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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.
M. F. Murphy, A. Lüthi, R. Seiler, P. Grimm, O. Joneja, A. Meister, R. van Geemert, F. Jatuff, R. Brogli, R. Jacot-Guillarmod, T. Williams, S. Helmersson, R. Chawla
Nuclear Science and Engineering | Volume 141 | Number 1 | May 2002 | Pages 32-45
Technical Paper | doi.org/10.13182/NSE02-A2264
Articles are hosted by Taylor and Francis Online.
Accurate critical experiments have been performed for the validation of total fission (Ftot) and 238U-capture (C8) reaction rate distributions obtained with CASMO-4, HELIOS, BOXER, and MCNP4B for the lower axial region of a real Westinghouse SVEA-96+ fuel assembly. The assembly comprised fresh fuel with an average 235U enrichment of 4.02 wt%, a maximum enrichment of 4.74 wt%, 14 burnable-absorber fuel pins, and full-density water moderation. The experimental configuration investigated was core 1A of the LWR-PROTEUS Phase I project, where 61 different fuel pins, representing ~64% of the assembly, were gamma-scanned individually. Calculated (C) and measured (E) values have been compared in terms of C/E distributions. For Ftot, the standard deviations are 1.2% for HELIOS, 0.9% for CASMO-4, 0.8% for MCNP4B, and 1.7% for BOXER. Standard deviations of 1.1% for HELIOS, CASMO-4, and MCNP4B and 1.2% for BOXER were obtained in the case of C8. Despite the high degree of accuracy observed on the average, it was found that the five burnable-absorber fuel pins investigated showed a noticeable underprediction of Ftot, quite systematically, for the deterministic codes evaluated (average C/E for the burnable-absorber fuel pins in the range 0.974 to 0.988, depending on the code).
