Multi-physics and multi-scale benchmarking and uncertainty quantification within OECD/NEA framework M. Avramova a,⇑ , K. Ivanov a , T. Kozlowski b , I. Pasichnyk c , W. Zwermann c , K. Velkov c , E. Royer d , A. Yamaji e , J. Gulliford e a The Pennsylvania State University (PSU), USA b University of Illinois at Urbana-Champaign, USA c Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, Germany d INSTN – CEA Saclay, France e OECD/NEA, France article info Article history: Received 8 July 2014 Accepted 11 December 2014 Available online 3 January 2015 Keywords: Benchmark Uncertainty Multi-physics Multi-scale abstract The development of multi-physics multi-scale coupled methodologies for Light Water Reactor (LWR) analysis requires comprehensive validation and verification procedures, which include well-established benchmarks developed in international cooperation. The Nuclear Energy Agency (NEA) of the Organiza- tion for Economic Co-operation and Development (OECD) has provided such framework, and over the years a number of LWR benchmarks have been developed and successfully conducted. The first set of NEA/OECD benchmarks that permits testing of the neutronics/thermal–hydraulics coupling, and verifying the capability of the coupled codes to analyze complex transients with coupled core/plant interactions have been completed and documented. These benchmarks provided a validation basis for the new gen- eration of coupled ‘‘best-estimate’’ codes. The above mentioned OECD/NEA LWR benchmark activities have also stimulated follow up developments and benchmarks to test these developments. The models utilized have been improved when moving from one benchmark to the next and this created a need to validate them using high-quality experimental data. Second set of the NEA/OECD benchmarks have been initiated by the Expert Group on Uncertainty Analysis in Modelling (EGUAM) at the Nuclear Science Com- mittee (NSC), NEA/OECD to address the current trends in the development of LWR multi-physics and multi-scale modeling and simulation. These benchmarks include the following common features, which address some of the issues identified in the first set of OECD/NEA benchmarks: (a) utilization of high- quality experimental data; (b) refined local scale modeling in addition to global predictions; (c) more detailed comparisons and analysis; (d) including uncertainty and sensitivity analysis of modeling predic- tions. The paper presents each of these new benchmarks by providing description and discussion of com- parative analysis of obtained results. Special attention is devoted to uncertainty propagation in LWR multi-physics and multi-scale simulations for design and safety evaluations. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction The development of multi-physics multi-scale coupled method- ologies for Light Water Reactor (LWR) analysis requires compre- hensive validation and verification procedures, which include well-established benchmarks developed in international coopera- tion. The Nuclear Energy Agency (NEA) of the Organization for Eco- nomic Co-operation and Development (OECD) has provided such framework, and over the years a number of LWR benchmarks have been developed and successfully conducted. The first set of NEA/ OECD benchmarks that permits testing of the neutronics/ thermal–hydraulics coupling, and verifying the capability of the coupled codes to analyze complex transients with coupled core/ plant interactions have been summarized in Ivanov et al. (2007). Such benchmarks are the OECD/US Nuclear Regulatory Commis- sion (NRC) Pressurized Water Reactor (PWR) Main Steam Line Break (MSLB) benchmark, the OECD/NRC Boiling Water Reactor (BWR) Turbine Trip (TT) benchmark, and the OECD/US Department of Energy (DOE)/CEA VVER-1000 Coolant Transient (V1000CT) benchmark. These benchmarks provide a validation basis for the http://dx.doi.org/10.1016/j.anucene.2014.12.014 0306-4549/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +1 814 865 0043; fax: +1 814 865 8499. E-mail address: mna109@psu.edu (M. Avramova). Annals of Nuclear Energy 84 (2015) 178–196 Contents lists available at ScienceDirect Annals of Nuclear Energy journal homepage: www.elsevier.com/locate/anucene