Integration of Several Elements of the DOE Nuclear Criticality Safety Program

Conference · Tue Nov 13 04:00:00 EST 2001

OSTI ID:788578

Valentine, Timothy E. ^[1]; Derrien, Herve ^[2]; Leal, Luiz C. ^[2]; Guber, Klaus H. ^[2]; Briggs, J. Blair ^[3]; Tsiboulia, Anatoli ^[4]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); ORNL
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Idaho National Lab. (INL), Idaho Falls, ID (United States)
4. Leypunsky Inst. of Physics and Power Engineering (IPPE), Obninsk (Russian Federation)

The U.S. Department of Energy established the Nuclear Criticality Safety Program (NCSP) to maintain the infrastructure and expertise in nuclear criticality safety to support line criticality safety programs at various DOE sites. The seven tasks of the NCSP include critical experiments, benchmarking, nuclear data, analytical methods, applicable ranges of bounding curves and data, information preservation and dissemination, and training and qualification. The goals of this program are to improve the knowledge, tools, data, guidance, and information available to the nuclear criticality safety community. In addition, various elements of the NCSP are integrated together to provide the nuclear criticality safety community with the most precise nuclear data for criticality safety analyses. This paper describes how several elements of the NCSP were integrated together in the evaluation of the silicon nuclear data. Silicon is frequently encountered in decontamination and decommissioning efforts, process sludge and settling tanks, in situ vitrification, and waste remediation efforts (including waste storage, retrieval, characterization, volume reduction, and stabilization). Silicon was also identified as an important isotope for addressing concerns associated with the storage of spent nuclear fuels in a geologic repository. The inadequacy of the silicon nuclear data in the intermediate energy region mandated that additional neutron capture cross-section measurements had to be performed that encompassed the resolved resonance region. An evaluation was performed that included analysis of the most recent neutron capture and existing transmission cross-section measurements performed at the Oak Ridge Electron Linear Accelerator. Critical experiments were performed at the Institute of Physics and Power Engineering in Obninsk, Russia because of the lack of critical experiment data for analysis of storage of nuclear material in a geologic repository. These critical experiments were evaluated, and benchmark models were developed and submitted to the International Criticality Safety Benchmark Evaluation Project for review and publication in the ''International Handbook of Evaluated Criticality Safety Benchmark Experiments''. Sensitivity analyses were performed as a part of the benchmark evaluation to determine the sensitivity of the critical experiments to the various constituents of the assembly. The benchmark models were then used to determine the computed k_eff for various cross section data sets. The variation in the computed k_eff value for the new evaluated data set was then used as an indicator to adjust the negative energy capture widths for the capture cross section data. Furthermore, the changes in k_eff were used as an indicator to the inadequacy of previous measured data in the unresolved resonance region. The result of the efforts of the NCSP provided the most precise set of nuclear data for silicon. The resulting ORNL evaluation produced the most consistent evaluation for silicon. This result could only be achieved through integration of many components of the NCSP.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 788578
• Report Number(s): P01-111315
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
96 KNOWLEDGE MANAGEMENT AND PRESERVATION
BENCHMARKS
CRITICALITY
CROSS SECTIONS
Evaluated Nuclear Data File (ENDF)
International Criticality Safety Benchmark Evaluation Project (ICSBEP)
LINEAR ACCELERATORS
MANUALS
Monte Carlo N-Particle (MCNP)
NEUTRON REACTIONS
NJOY
Nuclear Criticality Safety Program (NCSP)
ORELA
PROGRAM MANAGEMENT
RADIOACTIVE WASTE STORAGE
SAFETY
SAMMY
SILICON
SPENT FUELS
Silicon Nuclear Data
US DOE