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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The RAIN scale: A good intention that falls short
Radiation protection specialists agree that clear communication of radiation risks remains a vexing challenge that cannot be solved solely by finding new ways to convey technical information.
Earlier this year, an article in Nuclear News described a new radiation risk communication tool, known as the Radiation Index, or, RAIN (“Let it RAIN: A new approach to radiation communication,” NN, Jan. 2025, p. 36). The authors of the article created the RAIN scale to improve radiation risk communication to the general public who are not well-versed in important aspects of radiation exposures, including radiation dose quantities, units, and values; associated health consequences; and the benefits derived from radiation exposures.
Cliff B. Davis
Nuclear Technology | Volume 90 | Number 3 | June 1990 | Pages 286-293
Technical Paper | RELAP/MOD2 / Nuclear Safety | doi.org/10.13182/NT90-A34394
Articles are hosted by Taylor and Francis Online.
The possibility of a flow instability in a fuel assembly during a hypothetical loss-of-coolant accident (LOCA) in the production reactors at the Savannah River Site (SRS) is currently the subject of many analyses. The Bingham pumps, which circulate flow through the Savannah River reactors, may be susceptible to cavitation because of the decrease in pressure that accompanies a LOCA. Cavitation in the Bingham pumps during a LOCA could reduce the forced flow through the assemblies and thus could promote flow instability. An analysis was performed at the Idaho National Engineering Laboratory to aid in the evaluation of the potential significance of cavitation on flow instability. The RELAP5 computer code and a model of the L-Reactor at the SRS were the primary analysis tools. A cavitation model was developed using correlations generated at Savannah River and the RELAP5 control system. Benchmark comparisons were performed between the RELAP5 cavitation model and cavitation tests performed in L-Reactor. Best-estimate calculations of a LOCA initiated by a double-ended guillotine break in the inlet piping to the reactor were then performed for a range of core powers. The LOCA calculations were used to determine the initial core power leading to the onset of cavitation and the effects of cavitation on system response. Cavitation was calculated to occur in the broken loop when the initial core power was >1400 MW. Cavitation did not cause a catastrophic reduction in core flow. The effects of cavitation were self-limiting because of feedback among the pump head, loop flow, and the available and required net positive suction head.