Safety design reviews scope

Major design decisions to be taken in the course of the design may require special independent design reviews by the operating organization which are limited to the scope of the decision to be taken, and which may consider compliance with the safety requirements applicable to the matter to be decided. 

The scope of an SSP includes hardware, software, firmware, and HSI for all system life-cycle phases. It should be noted that in addition to the core elements, an SSP also includes many program support tasks that are necessary, such as design reviews, technical review boards, SSWGs, etc. The support tasks may vary depending on the type, size, and safety-criticality of system. The SSP and organization can be tailored to a program s size, complexity, and safety-criticaUty. The SSP is planned and documented in the SSPP. 

All safety systems of the Lungmen plant are covered in the software IV V woik. In addition, five (5) R (reliable)- class systems are selected and included. The work scope is described in this section. Design documents related to all of these systems are reviewed by the OIVVT, the GE IVVT reviewed only design documents related to safety systems. 

As illustrated in Fig. 3.2, before proceeding with a detailed System Safety Assessment (SSA), the FHA is often used to determine the need for and scope of any subseqnent analysis. An FHA may contain a high level of detail in some cases (such as for a Flight Guidance and Control System with many functional modes), but many installations may need only a simple review of the system design [AMC25.1309 para 10b(3)]. If further safety analysis is not required, then the FHA could itself be used as a complete safety assessment. 

The application must cover fhe design basis the limits on operation and a safety analysis of structures, systems, and components (SSC) of the plant as a whole. The scope and contents of the application are equivalent to the level of detail foimd in an FSAR for a currently operating commercial nuclear power plant. The NRC staff prepares an SER that describes its review findings of the plant design and how such a design meets all applicable regulations. 

The scope of design basis accident analysis and acceptance criteria have been examined by the Nuclear Safety Commission and included in the guide. Nuclear power plants are subjected to safety review through a deterministic evaluation based on the guide and confirmed that the radioactive release to the environment is less than the limit. The appropriateness of analysis techniques and the scope of analysis... 

The scope of the review was limited to several selected safety principles related to Levels 3 and 4 of defence in the areas of siting and design, namely to the safety principles as follows ... 

The plant Safety Analysis Report, updated in 1996, the operational documentation and the operational feedback database were used as background documents for the review. In addition, the results of a PSA Level 1 study developed for full power, low power and shutdown operational regimes were available for the review, as well as specific analyses of internal flooding and fires. Plant design documentation was also used to an appropriate extent. However, it should be emphasized that due to the hmited scope and time available for the review, the objectives of the screening were more related to verification of the applicabihty of the approach than to evaluation of the safety status of the plant. Therefore, this section cannot be considered as a formal safety review of the plant. 

The safety analyses should proceed in parallel with the design process, with iteration between the two activities. The scope and the level of detail of the analyses should increase as the design progresses so that the final safety analyses reflect the final plant design. Further analyses may be necessary for the justification of proposed design modifications, for taking into account more sophisticated tools or methods for periodic safety reviews. 

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