Estimation of argon activation in HFRR pool water and primary coolant system

Abstract

Ar-41 being hard gamma emitter is one of the key radio-nuclide for operational and radiological safety during the normal operation of pool type research reactor. This paper discusses the estimation of Ar-41 activity in pool water and primary coolant system of 30 MW HFRR open pool type reactor. This study is carried out to estimate the dose rate due to Ar-41 in the areas occupied partially or fully by operation and maintenance personnel. For the argon activation calculation, uniform temperature throughout the pool water (excluding hot water layer) is assumed at constant reactor power operation. Three different sources viz. reactor core, pool water and thimbles in reflector vessel are considered for Ar-41 production in HFRR. The saturation activity of Ar-41 in pool water and primary coolant system is calculated for three different temperatures and the results show that Ar-41 activity decreases with increasing temperature.