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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Fusion Science and Technology
Latest News
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.
A. Ying, N. Morley, K. Gulec, B. Nelson, M. Youssef, M. Abdou
Fusion Science and Technology | Volume 34 | Number 3 | November 1998 | Pages 855-862
Fusion Blanket and Shield Technology (Poster Session) | doi.org/10.13182/FST98-A11963719
Articles are hosted by Taylor and Francis Online.
The attractive features and scientific challenges offered by the liquid wall systems render them strong candidates for investigation in the APEX project[1]. In particular, their high power density capabilities make the fusion reactors economically competitive. In this paper, as part of evolving a practical design based on this evolutionary idea, issues concerning thermalhydraulics of liquid surface first wall/blankets were analyzed. Design approaches as presently envisioned include both liquid films over the solid surface and gravity driven thick liquid jets using lithium and flibe as working fluids. The analyses involved defining liquid systems operating conditions, such as velocity and inlet/outlet temperatures, as well as to calculate free surface temperature so that the evaporation rate from the free surface would not jeopardize plasma operation while maintaining the liquid temperature within the operating windows for high thermal efficiencies. All analyses were performed for a neutron wall load of 10 MW/m2 and its corresponding surface heat flux of 2 MW/m2. The results indicated that high velocities, hard x-ray spectra and turbulent heat transfer enhancement were necessary conditions for keeping flibe first wall temperature low. On the other hand, at velocities of 20 m/s or higher, it appears possible to maintain lithium film evaporation rate below 1020#/m2s in an ARIES-RS type configuration. Nevertheless, present analyses have not uncovered any basic flaws or major shortcomings in the underlying scientific or technical arguments for the concepts. Yet, engineering innovations of how to maintain and control the flow and the associated analyses are still needed.