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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.
C. P. Marcel, M. Rohde, T. H. J. J. Van der Hagen
Nuclear Technology | Volume 164 | Number 2 | November 2008 | Pages 232-244
Technical Paper | Reactor Safety | doi.org/10.13182/NT08-A4022
Articles are hosted by Taylor and Francis Online.
The stability performance of the Economic Simplified Boiling Water Reactor (ESBWR) is studied with the downscaled GENESIS facility. The GENESIS design is based on fluid-to-fluid modeling and includes an artificial void reactivity feedback system for simulating the neutronic-thermal-hydraulic coupling. The experiments show that the ESBWR thermal-hydraulic oscillatory mode is very stable at nominal conditions, exhibiting a decay ratio DR = 0.12 and a remarkably low resonance frequency fres = 0.11 Hz. This result indicates a static pressure head-driven phenomenon since this frequency corresponds well to typical frequencies found for density wave oscillations traveling through the core plus chimney sections. For the reactor-kinetic oscillatory mode, we found a decay ratio DR = 0.30 and a resonance frequency fres = 0.75 Hz. This corresponds well to density wave oscillations traveling through the core indicating the instability mechanism is driven by the interplay between the core friction and the neutronic response due to void changes in the core. By comparing these results with those obtained with the TRACG computational code, it was found that they agree very well. In addition, the stability performance of the thermal-hydraulic and the reactor-kinetic mode is investigated for a wide range of conditions, confirming the existence of large margins to instabilities of the ESBWR design.
