Validation of criticality safety calculations with subcriticality measurements by the {sup 252}Cf-source-driven noise method

Conference · Thu Sep 01 04:00:00 EDT 1994

OSTI ID:68739

Mihalczo, J T; Krass, A W ^[1]; Valentine, T E ^[2]; Ficaro, E P

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1. Oak Ridge National Lab., TN (United States)
2. Univ. of Tennessee, Knoxville, TN (United States)

The {sup 252}Cf-source-driven noise analysis method has successfully measured the subcritical neutron multiplication factor k for a wide variety of fissile systems. The recent modifications of the KENO Va Monte Carlo code to calculate directly the measured noise analysis data allow the use of this experimental data for validation of calculational methods and cross sections. High sensitivity of noise-measured parameters to small changes in fissile systems has been observed in several measurements. To investigate this sensitivity, a series of calculations was performed for a 3 by 3 array of PWR spent-fuel elements in unborated water. The macroscopic fission-product cross sections were changed, and the resulting ratios of spectral densities, coherence between detectors, and values of k were obtained from this Monte Carlo simulation of the measurement. The sensitivity of the ratios of spectral densities and coherences to changes in fission-product cross sections were a factor of 10 and 4{degrees}, respectively, more than that of k. These Monte Carlo calculations have shown that this type of subcritical measurement can be used to benchmark fission-product cross sections for spent PWR fuel and, because of the high sensitivity of the noise analysis quantities, would provide a more stringent test of the fission-product cross sections than comparison of calculation with experiments at delayed criticality, even though the value of k can be measured more accurately at delayed criticality.

• Research Organization: Los Alamos National Lab., NM (United States)
• OSTI ID: 68739
• Report Number(s): LA--12556-C; CONF-9205206--; ON: DE95000557
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
22 GENERAL STUDIES OF NUCLEAR REACTORS
42 ENGINEERING
CALIFORNIUM 252
CRITICALITY
K CODES
MONTE CARLO METHOD
SPENT FUEL ELEMENTS
VERIFICATION