IAEA-TECDOC-1378 Practices and developments in spent fuel burnup credit applications Proceedings of an Technical Committee meeting held in Madrid, 22–26 April 2002 October 2003 The originating Section of this publication in the IAEA was: Nuclear Fuel Cycle and Materials Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria PRACTICES AND DEVELOPMENTS IN SPENT FUEL BURNUP CREDIT APPLICATIONS IAEA, VIENNA, 2003 IAEA-TECDOC-1378 ISBN 92–0–111203–3 ISSN 1011–4289 © IAEA, 2003 Printed by the IAEA in Austria October 2003 CONTENTS Summary .................................................................................................................................... 1 INTERNATIONAL ACTIVITIES (Session 1) Overview on the BUC activities at the IAEA .......................................................................... 53 P. Dyck OECD/NEA report ................................................................................................................... 55 M.C. Brady Raap TECHNICAL TOPICS (Session 2) Experimental validation: Isotopic composition and reactivity calculations, high burnup fuel implications, nuclear data quality (Session 2.1) Experimental validation of actinide and fission products inventory from chemical assays in French PWR spent fuels .................................................................................. 69 B. Roque, A. Santamarina Improvement of the BUC-FP nuclear data in the JEFF library................................................ 83 A. Courcelle, A. Santamarina, O. Serot, C. Chabert, B. Roque Measurements of reactivity effects and isotopic composition of highly burnt fuel in LWR-PROTEUS Phase II.......................................................................... 94 P. Grimm, F. Jatuff, M. Murphy, R. Seiler, A. Meister, R. van Geemert, R. Brogli, G. Meier, H.-D. Berger, R. Chawla Experimental measurement of the isotopic composition of high enrichment and high burnup fuel ..................................................................................................... 104 C. Alejano, J.M. Conde, J.A. Gago, M. Quecedo, J.M. Alonso The burnup credit experimental programme REBUS ............................................................ 108 P. Baeten, K. van der Meer, S. Van Winckel, M. Gysemans, L. Sannen, D. Marloye, B. Lance, J. Basselier BUC validation in the UK: Design of experiments and lessons learnt .................................. 117 N.T. Gulliford EPRI R&D perspective on burnup credit ............................................................................... 124 A. Machiels, A. Wells Depletion criticality parameters that guarantee a bounding approach. Application dependence of BUC parameter importance (Session 2.2) Impact of the initial enrichment on the end effect.................................................................. 137 J.C. Neuber Studies of the influence of the spatial change of the fuel burnup on criticality in WWER-440 systems................................................................................. 148 G. Hordósy Evaluation of horizontal burnup profile for WWER-440 fuel assembly ............................... 156 V. Chrapþiak, P. Mikoláš Burnup credit methodology in the NPP Krzko spent fuel pool reracking project.................. 162 M. Kromar, B. Kurincic WWER fuel rod isotopics by MONTEBURNS 1.0 — Influence on the multiplication factor and comparison with the CB3 benchmark data........................... 169 D. López, C. Töre Research to support expansion of U.S. regulatory position on burnup credit for transport and storage casks ............................................................... 175 C.V. Parks, J.C. Wagner, I.C. Gauld Bounding approach in burnup credit criticality safety analysis.............................................. 185 J.C. Neuber Comparative analysis of multiplicating properties of WWER-1000 spent fuel depending on assembly layout in the reactor core and their operation conditions ....... 197 Y. Kovbasenko Practical issues with implementation of burnup credit in the USA for storage and transportation................................................................................................................205 D. Lancaster Safety margin, bias, uncertainty and statistical confidence (Session 2.3) Risk, confidence, tolerances and bias — Brief outlines of the basic concepts ...................... 211 J.C. Neuber Strategies for applying isotopic uncertainties in burnup credit .............................................. 236 I.C. Gauld, C.V. Parks Risk perspective and perception, building consensus (Session 2.4) Probabilistic assessment of dry transport with burnup credit................................................. 253 W.H. Lake UK regulatory perspective on the application of burnup credit in plant criticality safety cases ................................................................................................... 261 D.N. Simister Risk informed criticality process............................................................................................ 266 T. Doering, D. Brownson, J. Knudson BUC assessment scheme: Implementation, fuel and loading verification, review of analysis assumptions against changes in the fuel parameters (Session 2.5) Burnup factor in the licensing of Armenian NPP SFDS ........................................................ 289 R. Aydinyan Criticality calculations of WWER spent fuel casks implementing burnup credit.................. 294 M.A. Manolova, R.I. Prodanova, T.G. Apostolov Research and application of burnup credit technology in China............................................ 303 S. Zhao, X. Xioagang, L. Zhenhua, S. Leisheng, R. Keqiang Burnup credit implementation in WWER-440 dual purpose cask......................................... 309 L. Markova, J. Svarny Computer codes qualification in the Czech Republic ............................................................ 319 A. Miasnikov A new method to take burnup into account in criticality studies considering an axial profile of burnup plus some fission products .................................................. 327 C. Lavarenne, D. Biron, D. Janvier, R. Cousin, M. Doucet, J.P. Grouiller, A. Lebrun, N. Thiollay, E. Guillou, G. Leka, H. Toubon Utilization of BUC in Slovakia .............................................................................................. 340 J. Vaclav Criticality analysis with burnup credit for APR1400 in the Republic of Korea..................... 344 S.H. Lee, J.G. Ahn, H.R. Hwang Possibility for BUC implementation in RBMK-1500 fuel dual purpose storage casks ......... 350 A. Smaizys, P. Poskas BUC — A simple nuclear criticality safety concept that can be very difficult to implement ........................................................................................... 359 D. Mennerdahl BUC application to long term storage and disposal (Session 2.6) Future disposal burnup credit process and effort ................................................................... 377 D.A. Thomas, J. Scaglione, P. Noel, T.W. Doering Consideration of burnup in criticality analyses for long term storage and final disposal of spent nuclear fuel in Germany..................................................... 386 B. Gmal, E.F. Moser, H. Scheib BUC for MOX and advanced fuel designs (Session 2.7) Burnup credit methodology for UO2 and MOX fuel assemblies in AREVA/COGEMA ...................................................................................................... 395 H. Toubon, A. Lebrun, C. Riffard, C. Fayolle Cross-checking of the operator data used for burnup measurements..................................... 402 A. Lebrun, C. Riffard, H. Toubon Burnup credit in the evaluation of MOX fuel storage in the USA......................................... 413 J. Coletta, M.B. Raap Burnup credit calculation route for PWR MOX assemblies and experimental validation in Minerve R1-MOX and SLB1 P.I.E........................................................................... 424 B. Roque, A. Santamarina, N. Thiollay List of Participants.................................................................................................................. 441 INTERNATIONAL ACTIVITIES (Session 1) Overview on the BUC activities at the IAEA P. Dyck International Atomic Energy Agency, Vienna Due to the worldwide interest and broad applicability of BUC for spent fuel management, the International Atomic Energy Agency (IAEA) has taken an active interest in the subject. The IAEA role has been one of an observer and disseminator of appropriate information. In 1997, the International Atomic Energy Agency (IAEA) started a task to monitor the implementation of BUC in spent fuel management systems, to provide a forum to exchange information, to discuss the matter and to gather and disseminate information on the status of national practices of BUC implementation in the Member States. The task addressed current and future aspects of BUC. In October 1997, the IAEA organized an advisory group meeting (AGM) to examine and report on the status of BUC for storage, transport, reprocessing, and disposal of PWR, BWR, WWER, RBMK and MOX spent fuel. Since the proceedings of the AGM were published in April 1998 (IAEA-TECDOC-1013), significant developments have served to advance the use of BUC throughout the world. Experts from countries with nuclear programmes that range from very small to very large have made important contributions. The use of BUC has progressed along the lines of greatest