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The human factor in licensing and operating the next generation of nuclear plants
As human factors specialists working at the intersection of human performance and nuclear operations, we are witnessing one of the nuclear sector’s most significant transitions in decades. The emergence of small modular reactors, microreactors, and other advanced designs is reshaping the industry’s landscape. Digital instrumentation and controls, passive safety systems, and increased automation are creating opportunities for greater safety margins and more flexible operation. These same features also fundamentally redefine what it means to “operate” a nuclear plant. Interactions among human roles, automation, and passive systems shape how people maintain awareness, exercise judgment, and intervene when necessary. These developments affect both operational realities and the regulatory foundations on which nuclear safety is built.
Yong Jin Cho, Gyoo Dong Jeun
Nuclear Technology | Volume 158 | Number 3 | June 2007 | Pages 366-377
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT07-A3848
Articles are hosted by Taylor and Francis Online.
The header of a Canada deuterium uranium reactor (CANDU) is an important component in simulating the fuel channel behavior because the header's hydraulic behavior controls the feeder void fraction, which affects the fuel bundle coolability. In CANDU accident analyses, the liquid entrainment and vapor pull-through (off-take) phenomena should be considered when horizontal stratification is achieved inside the header. The current RELAP5 off-take model can treat only three directions: vertical upward, vertical downward, and side oriented junctions. In this study, the RELAP5 off-take model was modified and generalized by considering the geometric effect of branch angles. Based on Craya's approach, the critical height correlation was reconstructed by use of the branch line connection angle. The new model in RELAP5/CANDU could be applied to vertical upward, vertical downward, and angled branch. The verification and validation analyses for this new model were performed using separate effect test and integral effect test results. The verification and validation analyses show improved accuracy with the new model.