2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009
The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors)... more The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of running French PWR reactors and EPR reactor, and innovating systems. In this framework, specific neutron integral experiments have been carried out in the critical facilities of the CEA Cadarache, such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE pool Zero Power Reactor experiments.
To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to b... more To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to be reduced from ±15% (current standard deviation) to ±5%. The improvement of 238 U scattering data has been achieved through the use of targeted integral measurements with a strong sensitivity to 238 U(n,n ). From the C/E biases and sensitivity coefficients, obtained from Monte Carlo TRIPOLI4/JEFF-3.1.1 calculations, we have re-estimated the 238 U data. A clear trend to reduce 238 U(n,n ) cross-section by (-11±3)% in the 2-5 MeV range is obtained, and the analysis using inelastic level sensitivities highlights a required (n,n continuum ) modification by (-10±2)%.
This paper describes innovative measurements of integral radiative capture rates of minor actinid... more This paper describes innovative measurements of integral radiative capture rates of minor actinides, performed in the MINERVE facility. They aim at resolving potential discrepancies on capture cross sections, especially in the framework of nuclear safety and of waste management.
ABSTRACT Benchmark measurements of irradiated and un-irradiated fuel samples were performed in th... more ABSTRACT Benchmark measurements of irradiated and un-irradiated fuel samples were performed in the framework of the CERES collaborative program between AEA (UK Atomic Energy Agency) and CEA (French Atomic Energy Commission). These experiments provide relevant data for the validation of fuel burn-up and criticality-safety calculations for the whole fuel cycle. As part of this program, pile-oscillation measurements were carried out on a range of mixed-oxide samples with plutonium of various mass and isotopic contents, both in the MINERVE and DIMPLE reactors. Four core configurations, two over-thermalized situations and two pressurized water reactor (PWR)-type situations, were constituted with different forward and adjoint flux spectra, emphasizing fission and/or capture contributions. The experiments were analyzed using reference TRIPOLI4 calculations with the JEFF-3.1.1 library, using exact three-dimensional models of the core configurations. In a first step, calculations of each DIMPLE configuration were performed and compared with the experiment, showing very good agreements with a maximum C-E of −230 pcm. In the second step, reactivity worth experiments were analyzed, using recently developed exact-perturbation capabilities in TRIPOLI4. A consistent assimilation of calculation over experiment discrepancies was performed with the CONRAD code, using the integral data assimilation method. Covariance matrix on multigroup neutron cross sections and multiplicities were generated and significant trends were identified, especially on the 239 Pu and 240 Pu capture cross sections in the thermal energy range (E < 0.1 eV). Further investigations should be required to confirm these conclusions, due to the strong dependence of these trends and of posterior covariances to prior covariances.
ABSTRACT The absolute emission probabilities of gamma rays from the decay of 238Np and 233Pa have... more ABSTRACT The absolute emission probabilities of gamma rays from the decay of 238Np and 233Pa have been measured by an innovative method combining pile oscillation and neutron activation techniques. We obtained values of (24.99 ± 0.34)% and (37.79 ± 0.64)% for the 984.5- and 311.9-keV gamma rays from 238Np and 233Pa, respectively, in good agreement with the recommended values proposed by the Decay Data Evaluation Project (DDEP): (25.18 ± 0.13)% and (38.3 ± 0.5)%. The influence of gamma-ray emission probabilities from 238Np and 233Pa on neutron capture cross-section measurements of 237Np and 232Th, respectively, are discussed and tend to confirm the recommended values from the DDEP. A patent has been granted for this method.
The need for accurate nuclear data represents a permanent challenge to improve the calculation to... more The need for accurate nuclear data represents a permanent challenge to improve the calculation tools used in reactor physics. Uranium-235 is one of the most important isotopes, and its related nuclear data need to be known with a high degree of accuracy. In this context, many studies have been undertaken to improve the fission yields of 235 U for the main fission products in spent fuels.
ABSTRACT To take into account the reactivity loss in spent fuels, an experimental program was set... more ABSTRACT To take into account the reactivity loss in spent fuels, an experimental program was set up in 1993 at CEA-Cadarache, France, oscillating separated fission products (FPs) in the MINERVE reactor. Reactivity worth measurements of small samples allow the extraction of information about nuclear data of the studied isotopes. A fully validated calculation scheme has been implemented to interpret pileoscillation measurements. Therefore, calculation over experiment ratios can be accurately transposed to trends in the integral capture cross section of the FPs. With the European JEFF3.1.1 library, results show a discrepancy below 3% for several nuclides: 155Gd, 149, 152Sm, 143Nd, and 95Mo, but improvements may be needed for some others: 133Cs, 103Rh, 99Ru, and 153Eu. Based on the Integral Data Assimilation technique, we propose new thermal cross-section values, (348+/-14) b and (42478+/-1793) b, for two of the most absorbing nuclides, 143Nd and 149Sm, respectively.
2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA), 2013
ABSTRACT The MAESTRO experimental programme has been designed to improve the nuclear data uncerta... more ABSTRACT The MAESTRO experimental programme has been designed to improve the nuclear data uncertainty on a large range of materials used for detection, absorption, moderation and structures in LWRs. Samples of high purity elements have been manufactured with severe constraints to reach a target accuracy of ±2% (1σ) on the measurement. Experiments are carried out in the MINERVE low-power facility between 2011 and 2014. Neutron activation and pile-oscillation techniques are used to provide complementary information on the capture and scattering cross sections through the measurement of isotopic capture rate and global reactivity-worth for each material. Preliminary results were obtained for natV, 55Mn, and 59Co in support to the instrumentation of GEN-III reactors, just like for 103Rh due to its major contribution to the reactivity loss in LWR. They show that the JEFF-3.1.1 evaluations are in close agreement with the experiment, especially for 103Rh where consistent results were obtained from microscopic experiments at GELINA.
The paper describes the Uncertainty Quantification approach currently implemented in the global v... more The paper describes the Uncertainty Quantification approach currently implemented in the global validation of APOLLO [1] and ERANOS [2] Neutron Code packages at CEA, with a special emphasis on the uncertainty management and its feedback on modern Nuclear Data assimilation and multi-parametric Transposition to Design parameters, for both thermal and fast complex nuclear systems.
To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to b... more To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to be reduced from ±15% (current standard deviation) to ±5%. The improvement of 238 U scattering data has been achieved through the use of targeted integral measurements with a strong sensitivity to 238 U(n,n ). From the C/E biases and sensitivity coefficients, obtained from Monte Carlo TRIPOLI4/JEFF-3.1.1 calculations, we have re-estimated the 238 U data. A clear trend to reduce 238 U(n,n ) cross-section by (-11±3)% in the 2-5 MeV range is obtained, and the analysis using inelastic level sensitivities highlights a required (n,n continuum ) modification by (-10±2)%.
The CERES collaborative program between the French Atomic Energy Commission (CEA) and the United ... more The CERES collaborative program between the French Atomic Energy Commission (CEA) and the United Kingdom Atomic Energy Agency (UKAEA) was performed in the MINERVE and DIMPLE reactors at Cadarache and Winfrith, respectively. CERES Phase II was devoted to the validation of fission product (FP) poisoning through the reactivity worth measurements of FP samples. This paper describes the oscillation experiment at the center of the MINERVE pressurized water reactor-type test lattice. This experiment is strongly representative of the FP poisoning in light water reactor spent fuels because the separated FP isotope is introduced into real UO 2 pellets where 238
The CEA is deeply involved in a research program (MTR, ZPR) concerning the nuclear fuel advanced ... more The CEA is deeply involved in a research program (MTR, ZPR) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of French PWR reactors and EPR reactor, and innovative systems. In this framework, specific neutron integral experiments have been carried out in the critical ZPR facilities of the CEA Cadarache such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE Pool Reactor experiments. MINERVE is mainly devoted to neutronics studies of different reactor core types. The aim is to improve the knowledge of the integral absorption cross sections of actinides (OSMOSE program), of new absorbers (OCEAN program) and also for fission Products (CBU program) in thermal, epithermal and fast neutron spectra.
Several calculations methods for the analysis of small-sample reactivity experiments are presente... more Several calculations methods for the analysis of small-sample reactivity experiments are presented, as their main advantages and drawbacks. A numerical benchmark has been defined for this study consisting in a regular lattice of UO2 fuel pins, in which the central one is successively poisoned with isotopes of interest (actinides, absorbers, …). A first method, based on a forward calculation (“eigenvalues difference method”), is presented, using either a deterministic or a stochastic calculation code. A first perturbative method studied is based on the “Exact Perturbation Theory” (EPT) implemented in the deterministic code APOLLO2.8, and gives consistent results against forward calculations. A second perturbative method, the “correlated sampling method”, implemented in the stochastic calculation code TRIPOLI4.7 is tested. It should be use carefully as it is generally validated against small atomic density changes, but can be useful for conception studies. An “hybrid method”, based on...
2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009
The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors)... more The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of running French PWR reactors and EPR reactor, and innovating systems. In this framework, specific neutron integral experiments have been carried out in the critical facilities of the CEA Cadarache, such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE pool Zero Power Reactor experiments.
This paper summarizes the Qualification work performed to demonstrate the accuracy of the new APO... more This paper summarizes the Qualification work performed to demonstrate the accuracy of the new APOLLO2.8/SHEM-MOC package based on JEFF3.1.1 nuclear data file for the prediction of PWR neutronics parameters. This experimental validation is based on PWR mock-up critical experiments performed in the EOLE reactor and on P.I.Es on spent fuel assemblies from the French PWRs. The Calculation-Experiment comparison for the main design parameters is presented: reactivity of UOX and MOX lattices, depletion calculation and fuel inventory, pin-by-pin power maps, Doppler coefficient, Moderator Temperature Coefficient, Void coefficient, UO2-Gd2O3 poisoning worth, Efficiency of Ag-In-Cd control rods, Reflector Saving for both standard 2-cm baffle and advanced thick SS reflector implemented in GEN3 reactors. From this qualification process, scaling factors and associated uncertainties are derived. This code package APOLLO2.8 is already implemented in the new LWR calculation tool ARCADIA of AREVA-NP ...
2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009
The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors)... more The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of running French PWR reactors and EPR reactor, and innovating systems. In this framework, specific neutron integral experiments have been carried out in the critical facilities of the CEA Cadarache, such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE pool Zero Power Reactor experiments.
To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to b... more To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to be reduced from ±15% (current standard deviation) to ±5%. The improvement of 238 U scattering data has been achieved through the use of targeted integral measurements with a strong sensitivity to 238 U(n,n ). From the C/E biases and sensitivity coefficients, obtained from Monte Carlo TRIPOLI4/JEFF-3.1.1 calculations, we have re-estimated the 238 U data. A clear trend to reduce 238 U(n,n ) cross-section by (-11±3)% in the 2-5 MeV range is obtained, and the analysis using inelastic level sensitivities highlights a required (n,n continuum ) modification by (-10±2)%.
This paper describes innovative measurements of integral radiative capture rates of minor actinid... more This paper describes innovative measurements of integral radiative capture rates of minor actinides, performed in the MINERVE facility. They aim at resolving potential discrepancies on capture cross sections, especially in the framework of nuclear safety and of waste management.
ABSTRACT Benchmark measurements of irradiated and un-irradiated fuel samples were performed in th... more ABSTRACT Benchmark measurements of irradiated and un-irradiated fuel samples were performed in the framework of the CERES collaborative program between AEA (UK Atomic Energy Agency) and CEA (French Atomic Energy Commission). These experiments provide relevant data for the validation of fuel burn-up and criticality-safety calculations for the whole fuel cycle. As part of this program, pile-oscillation measurements were carried out on a range of mixed-oxide samples with plutonium of various mass and isotopic contents, both in the MINERVE and DIMPLE reactors. Four core configurations, two over-thermalized situations and two pressurized water reactor (PWR)-type situations, were constituted with different forward and adjoint flux spectra, emphasizing fission and/or capture contributions. The experiments were analyzed using reference TRIPOLI4 calculations with the JEFF-3.1.1 library, using exact three-dimensional models of the core configurations. In a first step, calculations of each DIMPLE configuration were performed and compared with the experiment, showing very good agreements with a maximum C-E of −230 pcm. In the second step, reactivity worth experiments were analyzed, using recently developed exact-perturbation capabilities in TRIPOLI4. A consistent assimilation of calculation over experiment discrepancies was performed with the CONRAD code, using the integral data assimilation method. Covariance matrix on multigroup neutron cross sections and multiplicities were generated and significant trends were identified, especially on the 239 Pu and 240 Pu capture cross sections in the thermal energy range (E < 0.1 eV). Further investigations should be required to confirm these conclusions, due to the strong dependence of these trends and of posterior covariances to prior covariances.
ABSTRACT The absolute emission probabilities of gamma rays from the decay of 238Np and 233Pa have... more ABSTRACT The absolute emission probabilities of gamma rays from the decay of 238Np and 233Pa have been measured by an innovative method combining pile oscillation and neutron activation techniques. We obtained values of (24.99 ± 0.34)% and (37.79 ± 0.64)% for the 984.5- and 311.9-keV gamma rays from 238Np and 233Pa, respectively, in good agreement with the recommended values proposed by the Decay Data Evaluation Project (DDEP): (25.18 ± 0.13)% and (38.3 ± 0.5)%. The influence of gamma-ray emission probabilities from 238Np and 233Pa on neutron capture cross-section measurements of 237Np and 232Th, respectively, are discussed and tend to confirm the recommended values from the DDEP. A patent has been granted for this method.
The need for accurate nuclear data represents a permanent challenge to improve the calculation to... more The need for accurate nuclear data represents a permanent challenge to improve the calculation tools used in reactor physics. Uranium-235 is one of the most important isotopes, and its related nuclear data need to be known with a high degree of accuracy. In this context, many studies have been undertaken to improve the fission yields of 235 U for the main fission products in spent fuels.
ABSTRACT To take into account the reactivity loss in spent fuels, an experimental program was set... more ABSTRACT To take into account the reactivity loss in spent fuels, an experimental program was set up in 1993 at CEA-Cadarache, France, oscillating separated fission products (FPs) in the MINERVE reactor. Reactivity worth measurements of small samples allow the extraction of information about nuclear data of the studied isotopes. A fully validated calculation scheme has been implemented to interpret pileoscillation measurements. Therefore, calculation over experiment ratios can be accurately transposed to trends in the integral capture cross section of the FPs. With the European JEFF3.1.1 library, results show a discrepancy below 3% for several nuclides: 155Gd, 149, 152Sm, 143Nd, and 95Mo, but improvements may be needed for some others: 133Cs, 103Rh, 99Ru, and 153Eu. Based on the Integral Data Assimilation technique, we propose new thermal cross-section values, (348+/-14) b and (42478+/-1793) b, for two of the most absorbing nuclides, 143Nd and 149Sm, respectively.
2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA), 2013
ABSTRACT The MAESTRO experimental programme has been designed to improve the nuclear data uncerta... more ABSTRACT The MAESTRO experimental programme has been designed to improve the nuclear data uncertainty on a large range of materials used for detection, absorption, moderation and structures in LWRs. Samples of high purity elements have been manufactured with severe constraints to reach a target accuracy of ±2% (1σ) on the measurement. Experiments are carried out in the MINERVE low-power facility between 2011 and 2014. Neutron activation and pile-oscillation techniques are used to provide complementary information on the capture and scattering cross sections through the measurement of isotopic capture rate and global reactivity-worth for each material. Preliminary results were obtained for natV, 55Mn, and 59Co in support to the instrumentation of GEN-III reactors, just like for 103Rh due to its major contribution to the reactivity loss in LWR. They show that the JEFF-3.1.1 evaluations are in close agreement with the experiment, especially for 103Rh where consistent results were obtained from microscopic experiments at GELINA.
The paper describes the Uncertainty Quantification approach currently implemented in the global v... more The paper describes the Uncertainty Quantification approach currently implemented in the global validation of APOLLO [1] and ERANOS [2] Neutron Code packages at CEA, with a special emphasis on the uncertainty management and its feedback on modern Nuclear Data assimilation and multi-parametric Transposition to Design parameters, for both thermal and fast complex nuclear systems.
To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to b... more To meet the target-accuracy required by GEN-3 and GEN-4 designs, 238 U(n,n ) uncertainty has to be reduced from ±15% (current standard deviation) to ±5%. The improvement of 238 U scattering data has been achieved through the use of targeted integral measurements with a strong sensitivity to 238 U(n,n ). From the C/E biases and sensitivity coefficients, obtained from Monte Carlo TRIPOLI4/JEFF-3.1.1 calculations, we have re-estimated the 238 U data. A clear trend to reduce 238 U(n,n ) cross-section by (-11±3)% in the 2-5 MeV range is obtained, and the analysis using inelastic level sensitivities highlights a required (n,n continuum ) modification by (-10±2)%.
The CERES collaborative program between the French Atomic Energy Commission (CEA) and the United ... more The CERES collaborative program between the French Atomic Energy Commission (CEA) and the United Kingdom Atomic Energy Agency (UKAEA) was performed in the MINERVE and DIMPLE reactors at Cadarache and Winfrith, respectively. CERES Phase II was devoted to the validation of fission product (FP) poisoning through the reactivity worth measurements of FP samples. This paper describes the oscillation experiment at the center of the MINERVE pressurized water reactor-type test lattice. This experiment is strongly representative of the FP poisoning in light water reactor spent fuels because the separated FP isotope is introduced into real UO 2 pellets where 238
The CEA is deeply involved in a research program (MTR, ZPR) concerning the nuclear fuel advanced ... more The CEA is deeply involved in a research program (MTR, ZPR) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of French PWR reactors and EPR reactor, and innovative systems. In this framework, specific neutron integral experiments have been carried out in the critical ZPR facilities of the CEA Cadarache such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE Pool Reactor experiments. MINERVE is mainly devoted to neutronics studies of different reactor core types. The aim is to improve the knowledge of the integral absorption cross sections of actinides (OSMOSE program), of new absorbers (OCEAN program) and also for fission Products (CBU program) in thermal, epithermal and fast neutron spectra.
Several calculations methods for the analysis of small-sample reactivity experiments are presente... more Several calculations methods for the analysis of small-sample reactivity experiments are presented, as their main advantages and drawbacks. A numerical benchmark has been defined for this study consisting in a regular lattice of UO2 fuel pins, in which the central one is successively poisoned with isotopes of interest (actinides, absorbers, …). A first method, based on a forward calculation (“eigenvalues difference method”), is presented, using either a deterministic or a stochastic calculation code. A first perturbative method studied is based on the “Exact Perturbation Theory” (EPT) implemented in the deterministic code APOLLO2.8, and gives consistent results against forward calculations. A second perturbative method, the “correlated sampling method”, implemented in the stochastic calculation code TRIPOLI4.7 is tested. It should be use carefully as it is generally validated against small atomic density changes, but can be useful for conception studies. An “hybrid method”, based on...
2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009
The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors)... more The CEA is deeply involved in a research program (Material Testing Reactors, Zero Power Reactors) concerning the nuclear fuel advanced studies (actinides, plutonium), the waste management, the scientific and technical support of running French PWR reactors and EPR reactor, and innovating systems. In this framework, specific neutron integral experiments have been carried out in the critical facilities of the CEA Cadarache, such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE pool Zero Power Reactor experiments.
This paper summarizes the Qualification work performed to demonstrate the accuracy of the new APO... more This paper summarizes the Qualification work performed to demonstrate the accuracy of the new APOLLO2.8/SHEM-MOC package based on JEFF3.1.1 nuclear data file for the prediction of PWR neutronics parameters. This experimental validation is based on PWR mock-up critical experiments performed in the EOLE reactor and on P.I.Es on spent fuel assemblies from the French PWRs. The Calculation-Experiment comparison for the main design parameters is presented: reactivity of UOX and MOX lattices, depletion calculation and fuel inventory, pin-by-pin power maps, Doppler coefficient, Moderator Temperature Coefficient, Void coefficient, UO2-Gd2O3 poisoning worth, Efficiency of Ag-In-Cd control rods, Reflector Saving for both standard 2-cm baffle and advanced thick SS reflector implemented in GEN3 reactors. From this qualification process, scaling factors and associated uncertainties are derived. This code package APOLLO2.8 is already implemented in the new LWR calculation tool ARCADIA of AREVA-NP ...
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