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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
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.
M. G. Silbert, J. R. Berreth
Nuclear Science and Engineering | Volume 52 | Number 2 | October 1973 | Pages 187-200
Technical Paper | doi.org/10.13182/NSE73-A28188
Articles are hosted by Taylor and Francis Online.
The radiative capture cross section of 238Pu has been measured from 18-eV to 200-keV neutron energy. A time-of-flight experiment with a 306-m flight path was carried out in conjunction with the underground nuclear explosion Persimmon. Fission-fragment detectors viewed a thin 238Pu target to measure the fission cross section, while modified Moxon-Rae detectors viewed a second, thicker 238Pu target to measure the gamma-ray emission. Subtraction of the fission gamma-ray contribution from the Moxon-Rae signal yielded the contribution due to radiative capture. Single-level area analysis of the measured fission and capture cross sections gave values for the neutron and fission widths of 49 resonances below 500 eV, under the assumption of a known, constant radiative capture width. The s-wave neutron strength function was determined to be (1.27 ± 0.25) × 10-4. The derived fission widths exhibit a distinct maximum near 300-eV neutron energy. At higher energies, the fission-to-capture ratio shows pronounced intermediate-structure peaks attributed to second-well effects in the fission barrier.
