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NRC adopts ROP updates
The Nuclear Regulatory Commission has approved a significant overhaul of its Reactor Oversight Process (ROP) baseline inspection program that stresses a leaner, more risk-focused inspection process.
This adoption comes just over a month after NRC officials published their findings on the proposed ROP changes. The changes would reduce the number of hours spent annually on direct inspections at U.S. nuclear power plants by 38 percent.
Justin M. Pounders, Farzad Rahnema
Nuclear Science and Engineering | Volume 176 | Number 3 | March 2014 | Pages 273-291
Technical Paper | doi.org/10.13182/NSE12-108
Articles are hosted by Taylor and Francis Online.
A new solution technique is derived for the time-dependent transport equation. This approach extends the steady-state coarse-mesh transport method that is based on global-local decompositions of large (i.e., full-core) neutron transport problems. The new method is based on polynomial expansions of the space, angle, and time variables in a response-based formulation of the transport equation. The local problem (coarse-mesh) solutions, which are entirely decoupled from each other, are characterized by space-, angle-, and time-dependent response functions. These response functions are, in turn, used to couple an arbitrary sequence of local problems to form the solution of a much larger global problem. In the current work, the local problem (response function) computations are performed using the Monte Carlo method, while the global (coupling) problem is solved deterministically. The spatial coupling is performed by orthogonal polynomial expansions of the partial currents on the local problem surfaces, and similarly, the time-dependent response of the system (i.e., the time-varying flux) is computed by convolving the time-dependent surface partial currents and time-dependent volumetric sources against precomputed time-dependent response kernels.