PARAMETRIC NUMERICAL ASSESSMENT OF AN AEROJET GENERAL NUCLEONICS REACTOR AGAINST POSTULATED FIRE CONDITIONS

As a part of periodic safety review of nuclear power plants, it is required to ensure fire protection of major facilities and structures in accordance with consolidated international and national legislations. However, most of studies have been focused on huge commercial reactors and lack of information on small research or educational reactors. The objectives of this research are to implement fire hazard analyses of an aerojet general nucleonics (AGN) reactor by using two numerical softwares and to address effect of relevant parameters. Firstly, a remarkable oil fire scenario was assumed by taking into account characteristics of compartments with various fire areas, ventilation conditions, duration time, and so on. Then, thermal integrity of reactor room was evaluated by computational fluid dynamics simulation and structural integrity of the simplified AGN reactor module was checked by systematic finite element simulation. Further, contributions of each parameter and interaction among parameters were quantified, from which not only temperature histories but also von-Mises stress distributions were calculated. As results, it was proven that all the maximum stress values were lower than the corresponding allowable criterion to sustain integrity of the reactor module. Also, the duration time was determined as the most influential parameter and interaction effect between fire area and duration time were significant.