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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.
O. Graf, A. Bayer
Nuclear Technology | Volume 96 | Number 1 | October 1991 | Pages 50-71
Technical Paper | Nuclear Safety | doi.org/10.13182/NT91-A35533
Articles are hosted by Taylor and Francis Online.
Realistic probabilistic safety assessment and risk studies for nuclear power facilities and for emergency planning call for detailed knowledge of the shielding properties of buildings. The investigations described here focus on the building types encountered in central Europe, with its high population density. The necessary dose rate calculations are performed with a new combination of the point kernel integration technique (the QAD-CG-E code) and the Sn transport method (the DOT 4.2 code). This procedure seems to be optimal for irregular three-dimensional shielding structures, providing good accuracy and performing a great number of individual calculations. The validity and accuracy of the procedure are checked by Monte Carlo calculations (the SAM-CE code) and by recalculating a U.S. shielding experiment. The evaluation of literature and the examination of data led to a list of 12 building types representative of those in central Europe. The geometries of the buildings are composed of ∼150 to 300 basic geometrical bodies. This is the input for the QAD-CG-E computer code (i.e., combinatorial geometry). Shielding calculations are performed for these 12 building types assuming contamination by 137Cs. The high-rise apartment and row house building types show a good shielding efficiency (a shielding factor <0.1), while the bungalow and prefabricated house offer the lowest shielding value (a shielding factor of 0.3). The other building types have a mean shielding factor value of 0.1. Additional calculations with 131I and 140La show the influence of the gamma energy on the shielding factor. Moreover, gamma fields or spatial dose rate distributions are calculated for a semidetached house, a prefabricated house, and a high rise. The results are presented by isodose lines drawn through vertical and horizontal cross sections of the buildings.
