Contamination surveys of plant room and roof-void in B. 154 at the National Physical Laboratory, Teddington

Surveys of the roof-void, the plant room, the precipitron room and certain ventilation extracts, of Building 154 were carried out at the National Physical Laboratory, Teddington, on 31 January 1984 to identify any areas of either radioactive or beryllium contamination. The results show that there was no significant radioactive contamination; where activity was detected it was confined to a few isolated spots, none of which exceeded the derived limit (DL). In two areas of the roof-void the gamma radiation level was greater than background, although in neither case was it radiologically significant. The first of the increased readings was found above Room 38, which contained the experimental radioactive sources identified in the earlier survey of the laboratories, and the other was traced to the radiation emitted from the luminised dial of a clock hanging above the doorway to Room 36. The results of the beryllium survey showed that in no area was the control limit exceeded. (U.K.)