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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.
Massimiliano Rosa, James S. Warsa, Jae H. Chang
Nuclear Science and Engineering | Volume 164 | Number 3 | March 2010 | Pages 248-263
Technical Paper | doi.org/10.13182/NSE09-26
Articles are hosted by Taylor and Francis Online.
A Fourier analysis is conducted for the discrete ordinates, or SN, approximation of the neutron transport problem solved with Richardson iteration (source iteration) and Richardson iteration preconditioned with transport synthetic acceleration (TSA), using the inexact parallel block-Jacobi (IPBJ) algorithm both in slab and two-dimensional Cartesian geometry. Both traditional, or “beta,” TSA (TTSA) and a modified TSA (MTSA), in which only the scattering in the low-order equations is reduced by some nonnegative factor < 1, are considered.The results for the unaccelerated algorithm show that convergence of IPBJ can degrade, leading in particular to stagnation of the generalized minimum residual method with restart parameter m, GMRES(m), in problems containing optically thin subdomains. The IPBJ algorithm preconditioned with TTSA can be effective, provided the parameter is properly tuned for a given scattering ratio c, but is potentially unstable. Compared to TTSA, MTSA is less sensitive to the choice of , more effective for the same computational effort, measured in terms of the effective scattering ratio c′, and it is unconditionally stable.