Establishing an Effective Dose Equivalent Monitoring Program for a Commercial Nuclear Power Station

Abstract

ESTABLISHING AN EFFECTIVE DOSE EQUIVALENT MONITORING PROGRAM

FOR A COMMERICAL NUCLEAR POWER STATION

Barbara Jane Thompson. M.B.A.

Thesis Advisor: Dr. Allen Brodsky, Sc.D., CHP, CIH, DABR

ABSTRACT

The purpose of this thesis is to determine whether monitoring personnel with multiple dosimeter badges to determine effective dose equivalent (EDE) is both acceptable to the Nuclear Regulatory Commission (NRC) and practical for the nuclear power industry. Until now, most nuclear power plants have used a single dosimeter or occasionally multiple dosimeters to monitor the "deep dose equivalent (DDE)" as defined by the International Commission on Radiological Units (ICRU). The measurement of EDE, to replace DDE, is now deemed by international and regulatory agencies to better approximate a worker's dose related to long-term risks of occupational radiation exposure. The definition of DDE, and the formulation of EDE for use as a new indicator of occupational exposure, are presented in this thesis.

Radiation exposure measurements using multiple dosimeters on each worker for certain tasks were collected for this thesis on workers at a Dominion/Virginia Company nuclear power plant. These multiple dosimeter measurements have been examined to determine how such a new personnel monitoring system compares to the former one at the Dominion plant, in which only one dosimeter reading was used predominately to calculated deep dose equivalent. This is based on the assumption that most workers were exposed to uniform radiation fields and that the single dosimeter reading was representative of the highest average exposure for the worker's task. These multiple dosimetry measurements show that it is both feasible and advantageous to provide such dosimetry in situations where exposures may be non-uniform and significant enough to approach yearly exposure limits in a single day, such as in the tasks required during refueling outages.