FINAL REPORT OF OFF-SITE SURVEILLANCE FOR THE x x X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXX X X X X X X XXX X X X X X X X X X X X X X X X X X X X X X X by the South-western Radiological Health Laboratory U. S. Public Health Service Department of Health, Education, and Welfare Las Vegas, Nevada February 3, 1965 This surveillance performed under a Memorandum of Understanding (No. SF 54 373) for the U. S. ATOMIC ENERGY COMMISSION ------- LEGAL NOTICE This report was prepared as an account of Government-sponsored work. Neither the United States, nor the Atomic Energy Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or pro- cess disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, dissemin- ates, or provides access to, any information pursuant to his employ- ment or contract with the Commission, or his employment with such contractor. 01 ------- SWRHL-l6r FINAL, REPORT OF OFF-SITE SURVEILLANCE FOR THE NRX-A2 EXPERIMENT by the Southwestern Radiological Health Laboratory U. S. Public Health Service Department of Health, Education, and Welfare Las Vegas, Nevada Copy No. 1 0. R. Placak SWRHL Las Vegas, Nevada February 3, 1965 This surveillance performed under a Memorandum of Understanding (No. SF 54 373) for the U. S. ATOMIC ENERGY COMMISSION ------- ABSTRACT The Public Health Service provided off-site surveillance in support of the NRX-A2 reactor tests conducted on September 24 and October 15, 1964. This support consisted of tracking the effluent, monitoring radiation dosage to the off-site population, and collecting environ- mental samples (air, milk, water and vegetation). Analyses of these data indicate that no hazard •was created to the off-site population from the NRX-A2 tests. ------- TABLE OF CONTENTS ABSTRACT i TABLE OF CONTENTS ii LIST OF FIGURES iii LIST OF TABLES iii INTRODUCTION 1 Section 1. NRX-A2 EPIV, September 24, 1964 I. , OPERATIONAL PROCEDURES 2 A. External Measurements 2 B. Environmental Measurements 4 II. RESULTS 9 A. Ground Monitoring Data 9 B. Dose Rate Recorder Data 10 C. Film Badge Data 10 D. Air Sample Data 11 E. Milk Sample Data 12 F. Water Sample Data 12 III. CONCLUSIONS 14 Section 2. NRX-A2 EPV, October 15, 1964 I. OPERATIONAL PROCEDURES 15 II. RESULTS A. Ground Monitoring Data 16 B. Dose Rate Recorder Data 16 C. Film Badge Data 16 D. Air Sample Data 16 E. Milk Sample Data 17 F. Water Sample Data 17 G. Vegetation Sample Data 19 III. CONCLUSIONS 20 ii ------- LIST OF FIGURES Figure 1. Location of air samplers and dose rate recorders for NRX-A2 EPIV. 3 Figure 2. Location of air samplers and dose rate recorders for NRX-A2 EPV. 5 Figure 3. Environmental sampling locations for EPIV and EPV. 18 LIST OF TABLES Table 1. Dose rate measurements off the test range complex on September 24, 1964. 9 Table 2. Meteorological Data for EPIV. 10 Table 3. Analysis of air samples collected following the NRX-A2 EPIV Experiment. 11 Table 4. Analyses of milk and vegetation samples collected following NRX-A2 EPIV. 13 TableS. Meteorological Data for EPV. 17 111 ------- INTRODUCTION As' a part of the ROVER Program, testing and disassembling of a series of reactors designated NRX-A is being carried on under the Nuclear Engine for Rocket Vehicle Application (NERVA) Project at the Nuclear Rocket Development Station. The subject of this report is the off-site surveillance provided by the Public Health Service(PHS) for the Atomic Energy Commission (AEC) in support of the NRX-A2 experiments conducted at Test Cell A onSeptember 24 and October 15, 1964. Each test will be covered in a separate section of this report. Under a Memorandum of Understanding with the Atomic Energy Commission, the U. S. Public Health Service conducts a program of radiological monitoring and environmental sampling in the off-site area surrounding the Nevada Test Site and the Nellis Air Force Range. The overall complex of the Nevada Test Site (NTS) and the Nellis Air Force Range (NAFR) includes the Nuclear Rocket Devel- opment Station (NRDS) and the Tonopah Test Range (TTR) and for simplicity will be called the test range complex throughout this report. Since Public Health Service monitors must begin tracking and moni- toring an effluent cloud close to its point of origin, measurements are also made within the test range complex, but are used only as a guide to trajectory determination or for purposes of checking instru- mentation and methodology. They did not serve as parameters in determining dose to people or contamination of property in the off-site area during the NRX-A2 tests and are not a subject of this report. 1 ------- Section 1. NRX-A2 EPIV, September 24, 1964 I. OPERATIONAL PROCEDURES On September 24, the reactor was tested under the conditions known as Experimental Plan IV (EPIV) and was operated at design power from 1055 to 1105 PDT. The reactor was tested in an upright posi- tion so that the hydrogen coolant exhausted upward along with escap- ing fission products. A. External Measurements Ground Monitoring Thirteen ground monitors tracked the reactor effluent passage with portable instruments. Each monitor was equipped with an Eberline E-500B, a Precision Model 111 Standard "Scintillator", and a Victoreen Radector Model No. AGB-50B-SR. The Eberline E-500B has a range of 0 to 200 milliroentgens per hour (mr/hr) gamma and beta-gamma detection in four scales with an external halogen filled GM tube and a 0 to 2000 mr/hr range from an internal Anton 302 tube. The Precision Model 111 "Scintillator" is used primarily for low level detection and pro- vides for a range of 0 to 5 mr/hr in six scales. The Radector has a range of 0 to 50, 000 mr/hr on two scales. This instrument employs an air ionization chamber. These instruments are accurate to +_ 20%, and readings can be taken to two significant figures. Remote Dose Rate Recorders Eberline RM-11 dose rate recorders were placed at sixteen sta- tions around the test range complex. These recorders utilize a Geiger tube detector to document radiation levels at specific lo- cations. The instrument has a 0. 01 to 100 mr/hr range and the 2 ------- Figure 1. Location of air samplers and dose rate recorders for NRX-A2 EPIV. 3 ------- gamma dose rate is recorded on a 30-hour strip chart. The RM-11 is accurate to +_ 20% as calibrated with a Co source. The locations of dose rate recorders are presented in Figure 1. Aerial Cloud Tracking An Air Force U-3A aircraft, manned by two Public Health Service monitors equipped with portable instruments identical to those of the ground monitors, tracked the reactor effluent to position ground monitors. Two Public Health Service C-45 aircraft con- taining sampling equipment were also used as aids in cloud tracking. However, their primary purpose was cloud sampling in order to determine cloud size and inventory. The results of their sampling are reported separately. Film Badges The PHS maintains 65 film badge stations off the test range com- plex and assigns badges to 166 off-site residents. The badge used is made up of Dupont Type 555 film. This film is accurate to +_50% in the 20 to lOOmr range and +_10% in the 100 to 2000 mr range. B. Environmental Measurements Air Samples On the test day the PHS maintained General Metal Works high volume air samplers containing glass fiber prefilters at 36 off-site locations as shown in Figures 1 and 2. Thirteen of the air samplers were equipped with MSA* charcoal cartridges in addition to the prefilters. All air sample prefilters collected following the NRX reactor runs were returned to the Southwestern Radiological Health Laboratory (SWRHL) in Las Vegas to be counted for gross beta activity with a thin window, large area *Mine Safety Appliance Company 4 ------- Figure 2. Location of air samplers and dose rate recorders for NRX-A2 EPV. 5 ------- proportional probe connected to a high speed sealer. The sys- tem has an efficiency of approximately 30% for 1. 5 Mev betas and has a background of 575 +_ 20 counts per minute. Gross beta concentrations were computed at the time of count for the purpose of screening samples and delineating the effluent trajectory. These samples were then stored for five days to allow natural activity to decay. They were recounted at this time and again seven days later. Activity levels were then re- computed to end of collection from these two later counts. Sev- eral air samples exhibiting levels of activity significantly above natural background were recounted frequently to obtain a decay curve. The curve obtained was then analyzed for best fit to the general equation y=ax . Based on an analysis of decay curves, a T ' relationship was found to exist with a mean error of _+ 5%. This relationship was then used to extrapolate the activity to the end of the collection period. All charcoal cartridges were analyzed for gamma isotopes by placing each cartridge directly on a 4" x 4" sodium iodide crys- tal coupled to a 400-channel pulse height analyzer set to view energies from 0 to 2 Mev. Assuming no break in the prefilter, the activity on the cartridge should represent the gaseous fission products such as isotopes of iodine. Overall detection efficiency for this geometry is about 18% at 0. 53 Mev (I ). The mini- mum detectable activity for I ,1 ,1 , and I is taken 131 to be 200 picocuries with an associated error of + 50% for I , I ,1 , and +_ 100% for I . The time of count is 10 minutes. Error estimates are such that values less than 1 picocurie per cubic meter (pc/M ) are generally not reported. Since it is not possible to define duration of effluent passage at all locations. ------- the reported values given as pc/M assume an average concen- tration over each entire sampling period. Milk and Water Samples After each release of activity from NRDS, milk samples are collected from dairies (processing plants), producing dairy farms, and farms producing milk for their own consumption. Milk samples were collected, relative to this event, from the locations shown in Figure 2. Each sample w a s counted for 50 minutes. No attempt was made to recount samples giving low positive values. The lower limit of detection for gamma emitters in milk samples is taken to be 20 picocuries per liter (pc/1) at the time of count, and all results below that value are reported as <20 pc/1. The error associated with reported values is _+ 20 pc/1. All reported values are extrapolated to collection time. All liquid samples are counted in 3. 5 liter inverted well alumi- num beakers which are placed on top of a 4" x4" crystal coupled to a 400-channel gamma pulse height analyzer. Overall detec- tion efficiency for the 0. 364 Mev photo-peak of I is 6.4%. A matrix technique is employed in computation to compensate for the interference due to the presence of other isotopes. The in- put to this matrix i s variable, allowing for the simultaneous determination of any eight nuclides for which detection efficien- cies and interference factors have been obtained. Actual com- putation is performed by an IBM 1620 computer. Vegetation Samples Vegetation samples were obtained at most milk sampling loca- tions. An attempt was made to make the samples representative of the cow's feed; however, the samples were taken primarily 7 ------- as early indicators of where milk might be contaminated and were not intended to yield a cow intake-excretion formula. For this reason the vegetation samples are reported simply as fresh fission products present or not present. ------- II RESULTS Experimental Plan IV re suited in low levels of radioactivity being de- tected off the test range complex. Radiation monitors were posi- tioned in an area southwest of the test area according to information furnished by aerial monitors and the U. S. Weather Bureau. (See Table 2). A. Ground Monitor Data Gamma dose rates above background were detected in the vicin- ity of Lathrop Wells, on Highway 95, and at Dansby's Ranch located 10 miles southwest of Lathrop Wells. (See Table 1 below). Lathrop Wells has a population of about fifty people. Monitoring at these places on the day following the test produced only back- ground readings. Monitors were also called upon to check the off-site area during the night following the test when activity was detected on the NRDS. Readings above background were found off the test range complex for five miles along Highway 95 starting nine miles northwest of Lathrop Wells. The maximum reading of 0. 12 mr/hr was found 9. 8 miles NW of Lathrop Wells at approximately 0100 hours on September 25. Table 1. Dose rates occurring off the test range complex on September 24, 1964. Location (See Fig. 1) Lathrop Wells Dansby's Ranch Hwy 95(4.5 mi NW of Lathrop Wells) Time of Peak Dose Rate (PDT) 1234 1320 1220 Time of dose rates greater than background 1215-1500 1250-1450 1240-1330 Net Peak Dose Rate (mr/hr) 0.43 0. 07 0. 23 ------- Table 2. Meteorological Data for EPIV Upper Air Data: Jackass Flats, Nevada, 1100PDT, September 24, 1964 Height Wind Pressure Temperature Dew Point Relative (Ft. MSL) SFC 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 (Deg/Kts) 070/18 060/22 060/13 080/11 040/04 030/04 090/08 090/08 098/11 080/12 073/18 070/19 (mb) 895 883 854 824 794 768 738 712 687 662 638 614 ,o . 28. 6 25. 0 22. 7 20. 0 17. 3 15. 3 12.9 10. 7 8. 0 5. 5 3.6 1. 7 <°C) 0.6 - 3.4 - 2. 7 - 3.6 - 4. 0 - 4. 2 - 4.6 - 5.6 - 7.6 - 9. 1 -12. 6 -18.8 Humidit- 15 15 18 20 23 26 29 31 32 34 29 20 B. Dose Rate Recorder Data The recorder at Lathrop Wells indicated radioactivity associ- ated with effluent from the NRX-A2 test on September 24. This instrument recorded a net peak dose rate of 0.18 mr/hr at 1230 hours PDT. The time interval in which the dose rate ex- ceeded background was 1210 to 1340 hours and the estimated external dose during cloud passage was 0. 08 mr. C. Film Badge Data Due to the low dose rates encountered at points south and west of the test range complex, no off-site film badges were collected immediately following the NRX-A2 test. Badges collected since that time, however; have had no exposure which could be attri- buted to the EPIV test. 10 ------- D. Air Sample Data Several samples taken following the test contained fresh fission products. The results of analysis of the prefilters and charcoal cartridges are presented in Table 3. Table 3. Analysis of air samples containing fresh fission products collected following the NRX-A2 EPIV Experiment reported in c/M-^ at end of collection. ON OFF Vol- Prefilter Location Time-Date Time-Date ume Gross PDT PDT (M3) Beta Activity Gamma Pulse Height Analysis jlSl 133 135 Lathrop 0715, 9-24 1455, 9-24 261 450 Wells 1500,9-24 0715,9-25 553 2.3 Dansby 1050, 9-24 1550, 9-24 183 420 Ranch Death 0940,9-24 1500,9-24 211 2.5 Valley Jet. 1500,9-24 0625,9-25 642 2.2 Stovepipe 1045, 9-24 1500, 9-24 181 <1 Wells 1510,9-24 1030,9-25 804 1.5 Furnace 1100,9-24 1500,9-24 146 3.6 Creek 1510, 9-24 0955, 9-25 750 19 P C P C P C 13 <1 ND 12 57 42 55 45 84 37 ND 82 ND C ND ND ND P C ND <1 ND P C ND ND ND P 0.5 2.4 3.5 C <1 4. 9 ND P C ND ND ND P 0.5 2.4 3.5 C <1 3. 9 ND P=prefilter C = charcoal cartridge ND=not detectable Air samples taken on September 24 atScotty's Castle, Beatty and Springdale showed no fresh fission products when analyzed. 11 ------- E. Milk Sample Data Milk samples obtained on the test day and the two following days 133 at Dansby's Ranch indicated low levels of I . Iodine-131 was not present in detectable quantities. Dansby's Ranch is 22 miles southwest of Test Cell A. Six other milk samples collected did not contain fresh fission products in detectable quantities. (See Table 4). The cesium values reported are within the range of the cesium levels generally found in the particular areas sampled. F. Water Sample Data Water samples collected on the day of the test at Dansby's Ranch and the day after the test at the Watson and Selbach Ranches near L/athrop Wells, Lathrop Wells Gas Station, Furnace Creek and Stovepipe Wells did not show detectable levels of radio- activity. 12 ------- Table 4. Analyses of milk and vegetation samples collected following NRX-A2 EPIV COLLECTION DATA LOCATION (Azimuth and Distance from Test Cel 1 A) Dansby Ranch Lathrop Wei 1 s 225° 22 mi . Hunter's Ranch Olancha, California 248° 100 mi. Lone Pine Dai ry Lone Pine, California 261° 98 mi. M&R Cattle Company Canti 1 , Cal i forni a 221° 140 mi . Hills Dai ry Barstow, California 200° 140 mi . DATE COLrf&TED 9-24 9-25 9-26 9-27 9-26 9-26 9-27 9-27 Milk Radioassay Data ACTIVITY (pc/l) ,13. ,133 Cs137 <20 200 20 <20 70 30 <20 20 20 <20 <20 25 <20 <20 65 <20 <20 40 <20 <20 40 <20 <20 20 Vegetat ion Samples Taken P P P — — — ND ND ND ND OJ ND=fresh fission products not present in vegetation. P=presence of fresh fission products in vegetation samples. =vegetation samples not taken. ------- Ill CONCLUSIONS The NRX-A2 test of September 24, 1964, yielded low levels of radio- activity to the off-site area. The effluent was encountered in a small area of the Armagosa Desert between Death Valley Junction, Stove- pipe Wells, and the NRDS. Fresh fission products were detected as far away as Stovepipe Wells (45 miles) and Furnace Creek (40 miles) in the form of radioiodines on air filters. In both cases the concen- trations were less than five picocuries per cubic meter of air. The maximum levels of radioactivity detected off the test range complex were found at Lathrop Wells, Nevada. These levels of 0.43 mr/hr net gamma and 450 pc/M3 of gross beta activity were not considered health hazards to the population. Environmental samples collected following the test did not show de- tectable amounts of radioactivity more than thirty miles from NRDS. Only one milk cow was in the effluent path -within 80 miles of the test area. This cow was located at Dansby's Ranch which is 22 miles south-west of Test Cell A and eight miles south-west of Lathrop Wells, Nevada. Although the milk from this cow was not used for human consumption at the time of the test, samples were taken for several days following NRX-A2 EPIV. This milk contained no I in detect- able quantities and the peak I concentration was 200 pc/1 -which occurred on the day of the test. Since this milk sample -was collected only two to three hours after cloud milk -was evidently due to inhalation. only two to three hours after cloud passage, the I found in the 14 ------- Section 2. NRX-A2 EPV, October 15, 1964 I. OPERATIONAL PROCEDURES The reactor was tested under the conditions known as Experimental Plan V (EPV) on October 15, 1964 at 1210 hours PDT. The test was approximately a twenty minute run at less than 20 per cent of design power. The reactor was in an upright position so that the fission products exhausted upward. The operational procedures followed on this experiment were simi- lar to those used in support of the September 24 test. 15 ------- II. RESULTS On October 15, 1964 Experimental Plan V was conducted with low levels of radioactivity being detected northeast of the test range com- plex. A summary of weather conditions at 1230 on the test day is presented in Table 5. A. Ground Monitor Data Due to the low dose rates encountered by aerial monitors, no ground monitors were positioned off the test range complex. However, ground monitors located on the test range complex downwind from the reactor encountered no readings above back- ground. B. Dose Rate Recorder Data RM-11 recorder charts collected following NRX-A2 EPV indi- cated no dose rates above background. C. Film Badge Data Due to the low dose rates encountered, no film badges •were col- lected immediately following the NRX-A2 test. Badges collected since that time, however; have had no exposures which could be attributed to the EPV test. D. Air Sample Data Only one off-site air sample contained detectable quantities of fresh fission products. The charcoal cartridge at Indian Springs showed 150 total picocuries of I . This sample was started at 1800 on the test day and the air sampler motor failed during the night. However; if the sampler ran for only two hours, 150 total picocuries would b e less than one picocurie per cubic meter 16 ------- on the filter. Although the effluent from EPV went to the north- east, it is believed that northerly drainage winds carried some radioactivity to the south during the night resulting in radioiodine being detected at Indian Springs. Table 5. Meteorological data for EPV. Upper air data at: Jackass Flats, Nevada, 1230 PDT, October 15, 1964 Height Wind Pressure Temperature Dew Point Relative (Ft. MSL) (Deg/Kts) (mb) ( C) (°C) Humidity SFC 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 Calm 250/02 220/02 180/02 140/01 180/02 180/04 170/05 180/08 180/12 170/16 180/16 892 880 850 821 791 752 735 711 686 659 634 611 28. 3 26. 8 23. 3 20.4 17. 5 14.6 12. 1 9. 1 6.4 3. 2 0. 8 - 1.9 - 1.8 - 2.0 - 2.4 - 3.4 - 4. 0 - 4. 8 - 5. 0 - 6. 0 - 6. 3 -7.3 - 6.3 -11. 0 14 15 18 20 23 26 30 34 40 46 51 50 E. Milk Sample Data Milk samples were collected at Lund, Nevada on October 16 and at Alamo and Hiko on October 20. These samples did not contain detectable quantities of fresh fission products. F. Water Sample Data A water sample collected from a water trough at Goss Ranch on October 16 the sample. October 16 contained 75 pc/1 of I . No I was detectable in 17 ------- r V3C4 _. \c If ! \r^.^ \MfAO If Figure 3. Environmental sampling locations for EPIV and EPV. 18 ------- G. Vegetation Sample Data In order to determine cloud trajectory, vegetation samples were collected at Goss Ranch, Hiko and Alamo, Nevada. The samples from Goss Ranch and Hiko contained low levels of fresh fission products. 19 ------- III. CONCLUSIONS The NRX-A2 EPV experiment of October 15, 1964, yielded low levels of radioactivity off the test range complex. The effluent was found in an area northeast of the test range complex between Test Cell A and Hiko, Nevada. Low levels of fresh fission products -were found on vegetation sam- ples collected at Goss Ranch and Hiko and in a water sample from Goss Ranch but no radioactivity was found in milk sampled at Hiko, Lund and Alamo. It is concluded that the radioactivity from this test did not constitute a hazard to the off-site population. 20 ------- DISTRIBUTION 1-15 SWRHL, Las Vegas, Nevada 16 G. D. Ferber, USWB, MRPB (R-3. 3), Washington, D. C. 17 Phillip W. Allen, USWB, NVOO, Las Vegas, Nevada 18 Harold Mueller, USWB, NVOO, Las Vegas, Nevada 19-20 Col. E. G. Halligan, DASA, NVOO, Las Vegas, Nevada 21 C. S. Maupin, REECo, Mercury, Nevada 22 V. M. Milligan, REECo, Mercury, Nevada 23 Vincent Vespe, ALOO, Albuquerque, New Mexico 24-26 George T. Anton, SNPO-N, Jackass Flats, Nevada 27 B. P. Helgeson, SNPO-N, NRDS, Jackass Flats, Nevada 28 John C. Gallimore, WANL, NRDS, Jackass Flats, Nevada 29 Morton I. Goldman, NUS, Washington, D. C. 30 Elmer Hemmerle, Westinghouse Electric Corp. , Pittsburgh, Pa. 31 David Smith, Lewis Research Center, SNPO-C, Cleveland, Ohio 32 John M. Wright, SNPO-N, Jackass Flats, Nevada 33 Hugo G. Simens, NERVA Test Opns. , Aerojet-Gen. Corp. , Jackass Flats, Nevada 34 Bernd Kahn, DRH, RATSEC, Cincinnati, Ohio 35 Raymond Moore, DRH, PHS, Region VII, Dallas, Texas 36 James G. Terrill Jr. , DRH, PHS, Washington, D. C. 37-39 Robert H. Goeckermann, LRL, Livermore, California 40 John W. Gofman, LRL, Livermore, California 41 Keith Boyer, LASL, Los Alamos, New Mexico 42 Charles I. Browne, LASL, Los Alamos, New Mexico 43 Alvin C. Graves, LASL, Los Alamos, New Mexico 44 Harry S. Jordan, LASL, Los Alamos, New Mexico 45 L. D. P. King, LASL, Los Alamos, New Mexico 46 Herbert T. Knight, LASL, NRDS, Jackass Flats, Nevada ------- DISTRIBUTION (cont1) 47 William E. Ogle, LASL, Los Alamos, New Mexico 48 Fred Sanders, LASL, Mercury, Nevada 49 Oren Stopinski, LASL, Los Alamos, New Mexico 50 James E. Reeves, Manager^ NVOO, AEC, Las Vegas, Nevada 51 Otto H. Roehlk, OSD, NVOO, Las Vegas, Nevada 52 Henry G. Vermillion, NVOO, AEC, Las Vegas, Nevada 53 Robert E. Baker, AEC, Washington, D. C. 54 Col. Ralph S. Decker, SNPO, Washington, D. C. 55 Gordon M. Dunning, DOS, AEC, Washington, D. C. 56 Brig. Gen. D. L. Crowson, DMA, AEC, Washington, D. C. 57 Mail & Records, NVOO, AEC, Las Vegas, Nevada 58 J. A. Mohrbacher, Radiation Services, Pan American, NRDS, Jackass Flats, Nevada 59-75 Author's copies ------- |