The overall objective of commissioning is to prepare the SSCs for opera­tion. This involves verifying that the SSCs meet their design requirements for safety and performance, for both individual structures and components and integrated systems. These requirements cover normal operation, antici­pated operational occurrences, and design basis accidents. Verifying the design provisions for management of accidents beyond the design basis can also be done at this stage, as far as it is feasible. There is some overlap between construction and commissioning since some SSCs may be commis­sioned before completion of the entire plant. (The various aspects of com­missioning and related activities are considered at length in Chapter 22).

There are several steps during commissioning that may require regula­tory approval. The introduction of fissile material into the plant is an impor­tant event and is considered in some cases to be the first point where regulatory decisions are required. Since commissioning is performed typi­cally over a few months, the licensee and the RB must both be prepared for an intensive period of activity. Besides planning and organizing its own activities, the licensee should ensure that the RB establishes and commu­nicates a detailed plan outlining how it will review the commissioning work, the nature of the required approvals and hold-points, and what information is required to be submitted by the licensee at each hold point. For example, the licensee should understand the clearances that the on-site regulatory staff can issue at the various stages of commissioning, and the submissions that are required to ensure such clearances. The licensee must also be sensi­tive to the fact that results of commissioning could lead to further refining of the regulatory requirements for plant operation, for example in its oper­ating procedures and in-service inspections requirements.

An operating license requires the submission of FSAR based on the PSAR previously submitted for the construction license, as summarized in Table 20.3. However, it includes more information from both the construc­tion and commissioning programmes and may also be impacted by new R&D information and international safety developments that have arisen during the construction period. Obviously, the satisfactory completion of the training and certification of operating staff is an essential milestone for the operating license, and is considered further in Section 20.5.4.

Operational procedures are developed before a plant is transferred from construction to operations. These include procedures that cover normal and off-normal operations, surveillance, maintenance, and emer­gency operations. Emergency operations procedures normally have to be approved by the regulator before issuing the operating license and prior to initial fuel loading. Several other submissions could be required depending on the national licensing processes and FSAR content, as indicated in Table 20.3.

During operation, there will be ongoing requirements to submit various operational reports to the regulator depending on licensing requirements and on the occurrence of any events that impact or have the potential to impact safety. Some of these requirements are discussed in Section 20.5.