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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Fusion Science and Technology
Latest News
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.
Ralf-Dieter Penzhorn, Uwe Berndt, Erhard Kirste, Jacqueline Chabot
Fusion Science and Technology | Volume 32 | Number 2 | September 1997 | Pages 232-245
Technical Paper | Tritium System | doi.org/10.13182/FST97-A19893
Articles are hosted by Taylor and Francis Online.
The permeation of protium, deuterium, and an equimolar deuterium-tritium mixture through finger-type Pd-Ag permeators of various configurations operated either in/out or out/in has been compared in parametric studies. The parameters included the permeate pressures; the feed-and-bleed flow rates; and the feed-gas composition, i.e., helium, Q2, and CQ4 (Q-hydrogen, deuterium, tritium). Results on the dependence of the hydrogen isotope breakthrough into the bleed-gas stream and thus on hydrogen isotope decontamination factors were obtained as a function of feed-gas flow. The observed isotopic effects are large, i.e., H2/D2 = 1.72 ± 0.03 and H2/DT = 2.06 ± 0.03. No evidence of permeator deterioration was observed after 1.5 yr of discontinuous operation with hydrogen isotopes—mostly deuterium-tritide. In situ evidence on the integrity of a Pd-Ag permeator was obtained from empirical permeation curves, helium leak measurements, and hydrogen isotope breakthrough curves. Methane poisons Pd-Ag slowly but progressively at 360°C. When the hydrogens in methane are replaced by tritium, the rate of poisoning considerably increases, and after a few days, the overall poisoning becomes severe. The poisoning by hydrocarbons can be completely reversed by heat treatment in laboratory air.