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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
J. D. Spencer, T. G. Williamson
Nuclear Science and Engineering | Volume 27 | Number 3 | March 1967 | Pages 568-572
Technical Paper | doi.org/10.13182/NSE86-A17623
Articles are hosted by Taylor and Francis Online.
The age of fission neutrons was measured to the indium resonance energy for light water and three metal-to-water volume ratios (1/4, 1/2, 2/3) in aluminum- water mixtures. A large plane highly enriched 235U fission plate provided the source of neutrons. Aluminum plates (0.127 × 122 × 122 cm) oriented parallel to the source plane were used for the metal. Indium foil activities were taken in planes parallel to the source and integrated over these planes to obtain the equivalent activities that would result from an infinite source. From these data, the ages for the four cases were: M/W = 0, (26.24 ± 0.33 cm2); M/W = 1/4, (32.28 ± 0.50 cm2); M/W = 1/2, (39.96 ± 0.50 cm2); M/W = 2/3, (44.88 ± 0.59 cm2). To investigate heterogeneous effects, the plates were lumped to simulate 0.635-cm-thick plates and the measurements repeated for the 2/3 metal-to-water ratio. The measured age was 44.50 ± 0.49 cm2, indicating no lumping effect in this measurement. The data for the pure water measurement were also analyzed by applying geometric corrections for the finite size of the source plate. This resulted in a measured age of 27.82 ± 0.66 cm2, which agrees with previous measurements utilizing this method of data analysis.
