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Nuclear Energy Conference & Expo (NECX)
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.
K. D. Lathrop
Nuclear Science and Engineering | Volume 32 | Number 3 | June 1968 | Pages 357-369
Technical Paper | doi.org/10.13182/NSE68-4
Articles are hosted by Taylor and Francis Online.
The nature of anomalous computational effects due to the discretization of the angular variable in transport theory discrete ordinates approximations is described and analyzed. The origin of these effects within the derivation of the Sn discrete ordinates equations is shown, and the effects are related to the non-equivalence of the general geometry discrete ordinates equations and the corresponding spherical harmonics equations. Procedures are given for the definition of two-dimensional discrete ordinates equations that are equivalent to the spherical harmonics equations. Elimination of ray effects from the two-dimensional S2 equations by reduction to the diffusion theory equations is verified in a numerical example. Recipes for the elimination of ray effects are analyzed in the analytic solution of the infinite medium, isotropic line-source problem in the rectangular geometry, S2 approximation. Optimum magnitudes for corrective source terms are indicated by the analysis. It is concluded that ray effects may be eliminated by modification of the discrete ordinates formulation, but that the extra computational effort may be more expensive than the alternative of increasing the order of angular quadrature and that the presence of discretization effects may serve as an indicator of the adequacy of the angular quadrature used.
