Radiological survey of Ceer Rio Piedras Facility, San Juan, Puerto Rico, June 15-25, 1982. Surplus Facilities Management Program

Elevated radiation readings from residual radioactive material were measured at four locations during the course of the survey. Three of them (small-area spots) were assumed to be contaminated primarily with /sup 14/C. They exhibited maximum beta readings ranging from 14 to 96 k dis/m-100 cm/sup 2/ as measured with a gas-flow proportional survey meter. Alpha readings taken with the same instrument were indistinguishable from the determined instrument background levels. Low-energy x- and ..gamma..-ray survey instrument readings ranged from 1 to 10 k cts/min. The radiation exposure rate measured at contact ranged from 0.04 to 2.5 mR/h. Before the end of the survey, these three spots were cleaned to the point that no contamination was detectable. The fourth location exhibiting an elevated radiation reading was on the second floor of the Bio-Medical Building above a first-floor cave (a shielded enclosure in which radioactive materials can be handled with remote-controlled manipulators). The cave contained a quantity of /sup 99/Mo used as a generator of /sup 99m/Tc. Work with medical applications of radioisotopes continues on the first floor of the building. The strength of the /sup 99/Mo source changes due to decay and periodic replacement for further generation of /sup 99m/Tc. At themore » time of the survey, the radiation reading, measured with x- and ..gamma..-ray survey instruments on the second floor above the source, was 15 k cts/min for low-energy x- and ..gamma..-rays. The radiation exposure rate measured with the GM end window was 0.05 mR/h. The ambient radiation level at 1 m was 60 ..mu..R/h. Since this was the only radiation source noted in the area to be released for uncontrolled use, a hazard evaluation was made. For a person working on the second floor directly above this source for 40 h per week, the yearly dose would be about 110 mrem. This is 22% of the 500-mrem yearly whole-body dose commitment for an individual in an uncontrolled area.« less