Guidance for Reactor Operators and TSC personnel with the Severe Accident Management Guidelines

The Westinghouse Owners Group Severe Accident Management Guidelines (WOG SAMG) were developed between 1991 and 1994. The primary goals for severe accident management that form the basis of the WOG SAMG are to terminate any radioactive releases to the environment, to prevent failure of any containment fission product boundary and to return the plant to a controlled stable condition. The WOG SAMG is primarily a TSC tool for mitigation of low probability core damage events. Their philosophy is that control room operators should remain focused on the prevention of core damage, whereas the TSC personnel should concentrate on the mitigation of the severe accident. The symptom based package is built up as a structured process for choosing appropriate actions based on actual plant conditions. No detailed knowledge of severe accident phenomena is required. The WOG SAMG is made up of a number of components, among which the Graphical Computational Aids (CA). These CA's were defined to fulfill the need for information that is not available directly from plant instrumentation. The information they provide has to meet certain requirements: a. information on the CA must be directly needed within the decision - making process; b. quantification of the information must be necessary; c. the uncertainty of the computation should be low enough so as to provide direction to the decision maker. The purpose of this paper is to provide some insights on how WOG SAMG, and also more specifically CA's, can aid operators and especially TSC - personnel in the mitigation of a severe accident. (authors)