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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.
G. S. Brunson, E. N. Pettitt, and R. D. McCurdy
Nuclear Science and Engineering | Volume 1 | Number 2 | May 1956 | Pages 174-184
Technical Paper | doi.org/10.13182/NSE56-A17521
Articles are hosted by Taylor and Francis Online.
Delayed neutron studies have been made in the Experimental Breeder Reactor (EBR), using a conventional sample transfer system and a neutron counter comprised of BF3 tubes in a graphite geometry. Samples of Th, U233, U235, U238, and Pu were irradiated in a fast flux; samples of U233, U235, and Pu in a thermal flux. The ratio of the delayed neutron yield per fission (based on the longest four periods) to the delayed neutron yield per fast fission of U235 was determined as: for fast fission of U233, 0.414 ± 7.5%; for fast fission of Pu, 0.405± 7.5%; for fast fission of Th, 3.09 ± 17%; for fast fission of U238, 2.23 ± 7.5%. The ratio of fast fission to thermal fission delayed neutron yields was not significantly different from unity for all samples except Pu, where the ratio of thermal to fast fission yields was 0.888 ± 6%. This latter is believed to be primarily attributable to the 5% fraction of Pu240 in the sample.