Off-Site Environmental Contamination from Nuclear Explosives at the Nevada Test Site September 15, 1961 - September 15, 1962

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PRIVACY ACT MATERIAL REMOVED PRIVACY ACT MATERIAL REMOVED Thla report ««■ prepared u an account of Government aponaored work. Neither the United Btatea, nor the Commlaaion, nor any peraoo acting on behalf of the Commlaalon: A. Hakei any warranty or representation, expreaaed or Implied, with reaped to the accu racy, complete near or uaefulneaa of the Information contained In thla report, or that the use of any Information, apparatus, method, or process disclosed In this report may not infringe privately owned righta; or B. Assumes any liabllitlea with reaped to the use of, or tor damages resulting from the uee of any information, apperatua, method, or process disclosed in thla report. As used In the shove, "person acting on behalf of the Commission’' Includes any em ployee or contractor of the Commlaalon, or employee of each contractor, to the extent that such employee or contractor of the Commlaalon, or employee of such contractor prepares, disseminates, or provides access to, any Information pursuant to hla employment or contract with the Commission, or his employment with such contractor. This report has been reproduced directly from the best Printed in USA, Price $1.50. Available from the Office of Technical Services, Department of Commerce, Washington US DOE ARCHIVES PRIVACY ACT MATERIAL REMOVED

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PRIVACY ACT MATERIAL REMOVED US DOE ARCHIVES OFF-SITE ENVIRONMENTAL CONTAMINATION FROM NUCLEAR EXPLOSIVES AT THE NEVADA TEST SITE DIVISION OF OPERATIONAL WASH INC, taw 25, D.WASHINGTON PRIVACY ACT MATERIAL REMOVED 2—

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PRIVACY ACT MATERIAL REMOVED'"' TABLE OF CONTENTS II. Release of Radioactivity------------------------------------------ 1 III. Off-Site Monitoring Activity 2 IV. External Gamma Exposures---------------------------------------------------------------------- 3 E. Gross Beta and Isotopic Water Results------------------------------------ 5 Table I. Nuclear Events at Nevada Test Site--------------------------------6 Table II. Off-Site Personnel Film Badge Results---------------------------------9 Table III. Station Film Badge Results--------------------------------------------------32 Table Va. Gross Beta Concentrations in Air Above 100 uuc/m3---------51 Table Via. Isotopic Air Results, Pre-Filters--------------------------------------55 Table Vlb. Isotopic Air Results, Charcoal Cartridges--------------------- 57 Table Vila. Gross Beta Water Results------------------------------------------------------------------------- 5^ARC PRIVACY ACT MATERIAL REMOVED 3

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PRIVACY ACT MATERIAL REMOVED OFF-SITE ENVIRONMENTAL CONTAMINATION FROM NUCLEAR EXPLOSIVES AT THE NEVADA TEST SITE The data contained in this report were supplied to the Nuclear Explosives Environmental Safety Branch, Division of Operational Operational Safety Division, Nevada Operations Office, AEC, ■ Las Vegas, Nevada. The U. S. Public Health Service conducts for the AEC a program of radiological surveillance in an area up to 300 miles radius from the Nevada Test Site in accordance with a Memorandum of Understanding between the two agencies. The environ mental data in this report are based on the USERS surveillance H. RELEASE OF RADIOACTIVITY Since the resumption of nuclear tests on September 15, 1961, the AEC has announced the detonation of 52 nuclear devices in Nevada through September 15, 1962. Forty-six of these detonations oc curred underground, a technique designed to prevent the release of radioactive material. As indicated in Table I, seventeen of the detonations released some gaseous activity measurable off-site. Five devices were detonated either slightly aboveground or at a shallow depth underground, and a 100 KT thermonuclear device, Project Sedan, a Plowshare cratering experiment, was detonated at a depth of 635 feet. All devices were detonated only under condi tions that would minimize exposures to populated off-site areas. The physical characteristics and relative amounts of various iso topes released by these tests vary somewhat from those released by past tests at NTS. In test series prior to 1961, the majority of the nuclear devices were airdropped or were detonated on steel towers, balloons or in uncovered shallow holes; thus, fallout par ticles contained many kinds of debris in addition to the radioactivity. Induced activity in the debris contributed litt to the total radioactivity in the fallout. Although there have been six detonations between September 15, 1961, and September 15, 1962, giving off-site fallout resembling that from past test se ries, the major portion of the activity in the remainder of the series has been contained on-site or underground. Gaseous ac tivity, along with small quantities of particulate material con taining activity, have been released to the atmosphere from some events through venting of underground detonations.

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PRIVACY ACT MATERIAL REMOVED During the period of testing covered by this report, the nature of releases of gaseous material from the underground tests was such that the clouds formed did not rise to altitudes as those from surface or near surface detonations, but lingered near the surface and were acted upon by the lower tropospheric and surface winds. Normally, these clouds were so dispersed by the time they reached off-site populated areas that they were difficult to detect with portable monitoring equipment. However, in a few events, clouds did pass over areas where people were located; hence, there have been some off-site radiation exposures. III. OFF-SITE MONITOHING ACTIVITY The responsibility for off-site monitoring, collection and analysis of samples of the environment (air, water and milk), distribution and collection of film badges and submission of reports was as signed to the USFHS through a Memorandum of Understanding with the AEC. The off-site area established was approximately 3CO miles radius. It would have been impractical to monitor the entire area: however, the responsibility for radiological monitoring was as signed to this distance whenever the radiological situation made such action necessary. Areas beyond this radius were monitored by the radiation surveillance network, a nationwide network of moni toring stations established by the USFHS. Approximately 65O film badges were issued to 275 people in the off site area, mostly within the sector of the predominate winds from the test site and within approximately 200 miles from the NTS. The recorded radiation exposure received by these individuals is main tained as a permanent record by the AEC, and each individual is in formed of his exposure record. BEST AVAILABLE COPY In order that radiation exposure to people would be minimal, care ful evaluation of predicted fallout areas was made even though con tainment of the radiation or low off-site intensities were anticipated. Monitors were on duty and alert to possible difficulties. One such event occurred following the test of DOE ARCHIVES July 6, 1962, (Sedan event), when it was determined that the radio active cloud would pass over a sparsely populated area, ten persons were temporarily relocated for period of time up to six hours. Forty persons were requested to remain indoors for a period of time up to three hours. Eoadblocks were established on Highway 25 for approximately five hours. (See Figure I.) Tne highest recorded reading on the highway (about AO miles from ground zero) was about two roentgens per hour at H plus 2.3 hours during passage of the cloud, dropping to about 115 milliroentgens an hour afterwards. Thus, there was a substantial saving in potential radiation exposures. For example, persons who were temporarily relocated (from the Diablo Maintenance Station) showed an average exposure to July 9. 1962, of about 160 milliroentgens (rar), while station film badges remaining at Diablo read about 1500 mr. This was the only instance in which people were relocated during the period covered by this report. PRIVACY ACT MATERIAL REMOVED

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PRIVACY ACT MATERIAL REMOVED IV. EXTERNAL GAMMA EXPOSURES TaLle II presents the exposures received Ly off-site individuals These records have been corrected for natural background radiation exposure which is approximately 200 milliroentgens per year (mr/yr) for the general area. The lower limit of dose that could be rou tinely detected by analysis of these film badges was approximately 30 mr. Although the dose is listed for the place where a person lives, it was more typical of the place of residence, plus its Fifteen badges were reported lost or damaged. Persons in off-site areas were re-badged following suspected exposures; thus, the wear ing time for film badges varied among the population. Of the indi viduals badged (272), the findings are given in the following Hie highest external whole body gamma radiation exposure to off site personnel indicated as the "film badge reading between bOO - 500 mr" in the tabulation above was ^38 mr for one person at Mava„’Bevada BEST AVAILABLE COPY A. Station Film Badge Results Film badges were placed in various locations, such as on fence posts, barns, trees and similar places and left for varying lengths of time as indicated in Table III. All film badge results from September 1961, to January 1962, were below the limits of detection. Heat damage to film badges begins to be noticeable in as little time as two weeks, beginning as early as March or April at some locations. Thus, in order to have a meaningful result, recorded film badge readings were compared with radioactivity in the area as found by mobile monitors. Film badges suspected of being damaged by heat, light or water and not verified with radioactivity in the area are so indicated. Collections of milk samples in the area surrounding NTS were not conducted on a specific routine basis, but frequent (sometimes daily) samples were collected when the situation indicated the necessity. Additional collections were made for documentation PRIVACY ACT MATERIAL REMOVED

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PRIVACY ACT MATERIAL REMOVED The isotopic milk results are tabulated in Table IV. The nu measured include stable calcium and total potassium, together with barium-l^O and cesium-137. The measured levels of radioactivity reported were extrapolated to the date of collection. Calcium and potassium are reported in grams per liter (gm/l) of milk, and the radioactive isotopes are reported in micromicrocuries per liter C. Gross Beta Air Results There were permanent air sampling stations in operation 2k hours per day at the following 28 stations surrounding NTS: 25. Tonopah Test Range 28. Warm Springs Ranch 5. Death Valley Junction Ik. Indian Springs The air samplers used were Staplex high volume motors, drawing air through 8" x 10"!glass fiber filters. When deemed desirable, a secondary MSA activated charcoal cartridge was added for the col lection of gaseous fission products. Flow rates were approximately 50 cubic feet j>er minute (cfm) for the glass fiber filter alone, and 25 cfm with the charcoal cartridge added. ’ Glass fiber filters were counted for gross beta activity in the with lead shielded Eberline Model AC-1 large probes having efficien All charcoal cartridges and any glass fiber filters with gross beta activity significantly above background levels were assayed with a RIDL 100 channel gamma scintillation spectrometer, using a steel of eight per cent for identification of specific gamma-emitting PRIVACY ACT MATERIAL REMOVED ?

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PRIVACY ACT MATERIAL REMOVED Data presented In Tables Va and Vb include only those samples col lected during the periods of known off-site radioactivity and show ing 100 micromicrocuries per cubic meter (^c/M^) of air or greater. Additional data collected by the network are too voluminous to in clude in this report. Data included in the Tables indicated the presence of radioactivity and thus the possible need for further monitoring but were of no direct value in assessing radiation doses. D. Isotopic Air Results Table VI presents the results of isotopic air filter analysis. The activity concentrations listed have been extrapolated from count time activities to the mid collection time or cloud peah time ac cording to the radiological decay of the radionuclide. Table Via gives the pre-filter results, and Table Vlb gives charcoal car tridge results. Those samples (both glass fiber and charcoal filters) with gross beta activities significantly above background levels from September 15, 19^1, to September 15, 1962, were ana lyzed for specific gamma emitting radioactive isotopes. The iso E. Gross Beta and Isotopic Water Results Tables Vila and Vllb present the gross beta radioactivity in water results, and Table VIII presents the isotopic analysis results of samples of water supplies. The locations listed are routine sam pling stations, and except for Lake Mead, all are subsurface supplies. There are no known surface supplies for human use in the off-site area except for Lake Mead. No attempt to perform isotopic analysis of water samples has been made unless gross beta activity warrants it because of the low lev els encountered. The St. George supply, presented in Table VIII, has been routinely analyzed in conjunction with a continuing ecology study being conducted there. PRIVACY ACT MATERIAL REMOVED

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PRIVACY ACT MATERIAL REMOVED Nuclear Events at Nevada Test Site Event Date Type of Event Release Categories Shrew 9/16/61 low yield, underground 3, 5, 7 Chena 10/10/61 low yield, underground (tunnel) 3, 8 Mink 10/29/61 low yield, underground 3, 5, 8 Mad 12/13/61 130 tons, underground 3, 5, 8 Ringtail 12/17/61 low yield, underground 3, 5, 7 Feather 12/22/61 low yield, underground (tunnel) 3, 8 Dormouse 1/30/62 low yield, underground 3, 5, 7 Codsaw 2/19/62 low yield, underground 2, 7 Cimarron 2/23/62 11.2 KT, underground DOE ARCHIVES 3 Platypus 2/2A/62 low yield, underground 3, 7 Pampas 3/1/62 low yield, underground (UK device) 3, 8 Danny Boy 3/5/62 it30 tons, underground (cratering Ermine 3/6/62 low yield, underground 2, 7

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PRIVACY ACT MATERIAL REMOVED Event Date T^rpe of Event Release Categories Hognose 3/15/62 low yield, underground l, 8 Chinchilla II 3/31/62 low yield, underground 2, 8 Dormouse Prime L/5/62 9.7 KT, underground 1, 8 Passaic L/6/62 low yield, underground 1, 8 Hudson Vl2/62 low yield, underground 2, 3 Dead 4/21/62 low yield, underground 1, 8 Black 4/27/62 low yield, underground 1, T Paca 5/7/62 low yield, underground 1, 8 Eel 5/19/62 low yield, underground ^ 5, 7 White 5/25/62 low yield, underground 1, 7 Raccoon 6/1/62 low yield, underground 1, 7 Packrat 6/6/62 low yield, underground 2, 8 Des Moines 6/13/62 low yield, underground (tunnel) 6, 7 Daman I 6/21/62 low yield, underground 2, 8 Marshmallow 6/28/62 low yield, underground (tunnel) 3, 7 Sacramento 6/30/62 low' yield, underground 1, 7 Sedan 7/6/62 Plowshare cratering experiment* 4, 6, 7 Little Feller II 7/7/62 low yield, slightly aboveground 3, 6** *100 KT total yield, with less than 30 KT fission, 635 feet underground. **A1 though a cloud was fcrirsed, the U. S. Public Health Service off-site monitoring net work did not identify any radioactivity in the off-site area, as defined in category 3, which could be attributed to this event. PRIVACY ACT MATERIAL REMOVED

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PRIVACY ACT MATERIAL REMOVED Event Date Type of Event Release Categories Johnny Boy 7/11/62 500 tons, underground 4, 6 Merrimac 7/13/62 low yield, underground 3, 5, 8 Small Boy 7/14/62 low yield, slightly aboveground 4, 6 Little Feller I 7/17/62 low yield, slightly aboveground 3, 6* Wichita 7/27/62 low yield, underground 3, 5, 7 Bobac 8/24/62 low yield, underground 1, 8 York 8/24/62 low yield, underground Hydrax 9/14/62 low yield, underground 1, 8 Categories of Release of Radioactivity 1. No radiation levels detected above background on or off the Nevada Test Site from radioactivity released by this detonation. 2. Radiation levels detected near surface zero above normal background from radio activity released by this detonation. No other radiation levels detected on or off the Nevada Test Site from radioactivity released by this detonation. 3- Radiation detected on-site from radioactivity released by this detonation. No radiation levels above background detected off the Nevada Test Site in populated areas from radioactivity released by this detonation. (”On-site'' as used above …