Use of SSTRs and a Multi-Component Shield Assembly to Measure Radiation Penetrating the Reactor Biological Shield in the Presence of Radiation Streaming from Other Sources

摘要

This paper describes the results of neutron transport calculations and measurements that were performed for the concrete biological shield that surrounds a Westinghouse two-loop reactor. As a concrete shield ages a number of changes occur. Foremost among these, from a radiation shielding perspective, is the loss of water. The measurement of the neutron dose rate is a sensitive indicator of change in the biological shield concrete. For example, a 50% reduction in the water content of the shield as the result of age-related water loss results in a factor of 22 increase in the neutron dose rate but only a factor of three increase in the gamma ray dose rate. The measurements described herein employ solid state track recorders (SSTRs) and a multi-component shield assembly to separate the transmitted and background radiation field components.