Combined Use of Integral Experiments and Covariance Data

Palmiotti, G.; Salvatores, M.; Aliberti, G.; Herman, M.; Hoblit, S.; McKnight, R.D.; Obložinský, P.; Talou, P.; Hale, Gerald M.; Hiruta, Hikaru; Kawano, Toshihiko; Mattoon, Caleb; Nobre, G. P. A.; Palumbo, A.; Pigni, Marco T.; Rising, Michael Evan; Yang, Won Sik; Kahler, Albert C.

doi:10.1016/j.nds.2014.04.145

Cited by 19 publications

(17 citation statements)

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“…However, adjustments performed in the past have focused mostly on main isotopes (major actinide, structural and coolant isotopes) as the major goal was directed to reduce the uncertainties of fresh (startup) cores with limited presence during the cycle of other, more unusual, isotopes. Recently, a comprehensive adjustment of ENDF/B-VII.0 cross-section data [39] has included also experiments that were devoted to a better knowledge of MA and FP isotope cross sections. In the following, we will show how the results of such adjustment impact and reduce uncertainties for some of the integral parameters of the advanced systems already considered in the previous section.…”

Section: Nuclear Data Adjustmentsmentioning

confidence: 99%

“…How much reduced, it will depend on the representativity of the experiments used in the adjustment with respect to the target reactor. In the adjustment of [39], a total of 87 experiments were adopted. Table 15 summarizes experiment programs and type of measured quantities used in the adjustment.…”

Section: Nuclear Data Adjustmentsmentioning

confidence: 99%

“…The adjusted covariance matrix obtained in [39] has been applied to the systems and design parameters of Table 10. Reduced uncertainties and reduction factors are shown in Table 16.…”

Section: Nuclear Data Adjustmentsmentioning

confidence: 99%

See 2 more Smart Citations

Physics challenges for advanced fuel cycle assessment

Salvatores

Aliberti

Palmiotti

2014

Journal of Nuclear Science and Technology

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Section: Nuclear Data Adjustmentsmentioning

confidence: 99%

Section: Nuclear Data Adjustmentsmentioning

confidence: 99%

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Physics challenges for advanced fuel cycle assessment

Salvatores

Aliberti

Palmiotti

2014

Journal of Nuclear Science and Technology

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“…To obtain maximum benefit from recent simulation tools and neutron transport codes, significant efforts have been spent to improve the accuracy of input data, whose reliability is a fundamental aspect in estimating precise responses for nuclear technology applications [1]. Uncertainties and biases on nuclear reactor integral parameters have to be known with a certain degree of confidence in order to satisfy the safety-by-design standards required in modern nuclear technology.…”

Section: Introductionmentioning

confidence: 99%

Covariance generation and uncertainty propagation for thermal and fast neutron induced fission yields

et al. 2017

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Abstract. Fission product yields (FY) are fundamental nuclear data for several applications, including decay heat, shielding, dosimetry, burn-up calculations. To be safe and sustainable, modern and future nuclear systems require accurate knowledge on reactor parameters, with reduced margins of uncertainty. Present nuclear data libraries for FY do not provide consistent and complete uncertainty information which are limited, in many cases, to only variances. In the present work we propose a methodology to evaluate covariance matrices for thermal and fast neutron induced fission yields. The semi-empirical models adopted to evaluate the JEFF-3.1.1 FY library have been used in the Generalized Least Square Method available in CONRAD (COde for Nuclear Reaction Analysis and Data assimilation) to generate covariance matrices for several fissioning systems such as the thermal fission of U235, Pu239 and Pu241 and the fast fission of U238, Pu239 and Pu240. The impact of such covariances on nuclear applications has been estimated using deterministic and Monte Carlo uncertainty propagation techniques. We studied the effects on decay heat and reactivity loss uncertainty estimation for simplified test case geometries, such as PWR and SFR pin-cells. The impact on existing nuclear reactors, such as the Jules Horowitz Reactor under construction at CEA-Cadarache, has also been considered.

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“…Future innovative nuclear systems are in fact imposing strict safety-by-design standards that require highly accurate engineering parameter uncertainty estimation. It has been quickly recognized that the value and the credibility of any uncertainty analysis was strictly dependent on the scientific quality of variances and correlations [1,2] associated to the basic nuclear data. Supplying complete covariance information gives in fact the opportunity to estimate realistically the uncertainty on integral reactor parameters.…”

Section: Introductionmentioning

confidence: 99%

A Covariance Generation Methodology for Fission Product Yields

Terranova

Sérot

Archier

et al. 2016

EPJ Web of Conferences

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Abstract. Recent safety and economical concerns for modern nuclear reactor applications have fed an outstanding interest in basic nuclear data evaluation improvement and completion. It has been immediately clear that the accuracy of our predictive simulation models was strongly affected by our knowledge on input data. Therefore strong efforts have been made to improve nuclear data and to generate complete and reliable uncertainty information able to yield proper uncertainty propagation on integral reactor parameters. Since in modern nuclear data banks (such as JEFF-3.1.1 and ENDF/BVII.1) no correlations for fission yields are given, in the present work we propose a covariance generation methodology for fission product yields. The main goal is to reproduce the existing European library and to add covariance information to allow proper uncertainty propagation in depletion and decay heat calculations. To do so, we adopted the Generalized Least Square Method (GLSM) implemented in CONRAD (COde for Nuclear Reaction Analysis and Data assimilation), developed at CEA-Cadarache. Theoretical values employed in the Bayesian parameter adjustment are delivered thanks to a convolution of different models, representing several quantities in fission yield calculations: the Brosa fission modes for pre-neutron mass distribution, a simplified Gaussian model for prompt neutron emission probability, the Wahl systematics for charge distribution and the Madland-England model for the isomeric ratio. Some results will be presented for the thermal fission of U-235, Pu-239 and Pu-241.

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Combined Use of Integral Experiments and Covariance Data

Cited by 19 publications

References 0 publications

Physics challenges for advanced fuel cycle assessment

Physics challenges for advanced fuel cycle assessment

Covariance generation and uncertainty propagation for thermal and fast neutron induced fission yields

A Covariance Generation Methodology for Fission Product Yields

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