EPA-5 2 0/5 - 75- 01 8
16
N SKYSHINE SURVEY AT A
2400 MW(t] NUCLEAR POWER PLANT
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation Program s
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1 6
N SKYSHINE SURVEY AT A
2400 MW(t) NUCLEAR POWER PLANT
1
2
3
1
1
C.R. PHILLIPS
W.M. LOWDER
C.B. NELSON
S.T. WINDHAM
J.E. PARTRIDGE
DECEMBER, 1975
U.S. ENVIRONMENTAL PROTECTION AGENCY
EASTERN ENVIRONMENTAL RADIATION FACILITY
P.O. BOX 3009
MONTGOMERY, ALABAMA 36109
3
U.S. ENERGY RESEARCH AND DEVELOPMENT
HEALTH AND SAFETY LABORATORY
376 HUDSON ST.
NEW YORK, NEW YORK 10014
AGENCY
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RADIATION PROGRAMS
ENVIRONMENTAL ANALYSIS DIVISION (AW-461)
401 M ST. S .W .
WASHINGTON D.C. 20460
33
\
Ul
C3
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FOREWORD
The Eastern Environmental Radiation Facility (EERF)participates in the
identification of solutions to problem areas as defined by the Office of Radiation
Programs. The Facility provides analytical capability for evaluation and assess-
ment of radiation sources through environmental studies and surveillance and
analysis. The EERF provides technical assistance to the State and local health de-
partments in their radiological health programs and provides special analytical
support for EPA Regional Offices and other federal government agencies as
requested.
This study is one of several current projects which the EERF is conducting to
assess environmental radiation contributions from fixed nuclear facilities.
Charles R. Porter
Director
Eastern Environmental Radiation Facility
ii
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ACKNOWLEDGEMENT
This study was made possible by the cooperation of the staff of the Cooper
Nuclear Power Station, particularly Mr. Robert Wilbur. The progress of the study
was aided by the close coordination of staff from EPA, ERDA and NRC, includ-
ing Allan Richardson (EPA), Peter Raft (HASL), Mike Boyle (HASL), Elaine
Murray (NRC), and Jacob Kastner (NRC).
111
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CONTENTS
Page
FOREWORD ii
ACKNOWLEDGEMENT iii
ABSTRACT v
INTRODUCTION 1
SITE INFORMATION 1
FIELD MEASUREMENTS 1
EVALUATION OF SPECTRAL DATA 4
BACKGROUND CONSIDERATIONS 7
INTERCOMPARISON OF EPA/HASL DATA 7
POWER LEVEL DEPENDENCE 7
DISTANCE DEPENDENCE 8
SUMMARY 8
REFERENCES 1Q
TABLES
1. EPA Pressurized lonization Chamber
measurements - Cooper Nuclear Station
February 1975 ...............................
2. Health and Safety Laboratory survey
data - Cooper Plant - April 1975 ................... 15
3. Least squares estimation of power
variation parameters ............................ lg
4. Least squares estimates of distance
variation parameters ............................ , -
FIGURES
Pafie
1. Turbine Building - operating floor 2
2. February survey locations
3. February on-site survey locations n
4. February northern survey locations g
5. Annual "N dose rates at full
power vs. distance (North Axis) _
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ABSTRACT
A field study was executed to determine environmental levels, distribution, and
composition of turbine-contributed 16N gamma radiation from an operating boiling
water reactor electric generating plant.
Exposure measurements made with Pressurized lonization Chambers (PIC's)
at several distances and in several directions from the turbine building indicated
that I6N "skyshine" rather than direct gamma exposures contributed the major
portion of environmental exposures.
Power level and distance dependencies were determined and a predictive model
indicated that a distance of 500 meters and a power level of 801 MW(e) would yield
a dose rate of 10 mrad/yr.
v
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"N Skyshine Survey at a 2400 MW(t) Nuclear Power Plant
Introduction
The I6N dose from the turbine building of a boiling water reactor can be
considered to be composed of direct and scattered components. The direct
component is from full energy photons not affected by shielding or air scatter. The
scattered component is due to small- and large-angle (skyshine) scattered photons.
The small-angle scatter is primarily the result of interactions along the line-of-sight
between source and receptor. The large-angle or skyshine component is a result of
large-angle photon scatter by air molecules. At plants which have turbine build-
ings with substantial side shielding and open tops, skyshine can be the principal
source of "N exposure.
Several studies have been conducted to assess the dose rate from 16N in the
vicinity of a nuclear power reactor (1,2,3). In each of these direct radiation com-
prised some significant portion of the 16N exposure. Typical plans for future boiling
water reactors incorporate extensive side shielding for all components above the
operating floor of the turbine generator building and some top shielding as well, if
deemed necessary. The direct component of I6N dose from such plants should be
minimal. In contrast to earlier designs, where the principal source of 16N gammas
was the high pressure turbine and its associated steam lines, newer designs locate
the moisture separators (typically combined with reheaters) above the operating
floor making them the greatest potential source. In order to assess the ' N doses
from such a plant, a joint survey was conducted at the site of the Cooper Nuclear
Power Station in Brownville, Nebraska. An initial survey was conducted on
February 11 - 15, 1975, using instrumentation from the EPA Eastern
Environmental Radiation Facility (EERF) in Montgomery, Alabama. A follow-up
survey was performed April 21 - 24, 1975, primarily with instruments from the
ERDA Health and Safety Laboratory (HASL), New York City, New York.
Site Information
The Cooper Nuclear Power Station is an 801 MW(e) base-loaded nuclear
power plant utilizing a 2400 MW(t) boiling water reactor. High density concrete
walls (figure 1) shield the components above the operating floor (turbines, mois-
ture separators, and associated steam lines) along a line-of-sight to the outside
environment on the north, east, and west sides of the building. Components other
than the moisture separators are only partially shielded to the south. The terrain to
the north of the turbine building is relatively flat and unobstructed allowing
measurements to be made from the walls of the turbine generator building to dis-
tances of 500 to 600 meters. The Missouri River flows along the east side of the
plant with the plant property extending to the east of the river as shown in figure 2.
Access to this part of the site is difficult. The terrain to the south of the plant is
slightly rolling, but measurements could be made to distances of a few hundred
meters from the turbine generator building. The reactor building and switchyard
to the west of the turbine building precluded profile measurements in that
direction.
Field Measurements
The February measurements were intended to provide an overall indication of
the 16N radiation at different locations on the plant site as well as to provide an esti-
mate of the background exposure rate. Measurements were made primarily with
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Figure 1. Turbine building-operating floor
MOISTURE x
SEPARATORS
\
4—OPEN HATCH
i i
TURBINE
GENERATOR
PLANT
N
TRUE
N
£
7
! OPEN
! HATCH
HIGH
DENSITY
CONCRETE
MOISTURE
SEPARATORS
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Figure 2. February survey locations
\
TRUE
N
\
•ih-SAND
>TREE LINE
WATER
LINE
COOPER NUCLEAR
POWER STATION
SITE
TURBINE
BLDG.
(see inset)
0 20O 400
I I J
1600
SCALE (METERS)
INSET
fence
Q_
i
9K8
TURBINE BLDG.
I
o
125
i
250
I
SCALE (METERS)
-------
pressurized ionization chambers (PIC's) which had been previously calibrated at
the EERF using an NBS-certified 226Ra source. Spectral measurements were made
at some locations using a 10-cm x 10-cm NaI(Tl) detector in conjunction with a
multichannel pulse-height analyzer. Exposure rate profiles were made along the
turbine axis to the north and south of the plant. A partial profile perpendicular to
the turbine axis to the east was made but was limited to those locations accessible
on either side of the river. North-south profiles were also obtained along each side
of the river centered on this east axis. Several measurements were also made on the
roof of the cooling water intake structure, located to the east of the turbine gener-
ator building. The roof of this building is above the floor of the turbine generator
building and therefore provided a location close to the source shielded only by the
side walls. Additional measurements were made near the river bank at Brownville
State Park (About 4 km north of the plant) to provide an estimate of local back-
ground. Data from this survey are shown in table 1. The survey locations are indi-
cated on figures 2, 3 and 4. A short time prior to the survey the plant had shut
down for an inspection, and at the time of the survey was in the process of return-
ing to its normal operating level. The power level was increasing gradually from
76% to 90% of full power over the period of the study, except for a brief period
during measurement 63 when it was temporarily reduced. Measurements at loca-
tion 7 were taken at several power levels to observe exposure rate dependence with
power level.
During the follow-up survey (April 21 to 24), a complete profile of 16N expo-
sure rates was obtained in the northerly direction along the turbine axis, as well as
a partial profile along the south axis. Difficulties in gaining access to the east shore
of the river prevented measurements perpendicular to the turbine axis. The data
for this survey are shown in table 1 (Measurements B1-B10) and table 2. The re-
actor operated at 2355 MW(t) during this portion of the study, except for a brief
drop to 60% of full thermal power during the night of April 23-24. Measurements
were made primarily with PIC's. Nal(Tl) and Ge(Li) measurements were made at
selected locations to assess terrestrial background and to detect any direct com-
ponent of the 16N exposure. In order to provide an intercomparison between the
February and April data a few measurements using an EERF PIC were also made.
There were no indications of any exposure from other sources associated with the
reactor, including the plume, during either measurement period.
Analysis of Data
Evaluation of Spectral Data
Spectroscopic data indicated the presence of some high energy photons in the
profiles taken to the south and to the east. In the case of the south data, these are to
be expected due to the partial shield wall. In the east direction it would appear that
the shield wall is thin enough to permit direct radiation to make a small contri-
bution to the 16N exposure rate. Even though they contain some direct radiation,
the exposure rates to the south and east are of the same order of magnitude as ex-
posure rates at corresponding locations to the north. Because of its lack of any
direct component the north profile was used to evaluate skyshine.
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INTAKE
STRUCTURE
MISSOURI RIVER
SLUDGE
DIESEL
GEN.
HEATER
DISCHARGE
BOILERS
TREATM.
EXHAUST
FANS
CONDENSATE
STORAGE TANK
TURBINE
GENERATOR
BUILDING
CONTR.
ROOM
REACTOR
BUILDING
RAD-
WASTE
BLDG.
AUGM.
RAD-
WASTE
BLDG.
SCALE
(METERS)
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Figure 4. February northern survey locations
BROWNVILLE
RECREATION
AREA
0 200 400
i—' i
SCALE (METERS)
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Background Considerations
Background from terrestrial and fallout gamma emitters was estimated by ana-
lyzing spectroscopic data obtained during the April portion of the survey.1 Net I6N
levels were calculated by subtracting from the HASL ion chamber total readings
(1) a 3.9 yR/hr cosmic ray background and (2) the estimated gamma background
based on spectrometric measurements at the same or a nearby location. There is an
apparent discrepancy between the PIC and spectrometer gamma exposure rates
for the measurement at 581 meters south of the plant (table 2). For this location the
"N level was estimated from the 511 keV annihilation radiation peak in the Ge(Li)
spectrum as calibrated with data from other locations. EPA ion chamber data in
the vicinity of the plant were corrected using an 8.3 yR/hr background (3.9 yR/hr
cosmic + 4.4 yR/hr gamma). It was assumed for these measurements that the
background did not change appreciably from location to location or from
February to April. In this regard it should be noted that the total exposure rates at
the Brownville State Park; (9.4 yR/hr - EPA, Feb.; 9.2 yR/hr - HASL, April; and
9.3 yR/hr - EPA, April), are consistent from February to April but are about 1
yR/hr higher than the levels inferred for typical on-site locations.
Intercomparison of EPA/HASL Data
In addition to the 9.3 yR/hr (EPA) vs. 9.2 yR/hr (HASL) values at Brownville
State Park, the values 87.7 yR/hr (EPA) and 85.6 yR/hr (HASL) for essentially
the same location (#7) compare closely. Instrumental problems prevented addi-
tional comparisons.
Power Level Dependence
Lowder (1) has proposed a power level dependence for 16N exposures from
power reactors of the form d = d0p exp^Xx^p), where d0 is the exposure rate
that would result at full power with no reactor-turbine building delay, p is the frac-
tion of full power, A is the decay constant for 16N, and T 0 is the effective decay time
between the reactor and those turbine building components which comprise the
16N source. This model assumes (1) that the concentration of 16N steam (yCi/g)
leaving the reactor is independent of power level, (2) the steam flow rate (g/s) is
proportional to power level, and (3) that the effective time for 16N decay in the
source components does not depend on power level.
The data for location 7 were used to determine least squares estimates of d0and
TO . The results of this least squares fit are shown in table 3. The limited range of
power variation introduces a high correlation between the parameters (.995) and
large standard deviations in their estimates. While the model and its assumptions
cannot be considered verified on the basis of such limited data, the model does pro-
vide an adequate empirical description of the data. The effective steam delay time
of 7.0 seconds at full power is comparable to the value (8 seconds) Lowder, et al.
obtained at Oyster Creek (1).
'The analysis of the HASL data will be contained in the forthcoming publication, Lowder, et al., "Deter-
mination of "N Radiation Field at a BWR Power Station."
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Distance Dependence
A theoretical model of the skyshine would require transport calculations
beyond the scope of this study. Instead the following empirical model was used:
aoP
where: d - the 16N exposure rate (yR/hr)
a0 - a conversion factor [yR-mVhr per MW(e)]
p - the fraction of full power
P0 - the full plant power [MW(e)]
X - the decay constant for 16N (s~*)
T 0 - the effective delay time at full
power (seconds)
r - the distance between the receptor and
the center of the moisture separators
(meters)
£ - an effective attenuation length (meters)
b - an effective linear buildup factor
This model combines the power dependence model from the previous section with
a point source model corrected for attenuation and linear buildup.
The least squares fit of the distance data is summarized in table 4. Annual 16N
dose rates based on the empirical model and the observed data are plotted in figure
5. Exposure rates have been converted to dose rates using a conversion factor of 1
uR/hr = 7.688 mrad/yr. The February data have been adjusted to full power
using the assumed power dependence model. Note that while the fitted model pre-
dicts a dose rate of 10 mrad/yr at 500 meters there is considerable scatter of the ob-
served data about the model at this distance. The standard deviation of the cal-
culated value at 457 meters is 2.5 mrad/yr. Since this value assumes no error con-
tribution from the background determination or the model itself, it is a lower limit
for the uncertainty of the dose rate at this distance. The absolute values of the cor-
relation coefficients between parameters are all high ( > .9) so that while the model
provides a reasonable description of the data, there are substantial uncertainties in
individual parameters. The calculated linear buildup factor (3,0) is extreme for an
unshielded source, but is not unreasonable for this situation where the doses are
essentially from radiation scattered through large angles.
Summary
Spectrometric measurements made north of the turbine generator building at
Cooper Nuclear Power Station indicated that plant doses were predominately
from 16N skyshine. The power level dependence observed was consistent with a
model assuming a constant concentration of UN reactor steam and a reactor-
turbine building delay inversely proportional to power level. A 1/r2 distance model
with attenuation and buildup was fitted to the data. At a distance of 500 meters a
dose rate of 10 mrad/yr at 801 MW(e) is predicted. The lower bound for the stan-
dard deviation of this estimate is 2.5 mrad/yr. Both the power level and distance
models were chosen to provide an empirical fit to the data but do not have any
rigorous basis for their choice.
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Figure 5. Annual I6N dose rates at full power vs.
distance (North Axis)
1000
TJ
O
L.
CD
2
O
LJ
<
o:
LJ
LO
O
Q
100-
10-
o FEB. DATA
x APR. DATA
— EMPIRICAL MODEL
10 100 1000
DISTANCE FROM MOISTURE SEPARATORS
(METERS)
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Since the dose rate will depend on the particulars of the turbine building
components and shield configuration, it would be inappropriate to rely solely on
the use of the empirical models of this study to predict doses from other plants.
However, the data invite comparison to a more detailed analysis, which would
have to include source term as well as transport modeling.
REFERENCES
(1) LOWDER, W. M., P. O. RAFT, and C. V. GOGOLAK. "Environmental
Gamma Radiation through Nitrogen-16 Decay in the Turbines of a Large
Boiling Water Reactor," HASL-271, (January 1973).
(2) BRINCK, W., K. GROSS, G. GELS and J. PARTRIDGE. "Environ-
mental Radiation Study at Vermont Yankee," presented at the Nineteenth
Annual Meeting of the Health Physics Society held in Houston, Texas, (July
1974).
(3) HAIRR, L. M., P. C. LECLARE, T. W. PHILBIN, and J. R. TUDAY.
"The Evaluation of Direct Radiation in the Vicinity of Nuclear Power
Stations," 18th Annual Health Physics Meeting, (June 1973).
(4) DIXON, W. J., editor, BMD Biomedical Computer Programs, University of
California Press (1973).
10
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Table 1
EPA
Pressurized lonization Chamber measurements
Cooper Nuclear Station - February 1975
Measurement
Number
1
2
3
4
5
6
7
8
9
10
1 1
12
13
14
15
16
17
18
19
20
21
22
23
24
Location
3 m north of Turbine Bldg.
on center line
61 m north of Turbine Bldg.
on center line
80 m from north end of
Turbine Bldg. at 67.5°
30.5 m north of Turbine
Bldg. on center line
33.5 m from north end of
Turbine Bldg. at 336°
48 m from north end of
Turbine Bldg. at 50"
37 m north of Turbine Bldg.
on center line
117 m north of Turbine
Bldg. on center line
183 m north of Turbine
Bldg. on center line
244 m north of Turbine
Building on center line
305 m north of Turbine
Bldg. on center line
427 m north of Turbine
Bldg. on center line
Northwest corner of Intake
Bldg. on line with north
end of Turbine Bldg.
18.3 m east of Turbine
Bldg. just south of Intake
center of Intake Bldg.
East of Turbine - ground
level
Southwest corner of Intake
Bldg. - ground level
12.8 m east of Turbine Bldg.
on line with south end of
Intake
21.3 m east of Turbine Bldg.
and 22.9 m south of Intake
Bldg.
21.3 m east of Turbine Bldg.
and 38.1 m South of Intake
Bldg.
Top of first level of Intake
Bldg. - southwest corner
Top of upper level of Intake
Bldg. - southwest corner
Top of upper level of Intake
Bldg. of West side
Top of upper level of Intake
Bldg. - northwest comer of
Bldg.
Top of upper level of Intake
Bldg. - northeast corner of
Bldg.
Time &
Date
1113
2/12/75
1210
2/12/75
1200
2/12/75
1204
2/12/75
1212
2/12/75
1309
2/12/75
1315
2/12/75
1330
2/12/75
1335
2/12/75
1400
2/12/75
1513
2/12/75
1630
2/12/75
1632
2/12/75
1635
2/12/75
1640
2/12/75
1645
2/12/75
1650
2/12/75
1650
2/12/75
1700
2/12/75
1700
2/12/75
1705
2/12/75
1710
2/12/75
1714
2/12/75
1720
2/12/75
Gross Exp.
Rate
(UR/hr)
45.5
37.8
35.9
64.4
51.6
48.9
58.4
20.5
14.7
12.4
10.6*
9.2
63.9
123.7
82.7
106.2
118.4
81.9
53.4
134.4
150.4
118.4
94.0
68.6
Approx.
Power
Level (MWe)
606
613
612
612
612
612
612
612
612
614
617
617
617
617
617
617
617
617
617
617
617
617
617
617
11
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Table 1
(Cont.)
EPA
Pressurized lonization Chamber measurements
Cooper Nuclear Station - February 1975
Measurement
Number Location
25 Top of upper level of Intake
Bldg. - southeast corner of
Bldg.
26 21.3 m east of Turbine Bldg.
on line with south end
27 21.3 m east of Turbine Bldg.
even with north edge of
Waste Tank
28 East edge of sludge pond
even with stack
29 South edge of Sludge Pond
on line with West side of
Intake Bldg.
30 South end of Turbine Bldg.
at edge of building on
center line
31 South end of Turbine on
center line even with
Waste Tank
32 Back at Park near Brownville,
northeast, taken with Nal
33 527 m south of Turbine Bldg.
at gate on levee
34 79.3 m south of Turbine Bldg.
near center line
35 104 m south of Turbine Bldg.
near center line
36 128 m south of Turbine Bldg.
near center line
37 250 m south of Turbine Bldg.
at high voltage tower
38 405 m south of Turbine Bldg.
near center line
39 East bank of river under
high voltage lines
40 East bank of river between
locations 39 and 41
41 East bank of river directly
across river from stack
42 East bank of river directly
across river from south end
of Turbine Bldg.
43 East bank of river directly
across from center of Turbine
44 East bank of river - directly
across from north end of
Turbine Bldg.
45 East bank of river - directly
across from 61 m fence
46 East bank of river - directly
across from 274 m fence
47 East bank of river -131m
North of location #46
48 30.5 m West of Location #43
54.8 m from east Tree line
(on ice)
49 67.1 m east of #43 in trees
on east Bank (approx. 7.6
Time &
Date
1724
2/12/75
1708
2/12/75
1715
2/12/75
1720
2/12/75
1725
2/12/75
1740
2/12/75
1745
2/12/75
1815
2/12/75
0930
2/13/75
0940
2/13/75
0945
2/13/75
0950
2/13/75
0955
2/13/75
1005
2/13/75
1005
2/13/75
1120
2/13/75
1130
2/13/75
1135
2/13/75
1140
2/13/75
1145
2/13/75
1153
2/13/75
1200
2/13/75
1208
2/13/75
1225
2/13/75
1235
2/13/75
Gross Exp.
Rate
(yR/hr)
97.8
40.9
30.3
23.1
17.7
24.4
22.6
9.4
9.4
22.6
23.5
20.7
13.0
10.7
8.9
10.5
11.7
12.1
12.1
12.1
11.7
9.9
9.7
9.6
10.3
Approx.
Power
Level (MWe)
617
617
617
617
617
617
617
617
664
664
664
665
665
665
665
666
667
667
668
669
670
670
670
670
670
12
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Table 1
(Cont.)
EPA
Pressurized lonization Chamber measurements
Cooper Nuclear Station - February 1975
Measurement
Number Location
cm snow)
50 128 m east of #43 in trees
on east side (approx. 7.6
cm snow)
51 189 m east of #43 in trees
on East side (approx. 7.6
cm snow)
52 On top of levee 1097 m east
of Turbine Bldg. (approx. 5
cm snow)
53 Background in woods south of
Plant on east side of river
54 On West Sand Bar 305 m south
of Brownville State
Recreation Area - background
55 On West Sand Bar approx.
396 m South of Brownville
State Recreation Area
56 South of Plant on west bank
of river - sand bar -
background
57 305 m North of Turbine on
center line - retake of #11
58 36.6 m North of Turbine Bldg.
on center line - retake of
#7
59 79.6 m from north end of
Turbine Building at 67.5° -
retake of #3
60 3m north of Turbine Bldg.
on center line — retake of
#1
61 33.5 m from north end of
Turbine Bldg. at 336° -
retake of #5
62 61 m north of Turbine Bldg.
at center line - retake of
#2
63 36.6 m north of Turbine Bldg.
on center line - retake of
#7
By-Pass Valves opened
during measurements
Gross Exp.
Time & Rate
Date ( ^R/hr)
1242
2/13/75
1246
2/13/75
1330
2/13/75
1350
2/13/75
i 1425
2/13/75
1431
2/13/75
1500
2/13/75
1430
2/13/75
1605
2/13/75
1610
2/13/75
1612
2/13/75
1623
2/13/75
1700
2/13/75
0800
2/14/75
0805
2/14/75
0815
2/14/75
0820
2/14/75
0825
2/14/75
9.6
9.4
9.3
9.4
9.3
9.4
9.0
11.5
65.8
49.5
53.5
73.2
52.5
79.2
49.5
49.5
59.4
77.2
Approx.
Power
Level (MWe)
670
670
672
673
674
675
678
675
685
685
685
685
686
731
731
13
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Table 1
(Cont.)
EPA
Pressurized lonization Chamber measurements
Cooper Nuclear Station - April 1975
Measurement Time &
Number Location Date
B- 1 Upper Roof of Intake Bldg. 1057
southwest corner (repeat 4/22/75
of #21 on 2/12)
B- 2 Upper Roof of Intake Bldg. 1104
(repeat of #22 on 2/13) 4/22/75
B- 3 Upper Roof of Intake Bldg. - 1111
northwest corner (repeat of 4/22/75
#23 on 2/12)
B- 4 Upper Roof of Intake Bldg. - 1119
northeast corner (repeat of 4/22/75
#24 on 2/12)
B- 5 Upper Roof of Intake Bldg. - 1130
southeast corner (repeat of 4/22/75
#25 on 2/12)
B- 6 457 m north of Turbine Bldg. 1250
on center line 4/22/75
B- 7 283 m south of Turbine Bldg. 1440
under north edge of high 4/22/75
voltage tower
B- 8 Northwest corner of Intake 1517
Bldg. (on line with north 4/22/75
end of Turbine Bldg.)(repeat
of #13 on 2/12)
B- 9 36.6 m north of Turbine 1605
Bldg. on center line (repeat 4/22/75
of #7 on 2/12)
B-10 Brownville State Recreation 1654
Area (repeat of #32 on 4/22/75
2/12)
Gross Exp.
Rate
200
> 200
153.0
107.0
157.0
10.9
14.6
105.0
87.7
9.3
Approx.
Power
Level (MWe)
798
798
798
798
798
798
798
798
798
798
14
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Table 2
Health and Safety Laboratory
survey data - Cooper Plant
April 1975
Distance to
Turbine Bldg.
(meters)
North Axis
Detector 4°K
Gamma Exposure Rate ( yR/hr)
U Th '"Cs Total 16N
37
67
122
146
206
238
297
384
457
549
3500
South Axis
302
347
378
475
581
PIC
PIC
PIC*
PIC**
PIC
Ge(Li)
PIC
Ge(Li)
PIC
PIC
Ge(Li)
PIC
Nal
PIC
Ge(Li)
PIC
Nal
Ge(Li)
PIC
Nal
Ge(Li)
PIC
Ge(Li)
PIC
PIC
PIC
Ge(Li)
PIC
Ge(Li)
2.0
2.3
2.3
2.1
2.7
2.5
2.4
1.8
1.9
2.4
2.2
1.7
1.0
0.9
0.9
0.6
1.0
0.7
0.9
1.8
1.2
0.9
1.3
1.1
1.1
1.1
1.1
0.9
0.8
0,9
1.1
1.5
1.6
1.2
1.3
1.1
81.7 77
49.4 45
24.3 20
28.3 24
19.7 15.6
<0.1 (4.1)
12.7 8.4
<0.1 (4.3)
10.9 6.5
8.5 4.1
<0.1 (4.4)
6.9 2.8
(4-1)
5.7 1.2
<0.1 (4.5)
5.4 0.9
<0.1 (4.5)
5.3 <0.1
(5.2)
<0.1 (4.9)
9.0 4.5
<0.1 (4.5)
7.5
7.4
6.3 1.5
<0.1 (4.8)
5.6 1.7
<0.1 (3.9)
* 1 meter above ground.
** 15.2 meters above ground.
15
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Model:
Table 3
Least squares estimation of power variation parameters
d = dQp exp(-XtQ/p)
(1/X = 10.53 seconds
Parameters:
d - 154 ± 28 yR/hr
o
t = 7.0 ± 1.8 seconds
o
d cal
(yR/hr)
57.6
68.8
76.2
87.0
d obs
( ,. R/hr)
58.4
65.8
79.2
85.6
P
.764
.855
.913
.996
Mean square error of fit = 4.4 ( yR/hr)2
The data are for location 7 and assume a total background of 8.3 uR/hr, Least-Squares fit calculated using
BMD07R(4)
* 1 standard error
16
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Table 4
Model:
Least squares estimates of distance variation parameters
d -
a p exp(-Xt /p) P exp(-r/£)(l + br/A)
0 oo
Parameters:
i
b
1/X = 10.53 s
P - 801 MWe
o
t - 7 s
o
1.2 ± .37 x 10"
220 ± 54 meters
3.0 ± 1.5*
. m
MWe . hr
dcal+ 8-3t
(yR/hr)
38.9
64.3
57.2
21.9
14.9
12.1
10.6
9.2
11.0
68.3
45.9
75.6
86.3
90.0
54.6
29.4
24.2
16.9
14.8
12.2
10.3
10.0
9.0
* One standard error.
d + 8.3t
obs
(yR/hr)
37.8
64.4
58.4
20.5
14.7
12.4
10.6
9.2
11.5
65.8
52.5
79.2
87.7
85.3
53.3
28.3
23.9
16.7
14.8
12.4
11.1
9.5
9.2
f Background.
1 JJR/hr = 7.688 mrad/yr.
Mean square error of fit = 4.6 ( yR/1
'
(meters)
110
80
86
166
232
293
354
476
354
86
110
86
86
83
113
168
192
252
284
343
430
457
595
ir)2.
P
.765
.764
.764
.764
.764
.767
.770
.770
.843
.855
.856
.913
.996
.996
.996
.996
.996
.996
.996
.996
.996
.996
.996
Dcal
(mrad/yr)
235
431
376
104
50.5
30.0
17.7
2
20.9
461
289
517
600
635
356
162
123
66.4
49.7
30.4
15.7
13.0
5.2
The data fitted are for the north axis of both the February and April surveys. A background of 8.3 H R/hr
was added to the net HASL data and assumed for the EPA data for purposes of the fit. r includes the distance
between the center of the moisture separators and the north wall of the turbine building (49 m). Least squares
fit calculated using BMD07R (4).
17 AU GAFS. AL(761625)800
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