New exposure room shielding incorporated with ferro boron concrete for neutron radiography imaging (NURI) facility at TRIGA PUSPATI Research Reactor

Abstract

Simulation of the new exposure room shielding for Neutron Radiography Imaging (NURI) at 1 MW PUSPATI TRIGA MARK II (RTP) nuclear research reactor in Malaysian Nuclear Agency, Malaysia has been presented in this article. Previous exposure room shielding has to be disassembled due to various reasons such as radiation streaming problem and outdated since the exposure room was constructed in 1985. The NURI facility had been undergoing major upgrading for all their instrument including beam collimator, imaging system, sample positioning, instrumentation shielding, and exposure room shielding. This paper aims to simulate the radiation dose rate mapping for the new exposure room shielding for the NURI facility using the Monte Carlo simulation code of MCNPX. The exposure room shielding design consists of several modular blocks built from ordinary concrete and Ferro boron concrete. Ferro boron concrete is used to enhance the shielding performance of the facility. Results showed that exposure room shielding containing Ferro boron concrete manage to reduce the radiation by 1150 % at the critical area compared to ordinary concrete. The average radiation dose rate around the facility during operation at 1 MW reactor power ranging from 1 μSv/hr - 10 μSv/hr.