Coupled modeling of NPPs: evolution, current trends and future prospects

The foundation pillar in the peaceful utilization of fission nuclear power has always been the strong emphasis on nuclear safety. Safety has been accomplished through in-depth review of design and operations, incorporation of findings from safety R and D worldwide and improvement in methods of evaluation. In the entire chain of safety process, safety analysis has been a vital link which provides an estimation of the capability of the nuclear systems to control or accommodate departures from normal operation or postulated malfunctions or failures. Safety analysis is performed using numerical simulation tools (computer codes) which have evolved gradually in terms of accuracy and complexity over the past five decades. As a conventional practice, problem specific models addressing limited physical phenomenon were developed and used during design and analysis of present generation nuclear reactors. These code were based on strong emphasize on single physic phenomenon and they were improved and refined thoroughly in that dimension. The talk will present an overview of present generation best estimate coupled computing tools for NPPs which include mostly neutronics/thermal-hydraulics coupling into reactor core on assembly/channel basis