Calculation of LWR βeff kinetic parameters: Validation on the MISTRAL experimental program

Santamarina, A.; Blaise, Patrick; Erradi, L.; Fougeras, Philippe

doi:10.1016/j.anucene.2012.05.001

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…The uncertainties are the statistical uncertainties from MCNP5-v1. 6 and are given at one standard deviation. The CPSD estimates are more precise for this comparison.…”

Section: Comparison With Mcnp5-v16 Predictionsmentioning

confidence: 99%

“…The International Handbook of Evaluated Criticality Safety Benchmark Experiments database [5] together with several independent experiments (e.g. [6]) are already available for that purpose. Nonetheless, new experiments continue to be performed in zero-power facilities around the world to enlarge the benchmark database and reduce the experimental uncertainties (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Perret

2015

2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and Their Applications (ANIMMA

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The critical decay constant (β/Λ), delayed neutron fraction (β) and generation time (Λ) of the Minerve reactor were measured by the Paul Scherrer Institut (PSI) and the Commissariat à l'Energie Atomique (CEA) in September 2014 using the Feynman-α and Power Spectral Density neutron noise measurement techniques. Three slightly subcritical configuration were measured using two 1-g 235 U fission chambers. This paper reports on the results obtained by PSI in the near critical configuration (-2¢). The most reliable and precise results were obtained with the Cross-Power Spectral Density technique: β = 708.4±9.2 pcm, β/Λ = 79.0±0.6 s -1 and Λ = 89.7±1.4 μs. Predictions of the same kinetic parameters were obtained with MCNP5-v1.6 and the JEFF-3.1 and ENDF/B-VII.1 nuclear data libraries. On average the predictions for β and β/Λ overestimate the experimental results by 5% and 11%, respectively. The discrepancy is suspected to come from either a corruption of the data or from the inadequacy of the point kinetic equations to interpret the measurements in the Minerve driven system.

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“…The uncertainties are the statistical uncertainties from MCNP5-v1. 6 and are given at one standard deviation. The CPSD estimates are more precise for this comparison.…”

Section: Comparison With Mcnp5-v16 Predictionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Perret

2015

2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and Their Applications (ANIMMA

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“…In the present work, the contribution of the kinetic parameters to the final uncertainty is small because we have used b eff values which have been measured during the MISTRAL-1 and MISTRAL-2 programs. Results reported in reference [32] are 788 ± 12 pcm for MISTRAL-1 (UOX core) and 370 ± 6 pcm for MISTRAL-2 (MOX core). Technological uncertainties are not included.…”

Section: Reactivity Excess As a Function Of Temperaturementioning

confidence: 99%

Impact of the thermal scattering law of H in H₂O on the isothermal temperature reactivity coefficients for UOX and MOX fuel lattices in cold operating conditions

Scotta

Noguère

Bernard

et al. 2016

EPJ Nuclear Sci. Technol.

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Abstract. The contribution of the thermal scattering law of hydrogen in light water to isothermal temperature reactivity coefficients for UOX and MOX lattices was studied in the frame of the MISTRAL critical experiments carried out in the zero power reactor EOLE of CEA Cadarache (France). The interpretation of the core residual reactivity measured between 6°C to 80°C (by step of 5°C) was performed with the Monte-Carlo code TRIPOLI4 ® . The nuclear data from the JEFF-3.1.1 library were used in the calculations. Three different thermal scattering laws of hydrogen in light water were tested in order to evaluate their impact on the MISTRAL calculations. The thermal scattering laws of interest were firstly those recommended in JEFF-3.1.1 and ENDF/B-VII.1 and also that recently produced at the atomic center of Bariloche (CAB, Argentina) with molecular dynamic simulations. The present work indicates that the calculation-to-experimental bias is À0.4 ± 0.3 pcm/°C in the UOX core and À1.0 ± 0.3 pcm/°C in the MOX cores, when the JEFF-3.1.1 library is used. An improvement is observed over the whole temperature range with the CAB model. The calculation-to-experimental bias vanishes for the UOX core (À0.02 pcm/°C) and becomes close to À0.7 pcm/°C for the MOX cores. The magnitude of these bias have to be connected to the typical value of the temperature reactivity coefficient that ranges from À5 pcm/°C at Begining Of Cycle (BOC) up to À50 pcm/°C at End Of Cycle (EOC), in PWR conditions.

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“…The transfer function of the reactor links the reactor neutron population to the neutron source fluctuations. The zero power transfer function can be derived from point kinetic equations, where the source noise is considered to be entirely due to fluctuations in the core reactivity, in the neutron population and in the precursors concentration (Keepin, 1965;Williams, 1974;Santamarina et al, 2012). For large enough frequencies, i.e.…”

Section: The Cohn-α Formalismmentioning

confidence: 99%

“…The zero power transfer function amplitude |H(ω)| 2 can also be written in terms of two detectors' readings c 1 (t) and c 2 (t) (Cohn, 1960;Santamarina et al, 2012) in the following form…”

Section: The Cohn-α Formalismmentioning

confidence: 99%

Sensitivity of power spectral density techniques to numerical parameters in analyzing neutron noise experiments

Gilad

Geslot

Blaise

et al. 2017

Progress in Nuclear Energy

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Power spectral density methods (Cohn-α methods) are well-known and widely used for the analysis of neutron noise experiments and obtaining the reactor core integral kinetic parameters, i.e., the effective delayed neutron fraction β eff and the prompt neutron generation time Λ. The Cohn-α methods are considered as the standard data processing procedure in the case of a current acquisition system that works at high fission rates. Many uncertainties are usually considered in the Cohn-α method, e.g., statistical fluctuations in the neutron count, power drifts, uncertainties in the Diven factor, the integral fission rate, and in the reactivity value. However, the uncertainty associated with the numerical parameters used in the power spectra calculation procedure, e.g., time bin size and buffer size, is hardly discussed in the literature and generally overlooked. In this paper, The Cohn-α method is implemented to analyze critical and subcritical configurations of the MAESTRO core in the MINERVE zero power reactor in order to measure its β eff and Λ integral kinetic parameters. Both cross-correlation and auto-correlation power spectral densities are calculated and the kinetic parameters are obtained via Lorentzian curve fitting over the calculated spectra. The sensitivity of the obtained kinetic parameters to the choice of numerical parameters used for spectrum calculations is studied and found to be pronounced and comparable with other uncertainties. A novel methodology is proposed for analyzing the kinetic parameters' sensitivity to the power spectra calculations and for quantifying the associated uncertainties.

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Calculation of LWR βeff kinetic parameters: Validation on the MISTRAL experimental program

Cited by 9 publications

References 7 publications

Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Impact of the thermal scattering law of H in H₂O on the isothermal temperature reactivity coefficients for UOX and MOX fuel lattices in cold operating conditions

Sensitivity of power spectral density techniques to numerical parameters in analyzing neutron noise experiments

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Calculation of LWR βeff kinetic parameters: Validation on the MISTRAL experimental program

Cited by 9 publications

References 7 publications

Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Delayed neutron fraction and prompt decay constant measurement in the Minerve reactor using the PSI instrumentation

Impact of the thermal scattering law of H in H2O on the isothermal temperature reactivity coefficients for UOX and MOX fuel lattices in cold operating conditions

Sensitivity of power spectral density techniques to numerical parameters in analyzing neutron noise experiments

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Impact of the thermal scattering law of H in H₂O on the isothermal temperature reactivity coefficients for UOX and MOX fuel lattices in cold operating conditions