A Simulation of the Containment Activity Monitor

Abstract

ABSTRACT The response of a containment activity monitor was predicted using a Monte Carlo approach. The estimation of count rates was based on the photon reaction rates at the sodium iodide crystal in the scintillation counter. Nine Monte Carlo simulations were done using monoenergetic sources at 4.95, 2.05, 1.55, 1.00, 0.72, 0.52, 0.40, 0.32, and 0.20 MeV. The simulations were performed using the model of an experimental setup of the Gentilly-2 Nuclear Generating Station vapour recovery exhaust pipe. The simulation results were post-processed into a data base for use in an interactive program we developed called CRATES. CRATES accepts all radionuclides that are in the RADDECAY(l1 library. It estimates the count rates in the exhaust pipe by interpolating among the nine monoenergetic source spectra. The accuracy of the estimation was tested against experimental measurements for radionuclides 13'1, 13"cs, and 60~o. The use of the computer program CRATES to predict count rates at the containment activity monitor for a hypothetical situation was discussed.