Safety margins confidence estimation for a passive residual heat removal system

Generation III pressurized water reactors and China’s nuclear power

“…It would be meaningful to deepen studies of the pros and cons of passive and active safety approaches by improving the understanding of nuclear power plant safety from top-tier design philosophy and to scan and analyze the factors which may systematically impact their safety (Zio et al, 2010). Based on the work mentioned, it is necessary to combine passive and active features to improve the safety performance of nuclear power plants; it is important to understand how to make use of passive and active approaches to deal with design basis accidents, and to prevent and mitigate severe accidents.…”

A dynamic probabilistic safety margin characterization approach in support of Integrated Deterministic and Probabilistic Safety Analysis

“…In order to more realistically quantify the uncertainty of TH code outcomes, a probabilistic safety margin definition has been proposed for PSA, which better deals with epistemic uncertainties [Zio et al, 2010]. However, the effect of timing, order and magnitude of the component failures on the system dynamics is not considered.…”

“…By regulation, 1 is usually set equal to the 95 th percentile. Despite that, the estimation of the probability density function of y, ( ), and of its -th percentile 1 , ( 1 ), is a non-trivial task that requires guaranteeing a confidence 1 (e.g., 95% confidence), viz [Nutt et al, 2004;Zio et al, 2010]: The definition of probabilistic safety margin of equation (5) can be enriched by taking into account the resilience information related to the time required for reaching 1 .…”

Invariant methods for an ensemble-based sensitivity analysis of a passive containment cooling system of an AP1000 nuclear power plant

“…The output variable is the pressure value of P containment after 1000 s from the initiation of the LOCA. The D=51 input variables are listed in the Appendix A together with their distributions chosen from expert judgment and literature review (Zio et al 2008b, Zio et al 2010Yu et al, 2015). Three families of distributions have been used: seasonal, normal and uniform.…”