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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.
S. R. Bierman, E. D. Clayton, L. E. Hansen
Nuclear Science and Engineering | Volume 50 | Number 2 | February 1973 | Pages 115-126
Technical Paper | doi.org/10.13182/NSE73-2
Articles are hosted by Taylor and Francis Online.
Data are presented from critical experiments with mixed PuO2-UO2 fuels containing 30.0, 14.62, and 7.89 wt% Pu and having H/X (H:Pu + U) atomic ratios of 47.4, 30.6, and 51.8, respectively. In addition to the experimental results, which can be used directly as integral benchmark checkpoints, derived critical sizes are presented for homogeneous mixtures, at theoretical density, of 239PuO2-U(0.71)O2-water in slab, spherical, and cylindrical geometries at the three experimental H/X atomic ratios. These types of data provide the bases for establishing criticality safety control limits.Critical thicknesses of 10.80 ± 0.11, 11.56 ± 0.09, and 14.83 ± 0.60 cm were determined, respectively, for slabs of the 30.0, 14.62, and 7.89 wt% Pu-enriched fuels infinite in two dimensions and fully reflected with 15 cm of Plexiglas. Values of keff within 8 mk of unity were calculated for these three critical systems using either the diffusion theory code, HFN, or the transport theory code, DTF-IV, with the original GAMTEC-II cross-section data previously used at the Critical Mass Laboratory in correlating plutonium critical experiments with theory. Similar calculations with ENDF/B-II cross-section data yielded keff values within 12 mk of unity for these three one-dimensional slab assemblies. Except for the more highly moderated 8 wt% Pu-enriched fuel (H/Pu = 659), calculations with ENDF/B-II data resulted in higher keff values for the critical assemblies than did like calculations using the original GAMTEC-II cross-section library. In the case of the 8 wt% Pu enriched fuel, the computed values for were essentially the same for either of the cross-section sets used.