The construction license requires the submittal of a PSAR, already described in Section 20.3.3. As part of the submission, the licensee has to provide details of the project management arrangements and quality assurance provisions. The RB seeks assurance that the work will be conducted safely and in accordance with the environmental and transportation requirements of the terms of the license, and that the installation conforms to the approved design.

The safety assessment of this documentation requires a major display of the RB’s resources, and arrangements for obtaining external help and advice may need to be made. The analysis covers all the chapters of the PSAR and related information, conducted in accordance with pre-stated procedures. All evidence provided by the operator in support of the request for a construction license needs to be checked and verified by the RB, par­tially by scrutinizing the operator’s analyses but also often by performing independent analyses. The SER for the construction license will form the basis for the content of the license, its limits and conditions.

The analysis of the chapter on potential accidents requires expertise, as it is necessary to verify that potential accidents can be avoided or control­led. A deterministic approach is generally used: a set of potential accident scenarios is proposed, which the NPP design includes equipment and pro­cedures to manage. This constitutes what is called the design basis. A new methodology, a Probabilistic Safety Assessment (PSA), has started to be used as a complement to the deterministic approach. Recently, INSAG recommended integrating both approaches (INSAG, 2011).

Throughout construction, it should be ensured that, once approved, no alteration or amendment is made to the plant and equipment, or to any approved arrangement, unless the RB has approved such alteration or amendment. Normally construction schedules are divided into installation stages. The RB can specify hold points, beyond which work may not progress without its consent. Throughout construction, the RB carries out a programme of inspections, assessments and reviews of the activities per­formed. If at any stage the RB is not satisfied, a variety of options should be put into practice to improve the situation, including stopping all work until the issues in question are addressed. To achieve a high quality of systems and components relevant to safety, the components need to be qualified to properly respond to seismic and extreme environmental situa­tions. As far as possible, components that have already been proven in operation should be used. Manufacturing must conform to high quality standards.

The construction phase is considered complete when SSCs relevant to safety are tested under well-defined conditions and established standards. Examples of these pre-nuclear tests include pressure tests of the primary coolant system (including the reactor vessel), performance tests of emer­gency coolant systems, containment pressure and leakage rate tests, and electrical systems performance tests. Representatives of the RB, or special­ists working on their behalf, generally witness these tests for acceptance by the RB.