Assessment of the MARS code for design of water pool-type reactor cavity cooling system in HTGR

摘要

This paper reports an experimental and numerical study on the assessment of the MARS code as a tool for analyzing the water pool-type reactor cavity cooling system (RCCS), which was developed by Seoul National University (SNU). A series of experiments were performed to determine the heat removal capability of the proposed RCCS and assess the capability of MARS code to predict the forced convective, natural convective and radiative heat transfer under normal operation conditions and boiling heat transfer during accident conditions in the RCCS. In the loss of forced convection (LOFC) accident experiment performed at the integral effect test facility called RCCS-SNU, the MARS code underestimated the vapor generation rate at the inner wall of the water pool. Therefore, the newly developed models of the bubble departure and lift-off diameters were implemented into the MARS code to make a better prediction of the vapor generation rate. The improved MARS code was assessed again using the experimental data of the LOFC accident conditions in the RCCS-SNU facility.