Application of a Bayesian/Generalised Least-Squares method to generate correlations between independent neutron fission yield data

Fiorito, Luca and Diez de la Obra, Carlos Javier and Cabellos de Francisco, Oscar Luis and Stankovskiy, Alexey and Van Den Eynde, Gert and Labeau, Pierre-Etienne (2014). Application of a Bayesian/Generalised Least-Squares method to generate correlations between independent neutron fission yield data. In: "Workshop Proceedings Nuclear Measurements, Evaluations and Applications (NEMEA-7) - Collaborative International Evaluated Library Organisation (CIELO". NEA/NSC/DOC(2014)13 . OECD, Issy-les-Moulineaux, France, pp. 278-286.

Description

Title: Application of a Bayesian/Generalised Least-Squares method to generate correlations between independent neutron fission yield data
Author/s:
  • Fiorito, Luca
  • Diez de la Obra, Carlos Javier
  • Cabellos de Francisco, Oscar Luis
  • Stankovskiy, Alexey
  • Van Den Eynde, Gert
  • Labeau, Pierre-Etienne
Editor/s:
  • Nuclear Energy Agency, NEA
Item Type: Book Section
Event Title: Nuclear Measurements, Evaluations and Applications (NEMEA-7) - Collaborative International Evaluated Library Organisation (CIELO
Event Dates: 05/11/2013 - 08/11/2013
Event Location: Geel, Belgium
Title of Book: Workshop Proceedings Nuclear Measurements, Evaluations and Applications (NEMEA-7) - Collaborative International Evaluated Library Organisation (CIELO
Date: 2014
Subjects:
Faculty: E.T.S.I. Industriales (UPM)
Department: Ingeniería Nuclear [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Fission product yields are fundamental parameters for several nuclear engineering calculations and in particular for burn-up/activation problems. The impact of their uncertainties was widely studied in the past and valuations were released, although still incomplete. Recently, the nuclear community expressed the need for full fission yield covariance matrices to produce inventory calculation results that take into account the complete uncertainty data. In this work, we studied and applied a Bayesian/generalised least-squares method for covariance generation, and compared the generated uncertainties to the original data stored in the JEFF-3.1.2 library. Then, we focused on the effect of fission yield covariance information on fission pulse decay heat results for thermal fission of 235U. Calculations were carried out using different codes (ACAB and ALEPH-2) after introducing the new covariance values. Results were compared with those obtained with the uncertainty data currently provided by the library. The uncertainty quantification was performed with the Monte Carlo sampling technique. Indeed, correlations between fission yields strongly affect the statistics of decay heat. Introduction Nowadays, any engineering calculation performed in the nuclear field should be accompanied by an uncertainty analysis. In such an analysis, different sources of uncertainties are taken into account. Works such as those performed under the UAM project (Ivanov, et al., 2013) treat nuclear data as a source of uncertainty, in particular cross-section data for which uncertainties given in the form of covariance matrices are already provided in the major nuclear data libraries. Meanwhile, fission yield uncertainties were often neglected or treated shallowly, because their effects were considered of second order compared to cross-sections (Garcia-Herranz, et al., 2010). However, the Working Party on International Nuclear Data Evaluation Co-operation (WPEC)

More information

Item ID: 26200
DC Identifier: http://oa.upm.es/26200/
OAI Identifier: oai:oa.upm.es:26200
Official URL: https://www.oecd-nea.org/globalsearch/download.php?doc=78794
Deposited by: Memoria Investigacion
Deposited on: 16 Apr 2015 15:35
Last Modified: 10 Nov 2017 08:52
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