核电厂安全级DCS缺省值设置策略研究

Research on Strategy of Setting Default Values for Safety-Level DCS in Nuclear Power Plants

针对数字化仪控系统中无效信号的质量位随意蔓延使系统处于一种不确定状态的问题,结合核电厂运行工况和信号特性,对龙鳞平台故障诊断机制和信号质量位标识进行研究。考虑故障安全准则,系统性地提出缺省值设置原则。从信号执行功能和信号边界两个维度进行分析,确认缺省值的设置范围,并详细给出执行保护功能、报警功能、维护和试验功能信号的缺省值设置策略。同时,针对传统的缺省值验证方式无法全面、有效地进行缺省值验证的问题,提出一种利用全范围模拟机和虚拟数字化控制系统(DCS)进行缺省值验证的新方法。利用该方法可有效地对DCS内设置的缺省值进行系统性的验证。所提出的缺省值设置策略和验证方法可为后续核电厂安全级DCS的缺省值分析和设置提供全面的指导。

Aiming at the problem that the arbitrary spreading of quality bits of invalid signals in digital instrumentation and control systems puts the system in an uncertain state,the fault diagnosis mechanism of the NASPIC platform and the identification of signal quality bits are investigated in the light of the operating conditions and signal characteristics of nuclear power plants.Considering the fail-safe criterion,the default value setting principle is systematically proposed.Analyzing from two dimensions of signal execution function and signal boundary,the range of default value setting is confirmed,and the default value setting strategy for signals executing protection function,alarm function,maintenance and test function is given in detail.At the same time,a new method of default value verification using full-range simulator and virtual digital control system(DCS)is proposed to address the problem that the traditional default value verification method is unable to carry out default value verification in a comprehensive and effective way.The method can be utilized to effectively and systematically verify the default value settings in DCS.The proposed default value setting strategy and validation method can provide comprehensive guidance for the analysis and setting of default values in the safety-level DCS of subsequent nuclear power plants.