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The Civil Nuclear Credit Program: An overview
Officially established on November 15, 2021, with the signing of the $1.2 trillion Infrastructure Investment and Jobs Act—aka the Bipartisan Infrastructure Law, or BIL—the Department of Energy’s Civil Nuclear Credit Program was designed to give owners/operators of commercial U.S. reactors the opportunity to apply for certification and competitively bid on credits to help support the continued operation of economically troubled units. Finally, the federal government, and not just certain farsighted state governments, would recognize nuclear energy for its important grid reliability and decarbonization attributes.
Drew E. Kornreich
Nuclear Technology | Volume 181 | Number 2 | February 2013 | Pages 282-302
Technical Paper | Reactor Safety | doi.org/10.13182/NT13-A15784
Articles are hosted by Taylor and Francis Online.
This work involved estimating the homogeneous metal-water mixture critical mass curves of 34 fissionable nuclides from thorium to einsteinium. Calculations were performed using the discrete ordinates code PARTISN with ENDF/B-VII.0 69-group cross sections. Sample MCNP5 test cases indicate reasonable agreement between the two transport codes. In general, the results confirmed that there are three "forms" of the critical mass curves: (a) the traditional curve most well known as characterizing the "big 3" nuclides (233U, 235U, 239Pu), where the minimum critical mass is found in a dilute solution; (b) a simple monotonic curve characterized by a monotonically increasing critical mass as water is added to the metal, where the minimum critical mass is a metal system; and (c) a hybrid curve where the shape is similar to the traditional curve but the minimum critical mass is the pure metal. In general, the traditional and monotonic curves follow the "odd-even" rule of thumb that a nuclide with an even Z and an odd A or vice versa will have a traditionally shaped curve and that the other nuclides will have a monotonically shaped curve. The violations of this rule of thumb, i.e., the hybrid curves, in the set of nuclides analyzed are comprised of 232U and 252Cf. Plutonium-236 is especially interesting because it is a traditionally shaped curve with the minimum critical mass in a relatively dilute solution, but it violates the "odd-even" rule of thumb.