Radiological Safety Support Operation Hardtack Phase-I

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RADIOLOGICAL SAFETY SUPPORT OPERATION HARDTACK, PHASE I Compiled and Edited by Carl Minkkinen, Holmes & Narver, Inc. , Rad-Safe Officer Henry P. Schlacks, AEC Rad-Safe Assistant, Eniwetok Roscoe H. Goeke and Charles L. Weaver of the Albuquerque Operations Office Atomic Energy Commission Albuquerque, New Mexico Holmes & Narver, Inc.

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Task Force Seven Scientific Adviser, William Ogle Commander, James E. Reeves Commander, Donald B. Schuster Division of Military Application Division of Biology and Medicine Office of Information Health and Safety Central Mail and Records Office of Test Operations Los Angeles Branch Las Vegas Branch Mail and Records

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Los Alamos Scientific Laboratory Lawrence Radiation Laboratory Armed Forces Special Weapons Project Field Commander, Sandia Base San Francisco Operations Office New York Operations Office, DBM Holmes & Narver, Inc. Reynolds Electrical & Engineering Co. Public Health Service Division of Radiological Health, E. C. Anderson Office of Civilian Defense and Mobilization Technical Information Service Extension, Oak Ridge

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TABLE OF CONTENTS Organization and Responsibility Equipment and Supplies 2.4 Functioning of Equipment ...............8 Dosimetry and Records 3.3 Radiation Exposure Guides .............. 14 6.2 Personnel Decon Section ............lll 25 6.4 Decontamination of Mack Tower ............ 26

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VII, Sample Counting TABLE OF CONTENTS VIII. Radiation Levels APPENDIX A, Fallout Protection Study ............... 35 Summary of missions accompanied by trained TG 7, 5 Instruments and diving equipment used by the underwater Site Elmer Background Radiation Intensity Curve .... Fallout Tray Sample Decay Curve l *** Decon trucks located atthe check point for personnel Ropes prevented personnel from wandering into the more

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This report has been prepared, primarily, to document the radiological support furnished by Holmes & Narver, Inc. , the AEC Contractor, during Operation HARDTACK, Phase I. A secondary function of the report is to provide Rad-Safe information to be used in the planning of possible future operations. The primary mission of the H&N Rad-Safe organization during the Operation was to protect TG 7.5 personnel from unnecessary exposure to radiation, to prevent the spreading of contamination, and to assist TG 7. 1 in providing overall Rad-Safe support.

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The Rad-Safe organizational arrangement for this Operation - the Rad-Safe personnel of TG 7.5 functioning as an independent Rad-Safe organization for TG 7.5 - proved satisfactory and demonstrated that the AEC Contractor could adequately supply radiological safety service In previous operations the AEC and its Contractor Rad-Safe personnel were integrated into TG 7. 1, TU-6, and the CTU-6 became the

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I. ORGANIZATION AND RESPONSIBILITY The Rad-Safe personnel of AEC and its Contractor, Holmes & Narver, Inc. , functioned as an independent Rad-Safe organization for Task Group 7.5. TU-6, the Rad-Safe organization for TG 7. 1, acted as the overall Rad-Safe organization during the operational period; however, to keep radiation exposure to a minimum, TG 7.5 maintained control over services and operations as they affected TG 7.5 personnel, Close liaison was maintained between CTG 7.5 and CTG 7. 1 on all Rad-Safe matters of mutual interest. Facilities were shared, and work on common problems, such as dosimetry, decontamination, and equipment repair, was accomplished by agreement between the two An operational chart of the TG 7.5 Rad-Safe activities is shown The Holmes & Narver Rad-Safe organization maintained a com - plement of 14 persons during the operational period. The personnel assigned to each atoll were: 1 Rad-Safe Electronic Technic Ian

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I Operational Coordination RAD - SAFE OPERATIONS Figure 1.1 TG 7.5 RADIOLOGICAL SAFETY ORGANIZATION

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At the beginning of Operation HARDTACK, the Commander, Joint safety of all Seven assumed overall responsibility for the radiological Task Force personnel. The CTG 7.5 held Rad-Safe responsibility for the personnel of rection on all TG 7. 5 Rad-Safe policies. The AEC Rad-Safe Officer was designated the Assistant Chief of Staff, E-7, with responsibility to the TG 7.5 Deputy Commander for supervising the Rad-Safe operations and recommending protection measures. The Contractor’ s Rad-Safe Officer functioned as the Operations Officer and provided the necessary support. During periods when neither the Rad-Safe Adviser or the Assistant Chief of Staff, E-7 was at EPG, the AEC Rad-Safe Assistant acted as Assistant Chief of Staff, E-7. On 1 April 1958, the CTG 7.5 relinquished to CTG 7. 1 the operational control of the Rad-Safe facilities operated during the non-test periods by the AEC Contractor, H&N. This control was returned to CTG 7.5 on 3 September 1958, 15 days after the last detonation.

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II. EQUIPMENT AND SUPPLIES Prior to the Operation a complete inventory of all Rad-Safe protective clothing, decontamination materials, equipment and instrumentation at EPG was submitted to CTU-6, TG 7. 1, the organization responsible for providing The dosimetry and records and the instrument repair facilities at the Rad-Safe Center on Site Elmer were remodeled and air conditioned, and the vehicle and personnel decontamination centers were activated. A Rad-Safe laundry barge was put into operation to provide facilities for emergency personnel decontamination during the last phase of the Operation. At Site Nan the Rad-Safe Center and the personnel and vehicle decontamination centers were put into operable condition, and new facilities were provided for the dosimetry and instrument repair section in the Communication 2.2 Repair and Maintenance The care and maintenance of all radiological function of the TG 7.5 Rad. Safe organization and instrumentation was a joint equipment in the furnishing repair services on the portable instruments and photodosimetry room and the radiochemistry trailers at both The electronic equipment utilized during the Operation included portable survey instruments, air sampling equipment, do sage instruments, background monitoring detectors with recorder units, various types of test equipment, and radiation analysis in strum entat ion.

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2.4 Functioning of Equipment The AN/PDR-39 continued to be an excellent portable, rugged field monitoring instrument that required little maintenance. There was no moisture or and in general the accuracy was good with little or no drift with age or use. checked with a vibrating reed electrometer high range resistors were replaced at the The range resistors were bridge circuit. Defective beginning of the operation and checked periodically thereafter. The instruments, cord up to 500 r/hr, were used considerably for aerial surveys and re - The AN/PDR.27H, a beta-gamma survey meter, was a good low range personnel monitoring instrument that had rugged qualities and good stability. The AN/PDR- 18, a gamma scintillation survey meter, was used occasionally, and proved to be rugged. It operated with six easy to obfactorily in this high moisture climate, for the following reasons: a. Frequent power supply failures due to dead batteries, fragile terminal connections, etc.

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Leakage of tar-like substance from headset jack, resulting in shorts across the printed circuit board underneath calibration potentiometer r. Substandard printed circuit board with difficulties in unsoldering and re solde ring component connec - ti ons such as tubes, capacitors, resistors, etc. Calibration drift over a period of a few days. The Integrons were not used to a large extent. They calibrated and checked easily, and were relatively rugged. The Thyac alpha scintillation survey meter was gamma responsive in a radiation field above 500 mr/hr. However, for normal personnel or equipment monitoring, the instrument worked adequately. The Beckman MX-5 beta-gamma low range personnel monitoring instrument performed very well, though many were not used due to th’e lack of spare parts. The instrument was rugged, had good stability and was easy to calibrate. This instrument is no longer in production. The Eberline PAC-3-G alpha proportional survey meter was an adequate monitoring instrument but required a daily check-out and readjustment of the gas-flow system. The probe assembly was easily damaged in the field. However, if the monitor utilizing the instrument

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were carefully instructed, with emphasis placed upon handling care, adequate field monitoring could be accomplished. The Eberline beta-gamma continuous air monitors functioned adequately during the entire Operation. However, the background monitoring probes did not perform properly. It was thought that the probe assembly had a high voltage ground, but the probe could not be dis - mantled to remedy the situation. The TN-4D background monitor and recorder was used by the sessed a sensitive electronic circuit that caused trouble, primarily due to failure of the recorder. The Evershed recorder, Mark H, drive mo - tor gears stripped frequently, and it was necessary to replace the motor and enclosed main drive gear box. Only a few spare motors were avail - The Eberline film badge evaluation and recording system, FS-3, required the attention of a technician several hours daily to clean contacts, check tubes, and make miscellaneous adjustments, During the early phase of the operation the high voltage power supply caused trou - ble, until filtering was improved. The maximum, and only, voltage that could be obtained from the power supply was approximately 1275 volts. It is felt that 1400 volts

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would produce a stronger signal from the photomultiplier tube, which would result in faster servo response. The tachometer feedback circuit also warranted component changes to eliminate feedback voltage. Optimum operation resulted The light source strength was also a critical item. The best operation resulted with a General Electric 300 watt PH/300 TIOP - 120 volt projection lamp which had a lifetime of only 30 operating hours. The red-light (GE-328) indicator on the micro switch push button of the densitometer did not operate satisfactorily, due to the red bulb’ s lifetime of from only two to three days, ing only occasional cleaning and oiling. The correct reference voltage was obtained with an curve follower also performed excellently. The X-axis potentiometer had to be swabbed out with carbon tetrachloride every other day. The correct X-axis reference voltage was obtained The Jordan aerial survey instruments, PRAM-5, did not function properly and were deadlined at the start of the Operation. Considerable circuit checking and recalibration was performed to no

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The UW - 1 underwater Instruments functioned excellently. When check calibrated, they were found to retain accuracy with no The radiation measuring equipment in the Rad-Chem trailers functioned adequately. The Berkley Model 2000 scalers presented some trouble, but were generally accurate and reliable. These units were calibrated and tested with a Rutherford Model 300 pulse generator using a O. 25 volt, 1 ms rise time, 2 ms’ duration, The best GM tube was the Tracerlab TGC-2 thickness of less than 2 mg/cm3, which gave counting from 20 to 30 percent. effic iencies of The alpha counter head and amplifier -power supply system functioned well for low level alpha counting, providing good discrimination against beta and gamma pulses. The laboratory monitor, SU-3B, was used to monitor bench tops and miscellaneous items. Initially the voltage regulation at the Site Elmer trailer was poor, due to a defective Sorenson voltage regulator. The voltage regulation stability was carefully examined with a fast trigger oscilloscope, and line disturbances were damped out by careful tuning to resonance.

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HI. DOSIMIZTRY AND RECORDS Upon arrival at EPG each person was issued an addressograph identification plate and film badge. The identification plate of H&N employees was embossed with an eight digit serial number that designated the individual’s task group, task unit, department and payroll number. The identification plate and the film badge were attached to and worn with the security badge. The film badges were exchanged on a bimonthly basis or on return from a mission into a RADEX area. The Dosimetry and Records Section of TU-6, TG 7. 1, was responsible for providing the film badges for all per sonnel during the Ope ration. The sec - tion was also responsible for the processing of film badges and the evaluation and recording of radiation dosages. H&N Rad-Safe personnel assisted TU-6 in the issuing, collecting and processing of film. Dosage records were maintained for all TG 7.5 personnel with IBM dosage cards, obtained daily from During the Operation, the Eberline film badge evaluation and recording system, FS-3, was used for the first time. Two units were installed at Site Elmer and one at Site Nan. When the equipment was operating efficiently, approximately 2000 films could be read and recorded within a few hours. All film badge data at Site Nan was transmitted to the IBM section at Site Elmer by an IBM data trans - ceiver. An IBM 704 was used for storage and dosage print-out rosters,

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The bulk of the workload was on the 160 O to 2400 hour shift, Film badge processing commenced at 1900 hours, and the IBM dosage cards were sent to the IBM 704 for information storage at approximately 2300 hours. A print-out dosage roster was prepared each night for the previous day’ s film badges, and an extra deck of dosage cards was printed for the TG 7. 5 dosage file. Over 12, 000 film badges were processed for TG 7.5 personnel. The Dupont Film Packet, Type 559., with component films (502 for low range and 834 for high range) proved excellent for the Operation. The ceresin wax dip and vinyl plastic holder protected the film from the effects of handling and high humidity. The films were calibrated on a “constant time, variable distance” range, and the calibration curves were checked for accuracy approximately every two weeks. During the initial calibration a density inversion was noted. The area under the lead strip had a darker appearance than the rest of the film. Invest - igation indicated that this occurred only when the back of the film was exposed to the calibration source. A further check, however, showed that the optical density under the lead strip remained the same when the films were exposed The Cobalt 60 calibration source strength was 8, 67 r/hr at 50 cm, as of 3, 3 Radiation Exposure Guides The total cumulative exposure guide for JTF. Seven personnel during the Operation, as authorized by CJTF-Seven directive, was:

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Gamma - a maximum of 3. 75 roentgens per any consecutive 13 week period, with a maximum of 5. 0 r during the Operation. Exceptions - on an individual basis and approved by The gamma exposure criteria for TG 7.5 personnel was further restricted to 5. 0 r for the calendar year. A summary of the dosages received by TG 7.5 personnel from 1 April through 4 September 1958 follows. No. of Persons Percent The 48-hour fallout at Site Elmer that followed the Fir and Koa events contributed significantly to the radiation dose of TG 7.5 personnel, as much as 1500 mr for persons remaining at Site Elmer for the duration of the Oper - ation. Therefore, it was necessary to request that the guide of 3750 mr per 13 week period be increased, and also, the 5000 mr dose for be increased to 10, 000 mr for 35 key employees. Upon completion of the Operation only four of these 35 tually exceeded the 3750 mr guide, and none exceeded the 5000 mr limit.

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Prior to Operation HARDTACK a radiological safety course to tram sistance of the AEC Rad-Safe Assistant. The basic training course, given to H&N personnel of various departments and divisions, totaled 24 hours, and was conducted at Site Elmer from 24 through 28 February, and at Site Nan from 3 through 7 March 1958. Instruction was given in elementary radiatio:l theory, with emphasis on recovery party operations, use of protective …