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Conference 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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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
M. P. Riley, L. Mohanta, F. B. Cheung, S. M. Bajorek, K. Tien, C. L. Hoxie
Nuclear Technology | Volume 190 | Number 3 | June 2015 | Pages 336-344
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT14-80
Articles are hosted by Taylor and Francis Online.
Spacer grids have been found to enhance downstream convective heat transfer and to strongly influence droplet size distributions through early spacer grid rewet and droplet breakup. Existing models for enhancement of heat transfer and droplet breakup, however, do not appear to accurately account for these interactions between the coolant and the spacer grid. Data from two series of rod bundle heat transfer tests, low injection rate forced reflood tests, and droplet injection tests are presented in this paper to describe the effects of the spacer grids during dispersed flow film boiling. Heat transfer downstream of the spacer grids is clearly enhanced by the presence of the droplets, while the downstream droplet size was found to depend on the condition of the spacer grid: dry or wetted. Results of this study demonstrate the need to adequately account for the separate modes of dry and wet spacer grid heat transfer enhancement in predicting the thermal-hydraulic behavior during reflood transients.