UNCLASSIFIED SEC ATTY CLASSIFIGAT ON OF = 15 PAGE REPORT DOCUMENTATION PAGE Ta AEPORT SECLAITY CLASSIFICATION UNCLASSIFIED 2a SECURITY CLASSIFICATION AUTHORITY Tp RESTRICTIVE MARKINGS 7 OISTRIBUTION/ AVAILABILITY OF REPORT he Approved for public release; distribution is unlimited. 2b. DECLASSIFICATION / DOWNGRADING SCHEDULE @ PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) WT-1621 (EX) 6a. NAME OF PERFORMING ORGANIZATION $0. OFFICE SYMBOL Naval Radfological Defense (If applicable) Laboratory| 7a. NAME OF MONITORING ORGANIZATION Defense Atomic Support Agency 6c. ADORESS(City, Stare, and ZIP Code) 7. ADORESS(City, State, and ZIP Code) San Francisco, California Washington, DC Ba. NAME OF FUNDING s SPONSORING 86 OFFICE SYMa8OL ORGANIZATION (if applicable) de. ADORESS(City, State, and ZIP Code) 9 PROCUREMENT INSTRUMENT [OENTIFICATION NUMBER 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK ELEMENT NO. 11 NO WORK UNIT NO ACCESSION NO TITLE (inetude Security Classification) OPERATION HARDTACK, PROJECT 2.3 - Characteristics of the Radioactive Cloud from Underwater Bursts, Extracted Version . £. eeoBans Tiland T. H. Shirasawa lia. TYPE OF REPORT 13b. TIME COVERED FROM TO eae 1& DATE OF REPORT (Year, Month, Day) S$ °4Gz COUNT 201 ts £34 '6 SUPPLEMENTARY NOTATION [his report has had sensitive military information removed in order to provide an unclassified version for unlimited distribution. 17 Defense Nuclear FIELO 18 18 ncy_in COSATI COOES GROUP 3 SUB-GROUP 8 The work was performed by the 18. SUBJECT TERMS (Continue on reverse if necessary HARDTACK i and identify by block number) Umbrella Shot Fallout Radioactive Cloyds Wahoo Shot 19 ABSTRACT (Continue on reverse if necessary and identify by block number) The purpose of this project was to (1) measure the complex gamma field at a number of positions within 10,000 yards of each of the two underwater nuclear detonations (Wahoo and Umbrella}; (2) collect lfmtted samples of airborne debris resulting from these detonations; and (3) expose a number of test panels to this same debris. The total gamma field was measured by means of about 20 gamma-intensity-time recorders installed on floating platforms located within a radtus of 10,000 yards from surface zero. Samples of radioactive materials deposited from the cloud were obtained by incremental collectors associated with the basic gamma-intensity-time recorders. During both shots, nearly all of the total gamma dose occurred within 20 minutes after zero time and was due to the passage of airborne radioactive material. 20 OSTRIBUTION/ AVAILABILITY OF ABSTRACT UNCLASSIFIED/UNLIMITED (] same as RPT 22a NAME OF RESPONSIBLE INDIVIOUAL Mark D. Flohr DO FORM 1473, a4 mar CJoric users 21 ABSTRACT SECURITY CLASSIFICATION UNCLASSIFIED 22b TELEPHONE(Include Area Code) 22¢. OFFICE SYM8OL (202) 325-7559 DNA/ISCM 83 APR edition may be used until exhausted. All other editions are obsolete. SECURITY CLASSIFICATION OF THIS PAGE UNCLASSIFIED