Quantification of Uncertainties Associated With Using 28-Element BLA CHF Correlation

Abstract

This paper addresses concerns regarding the use of the 28-element Bundle Boiling Length-Averaged (BLA) Critical Heat Flux (CHF) correlation in safety analysis outside the range of conditions of the Stern Labs (SL) 28-element bundle CHF tests whose data are used to derive the correlation. An approach has been developed to address the concerns and is based on the capability of the subchannel ASSERT code Critical Heat Flux (CHF) models, namely the Table Look-up method and mechanistic dryout model, to represent the underlying physical phenomena. The approach has been applied and the results demonstrated the appropriateness of the continued use of the BLA CHF correlation and also established the basis for assessing the uncertainty allowances associated with its use for other applications.