Mr. Tom McCraw Page 2 30 January 1980 In addition levels were atolls, the gross count RSSD~80-026 to Bikini, Rongelap and Rongerik, average terrestrial exposure rate also determined for Ujelang and Utirik Atolls. For both of these levels observed were essentially constant over the entire atoll. The data gave an average exposure rate of 0.15 uR/h at Ujelang and 0.6 uR/h at Uterik. The primary source of activity at Uterik was due to '?7Cs. Levels were too low on Ujelang to positively identify any specific isotopes. In order to obtain the total external exposure rate, it is necessary to include cosmic ray contributions. A value of 3.3 uR/h has been assumed for this component. Where comparisions can be made, the resulting total external exposure rate values from the aerial survey agree quite well with those measured during 1976 and 1977 by Brookhaven National Laboratory using a* pressurized ion chamber (BNL 50797). The island numbering system and the Marshallese island names were based on rather old atoll] maps. The island names in some cases may reflect the influences of the Japanese. If you have any information on updated Marshallese spelling, please Jet me know. I hope to complete this type of analysis for the remaining atolls within the next few weeks. Please let me know if there is any atoll in particular where this data might prove useful to you for your mid-February meeting. Sincerely, EG&G, Inc. W. John Tipton Section Head IV WJT:es Enclosures cc: J. Deal DOE/HQ J. Doyle EG&G R. Ray DOE/NV W. Robison LL <@———amaaGiiy