An intercomparison of whole-body counters at participating region III nuclear power plants

Seventeen Region III nuclear stations originated and participated in an intercomparison study of their whole body counting procedures using the same calibration standard. The first phase of the study involved transporting a phantom containing four reactor-produced radionuclides and 40 K to each plant. The plant staff were asked to follow all procedures applicable for a human subject including routine and investigative counts, if necessary, and to provide a printout of the results to the project investigators. The results from each plant were normalized for intercomparison by calculating the ratio of the reported activity to the actual activity after correcting for the appropriate amount of decay to the time of the count. Five plants reported 60 Co values outside 1 standard deviation (SD) of the mean for 60 Co and one plant did not detect the presence of 60 Co. According to previously established procedures, these six plants were revisited after a period of time in which internal recalibration and corrective actions could be made. Four of the six plants had results which were still outside 1 SD of the mean for the original study. A final report in coded form to protect plant anonymity was provided to those stations to guide them in making further improvements, if they chose to do so.