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NRC proposes changes to its rules on nuclear materials
In response to Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” the NRC is proposing sweeping changes to its rules governing the use of nuclear materials that are widely used in industry, medicine, and research. The changes would amend NRC regulations for the licensing of nuclear byproduct material, some source material, and some special nuclear material.
As published in the May 18 Federal Register, the NRC is seeking public comment on this proposed rule and draft interim guidance until July 2.
Nam Zin Cho, Jae Man Noh
Nuclear Science and Engineering | Volume 121 | Number 2 | October 1995 | Pages 245-253
Technical Paper | doi.org/10.13182/NSE95-A28561
Articles are hosted by Taylor and Francis Online.
A new hexagonal nodal method that directly solves the multidimensional diffusion equation without the transverse integration procedure is described. The new method expands the homogeneous flux distributions within a node in nonseparable analytic basis functions satisfying the neutron diffusion equations at any point of the node. Because the new method does not use the transverse integration, it does not suffer from the need of approximating the transverse leakage shape and the nonphysical singular terms occurring in hexagonal nodes. And, because of the use of analytical basis functions and the corner-point flux included in the nodal coupling equations, the method accurately models large localized flux gradients in the vicinity of nodal corner points as well as nodal interfaces. The new method was tested on two hexagonal benchmark problems consisting of uranium-oxide and mixed-oxide fuel assemblies to demonstrate its accuracy and applicability to realistic problems. The results show that the new method accurately predicts the nodal flux distribution and the core multiplication factor.