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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Powering the future: How the DOE is fueling nuclear fuel cycle research and development
As global interest in nuclear energy surges, the United States must remain at the forefront of research and development to ensure national energy security, advance nuclear technologies, and promote international cooperation on safety and nonproliferation. A crucial step in achieving this is analyzing how funding and resources are allocated to better understand how to direct future research and development. The Department of Energy has spearheaded this effort by funding hundreds of research projects across the country through the Nuclear Energy University Program (NEUP). This initiative has empowered dozens of universities to collaborate toward a nuclear-friendly future.
M. Segev, G. Raitses, J. M. Paratte
Nuclear Science and Engineering | Volume 131 | Number 1 | January 1999 | Pages 123-131
Technical Paper | doi.org/10.13182/NSE99-A2023
Articles are hosted by Taylor and Francis Online.
The radial distribution of capture rate and effective cross section in fuel rods of radii R, forming a light water reactor (LWR) lattice, is derived with routine cell calculations. Any internal radial subrange (r1,r2) is treated through the assessment of absorption in the two corresponding annular absorbers (r1,R) and (r2,R). The lattice of the latter absorbers, whose pitch is exactly the original LWR lattice pitch, is equivalenced to a lattice of solid cylindrical rods. Thus, for example, to obtain a tenfold radial distribution, ten routine cell calculations are required.In determining the radius s of a cylinder equivalent to the annulus (r,R), the neutron escape from the annulus is first preserved by making the s rod have a circumference of 2R[1 - (0.5 - (1/)cos-1(r/R))G], where G is the "sticking" probability in the annulus for neutrons entering it from within. The radius s is then the result of making the solid rod and the annulus have the same average chord. In addition, a lattice is assigned to the s rods such that the original Dancoff factor is preserved. Finally, a Bell factor is determined for the s rod such that the actual grayness of the annulus (r,R) is preserved.A special program for transport-related probabilities is invoked in obtaining the sticking and Dancoff probabilities just described, as well as the Bell factor.Application of the theory was conducted with the ELCOS system BOXER cell code. Three benchmarks were considered. The first was the one suggested by Tellier et al. for a fuel pin of a typical pressurized water reactor cell. The second was almost identical to the first, except that the fuel was saturated with hydrogen to generate a flatter radial distribution than in the first benchmark. The third benchmark was based on detailed space-energy calculations for a boiling water reactor rod, performed in 1978.All three benchmark testings resulted in satisfactory comparisons. Hence, the present theory may provide a practical, routine way of obtaining the in-rod distribution of absorption and cross section, calling just for a repeated use of straightforward cell calculations.
