Operation Hardtack Project 2.1, Shipboard Radiation from Underwater Bursts (Deleted)

Page 1

Shipboard Radiation from Underwater Bursts U.S. Naval Radiological Defense Laboratory San Francisco, CA This is an extract of WT-1619, Operation HARDTACK, Project 2.1. Extracted version prepared for DEFENSE NUCLEAR AGENCY

Page 2

Destroy this report when it is no longer needed, Do not return PLEASE NOTIFY THE DEFENSE NUCLEAR AGENCY, ATTN: STTI, WASHINGTON, DC 20305-1000, IF YOUR ADDRESS IS INCORRECT, IF YOU WISH IT DELETED FROM THE DISTRIBUTION LIST, OR IF THE ADDRESSEE IS NO LONGER EMPLOYED BY YOUR ORGANIZATION.

Page 3

REPORT DOCUMENTATION PAGE I b iu~~\tMtN~ARfw-Ar,oNThis rerJort has had sensitive mil itary information removed in order to provide an unclassified version for unlimited distributi~n. The work was performed by the 18 3 Underwater Bursts Radiation Measurements The principal objectives of this project were: (1) the determination of total gamma-radiation dose and dose rate histories aboard three moored ships expo$ed to radiological environments at locations of possible operational interest about the surface zeros of two underwater nuclear detonations, shots Wahoo and Umbrella; (2) estimation of remote-source gamma-radiation dose and dose-rate histories at exposed weather-deck locations aboard ships; (3) estimation of tota gamma-radiation dose and dose-rate histories in the water adjacent to the ships; and (4) measurement of gamma-ionization decay of a fallout ~ample collected on one ship a few minutes after each shot. _ Although radiation from the water may have influenced the compartment/deck dose-rate ratios tc ~ considerable degree at later times, the contribution of contaminated water to the total dos: observed aboard the ships was probably of little significance.

Page 4

Classified material has been removed in order to make the information available on an unclassified, open publication basis, to any interested parties. The effort to declassify this report has been accomplished specifically to SUppOrt the Department of Defense Nuclear Test Personnel Review (NTPR) Program. The objective is to facilitate studies of the low levels of radiation received by some individuals during the atmospheric nuclear test program by making as much information as possible available to all interested parties. The material which has been deleted is either currently classified as Restricted Data or Formerly Restricted Data under the provisions of the Atomic Energy Act of 1954 (as amended), or is National Security Information, or has been determined to be critical military information which could reveal system or equipment vulnerabilities and is, therefore, not appropriate for open The Defense Nuclear Agency (DNA) believes that though all classified material has been deleted, the report accurately portrays the contents of the original. DNA also believes that the deleted material is of little or no significance to studies into the amounts, or types, of radiation received by any individuals during the atmospheric nuclear test program.

Page 6

The principal objectives were: (1) the determination of total gamma-radiation dose and doserate histories aboard three moored ships (destroyers) exposed to radiological environments at lccations of possible operational interest about the surface zeros of two underwater nuclear detomtions, Shots Wahoo and Umbrella: (2) estimation of remote-source gamma-radiation dose and dose-rate histories at exposed weather-deck locations aboard ship: (3) estimation of total gamma-radiation dose and dose-rate histories in the water adjacent to the ships; and (4). measurement of gamma-ionization decay of a fallout sample collected on one ship a few minutes after each shot. The ships, which were equipped with operating washdown systems, were instrumented with film badges and gamma- intensity-time recorders (GITR’s). The film badges and unshielded GITR’s supplied radiation data at locations representing major battle stations; GITR’s submerged in the water supplied some data on underwater radiation: and a fallout collector connected to a fully shielded GITR supplied gamma-ionization decay data. Radiation histories were obtained on only one ship for Shot Wahoo. Although histories were obtained on all three ships for Shot Umbrella, some data was lost because of shock damage. At least 95 percent of the total dose observed on the washed weather decks was attributed to radiation from airborne radioactivity. After Shot Umbrella, weather-deck dose accumulation (to 75 percent of final values) ranged between 600 r received w’ithm H -26 seconds at 1,900 feet from surface zero and 50 r received within H + 150 seconds at 7,900 feet from surface zero. After Shot Wahoo, the dose accumulation was slower, but the final deck doses were about 300 r higher, despite the fact that the ships were from 1,000 to 2,000 feet farther away from surface zero than was the case for Shot Umbrella. For nuclear-weapon-delivery situations simuLated by the two closer-in ships, temporary immobilization couid result in lethal or near-lethal doses. Aiter Shot Wahoo, the majority of compartments received doses in excess of 500 r aboard the closest ship and in excess of 200 r aboard the next-to-closest ship. After Sho~ Umbrella, the two ships received doses in excess of 200 r in many compartments. Ratios of dose or dose rate in compartments to dose or dose rate on washed weather decks were dependent upon changes in radiation- source geometries and upon the presence of contaminants within the ships. The long-term dose ratios ranged between 0.1 and 0.7 for nonmac hinery spaces, and between 0.02 and 0.2 for machinery spaces. Although radiation from the water may have influenced the compartment deck dose-rate ratios to a considerable degree at later times, the contribution of contaminated water to the total dose observed aboard the ships was probably of little significance. After Shot Umbrella, gamma- ionization decay was measured for the periods betvieer H -0.1 and 11.5 hours and between H*23. O and 34.9 hours. No decay measurements were obt. med for

Page 7

This report presents the final results of one of the projects participating in the military-effect programs of -Operation Hardtack. Overall information about this and the other military -effecl projects can be obtained from ITR– 1660, the ‘“summary Report of the Commander, Task Unit 3.” This technical summary includes: (1) tables listing each detonation with its yield, ty-pe, environment, meteorological conditions. etc. : (2) maps showing shot locations; (3) discussions of results by programs: (4) summaries of objectives. procedures, results, etc., for all projects: ‘ and (5) a listing of project reports for the military-effect programs. Project 2.1 gratefully acknowledges its indebtedness to the following organizations and per - sonnel for their contributions to the project: tails he developed for coUection of early-time decay samples. R. K. Fuller, Project 2.2, for implementing the collection and handling of the early decay sample in the field. Task Unit 6 of Task Group 7.1, for furnishing and processing the 1,700 film badges used for technical measurements. Personnel of Task Element 7.3.1.5, the Task Group 7.3 Decontamination Unit, who showed a high degree of initiative and cooperation in installing the film badges aboard ship, in sample recovery, and in sorting and handling the many fiim badges required. The officers and crews of the Task Group 7.3 Special Projects Unit, who manned the three target ships, for their frequent and cheerful assistance in maintaining support equipment, ac - complishing repair and alteration work, and furnishing work parties when requested. F. K. Kawahara, Project 2.2, for much needed help in reducing the gamma-radiation data required for the final report.

Page 8

3.3 Total Gamma Radtitionti Adjacent Water ------- ------------------- 4.1.1 Total Gamma Radiation Aboard Target Ships ------------ 4.1.3 Total Gamma Radiation in Adjacent Water -----------------------

Page 9

Deslgr, Limits for OperZ 3.1 Twenty- Four-Hour Gamma Doses at GITR Stations, - 31 3.2 Compartments Probably Influenced by Ingress of Radioactive Contam~nants 3.3 Average 24-Hour Gamma Doses Aboard Target Ships, - 32 3.4 Ratios of Gamma Dose in Compartments to Dose on Weather Decks, - 33 3.5 Athwartship Variation of 24-Hour Gamma Doses Aboard DD 474, 3.6 Athwartship Variation of 24-Hour Gamma Doses Aboard DD 592, - 34 3.7 Athwartship Variation of 24-Hour Gamma Doses Abmrd DD 593, - 34 3.9 Comparisons of GITR and Film-Badge Ratios of Dcse at GITR stations 3.10 Estimated Dose Contributed by Remote-Source Radiation Observed on Washed Weather Decks of the Target Ships ------------------ 4.1 Summary of Gamma Radiation Data for Washed Weather Decks ------------ 79 Aluminum Drum) to Beams of Various Radiations -------------- n -- Aluminum Drum) to Beams of Various Radiations ---------------- Aluminum Jacket) to Beams of Various Radiations ----------------- 90 Aluminum Jacket) to Beams of Various Radiations ----------------- 90 B.5 Directional Response of Low -IUmge Detector (Mounted Inside GITR Case) to Beams of Various mdiations --------------------- --- B.7 Gamma Dose Rates Contributed by Various Inter~a.ls of Assumed

Page 10

Gamma Dose Rates Contributed by Various Intervals of Assumed Gamma Doses in Gamma Dcses in Gamma Doses in Gamma Doses in Gamma Doses in Gamma Doses in Gamma Doses in Gamma Doses in Gamma Doses in Pilot House and Chart House ---------- 101 Forward Engine Room (Lower Level) ---- 103 C.19 Twenty-Four-Hour Gamma Doses in Steering Gear Room --------------- 107 Location and designation of GITR stations on target ships ---------------- 21 Area locations of film badgeson target ships ---------------------- -- 23 Example of estimating average dose rates on deck of DD 474 for Average gamma dose rates on weather decks of target ships, Shot Umbrella --- 37 Average gamma doses on weather decks of target ships, Shot Umbrella- ------ 38 Average gamma dose rates on weather decks of DD 593, Average gamma doses on weather decks of DD 593, Ratios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks 3.10 Ratios of dose in compartments to average dose on weather decks 3.11 Rat~os of dose in compartments to average dose ori weather cic~ks

Page 11

3.12 Ratios Of dose in compartments to average dose on weather decks Ratios of dose in compartments to a~erage dose on weather decks Ratios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks ~tios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks Ratios of dose in compartments to average dose on weather decks Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ra.tlos of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on weather decks of DD 593, Shot Umbrell a --------- -------------- Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Ratios of dose rate in compartments to average dose rate on Decay-corrected average dose rates on weather decks of

Page 12

3.38 Decay -c Qrrected arerage dose rates on weather decks of 3.39 Decay-corrected average dose rates on weather decksof 3.40 Decay-corrected average dose rates on weather decksof 3.41 Ratios of dose rate in adjacent water to average dose rate on 3..42 Gamma- ionization decay of contamimnt collected in 6-inch-thick A. 1 GXTR Model 103 instrument with the outer watertight case cover removed. The detector is shown mounted on mam instrument assembly- --------- 85 A.2 GITR Model 103 Instrument with watertight case- --------------------- 85 A.3 Block diagram of GITR Model 103 with remote detector ----------------- 86 A.4 Simplified schematic diagram of GITR Model 103 recycling electrometer ----- 86 A.5 Block diagram of GITR triggering system for target ships --------------- 86 B.1 GITR Model 103 low-range detector output pulse period as a function Of gamma intensity for Coso and CS12T- ------------------- 93 B.2 GITR Model 103 high-range detector output pulse period as a B.3 Energy-response characteristics of the GITR Model 103 B.4 Directional-response characteristics of the GITR Model 103 B.6 GITR station response to monoenergetic radiation when radiation is horizontally incident compared with GITR response to Cs13r radiation beam directed vertically at top of bare detector -------- ---- 95 B.7 GITR station response to monoenergetic radiation from hemispherical source above station compared with GITR response to Csi3: radiation beam directed vertically at top of bare detector- --------------- 96 B.8 GI’TR station response to monoenergetic radiation from spherical source around station compared with GITR response to CS13: B.9 GITR station response to monoenergetic radiation from source presenting solid angle of 1.7-; steradians below station compared with G1’TR response to CS13Tradiation beam directed vertically at top of bare detector- -------------------- -- 97 B.1O Degraded ener~ distributions of monoenergetic plane monodirectional gamma radiation after penetrating iron -------------------- ---- 97 B.11 Estimated degradation of gamma energy after penetrating 1 inch of steel ----- 98 C.2 Location and designation of film-badge stations in forward C.3 Location and designation of film-badge stations in crew’s mess (second platform) aboard target ships ------------------------- 109 C.4 Location and designation of film-badge stations in pilot house and chart house (02 level) aboard target ships --------- ------- ----- 110 C.5 Location and designation of film-badge stations in radio central

Page 13

C. 7 Location and designation of film-badge stations in forward C.8 Location and deswnation of film-badge stations in forward C.9 Location and designation of film-badge stations in forward C. 10 Location and designation of film-badge stations in galley C. 11 Location and designation of film-badge stations in aft fireroom C. 12 Location and designation of film-badge stations in aft fire room C. 13 Location and designation of film-badge stations in aft engine C.14 Location and designation of film-badge stations in aft engine C. 15 Location and designation of film-badge stations & main deck C.] 6 Location and designation of film-badge stations in crew”s C.17 Location and designation of film-badge stations in aft quarters C.18 Location and designation of film-badge stations on main deck C.] 9 Location and designation of film-badge stations in steering gear

Page 14

The principal objectives were: (1) the determination of total gamma-radiation dose and doserate histories aboard three moored ships (destroyers) exposed to radiological environments at locations of possible operational interest about the surface zeros of two underwater nuclear detonations, Shots Wahoo and Umbrella: (2) estimation of remote-source gamma-radiation dose and and dose-rate histories at exposed weather-deck locations aboard ship; (3) estimation of total gamma-radiation dose and dose-rate histories in the water adjacent to the ships; and (4) measurement of gamma-ionization decay of a fallout sample collected on one ship a few minutes titer An additional objective was the provision of preproduction evaluation, production liaison, instrument-maintenance consultation, and a field maintenance facility for all projects using In this …