tailieunhanh - Nuclear data correlation between different isotopes via integral information

This paper presents a Bayesian approach based on integral experiments to create correlations between different isotopes which do not appear with differential data. A simple Bayesian set of equations is presented with random nuclear data, similarly to the usual methods applied with differential data. | Nuclear data correlation between different isotopes via integral information EPJ Nuclear Sci. Technol. 4 7 2018 Nuclear Sciences . Rochman et al. published by EDP Sciences 2018 amp Technologies https epjn 2018006 Available online at https REGULAR ARTICLE Nuclear data correlation between different isotopes via integral information Dimitri A. Rochman1 Eric Bauge2 Alexander Vasiliev1 Hakim Ferroukhi1 and Gregory Perret1 1 Laboratory for Reactor Physics Systems Behaviour Paul Scherrer Institut Villigen Switzerland 2 CEA DAM DIF 91297 Arpajon Cedex France Received 15 September 2017 Received in final form 24 January 2018 Accepted 19 March 2018 Abstract. This paper presents a Bayesian approach based on integral experiments to create correlations between different isotopes which do not appear with differential data. A simple Bayesian set of equations is presented with random nuclear data similarly to the usual methods applied with differential data. As a consequence updated nuclear data cross sections n fission neutron spectra and covariance matrices are obtained leading to better integral results. An example for 235U and 238U is proposed taking into account the Bigten criticality benchmark. 1 Introduction In the following the case of the 235U and 238U isotopes will be considered and the Bayesian update will be It was recently demonstrated that an uncertainty decrease performed using a specific criticality benchmark with high and non-zero correlation terms between different nuclear sensitivity to these isotopes the intermediate metal fast data reactions can be obtained when using integral number 7 benchmark or imf7 also known as Bigten 5 . information such as criticality benchmarks 1 see Refs. First the method will be recalled in simple terms then the 2 4 for other examples . In reference 1 cross-correlation application with the imf7 benchmark will be presented. terms between n emitted neutrons per fission x fission The updated benchmark value