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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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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Latest News
MOU signed for Solo microreactor
Paragon Energy Solutions has signed a memorandum of understanding with Terra Innovatum, a developer of micro-modular nuclear reactors, to support the design and integration of instrumentation and control systems for Terra’s Solo micro-modular reactor. Paragon is a provider of safety-related I&C systems for the nuclear energy community,
Ashlea V. Colton, Blair P. Bromley
Nuclear Technology | Volume 196 | Number 1 | October 2016 | Pages 1-12
Technical Paper | doi.org/10.13182/NT16-70
Articles are hosted by Taylor and Francis Online.
Thorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. With the expected refurbishment and new construction of pressure tube heavy water reactors (PT-HWRs) within the international community, there is an opportunity to gain experience with thorium-based fuels and to start the transition toward the use of thorium as part of the nuclear fuel cycle.
This paper presents an evaluation of fuel types that could be implemented in the near-term to transition into thorium-based fuels in current PT-HWRs. The near-term fuel consists of small amounts of thorium (in a traditional 37-element fuel bundle that is mostly filled with natural uranium or slightly enriched uranium). In addition, a modified 37-element fuel bundle type comprised of slightly enriched uranium fuel (1.2 wt% 235U/U or less), a thorium central element, and the mass equivalent of 1-cm thorium end pellets was studied. Both lattice physics depletion simulations and full-core time-averaged neutron diffusion simulations were carried out to evaluate the performance and safety characteristics of the different studied full-core configurations.
The results demonstrate that adding small amounts of thorium into the fuel of a 37-element bundle is feasible, through enrichment, without reducing power in the reactor or incurring a severe burnup penalty. The most viable core configuration is a core filled with modified 37-element fuel containing slightly enriched uranium dioxide with 1.2 wt% 235U/U. Even with the addition of 1.2 kg of thorium metal to the bundle, significant gains are achieved, including an increased margin to maximum bundle power limit of 40 kW and a 50% increase in fissile utilization.
