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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.
Ahmed Badruzzaman
Nuclear Science and Engineering | Volume 112 | Number 4 | December 1992 | Pages 321-335
Technical Paper | doi.org/10.13182/NSE92-A23981
Articles are hosted by Taylor and Francis Online.
A theoretical analysis is presented that assesses the accuracy of the finite moments transport method in optically thick, scattering-dominated media. Two algorithms of the method, originally developed for neutronics problems, are considered. One algorithm uses a truncated balance relation, and the other uses a nodal integral relation to close the system of generalized balance equations that arise in the method. The analysis utilizes an asymptotic expansion of the flux with respect to a small parameter, ∈, which is the ratio of the mean free path of the radiation to a typical dimension of the domain. The behavior of the algorithms is analyzed both in the interior, where the correct solution is that of a diffusion equation, and near the boundary, where the flux should decay exponentially at a rate proportional to 1/∈. Relations valid for an arbitrary number of moments, and that contain earlier results for low-order neutronics methods as special cases, are derived for slab geometry. Preliminary conclusions are also drawn on the asymptotic and boundary-layer behaviors of the two finite moments algorithms in (x-y) geometry. Similar results are discussed for the finite moments algorithms to solve the time-dependent Boltzmann equation. The finite moments nodal integral scheme appears to be vastly superior to conventional deterministic schemes and higher order truncated balance schemes in optically thick problems.