7.1.2 Plant design and equipment manufacture

A NPP consists of the nuclear steam supply system (NSSS) and the balance of plant (BoP). The NSSS comprises the reactor core and all structures, systems and components (SSCs) required for controlling the reactor power, shutting down the reactor when required and maintaining it in a safe shut­down state. The other SSCs of the NSSS are those that are required for cooling the reactor core during the operating as well as shutdown state and for containment of radioactivity during normal and off-normal operating conditions, including accident conditions. Design, manufacture and con­struction of the SSCs of the NSSS have to meet stringent nuclear standards that require a great deal of specialized expertise and experience. For this reason it is unlikely that the industry in an emerging nuclear power country can undertake this work.

The BoP comprises SSCs that are also found in conventional industry. It may therefore be possible for local design and manufacturing organiza­tions to undertake some of this work. It is, however, to be borne in mind that many of the SSCs of the BoP are also directly or indirectly related to

NPP safety and hence have to be designed, manufactured and tested to high standards. It would be advisable that a careful survey is done in con­sultation with the reactor vendor to establish the feasibility of entrusting specific tasks to the local industry. For some of the tasks the capability of the local industry may have to be suitably augmented. All efforts should, however, be made to maximize the participation of national experts and manufacturing industries with a clear agreement with the reactor vendor. Such participation is very useful for enhancing national capabilities for supporting the future expansion of a nuclear power programme and for undertaking more complex tasks in future, including those related possibly to the NSSS also.

As stated earlier, all NPP equipment and components are to be manu­factured to meet stringent standards. This makes quality assurance (QA) an important part of their manufacture irrespective of the manufacture being done by local or any foreign industry. The NPP owner should there­fore establish early the capabilities and means for ensuring QA during various identified stages of manufacture of all components. The regulatory body should have its own independent capabilities and system in place for carrying out inspection during manufacture for QA. This can be achieved only if a sound infrastructure for QA is available in the country well before any manufacturing activity starts. While some of the QA-related tasks can be outsourced, it is essential that the plant owner as well as the regulatory body have their own technical core groups for reviewing such work.