Safety Criteria and Basis
A nuclear reactor performs various operating conditions that are well covered in the design. They are called design basis conditions as defined in Table 13.1. Design requirements under these conditions are specified to assure the plant availability and integrity of the fuel elements and mechanical components. With this, a set of design criteria are established (see Table 13.2 for the core integrity and Table 13.3 for hot and cold pool components of the reactor assembly). Safety demonstration requires not only meeting these design criteria during normal and transient conditions but also meeting the criteria relevant to the safe shutdown state following transient events. The consolidated composition of such criteria is termed as safety criteria. A few examples are given in Table 13.4. Thus, the safety criteria describe the design requirements for structures, systems, and components important to safety that shall be met for safe operation and also for the prevention or mitigation of the consequences of events that could jeopardize safety. Figure 13.1 shows the relationship between the categories, events, and safety targets [13.1].