being devoted to
measuring radionuclides in effluents from nuclear
facilities and in environmental media that may contribute
to population radiation exposure. To make certain that the
data are accurate, both the U. S. Atomic Energy Commission
(AEC) and the U. S. Environmental Protection Agency (EPA)
maintain active quality assurance programs. Attainment of
a consistent level of accuracy has been found difficult.
This is understandable in view of the variety of
radionuclides and media, the low radionuclide
concentrations, and the specialized nature of the
analytical and detection procedures.
The availability and correct use of appropriate
radioactivity standards are fundamental requirements for
accurately measuring radionuclides. Their importance to
radiation protection activities and a program to fulfill
needs for standard radioactive material were discussed in a
report published in 1970.(1) Since then, the number of
measurement programs has increased with the rapid expansion
in nuclear power production. Moreover, measurements have
had to be more detailed in response to recommendations for
achieving lowest practicable radiation exposures. The
Subcommittee on the Use of Radioactivity Standards of the
Committee on Nuclear Science, NAS-NRC, therefore, arranged
this meeting to determine whether additional activities
were necessary to meet the needs for radioactivity
standards in this field, and EPA has published the
proceedings to make this information generally available.
Specialists were invited to present papers on the most
important aspects of using radioactivity standards: avail-
ability of standardized solutions, of decay schemes needed
to interpret calibration, and of guidance for appropriately
applying the standards. A quality assurance program being
developed for producers and users of radiopharmaceuticals
was presented to describe a response to similar problems in
a related field. The participants (listed in the Appendix)
discussed current needs of users in considerable detail.
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Based on these presentations and discussions, the
following activities are recommended to the AEC, EPA, and
Committee on Nuclear Science to assure the quality of
environment-related radioactivity measurements:
Mi Establish a focal point for systematic planning. A
schedule of priorities needs to be developed for obtaining
"best" decay schemes, specific standards, analytical
methods, and quality assurance programs on the basis of the
radiation exposure potential and requirements of time and
manpower. Ongoing activities concerning radioactivity
standards can be evaluated for their applicability to the
specialized needs of environmental measurement programs.
(2) Develop traceabij.itY feo the National Bureau of
Standards. In the environmental field, a chain of
traceability through either the AEC Health Services
Laboratory or the EPA Quality Assurance Branch is
envisioned. As a supplement or alternative, cooperative
efforts by producers of standards to maintain traceability
could be extended to include participation by the
analytical laboratories that use standards. Consideration
will have to be given to defining traceability with regard
to the frequency of test, the magnitude of the acceptable
uncertainty, and the fraction (if any) of erroneous
intercomparison values that can be accepted.
(3)Prepare guides for standardizing radiation detection and
maintaining quality SSntrol. The special analytical
problems in this field must be considered: measuring
extremely low radionuclide levels, distinguishing small
increments above "background" levels, preventing
contamination of samples and detectors, and evaluating
detector stability very precisely. Relatively uniform
procedures should be recommended for resolving these
problems.
CO Train qualified analysts. The competence and
reliability of individual analysts is usually the most
important factor in obtaining satisfactory analytical
results. Thus, abrupt decreases in the quality of
analytical data are often observed when one analyst leaves
his laboratory. For the same reason, laboratories perform
some analyses accurately and others inaccurately. The
employment of additional qualified analysts would go far
toward eliminating these problems.
It is important to note that some related aspects of
effluent and environmental measurements were considered to
be potentially greater sources of error than radionuclide
standardization and instrument calibration. These included
sample collection and storage, radiochemical analysis, and
data reporting. They should be given at least as much
consideration as the appropriate use of radioactivity
standards.
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References
1. Ad Hoc Panel of the Committee on Nuclear Science,
"National uses and Needs for Standard Radioactive
Material", National Academy of Science, Washington, D. C.
20418 (1970).
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STATUS OF DECAY SCHEMES
D. J. Horen
Nuclear Data Project
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37830
As most of the members of this Subcommittee well know,
the use of radioisotopes is expanding at a rather rapid
rate. In a recent paper(1) presented at the IAEA Symposium
on Applications of Nuclear Data in Science and Technology,
Dr. Weinberg and I prepared a rather cursory table which
tried to depict some of the areas of usage and the level of
sophistication involved. One of our primary objectives was
to try to point out that the applications were many and
varied, and hence, so too the actual nuclear data needs.
During the past four years, as Director of the Nuclear
Data Project, I have been somewhat concerned with trying to
understand and place in perspective the needs of various
users—both basic and applied. Some of my thoughts on this
were summarized (2) in a paper also presented at the IAEA
Symposium. Recently, I have attended sessions at ANS and
Society of Nuclear Medicine Meetings in an effort to learn
more of the needs in these areas. Let me spend a few
minutes here to offer my impressions of the situation.
1*11 begin by saying that I've listened to many persons
in both the basic and applied areas who want! And 1*11
state here that, of course, we would be most happy if we
could give ! However, just as everyone else has to work in
an environment with boundaries, so too do we at the Data
Project.
Now from my reference frame, the picture seems to be
somewhat as follows. There are over 1500 identified
radionuclides, which have been studied to varying degrees.
During the past four years, the Data Project has provided
evaluated compilations on some seventy or more mass chains.
In conjunction with the NIRA Program, all of the mass
chains with A > 44 should be current to within seven years
or less by the end of 1974. In addition, the Data Project
has produced some specialized compilations such as
Radioactive Atoms(3) by Martin and Blichert-Toft, and
recently Martin has compiled data on about thirteen
additional decay schemes, mainly for fission product gases.
The precise status of our knowledge on many decay
schemes fluctuates drastically depending upon the specific
circumstances. For instance, in most cases where there is
direct decay to the ground state of the daughter product,
the absolute normalization for the decay is usually not
known, or if so, only rather poorly. Hence, if one is
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trying to use such an activity for quantitative purposes,
the accuracy achievable will be limited. It seems to me
from my attendance at the IAEA Symposium, the ANS and SNM
Meetings, and conversations with numerous users, the latter
do not always appreciate this point. In general,
determination of the absolute normalization factor
contributes little insight into the physics involved,
whereas the measurement can be rather tedious. Hence, it
is not uncommon to find many papers on decay schemes in
which the absolute normalization is essentially ignored.
Shortly after arriving at the Data Project, I requested the
compilers to explicitly indicate in the compilations how
each decay scheme has been normalized. It behooves the
user to examine such statements, especially if he is
interested in the intensity of radiations per 100 decays.
To me, the designation of standards is a human
endeavor, and the manner in which this is done very much
depends upon the persons involved and probably their
impressions of how the "standards" will be applied.
However, no matter how this is to be arrived at, I would
strongly suggest that the data be examined in sufficient
detail to ensure that the "standard data" fall within the
bounds of what is actually known.
Now I'd like to spend a few minutes discussing the
problems of the data producers, compilers, and users,
mainly as they pertain to decay data. I've already noted
that data producers, i.e., basic researchers, study decay
schemes primarily from the view of trying to learn
something of nuclear structure. In addition, they also
derive a living from such work, and their pay scale is
usually based upon numbers of papers published, and whether
or not the content proves of value to an applied user is
immaterial.
As regards the data users, we've already noted that
they each have a specific use in mind which stipulates what
type and quality of data they need.
Now the number of data producers probably outnumbers
the compilers by at least 100/1, and the number of users
outnumbers the compilers by most probably 1000/1. Hence,
to assume that a handful of compilers will be able to
satisfy the specific desires of each user is completely
unrealistic. Therefore, either the users must be capable
of satisfying some of their own needs, or some system has
to be worked out that makes it easy to satisfy large
numbers of users from a minimal effort. Frankly, I think
we've reached the point where the users or the committees
which purport to represent them should begin to examine
their actual needs in more detail, because obviously, the
compilers are going to have to devote more effort to the
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criteria of choice of what they compile, as well as the
time devoted to same.
References
1. Criteria of Choice for compilations of Nuclear Data -
D. J. Horen and A. M. Weinberg, IAEA Symposium on
Applications of Nuclear Data in Science and Technology,
Paris, France (March 1973).
2. Nuclear Data Project: Operations, Status, and Plans -
D. J. Horen, IAEA Symposium on Applications of Nuclear Data
in Science and Technology, Paris, France (March 1973).
3. Radioactive Atoms: Auger-Electron, Alpha-, Beta-,
Gamma-, and X-Ray Data, M. J. Martin and P. H. Blichert-
Toft, Nuclear Data Tables A8, 1 (1970).
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Discussion;
Additional comment by Horen: Funding for the Nuclear
Data Project arises from the AEC Division of Physical
Research (DPR) in an amount of approximately 1% of that
Division's $60 million budget.
Kahn: How much money is provided by "applied
agencies"?
Horen: We have never had funding outside the DPR. We
have just been given $10,000 for FY 7U by AEC Regulatory
for their decay scheme needs. Since our support is mainly
provided from basic research programs, we are getting
pressure to satisfy the basic researcher's needs. We may
have to modify the format.
Kahn: That is indeed a modest sum.
Horen: "Applied users" will have to define their decay
scheme needs.
Kastner: Is there a correlation between the amount of
money needed and the "resolution" of the data?
Horen: Certainly, the greater detail needed for highly
specialized needs requires more time. Beyond a certain
accuracy, there is little to be gained for nuclear physics
purposes. Applied users1 needs require more effort due to
the necessity for absolute normalization.
Kastner: Can you identify government agencies or other
groups that should support this effort?
Horen: It is up to the users themselves to define
their needs precisely.
Kahn: How can SOURS arrange for compilations of
simplified decay schemes?
Horen: I suggest that SOURS prepare documents
justifying the defining of the needs of users and then
approach each concerned agency for financial support. I
would like to ask that there be a feed-back of information
to AEC-DPR as to the usefulness of the compilations.
Meyers: I would like to mention the dosimetry data
bank that is supported by various agencies at Oak Ridge
Associated Universities. It is directed by Roger Cloutier.
Kastner: I suggest that SOURS be a "funnel" for feed-
back of information to compilers. I think SOURS could help
define format for simplified decay schemes and could be the
group to recommend changes in values used in practice.
Kahn: How could financial support be obtained by
defining needs and for preparation of additional simplified
decay schemes?
Kastner: Additional funding could be shifted from
other programs if justification is presented.
Meyers: FDA support would probably be available, but
not for 1500 nuclides. I would suggest 15 or 20—possibly
40. New radiopharmaceuticals require valid data.
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Jarvis: EPA might be able to give support, but again
for 20-30 radionuclides.
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SOME ACTIVITIES AND NEEDS FOR AEC REGULATORY
IN THE USE OF RADIOACTIVITY STANDARDS
Bernard H. Weiss
U. S. Atomic Energy Commission
Washington, D. C. 20545
I would like to thank the subcommittee for inviting a
representative of AEC Regulatory to participate in these
discussions. I plan to first describe our activities which
require laboratory support and some of our experiences with
regard to radioactivity standards. Then, I will speak
about some of the needs we have either encountered or can
foresee relating to Regulatory's own measurement programs,
licensees1 analytical requirements and those of companies
performing analytical measurements for licensees. Our
general approach to these needs may differ from many
participants in these discussions because our need for
accuracy is different from that of most research and
development laboratories.
Regulatory*s major need for laboratory capability is to
obtain reasonable assurance that the results of licensee's
analytical measurements and subsequent reports are valid.
In addition, it is our desire that the results be relatable
to our national standards organization, the National Bureau
of Standards. These efforts are involved in two major
programs - 1) safeguards and 2) independent effluent and
environmental measurements.
The safeguards program, through its field inspection
program, independently verifies those components of a
facilityfs material balance which are not verified by a
second party (e.g., the receiver of a shipment as well as
the shipper in order to determine the amount of material
involved in the transaction). This is done by both
destructive analyses (offsite) and by non-destructive
equipment at the site. We plan to increase the percentage
•of non-destructive analyses over the next several years so
that by 1978, over 75% will be done this way. This will be
accomplished by adding more measurement vans and upgrading
the equipment in our present vans. However, there will
continue to be a need for destructive analytical capability
because of its accuracy over present non-destructive
analytical methods.
At present, there are two major classes of safeguards
standards available. The first is a group of high purity,
extremely well-characterized materials, prepared in AEC
facilities and certified and distributed by the NBS as
Standard Reference Materials (SRM). The second is a group
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of working standards, prepared and standardized against
SRMs and distributed by various ABC and contractor
laboratories.
We are in the process of soliciting the views of
various AEC and contractor laboratories and special nuclear
material licensees in order to project the needs for
uranium and plutonium certified standard materials for
elemental and isotopic assay through 1980. We have sent
out a letter asking for their views as to new standards
needed and the rate at which the respondents might purchase
these new standards. This information would be made
available to the subcommittee, if desired.
In addition to these standards which are used for
destructive testing, we also utilize working standards in
suitable configurations for onsite testing in our vans.
These are essentially secondary standards for
nondestructive testing which are standardized against SRMs.
The program for independent measurements of plant
effluent and environmental effects has several components.
For the past few years special evaluations have been
conducted at operating nuclear power plants to assist
Regulatory in standards development and in the review of
reactor designs by empirically determining the value of key
variables in models describing the release, transport, and
uptake of radionuclides. This has included in-depth
measurements at six boiling water reactors (BWR) and a
field study to determine the fate of iodine from three
reactors in various media in the environment. In addition,
we are currently conducting source term measurements at a
pressurized water reactor and anticipate future studies at
a fuel reprocessing plant, high temperature gas cooled
reactor, fuel fabrication facilities, possibly uranium ore
processing mills and tailings piles and other AEC licensed
facilities which may have a significant impact on the
environment. During both of the studies already conducted,
BWRs and the iodine pathway study, we have had the problem
of relating data from the several laboratories involved in
the studies. At one of the BWRs, there were six
laboratories analyzing different samples from the reactor.
In connection with this study, we asked the NBS to supply
both standards and unknown test sources to these six
laboratories for the purpose of intercomparing their
ability to detect and identify radionuclides commonly found
in reactor effluents. NBS prepared a standard containing
seven radionuclides and an unknown solution with six
radionuclides of somewhat different radionuclide
composition. The NBS has previously reported the results
of the intercomparison.
In the iodine pathway study, we have a similar problem
of intercomparison which is compounded by the participation
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of nine laboratories in this study and the fact that these
were low level environmental measurements of a radionuclide
with a short half-life. In this case, we called on NBS to
prepare, on short notice, low level 1-131 liquid standards
to be distributed to the study participants. In addition,
we had planned to prepare a grass sample spiked with 1-131
and have this intercompared among the various laboratories
during the study. However, this had to be postponed until
the conclusion of the study because, as Dr. Kahn pointed
out, the spiked grass sample could conceivably contaminate
laboratory equipment because its activity would be quite
high compared to the barely perceptable levels we were
finding the environment. In addition, uniform
concentrations of iodine in the grass is difficult to
achieve. It would probably be best to have each laboratory
count the same sample but this is not practical because of
the transport times involved and the different methods of
sample preparations by each of the laboratories.
The laboratory analyses for these studies mentioned
above are performed primarily by AEC contractor
laboratories and occasionally by other government
laboratories. The needs of these sophisticated
laboratories relating to radioactivity standards will be
adequately covered by John Harley in his presentation and
pther presentations during this meeting so I will not go
into these needs.
Another major laboratory program which Regulatory has
embarked upon is our collaborative monitoring program with
the States. In this program the States will split or
obtain duplicate effluent and environmental samples for the
purpose of verifying a licensee's results which are
required to be reported to the AEC. In addition, we have
specified that the verified results should be traceable to
the NBS. This presents a two fold problem. There is a
need, first, to design a program to assure traceability of
States1 and licensees1 analyses results to the NBS and
secondly, to upgrade the capability of the States to the
point where an attempt to accomplish traceability would be
meaningful. To this end, the NBS is currently working with
our laboratory, the Health Services Laboratory (HSL). The
States, in turn, will not be directly traceable to the NBS
but rather will achieve some form of traceability through
standards prepared by HSL, analysis of duplicate samples
and test solutions and other means. In some States this
process will not be difficult; others will require much
assistance before they reach this point of accomplishment.
HSL has visited most of the contract states to gain an
insight as to their capability and has begun to provide
them with several of their own secondary standards in order
to calibrate their systems. In addition, it is necessary
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in some cases to instruct these State laboratories in the
proper use of standards. In other words, we are attempting
to develop a system whereby HSL will be directly traceable
to the NBS and the States and ultimately licensees would be
relatable to the NBS through HSL. We anticipate this will
be a continuing program which will require a significant
portion of HSL's time both in analyzing NBS standards and
test solutions and HSL preparing secondary calibration
standards and unknowns.
The AEC-State collaborative program is designed to
provide some verification of the analytical capability of
licensees and their laboratory contractors. What we are
trying to do is give some credibility to the massive amount
of environmental and effluent data we receive. But the
problem of providing credibility to data should not be ours
alone. Licensees and environmental consultant laboratories
must be willing to conduct workable quality control
programs. In order to do that, however, appropriate
standards, especially environmental standards, must be made
available. The AEC places a great emphasis on quality
assurance and quality control in the construction and
operation of nuclear power plants in relation to safety.
Similar emphasis on quality control in effluent and
environmental programs can be expected in the near future.
If commercial suppliers, environmental consultants or other
government agencies cannot provide appropriate standards
for acceptable quality control programs or these
laboratories providing environmental analyses do not
conduct satisfactory quality control programs, the AEC may
be reluctantly forced to become directly involved.
The AEC is now in the process of considering an
amendment to its regulations which would specify design
objectives for the "as low as practicable" philosophy. At
such time as that rule. Appendix I to Part 50, is adopted,
there will be increased emphasis on the measurement of
lower levels of radioactivity in the environment. As you
may be aware, the technical specifications of several
reactor licenses already require the determination of 1-131
in milk to 0.5 pCi/liter at the time of sampling. This
corresponds to an annual dose of less than 5 mrem/year to
the thyroid of a child drinking a liter of milk per day.
In the future there seems little doubt that
environmental monitoring of both sea water and fresh water
will be required to determine concentrations of
radionuclides at very low levels. A need exists to
establish "natural standards" of radionuclides in these
media. In such development, the AEC must be assured of a
proper mode of preparation and storage in the "standards"
such that the media will not deteriorate with time. In
addition, the chemical stability of the radioactive species
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composing the constituents for analysis must also be
assured over long periods of time.
Most AEC licensees of nuclear facilities do not have
the laboratory or support facilities which the laboratory
people at this meeting can call upon. They are not in a
position to prepare environmental standards or any other
secondary standards or even to check the standards
supplied. For these people, who in a sense cannot defend
themselves, we should devise a system which will, first of
all, provide an adequate selection of necessary standards
and additionally provide information to enable the user to
employ the standards correctly. One of the recommendations
of this subcommittee in its previous report was the "The
central agency responsible for supplying standards"
presumably the NBS, "should undertake an active program to
aid users of radioactivity standards through training
courses" and "published instruction material". That
recommendation is still valid and we would hope that the
NBS would be able to obtain the resources to implement that
recommendation.
At this time the NBS is attempting to develop the
concept of traceability to provide a link between the user
and the national and international measurements systems.
This is a difficult task but we would encourage the NBS to
give this prime attention. Regulatory does not require a
high degree of accuracy in the determination of activities
contained in effluent and environmental samples. In most
analyses, a measurement accurate to ± 25% of the true value
is sufficient for the purposes of Regulatory Operations.
As a consequence, secondary standards that can be related
to appropriate NBS primary standards can fulfill virtually
all of Regulatory's needs as required for environmental
monitoring. We feel it is not very important for licensees
and State laboratories to obtain expensive NBS standards
which have a 2% error when other less precise standards may
suffice. At the present time, we do not perceive the
accuracy of standards to be primary problem for Regulatory
and its licensees. The standards problem may be a question
of confidence in the manufacturer or distributor of these
secondary standards. If the NBS develops their
traceability concept to a point where it is convenient and
feasible for commercial suppliers to establish formal
traceability with the NBS, I would suspect that users and
government agencies would require traceability as a
condition of doing business. Consequently, we urge the NBS
to develop fully this concept and make it known to the
industry, and encourage standards manufacturers and
distributors to participate in achieving traceability to
the NBS.
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Another source of concern to the industry as well as
Regulatory is the chemical form of activity that is passed
through traps, filters, etc. and into the environment. In
general, the molal concentrations of these chemical forms
are very low and their chemical compositions are not well
known, if at all. In the determination of efficiencies of
removal mechanisms and systems, a need exists to have a
capacity to produce reproducibly or to maintain discrete
highly diluted chemical forms (particularly, iodine) at
known concentrations within appropriate diluent gases.
I would also like to mention another situation of
growing concern to us. Several long-lived radionuclides
that result from fission or capture are produced in
relatively large quantities in reactors. Minute quantities
of these radionuclides, as a consequence, are often
difficult to measure by direct counting. Methods are
available than can increase the sensitivities of these
measurements by means of neutron or charged particle
bombardments of samples followed by analyses of the product
nuclide (s). (This is particularly true for 1-129 and Tc-
99). A need exists for the development of standardized
systems and procedures that allow accurate determinations
of target nuclides by means of nuclear interactions.
Earlier in this meeting. Dr. Horen spoke about the
availability of decay schemes. We were glad to see this
topic on the agenda because one of Regulatory's pressing
needs is the available of this kind of information for the
calculation of dose to individuals and the measurement of
radioactivity. Consistency in the use of disintegration
schemes and energies by all parties involved in the
licensing process may not solve any of our major licensing
problems but it would certainly remove a current annoyance,
i.e., differing decay schemes used by several persons.
While I have the attention of this subcommittee I would
like to take the opportunity to relay some of the
complaints I have heard about standards which are currently
available. First, sufficient information about these
standards is not always available. It would allow the user
much more flexibility if he knows both the total quantity
of radioactivity in a solution plus the concentration. In
addition, the distributor should provide the purchaser not
only with a certificate indicating the decay rate and
concentration, but also the method used for calibrating the
radionuclide, the decay scheme, and clear instruction on
how to use the standards. second, frequently the
certifications for standards are late in arriving. It is
not at all helpful to have a standard certificate arrive
two or more months after the standard. Usually a standard
is ordered because it is needed immediately. Third,
standard solutions should be well characterized, i.e., how
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much carrier, whether acidified, concentration of acid,
other additives, if any, and any other pertinent
characteristics of the standard.
In summary, the AEC through licensees and State
contracts is requiring a large number of fairly
sophisticated radioactivity analyses. These analyses tell
us and the public how the environment is being affected.
However, in general, these are not performed by large
sophisticated laboratories where special standards or
reference materials can be readily developed. These
laboratories have limited expertise and have to place a
greater emphasis on "production", i.e., production of power
or number of analyses, rather than quality assurance. For
these laboratories we feel a reasonable variety of
secondary standards and reference materials which are
relatable to the NBS measurements systems should be
available in order for them to make measurements which are
accurate to within 25% of the true value and to conduct
adequate quality control programs. We support the NBS's
idea of traceability and feel that broader utilization of
that concept will help us in our overall objectives.
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Discussion;
Seidel: Have you thought further about the definition
of "traceability to NBS"?
Weiss: We have a contract with NBS and are hoping that
NBS will develop the concept of "traceability".
Seidel: The concept of "traceability" is of concern to
our AIF subcommittee of industrial users. Our approach is
to use "round-robins" with participating manufacturers
analyzing a standard sample, and if a manufacturer's result
is erroneous, NBS would attempt to determine the reason.
Coffman: May I comment about AEC-owned facilities? We
have about 30 facilities providing annual environmental
monitoring reports. These facilities spend 5-10 million
dollars per year—150 to 250 thousand dollars per year at
each site—for environmental monitoring programs. We've
been finding that a lot of our problems are not associated
with the physical standards or with counting, but rather
with the collection of samples or placement of the
monitoring system, etc. The procedures and techniques of
analysis are where the major inaccuracies are being
introduced. In addition, there is little or no inter-
facility comparability. We have started a contract to be
coordinated by Battelle (BNWL) and involving other
laboratories to determine current capabilities of all AEC-
owned facilities. We will have recommended and preferred
procedures for environmental monitoring.
Kahn: You say you are supporting a program?
Coffman: Yes, for FY 1974 we have committed $50,000.
We hope we can fund it at approximately $100,000 per year
and have an end product in about 18 months.
Flynn: Does this deal with collection procedures and
sample preparation techniques?
Coffman: Yes, the contractor is supposed to conduct a
survey of existing practices within AEC facilities
throughout the nation and critically evaluate them
(categories: soil sampling, Pu soil analysis, air sampling
techniques, etc.).
Eldridge: Battelle is doing the work?
Coffman: Yes, Carl Unruh, Jack Corbin et al. are
supposed to develop a current capabilities document which
defines deficiencies and gaps in environmental monitoring
practices. After that, we're supposed to develop a program
with John Barley, Claude Sill, and others that will result
(at least within the AEC) in a consensus document of
recommended and preferred methods of sampling in the
environment. We hope this will be a useful document and
that we can do it for about $200,000. It's supposed to
contain a "what if" section. That is, if you set limits at
a certain level, then the capabilities at that level are to
be given.
- 16 -
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Kahn: You may know that EPA has a document on
environmental surveillance with a table that tries to
approach this complicated subject, and I'm sure that years
will be devoted to debating the consequences of each
approach.
Flynn: At this stage of production reactor knowledge,
it might be appropriate to propose a "round-robin" for low-
level tritium analyses for laboratories that are required
to perform them. I have a feeling from talking to several
people that monumental errors may be made if suitable
techniques are not used. This would have to do with
counting techniques.
Weiss: Compared to some other problems, H-3 analyses
have been pretty good. Occasionally we see a problem where
a licensee fails to distill a sample, but it is not a
problem with standards.
Jarvis: We are sending out about 38 samples of HTO to
state and private laboratories on a monthly basis, and we
don't see much of a problem. Tritium is not very
difficult; however, we do see problems with Sr-89,90
determinations.
Kahn: Returning to the "traceability" question—Is it
correct that NBS will develop the concept and then publish
a document describing it?
Mann: It is not enough that a standard be bought from
NBS or anyone else to establish traceability. The only way
that complete traceability can be established between a lab
and NBS would be when NBS could send any radioactive
solution to the laboratory and get a correct answer back
within some stated accuracy—then that laboratory would be
"traceable" to the NBS measurement system. Due to the
ephemeral nature of radioactive standards, you may have
traceability today but not tomorrow.
Seidel: It becomes a commercial question too. Some
agencies wish to buy standards that are "NBS traceable".
We then ask them what they mean. We sometimes get back the
comment, "Well, say you have an NBS standard or something
•like that". Many times these comments are from a
purchasing agent.
Mann: Due to this ephemeral nature of radioactivity
standards, you can not have traceability in itself. The
traceability really lies in the reputation of the
laboratory in having good personnel and in doing reliable
work. It is physically impossible for NBS to participate
in every EPA round-robin. It would be valid for EPA to
establish traceability with NBS and then conduct
intercomparisons within their jurisdiction.
Kahn: You have given a broad definition, but is there
a quantitative numerical definition of "traceability"?
- 17 -
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Mann: I will describe the routes of traceability on an
international and national basis. We used to have
traceability with other national standards laboratories
through BIPM, but that organization has not conducted any
tests in several years. We have traceability studies with
the Canadian NRC and AECL and the British NPL at the
present time at the international level. We have strong
interactions with AEC, Atomic Industrial Forum, and the
College of American Pathologists at present. We have weak
or non-existent interactions with the Food and Drug
Administration. Interactions with the Environmental
Protection Agency have taken place through some nuclear
power effluent round-robins. These are quality control
interactions. With FDA we have had some input in trying to
revise the chapter on radioactivity in the U. S. P.t which
is sorely needed. Through the AEC, AIF, etc.,
traceability could be established with state health labs,
standards suppliers, hospitals, etc. Occasionally we might
have direct interaction with lower echelon laboratories.
Kahn: Is "traceability" going to be defined in the
near future?
Mann: I have given our interpretation.
Kahn: What about the situation where a laboratory gets
half of a series of test samples "right" and half "wrong"?
Mann: Seidel*s A. I. F. group is trying to become
associated with an ANSI group to make recommendations that
will be accepted. At the Bureau of Standards we have in
mind (not in practice yet due to a shortage of manpower)
being able to send out people to visit laboratories for
solving discrepancy problems. We are trying to organize a
seminar for nuclear medicine workers in November. There
has been little or no interest. Perhaps there will be more
when it is publicized. In an industry round-robin, one
laboratory was about 20% out in their value. In attempting
to find out if there was any problem that NBS might help
solve, the reply was given: "So what, the other
laboratories probably spent more time on it". However, the
industrial round-robin was the best of the lot.
Brantley: If the AIF is able to set up this pyramid
with ANSI and get procedures established, then FDA and AEC
Regulatory have the ability to make all users and
licensees "toe the line". There needs to be a driving
force to require conformity in measurements.
Weiss: We are experiencing quality assurance problems
with results supplied by some of our licensees that use
commercial analytical services. There is not a proper
concern about the quality of the results by some of our
licensees.
Kastner: Is the NBS going to prepare other types of
standards than those now supplied (e.g., simulated soils)?
- 18 -
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Hutchinson: We are working with some sediments and are
preparing to characterize them for radionuclide content.
Coffman: There is confusion about the use of
"traceability" and "quality assurance" in these loose terms
and I feel that generic definitions are needed.
Seidel: The definition must be a general one that most
manufacturers can adhere to. Our subcommittee sent out
letters to about 50 laboratories involved in radioactivity
measurements inviting their participation in a "round-
robin" analysis of cobalt-57. Only 16 laboratories
participated, and of this latter group, only 9 sent in
results. It is difficult to instruct a user how to use a
standard. It is extremely difficult to prepare simulated
standards. It is necessary to use equipment for
preparation of such simulated standards similar to that
used for the measurements.
Horen: The only solution to quality assurance is in
educating personnel involved in making radioactivity
determinations.
Eldridge: Has there been consideration about
certification of "metrologists"?
Mann: We have been asked to rewrite Handbook 80. This
is part of our educational effort.
Meyers: Each batch of antibiotics is certified and a
master standard is set aside and is made available for
calibration purposes.
Kahn: For years, SOURS has been searching for
definitions. Maybe we should term present standards as
"master standards".
Mann: Our standards (NBS) are called "national
standards".
Kastner: I would suggest that SOURS publish
recommendations for several topics included in these
discussions.
- 19 -
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STANDARDS FOR ENVIRONMENTAL STUDIES
John H. Barley
Health and Safety Laboratory
New York, New York 10014
The study of radioactivity and radiation in the
environment can include natural sources, fallout from
nuclear weapons or effluents from nuclear facilities. In
most cases it is necessary to distinguish among these
sources by radiochemistry or by measurement with some
qualitative distinction such as spectrometry. The majority
of the measurements are of concentrations of radioactive
materials in the laboratory or the field. Some direct dose
measurements are made while other dose estimates are
derived from in situ measurements of concentrations.
To carry out a program of this type requires three
types of standard materials. The first is the calibration
standard, either for energy or quantity of a specific
radionuclide. The second is the radioactive tracer for
checking the recovery in radiochemical procedures. The
third is the standard sample which can be used to test the
overall performance of the analytical system being used.
Most of these do not require an accuracy of greater than ±
5% and even greater variations are possible for the tracer
solutions.
It is probably worthwhile pointing out at this time
that AEC policy is to request that standards be traceable
to NBS. This is not a regulation and at the present time
it would not be possible to comply with such a regulation.
In the main part of this paper I will try to indicate
the recent experience of the Health and Safety Laboratory
with the three types of standards mentioned above.
Calibration Standards
We require calibration standards for field and
laboratory gamma spectrometers, and laboratory alpha
counters and spectrometers and beta counters. In addition
it is necessary to have sources for calibrating the steel-
walled high pressure ionization chambers used in our dose
studies.
The philosophies of calibration in our field and
laboratory gamma spectrometers differ. The field work is
mostly carried out with germanium diodes and point sources
of about 1 microcurie are used to determine the photopeak
area per unit flux. This group tends to require sources
for each radionuclide that is to be measured in the field.
- 20 -
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The laboratory spectrometers are calibrated for energy with
a single thorium-228 source. This is satisfactory since
the system is linear to one part in four thousand. For
efficiency calibration, a relative efficiency curve is
drawn up for an uncalibrated radium-226 source plus a
cerium-144 source for lower energies. Absolute calibration
is performed with a cesium-137 source of about 0.1
microcurie. The sodium iodide detectors of course require
a standard for each radionuclide in the library, but
fortunately these are being used very rarely.
Calibrations of alpha and beta counters and the alpha
spectrometers require solution standards to allow
preparation of the needed form of standard. The same holds
for the Cs-137 gamma spectrometer standards where we use
four different geometries.
The high pressure ion chambers are field instruments
and require source strengths in the neighborhood of 1
millicurie. The usual calibration requires six to seven
sources in the energy range from americium-2U1 to sodium-
24. Most of the energies are below 200 keV and a constant
potential x-ray machine is also used to assist in
calibration. It should be pointed out that the field
spectrometers and ion chambers when used together supply a
needed redundancy to build up our confidence in dose
estimates.
The procedures used at HASL for standardization are
described in our Procedures Manual (USAEC Report HASL-300,
revised annually). A critical feature that is not
described is a program of intercomparison of samples and
standards with other laboratories in the United states and
overseas.
The following table shows the HASL standards
requirements for 1971 and 1972, and the added radionuclides
needed this year. An odd requirement was preparation of a
5 mCi Ra-226 solution standard to be used as a high-level
Rn-222 source.
-------
Preparation of Standards (1971)
Alpha: Po-208 (2), Po-210 (2), U-232 (2),
Pu-236 (3) , Pu-238 (2), Pu-239 (7), Am-241 (2),
Am-2^3 (3) , Cm-244
Beta: P-32, Ca-U5, Co-60, Sr-89, Sr-90 (2), Y-91, Zr-95,
Nb-95, RU-103 (2), Ru-106, 1-131 (2), CS-13U,
Cs-137 (4), Ce-141 (3), Ce-144 (2) , W-185, Au-198r
T1-20U, Pb-210 (2)
Electron Capture: Be-7, Mn-54, Sr-85 (2) , Y-88 (2)
Positron-Electron Capture: Na-22 (4), Zn-65
Electrodeposited
Alpha Sources: Mixed Alpha 16 Pu-238 3
Th-228 1 Pu-239 27
U-232 1 Am-2U1 2
U-238 2 Am-2U3 10
Pu-236 26 Cm-24U 2
- 22 -
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Preparation of Standards (1972)
Alpha:
Beta:
Am-241, Am-243, Cm-243, Cm-244, Pu-238, Pu-239,
Pu-242 (3), Po-208, Po-210, Ra-226, Th-228
Ca-45, Ce-141, Ce-144, Cs-134, Cs-137, Co-60 (2),
Au-198, 1-131, Fe-59, Pb-210, Pr-143, Sr-89,
Sr-90, W-185
Electron Capture:
Be-7, Cr-51, Co-57, Mn-54 (2),
Sr-85, Y-88 (2)
Positron-Electron Capture: Co-58
Electrodeposited
Alpha sources:
Mixed Alpha 8
U-238 6
Pu-238 3
Pu-239 10
Pu-242 2
Preparation of Standards (1973)*
Sb-12U, Ba-140r Pu-236, T1-20U, U-232, Zr-95
* List of those not standardized in 1972, only
Tracers
Radioactive tracers are not basically standards but
they have many of the same requirements with respect to
purity and preparation so that we tend to treat them the
same as our standard solutions. They are mostly needed for
alpha or beta activity studies and for stable element work.
Since they are used for estimating radiochemical recovery
they are usually standardized adequately at the time the
samples are run.
A number of tracers required for radiochemical studies
are listed in the following table.
-23-
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Tracer Use
Be-7 Stable Be
Sr-85 Stable Sr, Sr-90
Tc-99m Tc-99
1-131 1-129
Ba-133 Po-210
Pb-212 Stable Pb, Pb-210
U-232 Natural U
Th-234 Th-228
Pu-236 Pu-238, 239
Pu-242 Pu-238, 239
Am-243 Am-241
Standard Samples
It is highly desirable to have standard samples
available for checking overall performance in radiochemical
analysis. Spikes are generally not satisfactory for
radiochemistry, since they do not have the added
radionuclide in the same form as in the sample. It is
probably an impossible task to set up a stock for all
radionuclides in all sample matrices. We have about 20
total standard samples which is many fewer than desirable.
These are all "natural" samples and became standards
through multiple analysis at several laboratories. The
quantities prepared were sufficient so that stocks for many
years are available (e.g., 500 Ibs of soil, 500 Ibs of milk
powder) .
I do not see any simple solution to the standard sample
problem, but certainly cooperation among the environmental
laboratories will be needed.
Special Problems
Some standard problems cannot be readily solved in our
own laboratory. While they are not widespread
requirements, it is possibly worthwhile to list them.
1. Standards for very high energy gamma emitters,
particularly N-16, which is a problem in reactor
monitoring.
2. Standards for the noble gases emitted by nuclear
reactors, since it is now necessary to know the
composition of releases.
3. Standard distributed sources for test of field
equipment and airborne spectrometers.
- 24 -
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Additional comments by Barley: I think that the
concept of a standard procedure is a backward step.
Quality control is an essential part of laboratory
operations. Recently a contracting laboratory began having
drifts in its quality control. This happened just before
the chief chemist of that laboratory left. After the
chemist left, we asked that the contract be requalified.
The laboratory quoted the "fine print" and said that the
contract was with the laboratory and not with its
employees. We asked the laboratory to requalify with 6
samples and their average deviation was 45%. It is an
indiyidual matter and I think we may end up with "Certified
Public Analysts" or something like that.
The Health and Safety Laboratory is the only lab in the
AEC General Managerfs Office. Our function is to develop
procedures and perform research.
-25 -
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D3.scussj.on:
Kahn led a general discussion of the meaning of "true
value" as applied to radioactivity measurements. The
consensus was that "true value" had to be discussed in
terms of statistical uncertainties.
Kahn: Is there any need for SOURS to organize studies
related to entire procedures that go from sample collection
through measurement process? The subcommittee is not
engaged in such activities, but they might be desirable.
Kastner: I can see the subcommittee involved in two
programs: one part would be to set up a measurement
program at a reactor site with a group of participants.
The second part would be to prepare standards for such a
program.
Harley: The problem with so many intercomparisons is
that it's difficult to get any work done.
Kahn: In order to have good quality control, isn't it
necessary for a laboratory to spend somewhat more than 5%
of its time conducting standardizations, intercomparisons,
etc.?
Harley: Fifteen percent of our samples are quality
control samples: blanks, standards, and blind duplicates.
Kahn: Is there a study related to the need for
multiple standards and matrices for environmental samples?
Is the AEC conducting a study of this type?
Sill: A lab that determines strontium-90 in milk with
good results would not necessarily be able to use the same
procedure for soil samples. In our laboratory, we are able
to spend only 5% of the time for quality control due to
large sample loads. More attention needs to be paid to
statistical uncertainties of results. Some laboratories
report counting uncertainties only. This causes
difficulties in determining whether two results are the
same or different. Pipette calibrations, timer checks,
etc., are problem areas that need to be checked on and
carried through in the error analysis.
Mann: If the statement of error accompanying a
standard is done properly, then it does not matter whether
it is called "primary", "secondary", etc. Our certificates
indicate the method of calibration with a detailed error
analyses and are not distinguished as primary or secondary
calibrations. We report the 995J confidence level.
Hutchinson: How many sample matrices are needed for
standards?
Sill: The more the better. Different soils with
differing chemical characteristics influence the choice of
chemical separation procedures.
Kastner: Enormous differences exist between, say,
soils from Florida and Minnesota. Monitoring programs need
to take into account different soil characteristics.
- 26 -
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Cobalt-60 in a marine environment may behave differently
than in other environments.
Sill: We*re not suggesting an infinite number of
standards, but the farther you get away from the several
standards used in a program, the higher the probability you
will miss something.
Kahn: Is there any written guidance available to
laboratories that you deal with at the present time, or
will such guidance be available later?
Sill: We provide standards with known disintegration
rates and then provide unknown samples to check their
methods and calibrations. These are state laboratories.
Kahn: How many states have participated?
Sill: Fifteen. Only 2 or 3 state laboratories are
well qualified. Most of the rest are real novices and need
to be "led by the hand".
- 27 -
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Programs and Activities
of the
Quality Assurance Branch,
National Environmental Research Center-Las Vegas
Arthur N. Jarvis
Quality Assurance Branch
U.S. Environmental Protection Agency
National Environmental Research Center
Las Vegas, Nevada 89114
I. INTRODUCTION
Environmental measurements are made daily by many
different Federal, State, local, and private agencies. The
data from these measurements are used by the U.S.
Environmental Protection Agency (EPA) for a wide variety of
purposes, including estimates of doses and health effects,
the establishment of standards and guides, and for
enforcement activities. It is therefore imperative that
the precision and accuracy of the data be assured in order
that policy decisions concerning environmental quality are
based on valid and comparable data.
The Quality Assurance Program of the EPA is designed to
encourage the development and implementation of quality
control procedures at all levels of sample collection,
analysis, data handling, and reporting. Quality control
responsibilities, in the radiation area, have been assigned
to the Quality Assurance Branch at the EPA1s National
Environmental Research Center-Las Vegas. This office, as
an integral part of its overall quality assurance effort,
conducts laboratory intercomparison studies and prepares
and distributes a variety of calibrated low-level
radioactive samples for use in the laboratories of Federal,
State, and private agencies.
The major objective of this program is to encourage the
development of intralaboratory and interlaboratory quality
control procedures and thus ensure that the data being
supplied to the EPA are valid. Providing accurately
calibrated samples and a variety of cross-checks assists
laboratories in calibrating new instruments, implementing
and maintaining routine instrument calibration programs,
evaluating analytical procedures, and developing and
revising data processing programs, and in the maintenance
of an internal cross-check program.
II. BACKGROUND
- 28 -
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When the U.S. Environmental Protection Agency (EPA) was
formed in December 1970, the Analytical Quality Control
Service (AQCS), located at Winchester, Massachusetts, was
transferred from the Bureau of Radiological Health to the
EPA.
Beginning in 1962, the AQCS provided radiochemical
standards and quality control for analytical measurements
to the Public Health Service and to State radiological
health programs. This laboratory also carried out a number
of cross-check studies and technical experiments with both
governmental and private agencies.
In addition to the AQCS program, an extensive
intralaboratory radiation quality control program, as well
as cooperative activities with State agencies, the AEC,
WHO, and the IAEA, were being conducted for a number of
years at the NERC-LV.
During November, 1972, the positions, functions, and
responsibilities of the AQCS were transferred to the NERC-
LV, merged with the existing quality control program, and
designated as the Office of Quality Assurance-Radiation.
More recently this program, as a result of the Center's
reorganization program, has been designated the Quality
Assurance Branch of the Division of Technical Services.
III. CURRENT ACTIVITIES
A. Laboratory Performance Studies
A number of laboratory performance studies
("cross-checks") involving the analysis of radionuclides in
environmental media are conducted on a continuing basis.
These studies enable participating laboratories to maintain
checks on their internal quality control programs and
assist them in documenting their data.
1. Types of studies.
Studies currently in operation or scheduled involve samples
of most media including milk, water, air, soil, food,
urine, and gases. The types of samples, the quantities
supplied, the activity levels involved, and other pertinent
information concerning the samples are summarized in Table
I. The distribution schedule for 1973-1974 appears in
Table II.
2. Participation
a. Cooperation with States
At present 38 State laboratories are participating in the
intercomparison studies either on a full-time or part-time
basis.
b. Interaction with Federal and
International Agencies
Interlaboratory programs are maintained with
other EPA laboratories and with other Federal and
International agencies. Included are the AEC, the U.S.
Army and Air Force, and the U.S. Geological Survey. In
- 29 -
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TABLE I
SUMMARY OF CROSS-CHECK PROGRAMS
SAMPLE
Milk
Water
Gross a, 6
Gamma
3H
239pu
226Ra
Air
Gross a, 3
239pu
Soil
Diet
Urine
Gas
ANALYSIS
89Sr, 90Sr, 131I,
13?cs, l"°Ba, K
Gross o, B*
60Co, loeRu, 12"Cr,
137CSt 51Cr> 65Zn
3H
239pu*
22SRa
Gross a, 0*
239pu*.
239Pu
89Sr, 90Sr, 131I,
137Cs> 140Ba> K
3H
85Kr, 133Xe
ACTIVITY
ISOTOPE
< 200 pCi/1
< 100 pCl/1
< 500 pCi/1
< 3500 pCi/1
< 10 pCi/1
< 20 pCi/1
< 200 pCi/sample
< 2 pCi/sample
< 50 pCl/sample
< 200 pCi/kg
< 3500 pCi/1
< 20 pCi/ml
QUANTITY
SUPPLIED
- 4 liters
- 4 liters
- 4 lifers
- 60 ml
- 4 .liters
- 4 liters
3 - 2" or 4"
diam. air filters
3 - 2" or 4"
diam. air filters
- 100 g
3 - 4-liter
samples
- 60 ml
10 liters
PRESERVATIVE
Formalin
0.5 N HN03
0.5 N HN03
none
0.5 N HN03
none
none
none
Formalin
Formalin
none
DISTRIBUTION
Monthly
Bimonthly
Bimonthly
Monthly
Semiannual ly
Quarterly
Quarterly
Quarterly
Semiannually
Quarterly
Quarterly
Semiannually
TIME FOR
ANALYSIS
& REPORT
6 weeks
4 weeks
4 weeks
4 weeks
6 weeks
6 weeks
4 weeks
6 weeks
6 weeks
6 weeks
4 weeks
6 weeks
I
Ul
o
I
laboratories are required to have the necessary licenses before receiving these samples.
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TABLE II
CROSS-CHECK SAMPLE DISTRIBUTION SCHEDULE
Numbers 1, 2, 3 & 4 indicate week of the month.
Month
1973
Aug
Sep
Oct
Nov
Dec
1974
Jan
Feb
Mar
Apr
May
Jun
Jul
Milk
Sr.y
1
1
1
1
1
1
1
1
1
1
1
1
Gross
ct,e
3
3
3
3
3
3
Y
4
4
4
4
4
4
Water
3H
2
2
2
2
2
2
2
2
2
2
2
2
239pu
2
2
226Ra
3
3
3
3
Air F:
Gross
ct',3
3
3
3
Liter
239pu
3
3
3
Soil
y,239Pu
3
4
Diet
Sr.y
2
4
4
4
Urine
3H
2
2
2
2
Gas
133Xe>85Kr
4
3
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addition, the Argonne, Los Alamos, and Lawrence Livermore
laboratories, as well as the National Laboratories of
Canada and New Zealand, participate in some phases of the
program.
c. Liaison with Nuclear Facility Operators
The Quality Assurance program also maintains
liaison with nuclear facility operators. There are 12
nuclear facility operators and/or their contractors
participating, on a voluntary basis, in one or more of the
cross-check programs.
B. Distribution of Calibrated Samples
Since radionuclides, with the low level activities
ordinarily required for the calibration of instruments
and/or the testing of radiochemical procedures, are not
available from commercial sources, the Quality Assurance
Branch maintains an inventory of 30 different
radionuclides. The radionuclides listed in Table III are
available for immediate delivery, while those indicated in
Table IV will become available on the dates indicated.
The calibrated samples, with activities ranging
from approximately 10,000 dpm/gm to 50,000 dpm/gm, are sent
upon request to any Federal, State, local or private
laboratory involved in, or concerned with, environmental
radiation measurements.
To assure the accuracy of the samples, which are
prepared by diluting higher-level standards obtained from
both government and commercial sources, calibration
facilities are maintained. To check the accuracy of
dilutions, aliquota of alpha or beta emitters are taken
from the stock solution, prepared for counting, and their
activity determined using appropriate counting instruments.
The solution is then pipetted into 5 ml glass ampoules,
weighed, and immediately flame sealed. All solutions of
gamma-emitting nuclides are pipetted directly into
ampoules, weighed, flame sealed, and counted.
C. Collaborative Studies
To effectively carry out its mission, it is
necessary for the Quality Assurance Program to aid in the
development, testing, and promulgation of standard methods.
This program, therefore, assists other federal
laboratories, technical societies, and international
agencies in the testing and evaluation of radiochemical
procedures and instrumental methods through the round-robin
testing of materials.
IV. PLANNED ACTIVITIES
A. The Development of Standard Procedures and/or
Standard Reference Methods
Although a number of methods and procedures for
the analysis of environmental samples have been published
by various governmental agencies, laboratories, and/or
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NUCLIDE
9°Sr
3H
131j
140Ba
22Na
54Mn
65Zn
137Cs
60Co
59 Fe
95Nb
95Zr-Nb
106Ru
TYPE OF
EMISSION
3~
3~
B", Y
3-, Y
3+, Y
Y
Y
3", Y
3~, Y
3~, Y
3', Y
3", Y
S~
HALF-LIFE
27.7 y
12.26 y
8.05 d
12.8 d
2.62 y
303 d
245 d
30 y
5.26 y
45.6 d
35.0 d
65.5 dd
368 d
TABLE III
- 33 -
-------
Calibrated Sample Distribution Schedule
NUCLIDE
«Sc
85Sr
89Sr
203Hg
226Ra***
232 Jh***
5*Cr
58CO
75Se
103RU
12l»Sb
125Sb
i«*i»Ce
238(J ***
239pu*
2tiAm**
63N1
99TC
iiomAg
13"Cs
i*iCe
TYPE OF
EMISSION
B-* Y
Y
B-, Y
B", Y
<*» Y
a
Y
B+ ( Y
Y
B-, Y
B~, Y
B-. Y
B", Y
a
a
a, Y
B-
B"
B~, Y
B-, Y
B-, Y
HALF-LIFE1"
83.9 d
64.0 d
52.7 d
46.9 d
1602 y
1.41 x 1010 y
27.8 d
71.3 d
120 d
39.5 d
60.4 d
2.7 y
284 d
4.51 x 109 y
24390 y
,458 y
92 y
2.12 x 105 y
255 d
2.04 y
32.5 d
MONTH AVAILABLE
September 1973
n
n
"
n
n
October 1973
n
11
"
11
11
n
»
November 1973
"
"
n
n
"
December 1973
TABLE IV
- 34 -
-------
Calibrated Sample Distribution Schedule
NUCLIDE
35S
«Ca
56CO
88Y
l°9Cd
32p
55Fe
133Ba
m?pm**
185W
2°m
57Co
125j
139Ce
9&Rb
"na
195Au
TYPE OF
EMISSION
B~
e~
P+, Y
Y
Y
e~
Y
Y
0"
0-
0-
Y
Y
Y
6", Y
e~, Y
Y
HALF-LIFE"1"
87.9 d
165 d
77.3 d
108 d
453 d
14.3 d
2.6 y
10 y
2.62 y
75 d
3.81 y
270 d
60.2 d
140 d
18.66 d
115 d
183 d
MONTH AVAILABLE
January 1974
ii
it
n
H
February 1974
M
n
n
n
M
March 1974
ii
n
April 1974
n
May 1974 .-.-^
Lederer, C., et al . , Table of Isotopes, sixth edition,
John Wiley and Sons, New York 1967.
Recommended half-lives will be indicated on the certificate
accompanying each sample.
* Special Nuclear Material License required.
** Byproducts License required.
*** Possible State license required.
TABLE IV cojitlnued
- 35 -
-------
standard setting groups, few if any have been widely
accepted as "standard methods". This lack of standard
methods and procedures results in data which are not truly
comparable and is probably the major weakness in the area
of quality assurance. Until such time as standard methods
(or standard reference procedures) are developed,
published, and accepted, a true quality assurance program
cannot exist. Moreover, before a true comparison and/or
evaluation of laboratories can be conducted, uniform
methods are required to insure the comparability of data.
Thus the development and promulgation of standard methods
must be accomplished before the quality assurance program
can be further expanded.
In order to alleviate this problem the Quality
Assurance Branch will begin early in 1974 to examine and
evaluate the methods currently being used for the analysis
of environmental samples containing radionuclides. Upon
completion of this evaluation, the Quality Assurance Branch
will recommend standard methods (or standard reference
methods) which should be accepted and promulgated by the
EPA.
B. The Publication of a Handbook on Quality Control
Methods^and Procedures
A handfiook,(1) similar to that recently published
by the Analytical Quality Control Laboratory, NERC-
Cincinnati, will be developed and published. This
publication, as envisioned by the Quality Assurance Branch
staff, will be designed for laboratory directors and other
professional personnel who have responsibility for
radiation data. The handbook will be primarily concerned
with the quality control of chemical and instrumental tests
and measurements. Sufficient information will be included
to enable the reader to develop and implement an analytical
quality control program.
C. The Development of New or Improved Analytical
Methods
There is a need for research on new and/or
improved methods of analyzing samples for certain
radionuclides. This is particularly true for Iodine-131,
Iodine-129, Krypton-85, and Xenon-133. For example, a
definite need exists to develop an analytical method which
will lower the detection limits for measuring Iodine-131
concentrations in both milk and aqueous solutions.
Recent reports have indicated that measurable levels of
Iodine-129 have been found in the environment in the
vicinity of nuclear fuel reprocessing facilities.(2,3)
Since the measurement of low levels of radionuclides in
critical pathways is important, a rapid means of analyzing
samples for Iodine-129 content must be developed, tested,
and standardized.
-------
Standards and cross-check procedures for gas samples
including Krypton-85 and Xenon-133 are currently being
tested.
D. Expansion of Quality Assurance to Other Aspects of
Monitoring
In order to assure the quality of all data it is
necessary to develop, implement, and maintain quality
control procedures for all aspects of the monitoring
program from sampling site selection to data handling and
reporting activities. To implement such a comprehensive
quality control program, the staff at the NERC-LV plans to
develop and issue a series of guidelines dealing with the
collection and handling of environmental samples. These
guidelines will discuss the equipment and materials
required to collect, preserve, and transport samples from
specific media, sampling periods, and essential quality
control information. Other guidelines, dealing with the
operational parameters and design characteristics of both
monitoring networks and instrumentation, will be developed
and procedures for routine field calibration of monitoring
instruments will be published.
To supplement and reinforce the published guidelines an
instructional program will be instituted. This program
will involve workshops, seminars, and "on-the-job" training
in quality control procedures for both management and
technical personnel.
References
1. Handbook for Analytical Quality Control in Water
and Wastewater Laboratories. Technology Transfer. EPA,
Analytical Quality Control Laboratory, NERC-Cincinnati
(June 1972) .
2. Magno, P. T., T. C. Reavey, and J. C. Apidianakis,
Iodine-129 in the environment around a nuclear fuel
reprocessing plant, ORP/SID 72-5. EPA, Office of Radiation
Programs, Rockville, Maryland (October 1972).
3. Bentley, W., 1971 annual report of environmental
radiation in New York State. State of New York, Department
of Environmental Conservation, Albany, New York (July 7,
1972).
-------
Additional comment by Jarvis: Request forms and
literature describing our services will be available in
September.
Discussion;
Kastner: How do you pay for this service? Do you
recover costs?
Jarvis: So far we have not. There has been some
discussion about charging for the calibrated samples,
especially for industry.
Mann: To some extent, this service is undermining the
efforts of NBS. You cannot expect laboratories that can
obtain free materials from EPA to pay $60 to $100 for
standards from NBS. This destroys the concept of
traceability to NBS.
Kastner: If you are interacting with EPA, then
traceability can be maintained.
Mann: At the present time we are not intereacting. We
have very weak links with the Food and Drug Administration,
Environmental Protection Agency, and Bureau of Radiological
Health. In a nutshell, I disapprove of the distribution of
free standards.
The College of American Pathologists, Atomic Industrial
Forum, and AEC have gotten us in a position that we can
devote the time and energy for intercomparison purposes.
Harley: When laboratories are analyzing
intercomparison samples identified as such, the quality of
results goes up. It is desirable that such samples not be
identified if they are to be useful in a quality control
sense.
Sill: We need standard solutions for instrument
calibrations; however, we also need "real world" samples
for checking the competence of a laboratory. This is one
area where I would cast a negative vote against the EPA
program since their samples are all water soluble
standards. Reactor rad-waste materials can be completely
different from settling basin samples as to adsorption
properties. You cannot check up on these type problems by
simply analyzing standards. There is an effort on my part
to prepare standards that will be homogeneous at higher
levels than those from HASL. For reactor surveillance
methods, you need standards at higher levels than those
available as fall-out standards from HASL. I would
recommend that SOURS expand its scope to include low-level
samples.
Flynn: With the complexity of equipment and sample
types for analysis, there should be some way to certify
that people doing analyses have competence for the
mea sure ments.
-------
ACTIVITIES OF COMMERCIAL RADIONUCLIDE PRODUCERS
Carl W. Seidel and J. Calvin Brantley
New England Nuclear corporation
Boston, Massachusetts 02118
In 1973, more than 100 radionuclides will be produced
by U.S. industry for use by industry, hospitals, and
universities. The value of these products at the end use
level will be greater than $80,000,000 in 1973.
Radiopharmaceuticals will account for 65% of the total,
labeled compounds and radiochemicals for 20X, and
radioactive sources for 15%.
This industry is based on four kinds of radioactivity
measurements:
1. Amount of radioactivity
2. Concentration of radioactivity
3. Radionuclidic purity
4. Radiochemical purity.
Over the last 25 years "standards11 for measurement of these
quantities have been established, ranging from highly
sophisticated ones to highly informal ones. Most of them
are of the latter quality and this fact has led to serious
questions and problems in the industries that produce them
and the users of them.
At the present time, NBS has established standards for
only 27 radionuclides of the 100 or more used. In
addition, even some of these 27 are not in a convenient
physical form or intensity, i.e., micro- instead of milli-
curies or on tape instead of in a vial. In the absence of
absolute or convenient standards, producers and users
resort to derived secondary standards based on instruments
calibrated with the absolute standards and on using decay
schemes that may come from any one of many sources.
Different groups of users tend to use different decay
schemes so that it is possible for two different groups to
be using two different millicuries.
To compound these basic difficulties, there are
thousands of users of radioactivity, varying from those
with an extremely high degree of sophistication to others
who appear to have only the most elementary knowledge and
capability of measuring radioactivity.
About three to four years ago, it became apparent that
these problems were building to a degree that was no longer
tolerable to the users, the producers or the government
agencies that regulate the industry. We must admit that
- 39 -
-------
the efforts of producers and users and government to meet
the problems in the last three years have been difficult,
confused, andr in some cases, ludicrous. However, some of
the activities now in progress offer us hope that something
may now be done.
If we examine the needs of producers, users and
governmental agencies for standards, we find several common
requirements:
1. Activity standards
2. Instrument calibration standards
3. Calibration protocols
U. Standards for the certification of statistics
(counting accuracy)
5. Internal quality assurance controls
6. Decay schemes.
Some specific examples of problems that have arisen in
the last 2-5 years will illustrate the need for more and
better standards.
. Gallium-67 is finding a growing market in nuclear
medicine as a diagnostic radionuclide. This nuclide was
originally produced at ORNL but it is now also produced in
industry. There is as yet no agreement on a decay scheme
and assays for this nuclide have disagreed by as much as
30%. Fortunately, users and producers are resolving this
problem by round-robin experiments to achieve at least a
uniform millicurie. It remains to be determined, however,
what the absolute millicurie is for this radionuclide.
Use ot xenon-133 is rapidly growing in lung studies.
NBS has now developed a microcurie standard while ORNL has
a multicurie gas reference standard developed by cross-
calibration studies. However, the principal use requires
assay in the 10-100 millicurie range. The dose calibrators
that are now so widely used by nuclear medicine departments
vary by a factor of 2 at these levels.
Barium-133, a widely used, long-lived instrument-
calibration standard, has been used for years assuming a
half-life of 7.2 years, although values from 7-10 years had
been reported. It now appears that 10.5 years is probably
the most nearly correct value but no uniform agreement has
been reached.
Iodine-125, used extensively in in vitro pharmaceutical
testing, is widely mishandled in assay procedures.
Although standards for activity are available, many users
are unaware of the problems raised by absorption of its
soft x-ray in vial walls and solvents. Protocols for its
assay need to be widely distributed.
This same kind of situation has come up in recent
months in the cases of Cobalt-60 and Cesium-137 nuclides
for which standards have long existed but not in the form
in which the discrepancy arose.
- 40 -
-------
Finally, three decay scheme compilations are used
extensively in the radionuclide industry:
1. Nuclear Data Tables
2. MIRD nuclear data tables from Society of Nuclear
Medicine
3. Isotope Tables by Lederer, et al.
It takes very little time to discover basic disagreement
among these tables, disagreements that can lead to widely
varying assay results.
We would now like to review some of the commercial and
user activities in establishing committees to resolve some
of these problems. In June 1972, the Atomic Industrial
Forum (AIF) and NBS called a meeting at NBS of various
manufacturers of radioactivity standards. The meeting was
called to consider the need for industry standards on
quality assurance, statistics, and radioactivity. As an
outgrowth of this meeting, the AIF Committee on
Radioisotope Production and Distribution established a
Subcommittee, chaired by Carl Seidel, to investigate the
needs and possible solutions. After several meetings
during the last year, this Subcommittee obtained the
enthusiastic participation of most manufacturers and
identified several areas in which they feld industrial
cooperation was needed. In June of this year, the group
made a formal request to Marshall Little, Chairman of ANSI
Committee N-4U, to be recognized as ANSI Subcommittee N-
4U.4 a Subcommittee on Radioactivity Measurements. They
described their goals as
1. Uniformity in reporting the accuracy of
measurements of radioactive standards
2. Initiation of a Quality Assurance Program for
manufacturers to include a Round-Robin Calibration
Program under the sponsorship of NBS
3. Developing and publishing recommended procedures
for measuring radioactivity.
This committee has now established a membership and a list
of companies and individuals who wish to be kept informed
of developments. They have recently adopted the principles
of ICRU Report 12 on "Certification of Standardized
Radioactive Sources" as the standards for the certification
of reference standards manufactured by them.
In cooperation with NBS, they are working on a schedule
of round-robins to cover Co-57, 1-129, C-14, Hg-203, and
Xe-133. Preliminary results have just been obtained on Co-
57.
Their activities have now expanded from covering just
the development of standards for the manufacturers of
radioactivity standards to include standards for other
areas (producers of radiopharmaceuticals and instruments)
-------
since they have found that their problems are essentially
the same.
Their inclusion of the radiopharmaceutical area grew
out of another meeting held in the fall of 1972, attended
by representatives of the FDA, BRH, NBS, and the AIF. The
attendees at this meeting concluded that a program of
quality assurance and improved and expanded radioactivity
standards was needed by manufacturers of
radiopharmaceuticals to satisfy the requirements of FDA and
DOB-AEC in licensing and regulation of
radiopharmaceuticals.
Although this conclusion was reached, no such effort
has been started, primarily because no one person has taken
the lead in organizing the effort. After recent reviews of
the situation, the Chairman of the AIF Committee on
Radiopharmaceuticals, which represents most of the
manufacturers, has agreed that it might be more effective
for this activity to be taken over by the proposed ANSI N-
UH.U. This would require the addition to the committee of
people from the radiopharmaceutical companies. We believe
that many of the problems of the two sets of manufacturers
are so similar that this approach can cut the time and
effort required.
Two other commercial activities that should be included
are sponsored by ASTM and SAMA. ASTM Committee E 10.05 has
been established to write procedures for using and
calibrating Ge (Li) and Nal(Tl) detector systems. SAMA has
established a committee to develop liquid scintillation
standards that will eventually be expanded to include
simulated 1-125 standards for radioimmunoassay. These
standards would be specifically designed for automatic
equipment manufactured by the member companies.
As contrasted to these commercially oriented
committees, there are several areas of activity that are
primarily user oriented but include enough commercial
participation to be included in this review. The oldest of
these is sponsored by the College of American Pathologists
(C.A.P.) as a part of their program to evaluate performance
of hospitals and individual departments in these hospitals.
This program is paid for by the individual hospital and
consists of periodic distributions by NBS of an unknown
radionuelide. The participant reports his analysis of
amount and identity of this program. We understand,
however, that the results indicate considerable need for
improvement in the capabilities of the hospitals and that,
thus far, the participation has been very poor.
Still another program aimed at 'nuclear medicine
departments of hospitals originated three years ago as a
Committee on Quality Control and Standards of the New
England Chapter of the Society of Nuclear Medicine and the
- 42 -
-------
New England Radiological Physics Organization (NEPO) . This
Committee has developed reference standards and protocols
for using these standards for one model of gamma
scintillation camera and most models of the dose
calibrators that are so widely used by hospitals today.
This program and the protocols are actively carried out in
New England by a Nuclear Medicine Quality Control Center
operating out of Boston University Medical Center. The
first yearfs operation was supported by the New England
Regional Commission. It is now supported by fees received
from hospitals for the service.
In June 1973, the Society of Nuclear Medicine
established a program to extend this regional activity to
all areas of the United States. It has formed a national
committee, has appropriated $20,000 to carry out the work,
and is looking for an additional $20,000 from a government
agency to complete the funding. It is not yet clear
whether the program will go ahead without the additional
funding.
Another f committee that was established a few years ago
is ANS-16. its main accomplishment to date has been a
questionnaire on Proposed Standards Activities. A
tabulation of the results is attached. The future of this
group depends on its success in replacing Sam Reynolds who
has resigned as Chairman.
We cannot vouch for the completeness of this review of
commercial activities, but we believe it covers the major
efforts. We believe it also shows that the needs for
improved standards have been recognized and accepted by
industry.
-&.->,-
-------
TABULATION OF QUESTIONNAIRE REPLIES
Proposed Standards Activities
Other Interested
Organizations
1
2
3
4.
5.
6.
7.
8.
9.
/io.
11.
12.
13.
14,
15.
a) Reference Materials
b) Nuclear Data (half-lives, decay schemes,
cross sections, etc.)
c) Radioanalytical Methods
d) Activation analysis
Measurement of Contrast and Definition
applicable to Medical Scintillation
Photography
Radiochemical Purity of Materials Used
in Isotope Generator Systems
Neutron Sources and Techniques
a)* calibration and measurement of flux
b) standard sources
c) index quality indicators
d) dosimetry
e) cross-sections
Biomedical Applications - Encapsulated
power sources, traces and therapeutic
materials
Medical Internal Radiation Dose
Photon Energy Absorption Coefficients
Toxicity of Heavy Metals
Isotope Packaging and Container Transport
Standards
a) Standards for Testing and Qualifying
Sources
b) Performance Standards for Sources
, Underwater Dosimetry
Ratings (curies) of large sources
Particle Accelerators
Low-Energy X-Rays
Containment of Radioactive Sources
with respect to:
a) corosion resistance
b) fize resistance
c) useable radiation
NBS. ORNL, FDA, ANSI Nil,
CAP
ANSI N44, SNM
NBS, ORNL, ANSI Nil
NBS, ANSI N43, ANSI N44,
ANSI Nil, IAEA, ASTM,
AJHR
AEC-ENEA, ANSI N44,
SNM
NCRPr HEW-BRH, ANSI W44
NBS
FDA., AOAC
AEC-IAEA, ORNL, DOT,
ANSI N14
ORNL. ARC, ANSI N43
ANSI N44
NCRP (SC-35)
ANSI N43, ANSI N44
ANSI N43, ANSI N44
AEC, ANSI N43
ASTM, ANSI H43, M?£J N44
-------
16.
17-
^.i ' -•
18.
19.
20.
21.
22
23.
24.
25.
26.
Dosimetry of X-Rays greater than 10 MeV
Isotopic Purity of Radiopharmaceuticals
Modular Instrument Standards
Film Badge Testing Standards
a) Biological Standards - Analytical
Limitations
b) Standard Techniques for Trace Element
Analysis
Physical Sizes for Standard Amounts
(millicuries) of Useful Radioisotopes
Accuracy of Calibration Sources
Calibration of Analytical Instruments
Radiation Detectors
Radioisotope Heat and Power Sources for
Space, Terrestrial and Ocean Use
Long Term Integrating Type Dosimeters
for Use in Nuclear Generating Stations
ICRU, NCRP, NBS, ANSI N43
ANSI N44, AAPM
AAPM, ANSI N44
ANSI N42, IEEE, ASTM,
ANIM, ORNL
AEG, ASTM, ANSI N13
ASTM, ANSI Nil
ANSI N43, ANSI N44, AEC,
ORNL
ANSI N43. ANSI N44, NBS,
ORNL, AEC
ANSI N43, ANSI N44, NBS,
ORNL, ARC, ANIM, IEEE
IEEE, ANSI N42, ANSI N13
AEC, ORNL, ANSI N43. IAEA
NASA & U.S. Naval Facili-
ties Engineering" Command
AEC, AECL, IEEE, ANSI N18,
ANSI N42
ANSI - American National Standards Institute
ANIM - Association of Nuclear Instrument Manufacturers
IEEE - Institute of Electrical & Electronic Engineers
ASTM - American Society for Testing Materials
AAPM - American Association of Physicists in Medicine
AOAC - Association of Official Analyzing Chemists
SNM - Society of Nuclear Medicine
CAP - College of American Pathologists
ANR - Association of Neutron Radiographers
-as-
-------
Discussion;
Kahn: How many years will be required before all
commonly utilized radionuclides have been covered in
"round-robins"?
Seidel: This is a continuing program and will require
several years before most common radionuclides have been
surveyed. There has not been enough publicity about
standards1 activities. Perhaps SOURS could serve as a
"sounding board".
Kastner: Concerning nuclear data compilations, has
there been cooperation between MIRD of the Society of
Nuclear Medicine and the Nuclear Data Group?
Horen: The MIRD version that's coming out is based on
Nuclear Data Sheets.
Kahn: It is based on the editor1s judgement for many
nuclides. It would be nice to know that there was
agreement between MIRD and the Nuclear Data Group.
Meyers: Perhaps SOURS could be a body to referee decay
scheme differences. It would be desirable to have a group
outside the U.S. Government to arbitrate and recommend
changes. Selenomethionine (Se-75) is an example of a
radiopharmaceutical in which decay scheme data are sent out
on a package insert. These data are used by physicians for
dose calculations, standardizations, etc. It would be
desirable that the latest recommended values be
incorporated in such package inserts.
Seidel: Our committee recommended that Nuclear Data
Tables be used whenever possible; in any case, the decay
scheme reference should be cited.
Baerg: Could we hear the results of the AIF round-
robin on Cobalt-57?
Seidel: It1s hard to show everything about the
intercomparison. Of 8 results, three were outside the NBS
error limits. All the rest overlapped to some extent.
Only one result was more than 5% off.
- 46 -
-------
RADIONUCLIDE METROLOGY AND QUALITY ASSURANCE
W. B. Mann
Radioactivity Section, Center for Radiation Research
National Bureau of Standards
Washington, D. C. 2023U
A series of six papers was given by members of the
National Bureau of Standards (NBS) Radioactivity Section at
the First International Summer School on Radionuclide
Metrology held in Herceg Novi, Yugoslavia, in August and
September 1972. (1-6) A seventh paper on Statistical
Methods Applicable to Counting Experiments and Evaluation
of Experimental Data was also given by Dr. H. H. Ku of the
Statistical Engineering Laboratory.(7)
With this recent outpouring of information from NBS, it
is difficult to prepare a review paper for this meeting
that is not grossly repetitive. I would therefore prefer
to refer the members of the Subcommittee to these
publications, in Nuclear Instruments and Methods.
In lieu of offering a detailed rehash of what has
already been prepared for publication, I can perhaps be
permitted to refer to just one subject, namely the question
of traceability of radioactivity measurements to NBS.
As I mentioned two years ago at the Las Vegas Tritium
Symposium,(8) organized by the University of Nevada and the
Environmental Protection Agency, "we at the National Bureau
of Standards do not consider that our mission is fulfilled
merely by the issuing of standards. Only when concordant
measurements based on these standards come back from other
laboratories do we feel that we have succeeded...".
With a radionuclide industry burgeoning to close to
S100M per annum sales, predominantly in the techniques of
nuclear medicine involving 8,000 to 10,000 hospital and
medical laboratories, it is clearly an impossible task for
NBS to maintain, in a practical way, traceability to every
user in the field.
The concept of traceability can be achieved in at least
two ways. Any laboratory will be considered traceable to
us if it can either (i) calibrate an unknown sample
supplied by NBS, and known to NBS, and obtain a result that
is within a certain specified range from the NBS result, or
(ii) the laboratory can produce calibrated reference
sources, of which one or more can be calibrated by NBS and
found to be consistent within an acceptable range. For
different purposes different ranges of value will be
- 47 -
-------
acceptable and a laboratory could consider whether it
wished to be one-percent, ten-percent, or, say, thirty-
percent traceable to NBS.
With a view to achieving such traceability we have
carried out a number of "round-robin" exercises under the
auspices of the College of American Pathologists (CAP), the
Atomic Energy Commission (AEC), and the Atomic Industrial
Forum (AIF). The first such round-robin traceability study
was organized by CAP and took place in October 1970, when
some 25 samples of iron-59, calibrated by NBS but unknown
to the participants were distributed for both radionuclidic
identification (together with a radionuclidic impurity
check) and activity measurement. Since that time cobalt-
57, iodine-125, and iodine-131 "unknowns" have been
distributed to participating laboratories for
identification and calibration under CAP auspices. In
addition a further test was organized, with the CAP, in
which the participants were asked to inject a known amount
of about 50 microcuries of chromium-51 in solution into a
serum bottle and to send it to NBS for verification.
In the case of the AEC, test solutions containing known
amounts of various gamma-ray emitting radionuclides,
covering the energy range from about 0.08 to 1.8 MeV, were
sent for identification and calibration to the monitoring
laboratories for different nuclear-power reactors and also
to the AEC Health Services Laboratory at Idaho Falls. The
certificate and report of calibration of typical
calibration and test sources are appended. Such a report
can be supplied to the participant either before or after
he has submitted his results, according to his wishes.
Lastly we have carried out a traceability study on
behalf of the AIF Committee on the Radioisotope Production
and Distribution's Subcommittee of Manufacturers of
Radioactive Reference Standards. This subcommittee
composed of representatives of industrial producers of
different forms of radioactive materials was organized with
a view to recommending procedures for the calibration of
such materials, and to achieving uniformity of reporting,
and traceability to NBS. Under the auspices of the
subcommittee, we have distributed "unknown" solutions of
cobalt-57 to 13 commercial companies for identification and
measurement.
The results submitted by commercial companies were not
greatly dispersed, but other values have ranged from 2% to
391% of the NBS value. Various publications by the various
bodies concerned are now being processed and the first of
the NBS contributions at Herceg Novi gives summaries of one
nuclear-power-reactor study and three CAP studies, namely
those of iron-59, iodine-131, and chromium-51.
-------
As I mentioned earlier, NBS cannot maintain direct
calibration traceability to every user of radioactive
material in the field for every available radionuclide. We
therefore envisage traceability as a pyramid structure with
the International Bureau of Weights and Measures, or, in
the case of the developing countries, the International
Atomic Energy Agency, organizing traceability, or the
consistency of measurement, on the international level.
Then, in turn, the national standardizing laboratories
should be responsible for the consistency of radioactivity
measurements in their own countries. In the United states
we would expect that industrial producers of radioactive
materials and reference sources, and the quality control
laboratories, such as those of the AEC, EPA, and Food and
Drug Administration (FDA), would be traceable to NBS.
These laboratories, in turn, would assure traceability to,
say, state health laboratories, nuclear-power reactor
licensees1 monitoring laboratories, EPA sampling
laboratories, and so on.
Occasionally NBS could be expected to carry out
traceability studies directly to the lower echelons of the
pyramid, but limitations of manpower currently preclude too
much of an effort in that direction.
Lastly I would like to digress for a moment on what
really constitutes traceability to the national and
international radioactivity measurements system. The life
of a radioactivity standard is generally quite limited and
none can be indefinitely preserved. We establish
traceability in 1-131 measurements with a laboratory in the
broad field of such measurements today, but what about
tomorrow, next month or next year? Clearly such
intercomparative measurements cannot be carried out every
week with of the order of 10,000 hospital and medical
laboratories. Ultimately NBS can only maintain
traceability with these laboratories through the commercial
producers of radioactive materials and
radiopharmaceuticals. Perhaps we will be able to certify a
limited number of laboratories as being an acceptable next
stage of the traceability pyramid. At the moment the
admirable CAP effort covers only some 50 medical
laboratories out of the order of 10,000!
Ultimately traceability becomes synonymous with
consistency, credibility and competence. If a laboratory
is found to be consistent with NBS, within a given range of
values, in its measurement of, say, twelve different
radionuclides a year, then the personnel of that laboratory
have demonstrated a pattern of reliability and continuing
competence to assume that their calibrations of several
hundred radi©pharmaceutical labelled compounds, and other
radioactive materials are equally competent.
- 49 -
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Radioactivity is ephemeral and passing and the problems
of traceability to NBS in radioactivity measurements are
just about inversely proportional in magnitude to the half
lives of the radioactive materials under consideration!
Many members of the Radioactivity Section have
contributed to these traceability exercises, particularly
Miss L. M. Cavallo, Dr. J. M. R. Hutchinson, Dr. B. M.
Coursey and Dr. J. R. Noyce. Much of the pioneer work in
the CAP intercomparisons was undertaken by our late
colleague, Samuel B. Garfinkel.
References
1. Needs for Radioactivity Standards and Measurements in
Different Fields. L. M. Cavallo, B. M. Coursey, S. B.
Garfinkel, J. M. R. Hutchinson and W. B. Mann, Nucl. Instr.
and Meth., ±U (1973) 5.
2. Present~Status in the Field of Internal Gas Counting.
S. B. Garfinkel, W. B. Mann, F. J. Schima and M. P.
Unterweger, Nucl. Instr. and Meth., 112 (1973) 59.
3. Sum-Peak Counting with Two Crystals. J. M. R.
Hutchinson, W. B. Mann and P. A. Mullen, Nucl. Instr. and
Meth., 112 (1973) 187.
U. The National Bureau of Standards 1-Pi Beta-Gamma
Coincidence-Counting and Gamma-Ray Intercomparator
Automatic Sample Changers. S. B. Garfinkel, W. B. Mann and
J. L. Pararas, Nucl. Instr. and Meth., J12 (1973) 213.
5. Radioactive Calorimetry, A Review of the Work at the
National Bureau of Standards. W. B. Mann, Nucl. Instr. and
Meth., 112 (1973) 273.
6. Low-Level Radioactivity Measurements. J. M. R.
Hutchinson, W. B. Mann and R. W. Perkins, Nucl. Instr. and
Meth., 112 (1973) 305.
7. Statistical Methods Applicable to Counting Experiments
and Evaluation of Experimental Data. H. H. Ku, Nucl.
Instr. and Meth., 112 (1973) 377.
8. The Calibration of the National Bureau of Standards1
Tritium Standards by Microcalorimetry and Gas Counting. W.
B. Mann, in Tritium, A. A. Moghissi and M. W. Carter, eds.
(Messenger Graphics, Phoenix, 1973) p. 101.
- 50 -
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U S.
Peter
of Commerce
terson
Bureau of j^tandard*
Certificate
Standard Reference Material 4242-B
Mixed Radionuclide Gamma-Ray Emission-Rate Standard
This sample consists of manganese-54, cobalt-57, cobalt-60, yttrium-88, cadmium-109,
tin-113-indium-113m, and cesium 137-barium-137m in "&£?. ygrams of approximately 4N HC1
in a flame-sealed borosilicate glass bottle of specified dimensions.
This sample was made by weighing an aliquot of a calibrated radionuclide mixture into
the bottle containing the acid, and flame sealing. The gamma-ray-emission rates of
the solutions used to prepare the radionuclide mixture were determined by means of the
NBS calibrated 4iTY ionization chamber, and assumed nuclear decay parameters.
The nuclear gamma-ray-emission rates at 1200 EST June 1, 1972, are shown in the
table below.
Nuclide
109Cd
57Co
113Sn-113mIn
137Cs-137mBa
54Mn
6°Co
88Y
Y-Ray
Energy (MeV)*
0.0877
0.122
0.392
0.662
0.835
1.173
1.333
0.898
1.836
Y-Ray
Intensity(%)*
85.610.2
84.610.4
99.97810.002
99.8810.02
100
93.4+0.7
99.3710.02
Half Life
1.2727y
271. 76d
115. 31d
29.93y
312. 27d
5.261y
106. 61d
Y/s
75-a.r
1140
73*y
Acvt
'1171*
<¥/<•>/
*t 10*
M.i.2
')te.c
Errors %
Random System Total
0.3 2.7 3.0
0.1 2.2 2.3
0.1 2.8 2.9
0.1 1.9 2.0
0.1 2.5 2.6
0.1 1.3 1.4
0.1 1.3 1.4
0.1 2.9 3.0
0.1 2.2 2.3
*Nuclear Data Tables, A8, Nos. 1-2 (Oct. 1970).
The total uncertainties in the gamma-ray-emission rates are the linear sums of the
respective random errors (limit of random error at the 99-percent confidence level),
the above-stated errors in the gamma-ray intensities, and the estimated upper limits
of conceivable systematic errors.
The gamma-ray-emission rate of all other observed contaminants was less than
0.02 percent of the total gamma-ray-emission rate on June 1, 1972.
This standard was prepared in the NBS Center for Radiation Research, Nuclear Radiation
Division, Radioactivity Section, W. B. Mann, Chief.
Washington, D.C. 20234
May 1972
J. Paul Call, Chief
Office of Standard Reference Materials
4242-B-
-------
U- S. Department of Commerce
Frederick B. Dent
Secretary
National Bunco of Standards
Richard W. Roberta, Director
Rational Bureau of j^tamtards
Certificate
Standard Reference Material 4252
Mixed Radionuclide Radioactivity Standard
This standard consists of chromium-51, manganese-54, cobalt-58, iron-39,
cobalt-60, zinc-65, cesium-134, cesium-137, and cerium-144 in ^•7'/.G grams
of approximately 4N HC1 in a flame-sealed borosilicate glass bottle of
standard dimensions. The solution also contains approximately 15 ppm by
weight of stable cation carrier for each of the radionuclides listed above.
This standard was made by weighing an aliquot of a calibrated radionuclide
mixture into the bottle containing the acid. This calibrated mixture was
prepared by mixing standardized solutions of the individual radionuclides.
The cerium-144 was calibrated by gamma-ray intercomparison with material
which had previously been standardized by 4ir[J-Y coincidence counting. The
radioactivities of the other standardized solutions used were determined
by means of the NBS calibrated 4iry-ionization chamber.
The radioactivities of the constituents in nuclear transformations per second
at 1200 EST January 15, 1973, are shown in the table below.
Radionuclide
51Cr
Si
54Mn
5®Co
S9
59Fe
fin
b°Co
* fiS
65Zn
134Cs
** 137Cs
144Ce
ntps
/7oS
23'4t>
3 fav? /
ff ^) 0 /
"70 '7 3
/ iff
W5I
i/OP
4JW
3**t
Uncertainty %
Random Systematic Total
O.I
0.1
0.1
O.I
0.1
0.1
0.1
0.1
0.7
4.2
2.5
2.9
2.6
1.3
2.6
2.5
2.0
2.3
4.3
2.6
3.0
2.7
1.4
2.7
2.6
2.1
3.0
* Assuming a gamma-ray intensity of 50.6 t 0.4% for the 1.1.15-MeV
gamma ray.
** Assuming a gamma-i'ay intensity of 85.0 ± 0.3% for the 0.662-MeV
gamma ray.
The uncertainties in the radioactivities are the 99-percent-confidence limits
for the random error components, and the linear sums of the estimated upper
limits of conceivable systematic errors.
This standard contains cobalt-57 as an impurity. The cobalt-57 activity was
less than 0.1 percent of the total activity on January 15, 1973. The gamma-
ray energy spectrum of the standard was examined with a Ge(Li)-spectrometer,
and no other impurity was observed.
This standard was prepared in the NBS Center for Radiation Research, Applied
Radiation Division, Radioactivity Section, W. B. Mann, Chief.
Washington, D.C.
January 1973
4252- ff
20234 J. Paul Call, Chief
Office of Standard Reference Materials
-52-
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Notes on the Use of Mixed Radlonucllde Radioactivity Standards:
SRM-4252 and SRM-4253
The table below gives the gamma-ray energies, their Intensities and the half-
lives for the component radionuclides In SRM-4252 and SRM-4253. The values
given for energies and Intensities were taken from Nuclear Data Tables, A8,
No§. 1-2(Oct. 1970) unless otherwise Indicated. The half-lives listed are
N.B.S. measured values. The underlined gamma-ray energies were found
to be • convenient set for use in the assay of these mixtures as unknowns.
Radionuclide
(Parent)
51Cr
5C
59Fe
60Co
65Zn
134Csb
137Csb
144Ce
144Pr°
Y-Ray Energy
(MeV)
0.3201
0.8348
0.8106
0.8636
1.6748
0.1425
0.1922
0.3348
0.3827
1.0993
1.2916
1.4818
1.1732
1.3325
1.1155
0.4754
0.5633
0.5694
0.6047
0.7958
0.8018
1.0390
1.1681
1.3651
0.6616
0.08012
0.09995
0.13353
0.6965
1.4891
2.1857
Y-Ray Intensity
9.9 1*
99.978 2
99.44 2
0.69 2
0.53 2
0.81 7
2.8 3
0.30 5
0.022 5
56 1
44 1
0.056 12
99.88 2
100
50.6 4
1.50 3
8.47 17
15.36 31
98 1
84.9 22
8.61 22
1.01 2
1.84 4
3.11 8
85.0 3
1.54 15
0.038 4
10.8 5
1.51 5
0.29 2
0.74 3
Half-Life
27.79d
312. 27d
71.3d
44.52d
5.261y
243. 79d
2.0632y
29.93y
284. 19d
17.28m
a 9.9 ± 0.1
The latest recommended values for these intensities were obtained from
Dr. Murray Martin, Oak Ridge National Laboratory.
0 Praseodymium-144 is In secular equilibrium with cerium-144.
USCOMM-NU-OC
-53-
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Discussion;
Hutchinson: New standards being prepared by NBS are:
chromium-51, silver-110m, iron-55 (X-ray calibration point
source), blanks for radon counting, mercury-203, yttrium-
88, cerium-139, set of mixed radionuclides and standards
(this is an annual set), xenon-133, cadmium-109, thorium-
229, strontium-89, strontium-90, and a mixed sample of
strontium-89,-90. Our development activities include
gaseous standards, sediment standards, and a "dose
calibrator" kit.
-------
APPENDIX: PARTICIPANTS
A. P. Baerg,* National Research Council, Canada
C. Brantley,* New England Nuclear Corporation
F. Coffman, Division of Operational Safety, USAEC
J. S. Eldridge,* Oak Ridge National Laboratory
K. Flynn,* Argonne National Laboratory
G. Kamada. Regulatory, USAEC
J. Barley,** Health and Safety Laboratory, USAEC
D. J. Horen,** Oak Ridge National Laboratory
J. M. R. Hutchinson, Radioactivity Section, NBS
A. Jarvis,** NERC-Las Vegas, USEPA
B. Kahn,* Office of Radiation Programs, USEPA
J. Kastner, Regulatory, USAEC
W. B. Mann*/**, Radioactivity Section, NBS
J. Merritt, Chalk River Nuclear Laboratories, AECL
E. L. Meyers, Food and Drug Administration, USDHEW
C. Seidel**, New England Nuclear Corporation
C. W. Sill, Health Services Laboratory, USAEC
B. H. Weiss**, Regulatory, USAEC
* member of Subcommittee on the Use of Radioactivity Standards
**presented paper
ACKNOWLEDGEMENT;
This meeting was sponsored by the Committee on Nuclear
Science, National Academy of Sciences - National Research
Council, Prof. D. Allan Bromley, chairman, Charles K. Reed,
executive secretary, and Janet Nunn, program assistant.
- 55 -
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-670/4-75-006
2.
4. TITLE AND SUBTITLE
ACTIVITIES AND NEEDS RELATED TO RADIOACTIVITY
STANDARDS FOR ENVIRONMENTAL MEASUREMENTS
7. AUTHOR(S)
James E. Eldridge and Bernd Kahn, Editors
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37830
and
Radiochemistry and Nuclear Engineering Facility
Cincinnati, Ohio 45268
12. SPONSORING AGENCY NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
3. RECIPIENT'S ACCESSIOWNO.
5. REPORT DATE
June 1975; Issuing Date
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1HA327; ROAP 24AAK; Task 003
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
In-house
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A symposium was held to discuss the needs for radioactivity standards in environ-
mental monitoring programs concerned with population radiation exposure. Papers
were presented on "Status of Decay Schemes," "Some Activities and Needs for AEC
Regulatory in the Use of Radioactivity Standards," "Standards for Environmental
Studies," "Program and Activities of the Quality Assurance Branch, NERC-Las Vegas,"
"Activities of Commercial Radionuclide Producers," and "Radionuclide Metrology and
Quality Assurance." The presentations indicated that numerous radioactivity standards
and aids for correctly utilizing them were available. New needs, however, had arisen
recently because lower levels of ambient radioactivity must be measured by many more
groups due to requirements that population radiation exposure from nuclear power
production be as low as practicable. Based on the presentations and resulting
discussions, the following actions were recommended: 1) Establish a focal point for
systematically planning activities to meet cited needs for decay schemes, specific
standards, analytical methods, and quality assurance programs; 2) Develop a clear
chain of traceability to the National Bureau of Standards; 3) Prepare guides for
standardizing radiation detection and maintaining quality control; and 4) Train
qualified analysts to obtain satisfactory analytical results.
17.
a. DESCRIPTORS
Radioactivity
Radioactive isotopes
Quality control
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
KEY WORDS AND DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS
Environmental radio-
activity
Environmental monitoring
Radioactivity standards
19. SECURITY CLASS (This Report)
UNCLASSIFIED
20. SECURITY CLASS (This page)
UNCLASSIFIED
c. cos AT I Field/Group
18F
21. NO. OF PAGES
62
22. PRICE
EPA Form 2220-1 (9-73)
56
•&U.S. GOVERNMENT PRINTING OFFICE: 1975-657-593/5393 Region No. 5-11
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