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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.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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
BWXT will scout potential TRISO fuel production sites in Wyoming
BWX Technologies Inc. announced today that its Advanced Technologies subsidiary has signed a cooperation agreement with the state of Wyoming to evaluate locations and requirements for siting a potential new TRISO nuclear fuel fabrication facility in the state.
Frigyes Reisch, Torsten Spanne
Nuclear Technology | Volume 3 | Number 10 | October 1967 | Pages 590-598
Technical Paper and Note | doi.org/10.13182/NT67-A27918
Articles are hosted by Taylor and Francis Online.
The quantitative influence of the void and Doppler coefficients on the dynamics of the Boiling Heavy-Water Reactor (BHWR) under different operating conditions has been examined extensively. Owing to the difficulty of calculating these coefficients exactly and their great influence on the dynamic behavior of the self-controlled reactor, these parameters have been studied over a wide range. The studies also improve understanding of the transient behavior of the BHWR concept. It has been found that undamped oscillations can arise with special combinations of the reactivity coefficients. In the nonlinear dynamic model used, the void reactivity contribution comes from the changes of the exit void and the subcooling. The oscillations induced by the reactivity feedbacks have different dampings and frequencies of ≈0.003 or ≈0.03 cps, depending on the sign and the magnitude of the void reactivity coefficients. The transient neutron flux responses to step reactivity perturbations that have the first peak (limited by the fuel Doppler coefficient) as the largest overshoot or that are strongly damped oscillations lie in a well definable area in the exit void and subcooling reactivity coefficient coordinate system. Disturbances introduced by reactivity variation and main steam-valve opening are discussed. The transient responses calculated were those of the neutron flux, reactivity, pressure, moderator temperature, exit void, average void, subcooling, and temperatures of the boiler and superheater fuel.