Mass and Energy Release Analysis of Postulated Main Steam Line Break Accident for APR1400 Using SPACE-ME Methodology

Abstract

The mass and energy (M/E) release from postulated main steam line break (MSLB) accidents is essential for reactor containment functional design. Korea Electric Power Corporation Engineering & Construction Company, Inc. (KEPCO E&C) is currently developing a novel M/E release analysis methodology, known as SPACE-ME methodology, utilizing the SPACE 3.3 and CAP 3.1 codes. In this study, the M/E release analysis of postulated MSLB accidents in Advanced Power Reactor 1400 MWe (APR1400) was performed using SPACE-ME methodology. The M/E release rates were calculated with various combinations of initial core power conditions of 102%, 75%, 50%, 20%, and 0 % of full power (%FP), break sizes of area fractions ranging from 0.1 to 1.0 for a total area of 0.8542 m². In addition, single failure, such as main steam isolation valve failure (MSIVF) or one train of containment spray system failure (CSSF) is assumed for each postulated MSLB accident. Subsequently, the containment response analysis to containment pressure and temperature (P/T) were conducted with the M/E release results by the stand-alone CAP 3.1 code. The highest containment peak pressure was obtained as 388,389 Pa (56.33 psia or 41.63 psig) at the MSLB accident with MSIVF, 102 %FP, and AF 0.3. The highest containment peak temperature was found to be 449.27 K (349.02 °F) in the MSLB accident with MSIVF, 102 %FP, and AF 0.4. The margins of containment peak P/T are determined as approximately 24.6% and 1.4%, respectively, compared to environmental qualification limits for design basis accidents. In addition, the containment peak pressure is lower than that of calculated by KIMERA methodology, while the containment peak temperature is higher. Consequently, this paper presents the SPACE-ME methodology is valid to analyze the M/E release of the postulated MSLB accidents.