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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.
Sung Joong Kim, Lin-Wen Hu, Floyd Dunn
Nuclear Technology | Volume 182 | Number 3 | June 2013 | Pages 315-334
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT12-81
Articles are hosted by Taylor and Francis Online.
The Massachusetts Institute of Technology Research Reactor (MITR) is evaluating a transitional core conversion strategy for converting from high-enrichment uranium (HEU) to low-enrichment uranium (LEU) fuel. The objective of this study is to analyze steady-state operational safety margins and loss of primary flow (LOF) accidents for the postulated HEU-LEU transitional core configurations. The thermal-hydraulic calculation was performed using the RELAP5 MOD 3.3 code based on 7.40-MW reactor power, which is the limiting safety system settings of the current licensed reactor power of 6 MW. A lumped average and a single hot channel were modeled in each core configuration with radial peaking factors of 2.0 and 1.76 for HEU and LEU fuel elements, respectively. Four natural convection valves and two antisiphon valves were modeled for natural convective heat removal during the LOF transient. Two different hot-channel configurations and full- and side-channel geometries were evaluated because the unique design of the MITR fuel element can form these two types of geometries. RELAP5 calculation results suggest that the transitional core conversion strategy is feasible and that sufficient thermal-hydraulic safety margins can be maintained.