TECHNICAL ARCHITECTURE ABOUT SAFETY I&C SYSTEM SOFTWARE V&V IN NUCLEAR POWER PLANT

Digital instrumentation and control (I&C) system has been widely applied in nuclear power plant (NPP), which brings some new problems like software failure. The software failure is easy to come into being the common cause failure (CCF), leading to the failure of the whole protection system for NPP, thus endangering the safety of the NPP. In order to obtain the high quality software for computer important to safety, it is necessary to implement the software verification and validation (V&V) to guarantee that the software can completely and correctly meet the expected requirements of safety functions and performances. Moreover, for the guidance of software V&V and to strengthen the reliability of the software, laws and regulation standards related to the software V&V, were analyzed. On the basis of requirements of the laws and regulations standards and the results of analysis, a technical architecture about nuclear safety digital instrumentation and control system (DCS) software V&V was proposed, which consists of a technical model of software V&V and a general quality assurance (QA) system. The technical model of software V&V mainly illustrated some problems and discussed how to deal with it on the specific implementation of V&V activities and tasks. Meanwhile, in order to support the software V&V activities and tasks carried out efficiently, the general QA system, corresponding to the technical model of software V&V, was established which can supply the visual evidence for quality control process. At this point, it is expected that the results as studied above can provide some technical references in the transformation, formulating or modifying related standards of China and to promote the quality of nuclear safety DCS software.