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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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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
High temperature fission chambers engineered for AMR/SMR safety and performance
As the global energy landscape shifts towards safer, smaller, and more flexible nuclear power, Small Modular Reactors (SMRs) and Gen. IV* technologies are at the forefront of innovation. These advanced designs pose new challenges in size, efficiency, and operating environment that traditional instrumentation and control solutions aren’t always designed to handle.
Swaminathan Vaidyanathan
Nuclear Technology | Volume 206 | Number 10 | October 2020 | Pages 1538-1552
Technical Paper | doi.org/10.1080/00295450.2019.1706377
Articles are hosted by Taylor and Francis Online.
A fuel rod design consisting of a bimetallic cladding tube of thorium metal bonded to a zirconium alloy and containing seed fuel in the interior space is proposed for thorium utilization in pressurized water reactors. The design mitigates the severe thermal penalty that arises in radial microheterogeneous designs when thorium is present as an oxide. The level of thorium loading has an important effect on the achievable discharge exposure as too high a loading results in a large reactivity penalty that is not compensated by rapid enough 233U breeding. In the bimetallic cladding design, the level of thorium loading could be adjusted by varying the thorium metal thickness, and analyses are presented to evaluate optimal levels of thorium loading. Results of cases for higher levels of initial seed loading are presented with a view to extending exposure and reducing the number of discharged assemblies. Liquid metal bonding the seed fuel–cladding gap is preferable as it reduces the seed fuel temperature and at the same time provides more room for fuel swelling. Helium bonding the gap is also possible with a seed fuel modified by an inert matrix. Both approaches need data for fuel thermal modeling, swelling, and fission gas release at high burnup not currently available.