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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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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.
Sol Pearlstein
Nuclear Technology | Volume 128 | Number 3 | December 1999 | Pages 402-408
Technical Paper | Reactor Safety | doi.org/10.13182/NT99-A3040
Articles are hosted by Taylor and Francis Online.
Given sufficient material, a large number of actinides could be used to form bare-metal criticals. The effective delayed neutron fraction for a bare critical comprised of a fissile material is comparable with the absolute delayed neutron fraction. The effective delayed neutron fraction for a bare critical composed of a fissionable material is reduced by factors of 2 to 10 when compared with the absolute delayed neutron fraction. When the effective delayed neutron fraction is small, the difference between delayed and prompt criticality is small, and extreme caution must be used in critical assemblies of these materials. This study uses an approximate but realistic model to survey the actinide region to compare effective delayed neutron fractions with absolute delayed neutron fractions.
