410183 | BNL, K BROOKHAVEN NATIONAL LABORATORY ASSOCIATED UNIVERSITIES. INC.. UPTON. L.I. N.Y. 11973 SAFETY & ENVIRONMENTAL PROTECTION DIVISION 7 TeverHone: (516) 345- 4250 October 27, 1976 Mr. T. F. McCraw USERDA/SSC Washington, D. C, 20545 Dear Tommy: The following is a preliminary report of the external radiation survey results for Wotje, Ailuk, Utirik, and Rongelap Atolls. Other details of the environmental survey are included in my trip report to, PASO (copy attached). I selected (arbitrarily) Wotje Island and Ailuk Island as gamma background "controls", At both of these locations, the average of all pressurized ion chamber gamma readings was 3.8 + 0.4 uR/hr. This corresponds to an annual whole-body gamma (plus cosmic ray) exposure of 33 mR, The average exposure rates at Utirik Atoll are listed below. Island Utirik Eorukku Aon Average Exposure Rate (UR/hr) - Annual Exposure (mR) 4.1 36 4.2 37 4.1 36 At Rongelap surveys were made at Naen Island in the northwest corner of the atoll, Kabelle Island in the northeast corner. Eniaetok Island midway along the east side, and Rongelap Island in all locations but Rongelap the external gamma fields over the islands were too heterogeneous for me to estimate an "island average’' exposure rate with this preliminary review of the data. Rongelap Island, however, was sufficiently uniform at the village (east end) to estimate an average exposure rate of 7.2 uR/hr, or 63 mR/yr, which is about twice "normal" background in the uncontaminated Marshalls, and slightly less than our annualbackground exposure on Long Island. INFORMATION OPERATOR(516) 345-2123