Development and application of an extensible engineering simulator for NPP DCS closed-loop test

LinAo Nuclear Power Plant (NPP) Phase II is a newly-built CPR1000 reactor in China and many new technologies including the incorporation of digital control system (DCS) substituting traditional analog control systems have been applied This is the first time for Chinese engineers to setup and adjust the DCS configurations Both the lack of the operating experiences and the plant safety requirements from the government make a necessity of the closed-loop DCS test before commercial plant operation The most practical way is to build a digital plant as the controlled target and this digital plant is used to provide the plant thermal-hydraulic parameters and feedbacks for the DCS Though the RELAP5 code has been developed for the best-estimate transient simulation of light water reactor coolant systems and is used worldwide its functionality is too limited to implement a digital plant such as the simulation of the complicated plant control and protection systems the 3-dimensional neutron kinetics and the fluid network for the plant auxiliary systems To overcome these drawbacks a RELAP5 based extensible simulator has been built to satisfy the new requirements for the implementation of a digital plant Any simulation code of desired functionality can be integrated into this simulator as a simulation module once it applies a set of well-defined data exchange interfaces At the present stage a RELAP5 module a control system modeling module a software-hardware data bridge module and some other auxiliary modules have been integrated into the simulator There are more than 60 systems that need to be tested with the DCS in LinAo Phase II and the whole testing work is separated into several phases In this paper we take the testing of the pressure control system and water level control system of pressurizer as example A typical transient of 10% load step change from 100%FP (full power) to 90%FP was performed for the closed-loop DCS test The necessity and capability of this RELAP5 based engineering simulator has been demonstrated Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved