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The busyness of the nuclear fuel supply chain
Ken Petersenpresident@ans.org
With all that is happening in the industry these days, the nuclear fuel supply chain is still a hot topic. The Russian assault in Ukraine continues to upend the “where” and “how” of attaining nuclear fuel—and it has also motivated U.S. legislators to act.
Two years into the Russian war with Ukraine, things are different. The Inflation Reduction Act was passed in 2022, authorizing $700 million in funding to support production of high-assay low-enriched uranium in the United States. Meanwhile, the Department of Energy this January issued a $500 million request for proposals to stimulate new HALEU production. The Emergency National Security Supplemental Appropriations Act of 2024 includes $2.7 billion in funding for new uranium enrichment production. This funding was diverted from the Civil Nuclear Credits program and will only be released if there is a ban on importing Russian uranium into the United States—which could happen by the time this column is published, as legislation that bans Russian uranium has passed the House as of this writing and is headed for the Senate. Also being considered is legislation that would sanction Russian uranium. Alternatively, the Biden-Harris administration may choose to ban Russian uranium without legislation in order to obtain access to the $2.7 billion in funding.
F. C. Difilippo, J. P. Renier, B. A. Worley
Nuclear Science and Engineering | Volume 124 | Number 3 | November 1996 | Pages 465-472
Technical Paper | doi.org/10.13182/NSE96-A17924
Articles are hosted by Taylor and Francis Online.
Calculations related to the temperature coefficient of reactivity of enriched gas-cooled reactors show the high sensitivity of this parameter to the proper description of thermalization effects in the moderator. Additionally, the calculation of the temperature dependence of the inelastic-scattering cross section with current ENDF/B formalisms correlates the errors of the cross sections as functions of the temperature. Neglecting this temperature correlation introduces unnecessary conservatism in the estimation of the error of the reactivity coefficient.These two facts drove our efforts to characterize the present status of the inelastic cross section of graphite and to calculate its covariance file. The ENDF/B evaluation of the scattering matrix S(α, β, T) is still based on the approximations (incoherent component only) andphonon spectra of the early 1960s. Subsequent measurements showed that the structure observed in S(α, β, T) cannot be described using the incoherent approximation, and soon after the availability of highly intense neutron beams and large specimens of pyrolitic graphite have allowed the direct measurement of elastic constants of relevance for a better calculation of the phonon spectra. Calculations of the probability distributions of the moment and energy transfer, a and β, in a Maxwellian spectrum allow us to define a range of α and β for which comparison of experimental and theoretical data are of most interest for reactor analysis, and to point out regions of deficient resolution or excessive details in the present α, β mesh used in the ENDF/B files. Because the phonon spectrum defines S(α, β, T), mathematical formulas have been found that allow the calculation of the covariance matrix of S by propagating the errors of the phonon spectra.