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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.
M. Fukushima, J. Goda, A. Oizumi, J. Bounds, T. Cutler, T. Grove, D. Hayes, J. Hutchinson, G. McKenzie, A. McSpaden, R. Sanchez, J. Walker, K. Tsujimoto
Nuclear Science and Engineering | Volume 194 | Number 2 | February 2020 | Pages 138-153
Technical Paper | doi.org/10.1080/00295639.2019.1663089
Articles are hosted by Taylor and Francis Online.
To validate lead (Pb) nuclear cross sections, a series of integral experiments to measure lead void reactivity worth was conducted systematically in three fast neutron spectra with different fuel compositions on the Comet critical assembly of the National Criticality Experiments Research Center. Previous experiments in high-enriched uranium (HEU)/Pb and low-enriched uranium (LEU)/Pb systems had been performed in 2016 and 2017, respectively. A follow-on experiment in a plutonium (Pu)/Pb system has been completed. The Pu/Pb system was constructed using lead plates and weapons-grade Pu plates that had been used in the Zero Power Physics Reactor (ZPPR) of Argonne National Laboratory until the 1990s. Furthermore, the HEU/Pb system was reexamined on the Comet critical assembly with a newly installed device that can measure the compression of the stack, improving reproducibility. Using the lead void reactivity worth measured in these three cores with different fuel compositions, the latest nuclear data libraries, JENDL-4.0 and ENDF/B-VIII.0, were tested with the Monte Carlo calculation code MCNP® version 6.1. As a result, the calculations by ENDF/B-VIII.0 were confirmed to agree with lead void reactivity worth measured in all the cores. It was furthermore found that the calculations by JENDL-4.0 overestimate by more than 20% for the Pu/Pb core while being in good agreement for the HEU/Pb and LEU/Pb cores.