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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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DOE issues new NEPA rule and procedures—and accelerates DOME reactor testing
Meeting a deadline set in President Trump’s May 23 executive order “Reforming Nuclear Reactor Testing at the Department of Energy,” the DOE on June 30 updated information on its National Environmental Policy Act (NEPA) rulemaking and implementation procedures and published on its website an interim final rule that rescinds existing regulations alongside new implementing procedures.
Andrey Ovcharov, Richard Szczepanski, Jacek Kosek, Nuno Pedrosa, Xiaofei Lu, Lorenzo Basili, Rosa Lo Frano, Donato Aquaro
Fusion Science and Technology | Volume 76 | Number 3 | April 2020 | Pages 179-190
Technical Paper | doi.org/10.1080/15361055.2019.1689891
Articles are hosted by Taylor and Francis Online.
Operation of the fuel cycle of a thermonuclear fusion reactor naturally leads to accumulation of surplus protium, but in some cases it can also lead to accumulation of surplus deuterium. Both surplus protium and deuterium have to be separated, detritiated, and discharged to the environment, normally passing a final detritiation stage based on either the liquid phase catalytic exchange or water distillation process. The concept of a multicolumn cryogenic distillation (CD) system capable of discharging a time-varying surplus of deuterium is presented in this paper. A model of a CD column based on a UV (internal energy U – volume V) flash formulation and equation of state (EOS) thermodynamic model for hydrogen isotopologue mixtures is also presented at the principal step to a comprehensive model of the isotope separation system. Although fundamental for constant volume systems, the UV formulation of the thermodynamic state has not been widely used in transient simulations; in particular, for distillation dynamics modeling, other approaches are much more common. At the same time, in helium cryogenics the UV formulation has gained wide usage in large-scale dynamic simulations. It is known from the literature that a UV formulation of the distillation problem is very challenging for a numerically stable implementation. To cope with this situation, we present our findings on the sources of numerical instabilities and approaches.