Ex-core detector response evaluation of kori 1 reactor using mcnp6 adjoint calculation

Abstract

This paper describes the verification of ex-core detector response calculation using Monte-Carlo code. The calculations were performed on a typical commercial PWR core Kori unit 1 in South Korea. The weighting factors of ex-core detector were evaluated through solving the multi-group adjoint equation. The deterministic SN code DORT and Monte-Carlo code MCNP6 were used and compared based on the same BUGLE96 47g cross section library. The results proves the feasibility of using MCNP to calculate the weighting function of ex-core detector. And, it shows the benefit of using Monte-Carlo modeling and simulation in this problem. Two aspects are concluded. First, the adjoint calculation in the radial geometry suffers strong ray effect while using SN method. It is well overcome by the Monte- Carlo calculation. Secondly, the geometry approximation is an inevitable effect. The powerful modeling capability of Monte-Carlo code shows obvious improvement for the ex-core response calculation.