Safety implications of a sensitivity analysis of the reactor kinetics parameters for fast breeder reactors
The delayed neutron spectra for LMFBRs are not as well known as those for LWRs. These spectra are necessary for kinetics calculations which play an important role in safety and accident analyses. In this study, a sensitivity analysis was performed to study the sensitivity of the reactor power and power density to uncertainties in the delayed neutron spectra during a rod ejection accident. The generalized methodology, developed by Cacuci et. al., was used to derive a set of sensitivity derivatives. This method is based on the use of adjoints so that it is not necessary to repeatedly solve the governing (kinetics) equations to obtain the sensitivity derivatives. This is of particular importance when large systems of equations are used. A two-energy multigroup and two precursor group model was formulated for the INFCE reference design MOX-fuelled LMFBR. The accidents studied were central control rod ejections with ejection times of 2, 10, and 30 seconds. The power and power density responses were found to be most sensitive to uncertainties in the spectrum of the second delayed neutron precursor group, resulting from the fission of U-238, producing neutrons in the first energy group. The versatility and accuracy of Cacuci's methodology has been demonstrated. The results of the sensitivity analysis indicates the need for improved delayed neutron spectral data in order to reduce the uncertainties in the accident analyses.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg (USA)
- OSTI ID:
- 6309847
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
LMFBR TYPE REACTORS
REACTOR KINETICS
REACTOR SAFETY
ROD DROP ACCIDENTS
SENSITIVITY ANALYSIS
DELAYED NEUTRONS
MATHEMATICAL MODELS
NEUTRON SPECTRA
POWER DENSITY
REACTOR ACCIDENTS
ACCIDENTS
BARYONS
BREEDER REACTORS
ELEMENTARY PARTICLES
EPITHERMAL REACTORS
FAST REACTORS
FBR TYPE REACTORS
FERMIONS
FISSION NEUTRONS
HADRONS
KINETICS
LIQUID METAL COOLED REACTORS
NEUTRONS
NUCLEONS
REACTIVITY
REACTIVITY INSERTIONS
REACTORS
SAFETY
SPECTRA
220900* - Nuclear Reactor Technology- Reactor Safety
210500 - Power Reactors
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