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Conference Spotlight
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.
Garry C. Gose, Thomas J. Downar, Karl O. Ott
Nuclear Technology | Volume 124 | Number 3 | December 1998 | Pages 284-290
Technical Note | Reactor Safety | doi.org/10.13182/NT98-A2927
Articles are hosted by Taylor and Francis Online.
The main-steam-line-break (MSLB) transient in a pressurized water reactor (PWR) is a core overcooling event that can result in a large positive reactivity insertion. In most analyses the shutdown margin is sufficiently large that the core does not return to critical. However, some researchers have reported an increase in the core power even though the core does not return to critical. A simplified kinetics model based on the prompt-jump-kinetics approximation is reported in new work, and a single delayed neutron group is used to explain the core power increase during subcriticality. Specifically, it is shown that the multiplication of the initial delayed-neutron source as predicted by the rate of change of the reactivity during the transient is the reason for the increase in power even though the core never returns to criticality after scram. The results are demonstrated using data from a RETRAN-03 model of a hot-zero-power MSLB analysis of the Three Mile Island unit 1 PWR.