Abstract
All walks of life are doubtful about the safety of nuclear power plant after the Fukushima accident. As a result, the Taipower company applies Ultimate Response Guideline(URG) to all nuclear power plants in Taiwan in a hope that reactor core damage won’t happen when any beyond design basis accident occurs. This essay uses Lumgmen TRACE model to investigate whether the URG is helpful or not to Lungmen NPP. The results reveal that cladding temperature can keep under the limit(1088 K) when URG is followed. This essay also establish an improved Lungmen TRACE/CONTAN model by containment analysis code─CONTAN. It utilizes FSAR boundary condition as well as calculates its thermal hydraulic boundary directly by TRACE to perform the main steam line break event. In a case study of FSAR boundary condition, the result of Lungmen CONTAN model coincides with that of FSAR and GOTHIC. In another case study of reactor core calculation, it has a higher temperature in the beginning and gradually decline which meets the same balance temperature of the other two codes’ results. By observing the real phenomenon, it is clear that it has experienced an energy balance process, which can’t be found in those two codes’ results. By the above-mentioned results, we can conclude that Lungmen TRACE/CONTAN model is more practical though it has a relatively high drywell temperature.