Shipboard Radiation from Underwater Bursts (Operation Hardtack-I) Project-2.1

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Thisdocument consists ot 128 ptgts SHIPBOARD RADIATION FROM UNDERWATER BURSTS (U) Sssuance Date: March 24, 1961 HEADCIUARTERS FIELD COMMAND DEFENSE ATOMIC SUPPORT AGENCY SANDIA BASE, AIBUOUEROUE. NEW MEXICO aterial COntalm Information affecting nae of the Un!ted Sates vi ,: espionage iaws manner to an unauthorized PC

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San Franc isco, California This material c(mtains information affecting the national defense of the United States within the meaning of the espionage laws Title 18, U. S. C., Sees. 793 and 794, the transmission or revelation of which in any manner to an unauthorized person is prohibited by law.

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The principal objectives were: (1) the determination of total gamma-radiation dose and dosera. e 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 dose-rate histories at exposed weather-deck locations aboard ship; (3) estimation of total gamma-radiation dose and dose -ra?e 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 ~ashdown sYstems, were instrumented with ftim badges and gamma- intensity -tinle recorders (G~R’.s). The film badges and unshielded merged 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 within 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. I 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 could result in lethal or near-lethal doses. Mter Shot Wahoo, the majority of compartments received doses in excess of 500 r aboard 1 the closest ship and in excess of 200 r aboard the next-to-closest ship. After Shot Umbrella, > i the two ships received doses in excess of 200 r in many compartments.7, Ratios of dose or dose rate in compartments to dose or dose rate on washed weather decks I 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 nonmachinery 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 contamimted water to the total dose observed aboard the ships was probably of little significance. After Shot Umbrella, gamma- ionization decay was measured for the per iods between H+ 0.1 and 11,5 hours and between H+23.O and 34.9 hours. No decay measurements were obtained for

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This report presents the final results of one of the projects participating in the military -ef:eci programs of Operation Hardtack. Overall information about this and the other milltary -ef!cc; projects can be obtained from ITR– 1660, the “Summary Report of the Commander, Task Uni~ 3.” This technical summary includes: (1) tables listing each detonation with its yield, typt, environment, meteorological conditions, etc. ; (2) maps showing shot locations; (3) discussion of results by programs; (4) summaries of objectives, procedures, results, etc., for all pro]ect.~: and (5) a listing of project reports for the military-effect programs. Project 2.1 gratefully acknowledges its indebtedness to the following organizations and personnel for their contributions to the project: tails he developed for collection 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 film 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, accomplishing 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.

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2.4.1 Data Obtained by Project 2.1- -------------------- ----------- 4.1.3 Total Gamtifidiation in Adjacent Water -------------- --------- 78

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APPENDIX C FILM-BADGE DATA, CALIBRATION, AND ESTIMATES OF ERROR- 99 3.1 Twenty-Four-Hour Gamma Doses at GITR Stations, 3.2 Compartments Probably Influenced by Ingress of FQdiMctive Contammants ---- 31 3.3 Average 24-Hour Gamma Doses Aboard Target Ships, 3.4 Ratios of Gamma Dose in Compartments to DOseon Wealher Decks, 3.5 Athwartship Variation of 24-Hour Gamma Doses Aboard DD 474, 3.6 Athwartship Variation of 24-Hour Gamma Doses Aboard DD 592, 3.7 Athwart ship Variation of 24-Hour Gamma Doses Aboard DD 593, 3.8 Comparisons of 24-Hour GITR and Film-Badge Doses at GITR Stations ------- 35 .- b.:+ 3.9 Comparisons of GITR and Film-Badge Ratios of Dcse at GITR Stations <~, to Average Dose on Weather Decks --------------------- ------ 35 A ~+ 3.10 Estimated Dose Contributed by Remote-Source Radiation Observed Jx&#&: on Washed Weather Decks of the Target Ships -------------------- 36 4.1 Summary of Gamma Radiation Data for Washed Weather Decks ------------ 79 Aluminum Drum) to Beams of Various Radiations ----------------- 89 Aluminum Drum) to Beams of Various Radiations ----------------- 89 Aluminum Jacket) to Beams of Various Radiations ----------------- 90 Aluminum Jacket) to Beams of Various Radiations ----------------- 90 B.7 Gamma Dose Rates Contributed by Various Intervals of Assumed

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Gamma Dose Rates Contributed by Various Intervals of Assumed Twenty-Four-Hour Gamma Doses in Pilot House and Chart House ---------- 101 Twenty-Four-Hour Gamma Doses in Radio Central -------------------- 102 C.20 Standard Errors of Gamma Doses in Aft Fireroom (Upper Level) ---------- 104 Gamma Doses in Aft Engine Room (Upper Level)- ------- 105 Gamma Doses in Aft Engine Room (Lower Level) ------- 103 Gamma Doses in Crew’s Washroom ---------------- 106 Gamma Doses on Main Deck (Fantail) --------------- 106 Gamma Doses in Steering Gear Room --------------- 107 Target ship array, Shot Wahoo -------------- -------------------- Location and designation of GITR stations on target ships ---------------- Area locations of ftim badgeson target ships ---------------------- -- Example of estimating average dose rates on deck of DD 474 for Average gamma dose rates on weather decks of target ships, Shot Umbrella --- Average gamma doses on weather decks of target ships, Shot Umbrella- ------ 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 Ratios of dose in compartments to average dose on weather decks

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3.12 Ratios of dose m compartments to average dose on w(ather ic cks 3.13 Ratios of dose in compartments to average dose on vreather decks 3.14 Ratios of dose in compartments to average dose on weather decks 3.15 Ratios of dose in compartments to a~erage dose on weather decks 3.16 Ratios of dose in compartments to average dose on weather decks 3.17 Ratios of dose in compartments to average dose on weather decks 3.18 Ratios of dose in compartments to average dose on weather decks 3.19 Ratios of dose rate in compartments to average dose rate on 3.20 Ratios of dose rate in compartments to average dose rate on weather decks of DD 474, Shot Umbrella ----------------------- 3.21 Ratios of dose rate in compartments to average dose rate on 56 3.22 Ratios of dose rate in compartments to average dose rate on 57 3.23 Ratios of dose rate in compartments to average dose rate on 3.24 Ratios of dose rate in compartments to average dose rate on 3.25 Ratios of dose rate in compartments to average dose rate on 3.26 Ratios of dose rate in compartments to average dose rate on 3.27 Ratios of dose rate in compartments to average dose rate on 3.28 Ratios of dose rate in compartments to average dose rate on 3.29 Ratios of dose rate fn compartments to average dose rate on 3.30 Ratios of dose rate in compartments to average dose rate on 3.31 Ratios of dose rate in compartments to average dose rate on 3.32 Ratios of dose rate in compartments to average dose rate on 3.33 Ratios of dose rate in compartments to average dose rate on 3.34 Ratios of dose rate in compartments to average dose rate on weather decks of DD 593, Shot Wahoo ------------------------- 3.35 Ratios of dose rate in compartments to average dose rate on 3.36 Ratios of dose rate in compartments to average dose rate on 3.37 Decay-corrected average dose rates on weather decks of

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3.38 Decay-corrected average dose rates on weather decks of 3.39 Decay-corrected average dose rates on weather decks of 3.40 Decay -corrected average dose rates on weather decks of 3.41 Ratios of dose rate in adjacent water to average dose rate on weather decks of DD 593, Shot Umbrella -------------------- --- 76 3.42 Gamma-ionization decay of contaminant collected in 6-inch-thick lead cave on DD 592, Shot Umbrella ----------- --------------- 77 A.1 GITR Model 103 instrument with the outer watertight case coyer removed. The detector is shown mounted on main instrument assembly- --------- 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 t=%et ships --------------- 86 B.1 GITR Model 103 low-range detector output pulse period as a function of gamma intensity for Co6:’ and CS13: -------------------- 93 B.2 GITR Model 103 high-range detector output pulse period as a function of gamma intensity for CoGu and CSi3:- ------------------- 93 B.3 Ener~-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 CS137 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 Csi3T radiation beam directed vertically at top of bare detector- --------------- 96 B.8 GITR station response to monoenergetic radiation from spherical source around station compared with GITR response to CS13? radiation beam directed vertically at top of bare detector ------ ------ 96 B,9 GITR station response to monoenergetic radiation from source presenting solid angle of 1.7-% steradians below station compared with GITR response to CS*37 radtition beam directed vertically at top of bare detector- -------------------- -- 97 B.1O Degraded energy distributions of monoenergetic plane monodirectional gamma radhtion titer 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% mess C.4 Location and designation of film-badge stations in pilot house and chart house (021evel) aboard target ships -------------------- 110 C.5 Location and designation of film-badge stations in radio central fireroom (upper level) aboard target ships ---------------------- IIZ

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C.7 Location and designation of film-badge stations in forward c.8 Location and designation of film-badge stations in forward C.9 Location and desigmition 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 fireroom 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 on main deck 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.19 Location and designation of film-badge stations in steering gear

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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 operatioml 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 abcard 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 ccllected on one ship a few minutes after An additional objective was the provision of preproduction evaluation, production liaison, instrument-maintenance consultation, and a field maintenance facility for all projects using GITR’s developed by the U.S. Naval Radiological Defense Laboratory (NRDL). In this report, total gamma-radiation dose indicates the combined contributions of all radiation sources that affect the detectors. Doses and dose rates are specified to apply to air ab1.3 BACKGROUND AND THEORY It is of interest to the Navy to find out whether the minimum safe standoff distance for antisubmarine nuclear-weapon-delivery ships is determined by radiological effects or by physical damage. (Standoff distance is defined as the distance of surface zero from the ship at the time of detonation. ) Each ~ctlcal maneuver by the ship, during and after delivery Of the WeapOn, will have assoc i.ated with it physical shock and radiation effects. For a given weapon detonated under a specific set of environmental conditions, the shock effects will be chiefly dependent upon the ship’s position and orientation with respect to surface zero at the time of shock arrival, whereas the radiation effects wm be dependent upon integration (with respect to time) of the shipboard dose rates received at each position along the entire track of the ship. Because it was not feasible to have the test ships actually perform representative tactical maneuvers in the radiologic~ environments, doses for such maneuvers were not measured dwectly. The alternative was to obtain data for spec ffic locations, which would be useful for the c~c~ation of dose rates ab~rd ships performing maneuvers in hypothetical weapon deParameters of interest in determinations of shipboard dose rates include: (1) the magnitudes of radiation sources on tie surfaces of the ship, in the surrounding and remote air, and fn the Stll’rounding ~d remote water; (2) the ingress of contamfints ~to tie ~terior of the ship; …