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The spark of the Super: Teller–Ulam and the birth of the H-bomb—rivalry, credit, and legacy at 75 years
In early 1951, Los Alamos scientists Edward Teller and Stanislaw Ulam devised a breakthrough that would lead to the hydrogen bomb [1]. Their design gave the United States an initial advantage in the Cold War, though comparable progress was soon achieved independently in the Soviet Union and the United Kingdom.
Weixiong Zheng, Ryan G. McClarren, Jim E. Morel
Nuclear Science and Engineering | Volume 189 | Number 3 | March 2018 | Pages 259-271
Technical Paper | doi.org/10.1080/00295639.2017.1407592
Articles are hosted by Taylor and Francis Online.
In this work, we present a subdomain discontinuous least-squares (SDLS) scheme for neutronics problems. Least-squares (LS) methods are known to be inaccurate for problems with sharp total cross-section interfaces. In addition, the LS scheme is known not to be globally conservative in heterogeneous problems. In problems where global conservation is important, e.g., k-eigenvalue problems, a conservative treatment must be applied. In this study, we propose an SDLS method that retains global conservation and, as a result, gives high accuracy on eigenvalue problems. Such a method resembles the LS formulation in each subdomain without a material interface and differs from LS in that an additional LS interface term appears for each interface. The scalar flux is continuous in each subdomain with the continuous finite element method while discontinuous on interfaces for every pair of contiguous subdomains. The SDLS numerical results are compared with those obtained from other numerical methods with test problems having material interfaces. High accuracy of scalar flux in fixed-source problems and in eigenvalue problems is demonstrated.