First Critical for Zeus, an Intermediate Neutron Energy Spectrum Experiment
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
In the past several years, the lack of benchmark data for critical experiments involving all forms of fissile/non-fissile systems operating on intermediate energy spectrum neutrons has become apparent. Intermediate energy spectrum systems are dominated by scattering and fission events induced by neutrons ranging in energy from 1 eV to Oil MeV. An intermediate energy spectrum system has been proposed for the potential disposition of surplus fissile materials. A review of criticality benchmark data shows that there have been no adequate tests of either fissile or non-fissile cross sections in intermediate energy spectrum critical assemblies. In this paper, the terms cross sections and nuclear data refer to actual cross sectional data, the evaluation of such data and finally, the processing of the data which produces the cross section sets used in the computer codes. Nuclear data uncertainties have been reported for some types of intermediate energy spectrum systems. Depending upon the available Monte Carlo cross sections used, Parks et al have reported significant variations in the & of intermediate energy spectrum metal/U-235 systems. ANSI standard ANSI/ANS-8. 1-1983 states, the “bias shall be established by correlating the results of criticality experiments with the results obtained for these same systems by the method being validated”. Thus, to resolve nuclear data uncertainties and ensure that adequate criticality safety margins are appropriately and economically obtained, it is necessary to have experimental benchmark data for fissile/non-fissile systems operating in an intermediate energy spectrum regime. The Zeus experiment is intended to provide benchmark quality nuclear criticality data for a wide variety of fissile and non-fissile materials in both fast and intermediate neutron energy spectra systems. In this paper, we will present a description of the Zeus assembly. We will then go onto present experimental results, from three configurations, produced during the first core loading and approach to critical.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 763260
- Report Number(s):
- LA-UR-00-93; TRN: US0100141
- Resource Relation:
- Conference: American Nuclear Society , Pittsburgh, PA (United States), 7-11 May 2000; Other Information: PBD: 1 Jan 2000
- Country of Publication:
- United States
- Language:
- English
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