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

Abstract

The Flattop critical assembly was built and operated from 1958 through 2004 at the Pajarito Site (Technical Area-18), home to the Los Alamos Critical Experiments Facility. Flattop was disassembled in 2005 and refurbished over the course of 3 years. In 2008, Flattop was installed in the National Criticality Experiments Research Center (NCERC) located in the Device Assembly Facility at the Nevada National Security Site. Startup of Flattop with a uranium core occurred in 2011. This paper details the first 10 years of Flattop operations at NCERC (2011-present).

A New Era of Nuclear Criticality Experiments: The First 10 Years of Radiation Test Object Operations at NCERC

“…Both utilize the same SNM, personnel, detection systems, and measurement methods. For this reason, some of the experiments presented in this work may look similar to, and share SNM with, experiments on the Planet, 8 Comet, 9 Flattop, 10 and Godiva IV (Ref. 11) critical assembly machines.…”

“…Some classes also include overviews of neutron and/or gamma detection and may include radiography. Demonstrations on the Planet, 8 Comet, 9 Flattop, 10 and/or Godiva IV (Ref. 11) critical assembly machines may also be performed.…”

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

“…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).…”