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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.
Liang Shi, J. Michael Doster, Charles W. Mayo
Nuclear Technology | Volume 127 | Number 1 | July 1999 | Pages 24-37
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT99-A2981
Articles are hosted by Taylor and Francis Online.
To estimate the range of impact velocities of potential reactor loose parts (LPs) requires information on regional flow velocities, LP mass, and LP drag coefficients. Flow velocities and the mass of potential LPs can generally be bounded and therefore are assumed to be known. In this work, drag coefficients for prototype LP shapes, including objects such as bolts, nuts, pins, and hand tools, were measured in the fluid velocity range typical of reactor coolant systems. Unlike drag coefficients measured for stationary objects, or by moving a body through a stagnant fluid, these experiments are performed on objects moving freely in a turbulent flow stream. In general, the measured drag coefficients for all tested LP shapes are shown to be close to the standard drag coefficient for a sphere, especially in the low-Reynolds-number region. However, significant differences exist in the wake transition region, which indicates that the drag coefficient for a freely moving body in turbulent flow is different from the drag coefficient for a confined body under the same flow conditions or for a body moving in a stagnant fluid.