Plant modifications have no effect on the plant's core damage frequency (CDF).

Plant modifications have no effect on the plant's core damage frequency (CDF).

• A. False
• B. True
• C. Not sure
• D. Cannot be determined

Answer: (A)

Plant modifications can change the plant’s probability of core damage because CDF depends on how equipment, protections, and human actions perform during accidents. When a modification is made, it can alter initiating-event frequencies, the reliability of safety systems, interlocks, or operator responses, all of which shape the likelihood that a severe sequence leads to core damage within a year. For example, adding a new cooling capability or upgrading protection logic may reduce risk by preventing or mitigating events, while introducing a new system or changing wiring and setpoints can introduce additional failure modes or human errors that raise risk. Because these changes can either increase or decrease the chances of core damage, the statement that modifications have no effect is not correct. In practice, any modification is evaluated for its risk impact through risk assessments and regulatory backfitting processes, so choices like true, not sure, or cannot be determined don’t align with how risk is treated in plant planning.

Plant modifications can change the plant’s probability of core damage because CDF depends on how equipment, protections, and human actions perform during accidents. When a modification is made, it can alter initiating-event frequencies, the reliability of safety systems, interlocks, or operator responses, all of which shape the likelihood that a severe sequence leads to core damage within a year. For example, adding a new cooling capability or upgrading protection logic may reduce risk by preventing or mitigating events, while introducing a new system or changing wiring and setpoints can introduce additional failure modes or human errors that raise risk. Because these changes can either increase or decrease the chances of core damage, the statement that modifications have no effect is not correct. In practice, any modification is evaluated for its risk impact through risk assessments and regulatory backfitting processes, so choices like true, not sure, or cannot be determined don’t align with how risk is treated in plant planning.