Savannah River Site generic data base development

Abstract

This report describes the results of a project to improve the generic component failure data base for the Savannah River Site (SRS). A representative list of components and failure modes for SRS risk models was generated by reviewing existing safety analyses and component failure data bases and from suggestions from SRS safety analysts. Then sources of data or failure rate estimates were identified and reviewed for applicability, A major source of information was the Nuclear Computerized Library for Assessing Reactor Reliability, or NUCLARR. 1 This source includes an extensive collection of failure data and failure rate estimates for commercial nuclear power plants. A recent Idaho National Engineering Laboratory report on failure data from the Idaho Chemical Processing Plant was also reviewed. 2 From these and other recent sources, failure data and failure rate estimates were collected for the components and failure modes of interest. This information was aggregated to obtain a recommended generic failure rate distribution (mean and error factor) for each component failure mode. Results are presented in Table 1 in this report. : A major difference between this generic data base and previous efforts is that this effort attempted to base failure rate estimates on actual data (failure events) rather than on existing failure rate estimates. This effort was successful in that over 75% of the results are now based on actual data.

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

“…The best available data were used, but these data are generic and are in no way specific to the TBM application. The data sources used here included some sparse helium-cooled and carbon dioxide-cooled fission reactor data ), compressed gas system data (Blanton 1993), and some inferred data were taken from water reactor data reports (NUREG 2007). While these coolants are dissimilar, the water-cooled fission reactors do have a wide body of data to draw from.…”

“…It is assumed if the cruciform grid plate deforms, the silicon carbide inserts will fail since ceramic materials tend to be weak against bending stresses. Back plate channel plugging is assigned a failure rate of 3E 06/h from Blanton (1993). Back plate leakage is assumed to be a single wall plate failure rate.…”

Preclosure Safety Analysis Guide

“…Sometimes in practice, a particular distribution may be mapped into its conjugate by moments matching, and after performing the Bayesian integration over the conjugate and likelihood function, the posterior distribution is mapped back to its conjugate (Blanton and Eide 1993).…”

“…An alternative method, applied at the Savannah River Site (described in Blanton and Eide 1993), converts the prior LN into a beta distribution, applies the specific evidence (number of failures, r, and number of trials, n) in the Bayesian integration, which in turn produces a beta posterior distribution. The beta posterior distribution is then converted to a LN.…”

Pre-title I safety evaluation for the retrieval operations of transuranic waste drums in the Solid Waste Disposal Facility. Revision 2

“…Based on the experimental data resulting from the explosion testing of the drum venting operation as previously discussed, the probability of ignition due to the drilling is calculated by employing the methodology used by SRS to determine failure rates (Blanton and Eide, 1993) as follows :…”