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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.
Mark S. Smith, Darren H. Wood, James D. Drischler
Nuclear Technology | Volume 104 | Number 1 | October 1993 | Pages 118-127
Technical Paper | Reactor Operation | doi.org/10.13182/NT93-A34874
Articles are hosted by Taylor and Francis Online.
The results of an analysis using data reports submitted to the Centralized Reliability Data Organization (CREDO) to predict the onset of the wearout life period for large sodium centrifugal pumps is described. For CREDO data collection and analysis purposes, a “mechanical pump” includes the pumping unit, its driver, and the coupling between the two. Statistical data were compiled from event reports received from three fast reactors: the Experimental Breeder Reactor II (EBR-II) and the Fast Flux Test Facility (FFTF) in the United States and the JOYO Experimental Fast Reactor operated by the Power Reactor and Nuclear Fuel Development Corporation of Japan. Cumulative event rates were calculated for the investigated pumps at each facility and for the entire population. For all pumps, the event rate was computed as 34.4 event/million operating hours with 5 and 95 % one-sided confidence limits of 26.3 and 44.4 event/million operating hours, respectively. The cumulative event rates for EBR-II, FFTF, and JOYO were computed as 30.0, 32.4, and 40.6 event/million pump operating hours, respectively. Results from EBR-II indicate that there is a definite time-dependent relationship between event rates and pump age; the common event mode at EBR-II is pump binding or seizing due to the buildup of sodium deposits in the vicinity of the lower labyrinth seal. There is no indication from FFTF that the six centrifugal pumps have reached the end of their useful life; these pumps have been event free for their last 40000 operating hours. Following a 50000-h event-free operating period at JOYO, bearings in the secondary pumps required additional unscheduled maintenance. However, there is no indication that these pumps have entered into the wearout life period; more data are required to draw any such conclusion.