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Conference Spotlight
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.
Yannick Nicolas Hörstensmeyer, Silvano Tosti, Alessia Santucci, Giacomo Bruni
Fusion Science and Technology | Volume 76 | Number 3 | April 2020 | Pages 232-237
Technical Paper | doi.org/10.1080/15361055.2019.1705690
Articles are hosted by Taylor and Francis Online.
Palladium alloy permeators are foreseen for the retrieval of hydrogen in the fusion fuel cycle of the European DEMO power plant. Driven by a pressure gradient, unburned fuel permeates through a thin-walled metallic membrane within the permeator while other gases cannot pass this barrier. With a theoretically unlimited selectivity with regard to nonhydrogenic species, a very high proportion of unburned fuel can be recovered in a continuous process from the exhaust gas and reused after a very short time. A potential candidate for the design of such a permeator consists of a tube (l = 500 mm, d = 10 mm) with a 125-μm-thick, self-supporting membrane made of a palladium-silver alloy all combined in the shape of a so-called finger-type design. A two-stage process then connects several of these permeators in parallel and in series to match the required throughput of DEMO during plasma operation at a given degree of separation. As the first design point in the scope of the current preconceptual design phase, a model was developed using the commercial software ASPEN Custom Modeler to estimate important parameters such as the tritium inventory and the scale of the permeator unit. How the hydrogen pressure profile is calculated over the length of a permeator using the Sieverts’ Law and the Finite Volume Method is thoroughly described. As a result, the integral performance of the combined permeators is presented as well as all important boundary conditions and assumptions that led to it. For the current DEMO baseline scenario, the total number of permeators of the abovementioned shape is found to be about 50.