ATWS: a reappraisal. Part I. An examination and analysis of ''WASH-1270, technical report on ATWS for water-cooled power reactors''

This document is the first of a series which will examine the basis for the problem of Anticipated Transients Without Scram (ATWS). The purpose of these documents is to evaluate risk due to ATWS in the light of developments subsequent to the publication of WASH-1270 and to reevaluate the probabilistic basis for ATWS. The purpose of Part I is to upgrade the numerical information presented in WASH-1270 by correcting deficiencies in that document and updating the input data. The two additions in the present approach are the use of a demand failure model instead of a time-dependent model for the scram system and the incorporation of Bayesian Priors into the probabilistic treatment of the data.