Operation Dominic Shot Swordfish Project Officers Report - Project 2.1 Radiological Effects from an Underwater Nuclear Explosion (U)

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BEST AVAILABLE COPY Project Officers Report — Project 2.1 RADIOLOGICAL EFFECTS FROM AN UNDERWATER NUCLEAR EXPLOSION (U) U.S. Naval Radiological Defense Laboratory San Francisco, California This is an extract of POR-2004, Operation DOMINIC, which remains classified SECRET/ RESTRICTED DATA as of this date. Extract version prepared for: DEFENSE NUCLEAR AGENCY Approved for public release; BEST AVAILABLE COPY

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UNCLASSIFIED BEST AVAILABLE COPY SECURITY CLASSIFICATION of This Face D»f» Enr«>«0 REPORT DOCUMENTATION PAGE READ INSTRUCTIONS BEFORE COMPLETING FORM 1. REPORT NUHRER 2. GOVT ACCESSION NO. Operation DOMINIC - Shot SWORD FISH - Project Officers Report - Project 2.1 - Radiological Effect From an Underwater Nuclear Explosion (U) 5. TrPE OF REPORT * PERIOD COVCRCD 4. PERFORMING ORG. REPORT NUMBER >. PERFORMING ORGANIZATION NAME ANO ADDRESS U.S. Naval Radiological Defense Laboratory San Francisco, California 10. PROGRAM ELEMENT. PROJECT. TASK AREA 4 WORK UNIT NUMBERS tl. CONTROLLING OFFICE NAME AND ADDRESS Chief, Defense Atomic Support Agency 11. NUMBER OF PAGES Approved for public release; unlimited distribution. 17- DISTRIBUTION STATEMENT (of tho obttrmet ttffd in Block 70. it dittmrwcit /rom Rwporl) IB. supplementary notes This report has had the classified information removed and has been republished in unclassified form for public release. This work was performed by Kaman Tempo under contract DNA001-79-C-0455 with the close cooperation of the Classification Management Division of the Defense Nuclear Agency. If. KEY WORDS (Cantinum on tovorto ttdo it nococmmry mid identity by bfocb nimibort Shot SWORD FISH Underwater Nuclear Explosion The surface gamma radiation fields resulting from the burst of an antisubmarine rocket (ASROC) with a nuclear warhead were measured at a limited number of stations. In addition, measurements were made and samples collected in order to study base surge physical and radiochemical characteristics. Early-time surface water samples of the residual radioactivity in the ocean about surface zero were collected for the radiochemical determination of the yield of the weapon. SECURITY classification of This PACE fWiwi Da»*

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BEST AVAILABLE COPY This report has had classified material removed in order to make the information available on an unclassified, open publication basis, to any interested parties. This 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 all currently classified as Restricted Data or Formerly Restricted Data under the provision of the Atomic Energy Act of 1954, (as amended) or is National Security Information. This report has been reproduced directly from available copies of the original material. The locations from which material has been deleted is generally obvious by the spacings and "holes" in the text. Thus the context of the material deleted is identified to assist the reader in the determination of whether the deleted information is germane to his study. It is the belief of the individuals who have participated in preparing this report by deleting the classified material and of the Defense Nuclear Agency that the report accurately portrays the contents of the original and 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. BEST AVAILABLE COPY

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BEST AVAILABLE COPY The surface gamma radiation fields resulting from the burst of an antisubmarine rocket (ASROC) with a nuclear warhead were measured at a limited number of stations* In additionf measure ments were made and samples collected in order to study base surge physical and radiochemical characteristics. Early-time surface water samples of the residual radioactivity in the ocean about surface zero were collected for the radiochemical determ ination of the yield of the weapon* The array consisted of eight stations extending from 7,500 feet upwind to 14,700 feet downwind from surface zero. The sur face wind was at an angle of approximately 40 degrees to the axis of the array* The base surge and the contaminated water patch were the predominant sources of gamma radiation generated by the deton ation of the weapon* Within 5 minutes in a 10-knot surface wind, the base surge expanded radially from surface zero to 6,500 feet upwind, 7,500 feet crosswind, and 14,000 feet downwind* By the end of that time, maximum upwind and crosswind extent had been reached, and the entire mass of the surge was carried downwind* Within the first 10 minutes, dose-rate levels of from 300 to 4,000 r/hr were re corded within the base surge with 100 r/hr being recorded at the edge of the surge as late as H / 20 minutes. The dose-rate gradient from the surge in the upwind direction was very steep, with 90 percent of the total dose to all upwind stations outside of the surge being delivered in the first 10 minutes after the detona tion. The deposit dose from the surge was not significant. The dose contribution by the surge to all stations was either from shine or from the passage of the surge over the station or both. The radioactive water patch formed by the detonation ex panded radially from surface zero to fom a roughly circular con taminated area on the surface of the water about 14,000 feet in diameter at the end of the first hour* At that time, gamma doserates of from 2,500 to 6,000 r/hr were recorded within the limits of the patch* Peak dose rates as high as 17,000 r/hr were re corded within the patch at H / 17 minutes and 100 r/hr as late as The yield of the weapon was independently determined from radiochemical analysis of samples taken from the contaminated water patch and quantitative knowledge of the device’s original BEST AVAILABLE COPY

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BEST AVAILABLE COPY oontlintentsThe results indicated a yield of Postshot radiological monitoring of all stations showed that those stations within the water patch were contaminated with an alpha emitter identified as Pu^9# The contamination was con centrated at the waterline of the station, indicating that at least the surface of the water patch contained a significant amount of this material. Postshot monitoring showed no sig nificant alpha or gamma contamination of the salt water systems operating on the vessel which collected the water samples from the contaminated water patch. The normal steaming operations of the vessel served as an effective decontamination procedure. The USS Bausell (DD-8A5) located 6,400 feet upwind of sur face zero, received its total gamma dose in the first 10 minutes of the event. Gamma dose-rates and total dose at below-deck locations was reduced by as much as a factor of 100 by the natural shielding afforded those locations by the structure of the ship. The three weatherdeck locations for which there were records show no such reduction. A table of the total gama dose versus station location is given below with notes indicating the sources from which the dose Total Gamma Dose (a; Shine from plume and surge only. (b) Surge and water patch. (*) This station capsized at about H / 50 seconds. BEST AVAILABLE COPY

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BEST AVAILABLE COPY Shot Sword Fish was an underwater weapon-effects test conducted In the Pacific Ocean off the southwest coast of the United States on 11 May 1962 as part of Operation Dominic. Sword Fish was also the first fully operational test of the Navy's antisubmarine rocket (ASROC) weapon system In which a nuclear war reserve weapon was expended* Radiological weapon-effects Information of Importance to the advancement of surface ship capability to conduct nuclear antisubmarine warfare was ob This report supersedes the Project Officer's Interim Report (P0IR-20Q4) "Radiological Effects from an ASROC Delivered Weapon", July 1962* It also supersedes the Information ab stracted from the above report which appears In the Scien tific Director Summary Report, for Shot Sword Fish of Opera tion Dominic, dated July 1962* The writing of a report of this nature limits the author ship to a very few people* Yet the material out of which the report is written is generated by a large number of people who served anonymously* Enforced brevity precludes full recogni tion of all of these contributors. The authors are nonethe less aware of this support and express their gratitude. A list of the principal contributors follows. Special thanks are extended by the authors to the officers and crew of the OSS Sioux (ATF-75), for their part In the samp ling and the radiological survey of the water patch* Thanks Is also extended to Dr. Nathan Ballou of NRDL and particularly to Leland R. Bunney and his group, who performed the radiochemical yield determination* For radiological safety consultation and advice, Albert For military liaison, CDR Thomas L. Birch, USN. For superior performance as staff assistant to the Pro ject Officer, Louis B. Gomez, YNC, USN* For Instrument maintenance. Installation and recovery, BEST AVAILABLE COPY

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BEST AVAILABLE COPY 1.1.1 Surface Gemma Radiation Measurements........................14 1.1.2 Radiochemical Yield Determination •••••• 15 1.1.3 Target Vessel Gamna Fields. •.••••••• 15 1.1.4 Base Surge Measurements and Sampling. .... 16 2.2.3 Automatic Droplet Counter 24 2.2.4 Gas Fraction Sampler.......................................................... 24 2.2.6 Instrument Control and Timing Fiducials ... 25 2.3.1 Staging Area Operations........................................... 27 CHAPTER 3 RESULTS AND DISCUSSION..................................................... 40 3.1 General Description of Data. ........... 40 3.2 Early Time Gamma Fields. 40 3.2.1 Gamma Fields, 0 to 5 Minutes 40 3.2.2 Gamma Fields, 5 to 30 Minutes ............................. 43 3.2.3 Gamma Fields, 30 Minutes to 2V2 Hours .... 46 CHAPTER 4 CONCLUSIONS AND RECOMMENDATIONS.................................... 69 BEST AVAILABLE COPY

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BEST AVAILABLE COPY 1.1 Previous Shot Data. .............................................••••20 2.1 Shot Data and Surface Weather at Shot Time. • • • • 30 3.1 Total Gamma Dose at All GITR Stations .......52 3.2 Radiochemical Analyses of Rainout and Water Patch 2.3 Coracle—simplified elevation, cross section, and 2.5 Shipboard GITR mounting............................................................ 35 2.6 Shipboard GITR locations................................... .... 2.7 Droplet size counter head....................................................>37 2.8 Gas fraction sampler. ....••.•......•38 3.2 Dfeta arrival time at station locations. ...... 55 3.5 Approximate base surge and water patch configura 3.6 Approximate base surge and water patch configura 3.7 Approximate base surge and water patch configura 3*8 Approximate base surge envelope and water patch at 3*9 Dose rates versus time for first USS Sioux entry 3*11 Dose rates versus time for second USS Sioux entry 3.12 Dose rates versus time for third USS Sioux entry 3.13 USS Sioux track in the radioactive patch......................... 66 3.14 Deep well counter decay curves. ......•.••67 3.15 Ion chamber decay curves. •........•■••68 A.l Gamma dose rate versus time (0-30 min) for A.2 Gamma dose rate versus time (0-30 min) for A.3 Gamma dose rate versus time (0-30 min) for BEST AVAILABLE COPY

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BEST AVAILABLE COPY A.4 Gama dose rate versus time (0-30 nin) for A.5 Gamma dose rate versus time (0-30 min) for A,6 Gamma dose rate versus time (0-30 min) for A.7 Gamma dose rate versus time (0-30 min) for A,8 Gamma dose rate versus time (0-30 min) for A.9 Gamma dose rate versus time (0-30 min) for Ship A,10 Gamma dose rate versus time (0-30 min) for Ship A,11 Gamma dose rate versus time (0-30 min) for Ship A.12 Gamma dose rate versus time (0-30 nin) for Ship A. 13 Gama dose rate versus time (0-30 min) for Ship A*14 Gamma dose rate versus time (0-30 min) for Ship A.15 Gamma dose rate versus tine (0-30 min) for Ship board location 10 (Forward engine room) •••.••79 A.16 Gamma dose rate versus time (0-30 min) for Ship board location 11 (5n gun turret. Mount 52) .... 80 BEST AVAILABLE COPY

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BEST AVAILABLE COPY The radiological environment created by the detonation of an antisubmarine rocket (ASROC) depth charge Is the principle factor governing the formation of attack strategy and sub sequent maneuvering tactics involved in the delivery of that The establishment of delivery stend-off distance based on shock as well as radiological considerations, is important but is involved only at the start of an attack problem* The radiological aspects are continuing however. They must be considered throughout the entire evolution of the attack situation and are compounded by successive attacks in the same area. Immediately following an attack, the delivery vessel must re-establish contact with the target for pur poses of kill confirmation or further pressing of the attack, either on the same or additional targets. It Is therefore necessary that the general nature of the radiological en vironment created be knovm in advance in order that proper strategy can be preformulated for varying attack situation* Since the base surge is known to be a predominant source of radiological effects', theoretical studies and operational analyses of underwater detonations have been based primarily on data from the base surge and cloud originating from highexplosive model work and the results of Operations Crossroads, Wigwam, and Hardtack (References 1 through 3). These analyses have suffered from uncertainties in the relation ship between the above-surface effects and the related dis tribution of radioactivity; from geometric simplification of the base surge and cloud required for mathematical treat ment; and from the assumption of no fission prodnct frac tionation in the base surge* It is evident that more empir ical data on these effects Is required to further evaluate the radiological environment and its military implications for the general case of the underwater nuclear detonation* Of even more importance is the acquiring of specific data applicable directly to the ASROC depth charge in view of Its present operational status in the fleet. Accordingly, this Project was designed to collect input data for a more pre cise description of the environment resulting from the det onation of that weapon, scheduled as Shot Sword Fish of . BEST AVAILABLE COPY

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BEST AVAILABLE COPY The general purpose of the Project was two-fold* to ob tain data which could be translated directly into a descrip tion of the radiological environment created by the detonation of the ASROC weapon for immediate application to the operational use of that weapon) and to secure data for a better theoretical understanding of the radiological aspects of all underwater nuc lear bursts. Several factors, notably the lack of sufficient preparation time and the nature of the Task Group Operation Plan, made a large-scale project impractical. The effort was therefore restricted to the following specific objectives. 1.1.1 Surface Gamma Radiation Measurements. These were the measurements of prime importance to the Project, and a major portion of the effort expended was in behalf of these data. The recording of the gamma fields were planned at eight floating stations, some upwind and some downwind from surface zero, on a line parallel with the direction of the wind. The station locations were established to allow the best possible separation of the gemma dose from the plume, base surge, and contaminated water patch. This placed some upwind stations beyond direct contamination by the base surge and yet close enough to record the gamma field created by it. It also placed both upwind and downwind stations within the limits of both the surge …