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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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
Terrestrial Energy, Schneider partner on molten salt reactor
Terrestrial Energy and Schneider Electric are teaming to deploy Terrestrial Energy's integral molten salt reactor (IMSR) to provide zero-emission power to industrial facilities and large data centers.
The companies signed a memorandum of understanding in April to jointly develop commercial opportunities with high-energy users looking for reliable, affordable, and zero-carbon baseload supply. Terrestrial Energy said that working with Schneider “offers solutions to the major energy challenges faced by data center operators and many heavy industries operating a wide range of industrial processes such as hydrogen, ammonia, aluminum, and steel production.”
Michael Y. Hua, Jesson D. Hutchinson, George E. McKenzie, Tony H. Shin, Shaun D. Clarke, Sara A. Pozzi
Nuclear Science and Engineering | Volume 194 | Number 1 | January 2020 | Pages 56-68
Technical Paper | doi.org/10.1080/00295639.2019.1654327
Articles are hosted by Taylor and Francis Online.
Rossi-alpha measurements of fissionable assemblies are used to estimate the prompt neutron decay constant α. Reactivity can be inferred from α if the values of the neutron generation time and effective delayed neutron fraction are assumed. If multiple measurements are performed on an assembly near delayed critical, one can determine α at delayed critical and directly infer reactivity (without needing to assume values for the neutron generation time or effective delayed neutron fraction). Previous works have demonstrated that two-exponential fits for Rossi-alpha measurements of reflected assemblies have better fit metrics than those of one-exponential fits; however, the two-exponential probability density function that is needed to obtain α from the fit parameters has not been derived. This paper derives the two-exponential fit based on a two-region point kinetics model for Rossi-alpha measurements of reflected assemblies, a generalization of the current, one-region model (one-exponential fit). The new model is validated for shielded assemblies, a special case of reflected assemblies where the reflector-to-core leakage is negligibly small. The validation is performed using shielded, fissionable assemblies (highly enriched uranium with keff ≈ 0.95 and weapons-grade plutonium with keff > 0.77). The results show that the two-exponential model can (1) predict the constant α within two standard deviations, and (2) deconvolve α and the time a neutron spends in the reflector region, neither of which is possible with the one-exponential model.