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Division Spotlight
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
Meeting Spotlight
2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
Rofida Hamad Khlifa, Nicolay N. Nikitenkov
Nuclear Technology | Volume 209 | Number 9 | September 2023 | Pages 1268-1281
Research Article | doi.org/10.1080/00295450.2023.2203282
Articles are hosted by Taylor and Francis Online.
To address concerns about the degradation of unprotected internal surfaces of nuclear fuel claddings, inner-side coatings have been proposed as a complementary approach to the accident tolerant fuel protective coating concept. In addition to the increased coping time during severe events, these coatings are expected to provide enhanced protection in normal operation conditions. This study analyzes the neutronic performance of chromium (Cr) inner-side coatings in VVER-type fuel assemblies. Different aspects, such as reactivity and cycle length penalties, enrichment requirements, neutron flux, and the associated isotopic concentration changes are discussed, considering both the coating thickness and position.
The results show that for the same thickness, reactivity penalties due to the use of inner-side Cr coatings will be (~30% on average) less compared to external coatings. The fuel assembly operating cycle showed reductions by ~ 5.5 effective full-power days when a 10-µm-thick internal Cr coating is introduced, while a 10-µm two-sided coated assembly possessed an ~13.6-day shorter operating cycle compared to an uncoated fuel assembly of the same specifications.
The neutron flux showed slight shifts and hardening in the thermal energy region. The analysis of nuclide inventories showed relative increases in these inventories, which were proportional to the thickness. For the fissile plutonium isotope 239Pu, this relative increase reached a peak of 0.25% and 0.42% (for the 10-µm and 20-µm internal Cr coatings) at a fuel burnup of 18 MWd/kg heavy metal (HM). While for 241Pu, the observed highest relative increases for the 10-µm- and 20-µm-thick internal Cr coatings were 0.74% and 1.03%, respectively. The 135Xe isotopic concentration showed a relative increase that reached 0.2% and 0.4% for the 10-µm and 20-µm internal Cr coatings at a burnup of 34 MWd/kgHM, while the 149Sm concentration increased by 0.2% and 0.5% for the 10-µm and 20-µm internal Cr coatings, respectively.
While these observed isotopic concentration changes were generally small for the studied inner-side coatings, the results showed that the changes remain subject to further increases as the amount of coating material gets higher. Therefore, it is important for the coating thickness to be optimized, taking into account the impact of such nuclide inventory changes. Possible fuel-clad gap reductions and the associated effects on heat transfer, as well as gap tolerance to fission products and fuel relocations, will require further studies, especially so that additional enrichments may be applied.
