Affiliation:
1. 1Institute of Nuclear Energy Research, 1000 Wenhua Rd. Jiaan Village, Longtan District, Taoyuan City 32546, Taiwan (R.O.C), ssma@iner.gov.tw, boyan@iner.gov.tw, ssshu@iner.gov.tw
Abstract
AbstractThe Condensate and Feedwater System of the Chinshan BWR units is used to provide reliable and high-quality water to maintain the reactor water level during operation. If a Loss of Feedwater Heating (LFWH) event occurs, the core inlet subcooling increases and then induces corresponding power excursion and the reactor pressure rise. In the Chinshan Final Safety Analysis Report (FSAR), a loss of the feedwater temperature of 55.6°C (100°F) is conservatively assumed in the event. This study analyzes the integral reactor system response with RETRAN. Furthermore, a partial vessel model (PVM) of CFD is used to acquire the conditions of the fuel channel inlet to compensate the weakness of the RETRAN system model to generate detailed thermal-hydraulic conditions. The evaluation shows that the feedwater temperature drop is about 40°C which is lower than the FSAR value. In addition, the sensitivity study shows that the hot channel method underestimates the ΔCPR about 0.025, and there is no direct relation between ΔCPR and either of inlet subcooling or power fraction in transient, which is quite different from the conclusion of the hot channel method. Finally, the sensitivity study also proves the ΔT of 55.6°C (100°F) used in FSAR analysis conservative enough to cover the worst channel with a margin of 0.015 in ΔCPR.
Subject
Safety, Risk, Reliability and Quality,General Materials Science,Nuclear Energy and Engineering,Nuclear and High Energy Physics,Radiation