Radiological surveys conducted at the J. R. Simplot's Wet Process Plant in Pocatello, Idaho indicate slightly elevated ambient levels of natural radioactivity. Compared to an estimated natural background annual dose equivalent rate of about 79 mrem, net gamma dose rates ranged from 42 mrem in general plant areas to 152 mrem per work year (2000 hours) on the ore piles. Ambient radon-222 concentrations, ranging from 0.14 to 1.9 pCi/l, were measured in several work areas, with polonium-210 and radium-226 being the most predominant radionuclides of the natural uranium decay series. Particle size characterization indicates roughly 52 percent of the arithmetic total radioactivity is associated with the particle size fraction less than one micrometer equivalent aerodynamic diameter. Stack sampling results also show that appreciable concentrations of the naturally-occurring radionuclides are being discharged into the local environs. In general, the dose estimates and the interpretation of results have been oriented toward evaluating the maximum potential impact of the plant on the environment; however, no attempt has been made to determine the annual average dose to workers within the plant from all exposure pathways.

"April 1978." "ORP-LV-78-1." Cover title.

Radiological surveys conducted at the J.R. Simplot's Wet Process Plant in Pocatello, Idaho indicate slightly elevated ambient levels of natural radioactivity. Compared to an estimated natural background annual dose equivalent rate of about 79 mrem, net gamma dose rates ranged from 42 mrem in general plant areas to 152 mrem per work year (2000 hours) on the ore piles. Ambient radon-222 concentrations, ranging from 0.14 to 1.9 pCi/l, were measured in several work areas, with polonium-210 and radium-226 being the most predominant radionuclides of the natural uranium decay series. Particle size characterization indicates roughly 52 percent of the arithmetic total radioactivity is associated with the particle size fraction less than one micrometer equivalent aerodynamic diameter. Stack sampling results also show that appreciable concentrations of the naturally-occurring radionuclides are being discharged into the local environs. In general, the dose estimates and the interpretation of results have been oriented toward evaluating the maximum potential impact of the plant on the environment; however, no attempt has been made to determine the annual average dose to workers within the plant from all exposure pathways.