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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 Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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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.
T. D. Gulden, C. L. Smith, D. P. Harmon, W. W. Hudritsch
Nuclear Technology | Volume 16 | Number 1 | October 1972 | Pages 100-109
Technical Paper | Reactor Materials Performance / Material | doi.org/10.13182/NT72-A31179
Articles are hosted by Taylor and Francis Online.
The performance of TRISO-coated carbide fissile particles, of the type to be used in the large HTGR, correlates well with statistically based calculations of stresses in the SiC coating. Three coated particle batches, containing a total of nearly 104 individual coated particles, showed insignificant coating failure (≤0.2%) after exposure to essentially the most severe combined conditions of fast neutron exposure, burnup, and temperature to be experienced by fuel in a large HTGR. This high reliability derives from the fact that less than 1% of the particles in each batch had SiC tensile stresses greater than 30 000 psi, while the SiC layer in about 80% of the coated particles in each batch remained in compression throughout life. Two additional experimental batches of TRISO-coated carbide fissile particles had thinner coatings that resulted in higher mean SiC stresses in each batch and in probabilities of SiC coating stresses greater than 30 000 psi of 3.5 and 8.5%. This compares with the observed incidence of coating failure during irradiation to full design exposures of about 4% in both cases. These results provide further confirmation of the value of analytical stress models in interpreting the results of coated particle irradiation experiments, and emphasize the importance of a statistical approach to coated particle design.