Recommendations for Addressing Axial Burnup in the PWR Burnup Credit Analyses

Wagner, J.C.

Oak Ridge National Laboratory

关键词: Criticality;    Storage;    Multiplication Factors;    Recommendations;    Casks;   

DOI  :  10.2172/885754
RP-ID  :  ORNL/TM-2001/273
RP-ID  :  DE-AC05-00OR22725
RP-ID  :  885754

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report presents studies performed to support the development of a technically justifiable approach for addressing the axial-burnup distribution in pressurized-water reactor (PWR) burnup-credit criticality safety analyses. The effect of the axial-burnup distribution on reactivity and proposed approaches for addressing the axial-burnup distribution are briefly reviewed. A publicly available database of profiles is examined in detail to identify profiles that maximize the neutron multiplication factor, k{sub eff}, assess its adequacy for PWR burnup credit analyses, and investigate the existence of trends with fuel type and/or reactor operations. A statistical evaluation of the k{sub eff} values associated with the profiles in the axial-burnup-profile database was performed, and the most reactive (bounding) profiles were identified as statistical outliers. The impact of these bounding profiles on k{sub eff} is quantified for a high-density burnup credit cask. Analyses are also presented to quantify the potential reactivity consequence of loading assemblies with axial-burnup profiles that are not bounded by the database. The report concludes with a discussion on the issues for consideration and recommendations for addressing axial burnup in criticality safety analyses using burnup credit for dry cask storage and transportation.