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Conference Spotlight
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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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.
Chin-Jen Chang, Samim Anghaie
Nuclear Science and Engineering | Volume 128 | Number 3 | March 1998 | Pages 297-311
Technical Paper | doi.org/10.13182/NSE98-A1957
Articles are hosted by Taylor and Francis Online.
A numerical experimental technique is presented to find an optimum solution to an undetermined inverse gamma-ray transport problem involving the nondestructive assay of radionuclide inventory in a nuclear waste drum. The method introduced is an optimization scheme based on performing a large number of numerical simulations that account for the counting statistics, the nonuniformity of source distribution, and the heterogeneous density of the self-absorbing medium inside the waste drum. The simulation model uses forward projection and backward reconstruction algorithms. The forward projection algorithm uses randomly selected source distribution and a first-flight kernel method to calculate external detector responses. The backward reconstruction algorithm uses the conjugate gradient with nonnegative constraint or the maximum likelihood expectation maximum method to reconstruct the source distribution based on calculated detector responses. Total source activity is determined by summing the reconstructed activity of each computational grid. By conducting 10 000 numerical simulations, the error bound and the associated confidence level for the prediction of total source activity are determined.The accuracy and reliability of the simulation model are verified by performing a series of experiments in a 208-l waste barrel. Density heterogeneity is simulated by using different materials distributed in 37 egg-crate-type compartments simulating a vertical segment of the barrel. Four orthogonal detector positions are used to measure the emerging radiation field from the distributed source. Results of the performed experiments are in full agreement with the estimated error and the confidence level, which are predicted by the simulation model.