Overview of the Burnup Credit Activities of the Organization for Economic Cooperation and Development/nuclear Energy Agency (Oecd/nea)

Abstract

This article summarises activities of the Organization for Economcc Cooperation and Development/Nuclear Energy Agency (OECD/NEA) Expert Group on Burnup Credit Criticality, a subordinate group to the Working Party on Nuclear Criticality Safety (WPNCS). The WPNCS of the OECD/NEA coordinates and carries out work in the domain of criticaltty safety at the internaiionll level. Particular attention is devoted to establishing sound databases required in this area and to addressing issues of high relevance such as burnup credit. The activities of the expert group are aimed toward improving safety and identifying economic solutions to issues concerning the back-end of the fuel cycle. The main objective of the activities of the OECD/NEA Expert Group on Burnup Credit Criticality is to demonstrate that the available criticality safety calculational tools are appropriate for applicaiion to irradiated (burned) nuclear fuel systems and that a reasonabee safety margin can be established. The method established by the expert group for investigating the physics and predictability of burnup credit is based on the specification and comparison of calculational benchmark problem. A wide range of fuel types, including PWR, BWR, MOX, and WER fuels, has been or is being addressed by the expert group. The objective and status of each of these benchmark problems is reviewed in this article. It is important to note that the focus of the expert group is the comparison of the results submitted by each participant to assess the capability of commonly used code systems, not to quantify the physical phenomena investigated in the comparssons or to make recommendations for licensing action.