The regulatory body should conduct reviews, assessments and inspections to evaluate the commissioning test programme and the operational limits; test acceptance criteria, conditions and procedures; as-built design of the nuclear installation; non-nuclear commissioning tests; the management system; and the programme for operation. Commissioning activities are considered in detail in Chapter 22.

The results of commissioning tests should address adequately the ability of the self-assessment procedures and internal audits of the licensee to deal with deviations from design parameters. The reviews, assessments and inspections of the regulatory body assess whether the commissioning test results are adequate to confirm the adequacy of all safety-related features of the nuclear installation.

116 Infrastructure and methodologies for justification of NPPs Operation

Operation is authorized only when regulatory requirements are met and the final safety analysis report has been approved, including completion of commissioning tests, recording of the results and their submission to the regulatory body for approval. Before operation, the regulator inspects, reviews and assesses the following: the results of commissioning tests; oper­ational limits and conditions; operating instructions and procedures; and adequacy of staffing to implement these properly. Operation is considered in detail in Chapter 23.

Before and during operation the regulator has to verify the safety expec­tations, the management system, the operators’ competence and the appli­cation of the operating experience. Any design or operational changes require significant regulatory attention.

Safety reviews should be performed on a periodic basis as requested by the regulatory body to determine the effects of ageing and to assess any plant modifications necessary to maintain safety. In general, a periodic safety review is carried out to assess the cumulative effects of plant ageing and plant modifications, operating experience, technical developments and siting aspects. The reviews include an assessment of plant design and opera­tion against current safety standards and practices, and have the objective of ensuring a high level of safety throughout the plant’s operating lifetime. They are complementary to the routine and special safety reviews and do not replace them.