Which term describes accidents that a nuclear power plant must be designed and built to withstand?

• A. Beyond-design-basis event
• B. Design-basis accident
• C. Postulated accident
• D. Normal operating upset

Answer: (B)

The key idea is that safety requirements are anchored to the design-basis accidents. These are the specific accidents a nuclear plant must be able to withstand while keeping radiation releases within regulatory limits, so the plant’s safety systems, cooling, and containment are proven to work under those conditions. This is why the correct term is design-basis accident: it defines the minimum set of events the plant must handle in its original design.

Beyond-design-basis events refer to more severe scenarios than those covered by the design, and while the plant may mitigate many consequences, it is not guaranteed to meet the same strict limits. A postulated accident is a broader term used during analysis to represent potential initiating events, but the formal requirement tied to safety design is the design-basis accident. Normal operating upsets are operational faults managed within the plant’s normal safety practices and are not the design basis for the plant’s overall safety design.