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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 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.
Liujun Pan, Ruihong Wang, Song Jiang
Nuclear Science and Engineering | Volume 180 | Number 2 | June 2015 | Pages 199-208
Technical Paper | doi.org/10.13182/NSE14-73
Articles are hosted by Taylor and Francis Online.
We propose a modified method to improve the stability of the Monte Carlo fission matrix acceleration (FM) method. In the existing FM method, the weights of fission neutrons are adjusted by the fundamental-mode eigenvector of the fission matrix, which can be calculated by power iteration (PI). In this paper, the PI procedure to calculate the fundamental-mode eigenvector of the fission matrix in each cycle is called the inner iteration to distinguish it from the Monte Carlo iteration cycles. In our proposed method, the fission source distribution tallied during the Monte Carlo simulation is taken as the initial vector for the inner iteration. The weights of the fission neutrons are not adjusted by the fundamental-mode eigenvector of the fission matrix but by the vector obtained with only a few inner iteration steps. We call the proposed method the Monte Carlo fission matrix acceleration method with limited inner iteration (FM_lii). The FM_lii method possesses the following properties: It is more stable than the existing fission matrix acceleration method, and it preserves considerable acceleration efficiency. Moreover, we analyze the stability property of the proposed method for the case of two weakly coupled fissile arrays. A number of numerical tests for practical large-scale, loosely coupled systems are presented that demonstrate the theoretical analysis and efficiency of our scheme.