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September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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.
Cris W. Barnes, Alvin R. Larson, A. L. Roquemore
Fusion Science and Technology | Volume 30 | Number 1 | September 1996 | Pages 63-72
Technical Paper | Blanket Engineering | doi.org/10.13182/FST96-A30763
Articles are hosted by Taylor and Francis Online.
The most accurate determination of neutron yields from fusion reactors maybe obtained from neutron activation measurements of elemental foils. On the Tokamak Fusion Test Reactor (TFTR), a re-entrant irradiation end has been installed to provide a low-scattering environment close to the plasma for neutron activation measurements. The ratio of energy-dependent fluence to total fusion yield is calculated using a fully three-dimensional Monte Carlo calculation with the Monte Carlo code for neutron and photon transport (MCNP). Corrections to the “virgin” fluence from attenuation and scattering are only 10 to 20% for deuterium-tritium (D-T) reactions and 30 to 40% for deuterium-deuterium reactions. A total 1-sigma accuracy of ±8% is achieved for D-T neutron yields over a wide dynamic range. This paper documents the response coefficients (hits per source neutron, where hits are activated nuclei per target nuclei) for use by the neutron activation system on TFTR; describes the possible systematic corrections needed (such as major radial variations or the impact of ion temperature on reactions with high-energy thresholds); and estimates uncertainties in the response coefficients. Results from in situ use of a D-T neutron generator are also analyzed using the MCNP modeling as an approximate benchmarking experiment; only 20% accuracy in the comparison is possible because of poor counting statistics in the calibration experiment.
