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Title: Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System

Abstract

The National Aeronautics and Space Administration (NASA) is providing funding to the Department of Energy (DOE) to assess, develop, and test nuclear technologies that could provide surface power to a lunar outpost. Sufficient testing of this fission surface power (FSP) system will need to be completed to enable a decision by NASA for flight development. The near-term goal for the FSP work is to conduct the minimum amount of testing needed to validate the system performance within an acceptable risk. This report attempts to assess the current modeling capabilities and quantify any bias associated with the modeling methods for designing the nuclear reactor. The baseline FSP system is a sodium-potassium (NaK) cooled, fast spectrum reactor with 93% 235U enriched HEU-O2 fuel, SS316 cladding, and beryllium reflectors with B4C control drums. The FSP is to produce approximately 40 kWe net power with a lifetime of at least 8 years at full power. A flight-ready FSP is to be ready for launch and deployment by 2020. Existing benchmarks from the International Criticality Safety Benchmark Evaluation Program (ICSBEP) were reviewed and modeled in MCNP. An average bias of less than 0.6% was determined using the ENDF/B-VII cross-section libraries except in the case ofmore » subcritical experiments, which exhibited an average bias of approximately 1.5%. The bias increases with increasing reflector worth of the beryllium. The uncertainties and sensitivities in cross section data for the FSP model and ZPPR-20 configurations were assessed using TSUNAMI-3D. The cross-section covariance uncertainty in the FSP model was calculated as 2.09%, which was dominated by the uncertainty in the 235U(n,?) reactions. Global integral indices were generated in TSUNAMI-IP using pre-release SCALE 6 cross-section covariance data. The ZPPR-20 benchmark models exhibit strong similarity with the FSP model. A penalty assessment was performed to determine the degree of which the FSP model could not be characterized by available ZPPR-20 benchmark data. The uncertainty in the FSP covariance data was reduced from 2.09% to 0.29%, where the bulk of the uncertainty was from the Be(n,n) reaction. Advanced analysis techniques using ZPPR-20C data should provide sufficient information to preclude the necessity of a cold critical of the FSP. Further testing to reduce uncertainties in the beryllium and uranium cross-section data should reduce the overall uncertainty in the computational models. The utilization of parameterization analysis software with perturbation techniques can help in understanding the computational uncertainty and relative systematic effects of parameters such as control drum, reflector, and material worth, temperature effects, and reaction rate measurements.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
961920
Report Number(s):
INL/CON-08-15138
TRN: US0903509
DOE Contract Number:  
DE-AC07-99ID-13727
Resource Type:
Conference
Resource Relation:
Conference: Nuclear and Emerging Technologies for Space (NETS) at the American Nuclear Society (ANS) Annual Meet,Atlanta, Georgia,06/14/2009,06/18/2009
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BENCHMARKS; BERYLLIUM; CRITICALITY; CROSS SECTIONS; FISSION; LIFETIME; NASA; POTASSIUM ALLOYS; POWER SYSTEMS; REACTION KINETICS; REACTORS; SAFETY; SODIUM ALLOYS; TEMPERATURE DEPENDENCE; TESTING; URANIUM; Fission Surface Power; Space Nuclear Power; Zero Power Critical Assessment

Citation Formats

Parry, Jim R, bess, John Darrell, Rearden, Brad T, and Harms, Gary A. Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System. United States: N. p., 2009. Web.
Parry, Jim R, bess, John Darrell, Rearden, Brad T, & Harms, Gary A. Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System. United States.
Parry, Jim R, bess, John Darrell, Rearden, Brad T, and Harms, Gary A. Mon . "Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System". United States. https://www.osti.gov/servlets/purl/961920.
@article{osti_961920,
title = {Assessment of Zero Power Critical Experiments and Needs for a Fission Surface Power System},
author = {Parry, Jim R and bess, John Darrell and Rearden, Brad T and Harms, Gary A},
abstractNote = {The National Aeronautics and Space Administration (NASA) is providing funding to the Department of Energy (DOE) to assess, develop, and test nuclear technologies that could provide surface power to a lunar outpost. Sufficient testing of this fission surface power (FSP) system will need to be completed to enable a decision by NASA for flight development. The near-term goal for the FSP work is to conduct the minimum amount of testing needed to validate the system performance within an acceptable risk. This report attempts to assess the current modeling capabilities and quantify any bias associated with the modeling methods for designing the nuclear reactor. The baseline FSP system is a sodium-potassium (NaK) cooled, fast spectrum reactor with 93% 235U enriched HEU-O2 fuel, SS316 cladding, and beryllium reflectors with B4C control drums. The FSP is to produce approximately 40 kWe net power with a lifetime of at least 8 years at full power. A flight-ready FSP is to be ready for launch and deployment by 2020. Existing benchmarks from the International Criticality Safety Benchmark Evaluation Program (ICSBEP) were reviewed and modeled in MCNP. An average bias of less than 0.6% was determined using the ENDF/B-VII cross-section libraries except in the case of subcritical experiments, which exhibited an average bias of approximately 1.5%. The bias increases with increasing reflector worth of the beryllium. The uncertainties and sensitivities in cross section data for the FSP model and ZPPR-20 configurations were assessed using TSUNAMI-3D. The cross-section covariance uncertainty in the FSP model was calculated as 2.09%, which was dominated by the uncertainty in the 235U(n,?) reactions. Global integral indices were generated in TSUNAMI-IP using pre-release SCALE 6 cross-section covariance data. The ZPPR-20 benchmark models exhibit strong similarity with the FSP model. A penalty assessment was performed to determine the degree of which the FSP model could not be characterized by available ZPPR-20 benchmark data. The uncertainty in the FSP covariance data was reduced from 2.09% to 0.29%, where the bulk of the uncertainty was from the Be(n,n) reaction. Advanced analysis techniques using ZPPR-20C data should provide sufficient information to preclude the necessity of a cold critical of the FSP. Further testing to reduce uncertainties in the beryllium and uranium cross-section data should reduce the overall uncertainty in the computational models. The utilization of parameterization analysis software with perturbation techniques can help in understanding the computational uncertainty and relative systematic effects of parameters such as control drum, reflector, and material worth, temperature effects, and reaction rate measurements.},
doi = {},
url = {https://www.osti.gov/biblio/961920}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {6}
}

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