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Mathematics & Computation
Division members promote the advancement of mathematical and computational methods for solving problems arising in all disciplines encompassed by the Society. They place particular emphasis on numerical techniques for efficient computer applications to aid in the dissemination, integration, and proper use of computer codes, including preparation of computational benchmark and development of standards for computing practices, and to encourage the development on new computer codes and broaden their use.
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Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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Reboot: Nuclear needs a success . . . anywhere
The media have gleefully resurrected the language of a past nuclear renaissance. Beyond the hype and PR, many people in the nuclear community are taking a more measured view of conditions that could lead to new construction: data center demand, the proliferation of new reactor designs and start-ups, and the sudden ascendance of nuclear energy as the power source everyone wants—or wants to talk about.
Once built, large nuclear reactors can provide clean power for at least 80 years—outlasting 10 to 20 presidential administrations. Smaller reactors can provide heat and power outputs tailored to an end user’s needs. With all the new attention, are we any closer to getting past persistent supply chain and workforce issues and building these new plants? And what will the election of Donald Trump to a second term as president mean for nuclear?
As usual, there are more questions than answers, and most come down to money. Several developers are engaging with the Nuclear Regulatory Commission or have already applied for a license, certification, or permit. But designs without paying customers won’t get built. So where are the customers, and what will it take for them to commit?
S. R. Bierman, E. D. Clayton
Nuclear Technology | Volume 15 | Number 1 | July 1972 | Pages 5-13
Technical Paper | Reactor | doi.org/10.13182/NT72-A31157
Articles are hosted by Taylor and Francis Online.
The results and analyses are presented from the latest series of experiments for determining the critical parameters of plutonium mixtures over the undermoderated region of the neutron energy spectrum. This latest series of experiments was conducted with PuO2-polystyrene fuel having anatomic H/Pu ratio of 49.6 and a 240Pu isotopic content of 18.53 wt%. In addition to providing basic criticality data, the experiments were designed to (a) establish the degree of correlation between the PuO2-polystyrene and the plutonium nitrate solution fueled critical experiments performed at the Hanford Critical Mass Laboratory, (b) provide data for checking previously reported differences obtained by the neutron diffusion theory code HFN and the neutron transport theory code DTF-IV in calculating critical sizes of plutonium-water systems between about 500 and 1000 g Pu/liter, and (c) substantiate that high exposure, subcritical, fixed volume, plutonium-water systems can be made critical by dilution with water. In contrast to the data previously obtained on this same PuO2 material unmoderated, the density effect of having the plutonium in the oxide form was found to have essentially no effect on the reactivity at 49.6 H/Pu. At 49.6 H/Pu, the minimum critical slab thickness was determined to be 5.22 ± 0.07 cm for 239Pu-H2O as compared to 5.34 ± 0.07 cm for 239PuO2-H2O However, the neutron poisoning effect of the 240Pu at 49.6 H/Pu was at least five times that observed for the PuO2 unmoderated. At this near-optimum concentration for maximum 240Pu effects, the percent change in spherical critical mass per percent change in 240Pu content was determined to be 12.1 for the reflected case and 10.2 for the bare case. Based on the data derived from these experiments at 49.6 H/Pu, the HFN code was found to accurately calculate the plutoniumwater systems at 521 g Pu/liter and should be used at this and lower concentrations in preference to the DTF-IV code for calculating critical parameters. As with the plutonium nitrate solutions at high concentrations, the DTF-IV neutron transport theory code calculations resulted in too small a critical size; however, the data obtained from the PuO2-polystyrene experiments correlated well with those that have been obtained from plutonium nitrate solutions. The experiments also showed that, for high exposure plutonium-water systems, a given size vessel could be just critical (Keff =1.0) at three different concentrations below about 1000 g Pu/liter. Consequently, a critically safe vessel could be made critical by dilution alone if the 240Pu content was high enough.
