Probabilistic analysis of safety: Increasing the reliability and safety of nuclear power plant components - Probabilistic Safety Assessment for Optimum Nuclear Power Plant Life Management (PLiM) - page 207

RIF

Time, years

6.7 Risk increase factor as a function of time: 1) CCF of electric
drives of pumps; 2) CCF of electric drives of pumps (basic variant);
3) reverse LPSI valves (basic variant); 4) LPSI reverse valves.

CDF

￿ ￿ ￿ ￿ ￿

Time, years
6.8 Time dependence of CDF using different reliability models:
1) CDF as a non-linear function of time; 2) CDF as a function of
time (analysis of sensitivity); 3) CDF (basic variant)

damage frequency in relation to the selected reliability model for the most
significant (from the viewpoint of ageing) components - the electric drives
of the pumps. As mentioned previously for this group of components,
the best interpolation of the data is obtained using the log-linear model.
The Weibull model also describes efficiently the initial data. However,
the extrapolated values of the probability of failure up to the end of the
operating life of the unit, obtained using the two models, differ by more
than three orders of magnitude. Taking this into account, two variants of
the calculations were carried out:
1. Using the log-linear model