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NRC looks to leverage previous approvals for large LWRs
During this time of resurging interest in nuclear power, many conversations have centered on one fundamental problem: Electricity is needed now, but nuclear projects (in recent decades) have taken many years to get permitted and built.
In the past few years, a bevy of new strategies have been pursued to fix this problem. Workforce programs that seek to laterally transition skilled people from other industries, plans to reuse the transmission infrastructure at shuttered coal sites, efforts to restart plants like Palisades or Duane Arnold, new reactor designs that build on the legacy of research done in the early days of atomic power—all of these plans share a common throughline: leveraging work already done instead of starting over from square one to get new plants designed and built.
P. M. Suárez, M. A. Arribére, S. Ribeiro Guevara, A. J. Kestelman
Nuclear Science and Engineering | Volume 127 | Number 3 | November 1997 | Pages 245-261
Technical Paper | doi.org/10.13182/NSE97-A1934
Articles are hosted by Taylor and Francis Online.
The reaction cross sections averaged over a 235U fission neutron spectrum have been measured for the 45Sc(n,)42K, 45Sc(n,2n)44Scg, and 45Sc(n,2n)44Scm threshold reactions. The values found for these cross sections are, respectively: 308 ± 16 b, 27.3 ± 1.3 b, and 22.0 ± 2.7 b, using 111 ± 3 mb as the averaged cross section for the 58Ni(n,p)58Com+g reaction that was used as a standard. To the authors' knowledge, these are the first experimental determinations of the 45Sc(n,2n)44Scg and 45Sc(n,2n)44Scm spectrum-averaged cross sections, which were measured using a new method for the case when both the ground and an isomeric state are generated.By fitting with a suitable function the experimental differential cross sections found in the EXFOR data file for each of these reactions, the corresponding spectrum-averaged cross sections have been calculated for nine different analytical representations of the 235U fission neutron spectrum. This calculation was also performed for the representation based on the Madland-Nix model of prompt fission neutrons. The agreement between calculated and measured values is in general excellent for the 45Sc(n,)42K low-threshold reaction. However, the agreement is rather poor for the 45Sc(n,2n) high-threshold reactions, except for two, Maxwellian-type, representations tried. Since it is well known that Watt-type representations, rather than the Maxwellian type, produce an overall better description of the 235U fission spectrum, the recommended analytical representations to be used are the Watt type. Taking into account their poor performance for high-threshold reactions and recognizing the practical importance of having an analytical representation that agrees with experimental data in the whole energy range, two new representations are presented, based on the one recommended for the ENDF/B-V file, for the 235U fission neutron spectrum, whose main merit is better agreement with experimental results.
