A New Era of Nuclear Criticality Experiments: The First 10 Years of Comet Operations at NCERC

Abstract

Comet is a general-purpose, heavy-duty, vertical-lift assembly designed for flexibility in conducting a variety of critical experiments. It is currently located at the National Criticality Experiments Research Center (NCERC) in Nevada. In the past, Comet resided at Technical Area-18 in Los Alamos, New Mexico, as part of the Los Alamos Critical Experiments Facility (LACEF). The Comet assembly was relocated to NCERC in 2008 and became fully operational in June of 2011. The first critical experiment performed on Comet at NCERC was a verification of one of the previous configurations of theZeus experiment series. Over the next 10 years, many additional experiments followed including other Zeus configurations as well as completely new designs. This paper discusses the Comet vertical-lift assembly, the transition from LACEF to NCERC, and a selection of experiments that have been performed on Comet during its first 10 years of operation at NCERC.

A New Era of Nuclear Criticality Experiments: The First 10 Years of Flattop Operations at NCERC

“…Power DUFF successfully demonstrated the viability of a compact nuclear reactor-driven heat pipe/Stirling engine power conversion system, providing the data and confidence to proceed with the Kilopower Reactor Using Stirling Technology (KRUSTy) Experiment. 14,15…”

The National Criticality Experiments Research Center and its role in support of advanced reactor design

“…There was also a Jupiter configuration which utilized ZPPR plates with higher 240 Pu content. The HEU/Pb system had a negative lead void coefficient of reactivity, but the IEU/Pb had a positive lead void coefficient; this behavior was predicted in MCNP simulations, but it highlights the importance of demonstration experiments to prove that models are performing correctly (Goda et al, 2015;Goda et al, 2019, Thompson et al, 2021b. Work is ongoing to submit these experiments to the ICSBEP as benchmarks (McSpaden et al, 2019b, McSpaden et al, 2020Amundson et al, 2020).…”

“…This also includes many subcritical experiments. These experiments have been documented in a special issue of Nuclear Science and Engineering (Hutchinson et al, 2021b;Thompson et al, 2021b;Goda et al, 2021;Hayes et al, 2021;Sanchez et al, 2021).…”

“…Many other experiments have been performed at NCERC specifically focused on nuclear data validation, including the TEX HEU and TEX Pu series, the Zeus series, and others (Percher and Norris, 2019;Norris, 2020, Norris andAraj, 2021;Mosteller et al, 2004;Mosteller, 2005;Hayes and Sanchez, 2006). These experiments are detailed in the NCERC Ten Year Papers and other publications (Hutchinson et al, 2021b;Thompson et al, 2021b;Goda et al, 2021;Hayes et al, 2021;Sanchez et al, 2021).…”