IAEA-TECDOC-984 Advances in heavy water reactor technology Proceedings of a Technical Committee meeting held in Mumbai, India, 29 January- 1 February 1996 INTERNATIONAL ATOMIC ENERGY AGENCY 1 November 1997 The IAEA does not normally maintain stocks of reports in this series. However, microfiche copies of these reports can be obtained from INIS Clearinghouse International Atomic Energy Agency Wagramerstrasse 5 P.O. Box 100 A-1400 Vienna, Austria Orders should be accompanied by prepayment of Austrian Schillings 100, in the form of a cheque or in the form of IAEA microfiche service coupons which may be ordered separately from the INIS Clearinghouse. IAEA-TECDOC-984 Advances in heavy water reactor technology Proceedings of a Technical Committee meeting held in Mumbai, India, 29 January- 1 February 1996 WJ INTERNATIONAL ATOMIC ENERGY AGENCY The originating Section of this publication in the IAEA was: Nuclear Power Technology Development Section International Atomic Energy Agency Wagramerstrasse 5 P.O. Box 100 A-1400 Vienna, Austria ADVANCES IN HEAVY WATER REACTOR TECHNOLOGY IAEA, VIENNA, 1997 IAEA-TECDOC-984 ISSN 1011^289 ©IAEA, 1997 Printed by the IAEA in Austria November 1997 FOREWORD Heavy water reactor (HWR) technology for electric power production has been developed by relatively few industrialized countries, notably Canada and Japan, but successfully implemented by developing countries, notably by Argentina, India, Pakistan, the Republic of Korea and Romania. In addition, construction of two HWRs is planned to begin in 1997 in China. Recent advances in HWRs include: - development of new designs (for example the advanced CANDU-6 and CANDU-9 designs in Canada and the AHWR in India), - improved pressure tube materials, - improved in-service inspection techniques, - improved fuelling machines and fuel handling equipment, - validation of computer methods with experimental data, - investigations of a variety of fuel options (for example slightly enriched uranium fuel and thorium based fuel). Within the IAEA's nuclear power programme, activities in HWR technology development are conducted to foster information exchange among Member States with HWR power reactor programmes and to provide an objective source of information on HWR technology status and advances in HWRs that is available to all Member States. In order to document progress in HWR design and technology, the IAEA has published TECDOCs on advances in HWRs every few years. This is the third TECDOC in this series. The technical officer responsible for the preparation of this TECDOC was J. Cleveland of the IAEA's Nuclear Power Technology Development Section, Division of Nuclear Power and the Fuel Cycle. EDITORIAL NOTE In preparing this publication for press, staff of the IAEA have made up the pages from the original manuscripts as submitted by the authors. The views expressed do not necessarily reflect those of the IAEA, the governments of the nominating Member States or the nominating organizations. Throughout the text names of Member States are retained as they were when the text was compiled. The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights. CONTENTS SUMMARY 9 OPENING ADDRESSES Heavy water reactor technology: The need for information exchange and increased international co-operation 23 A.N. Prasad The Indian nuclear power programme: Challenges in PHWR technology 29 Y.S.R. Prasad NATIONAL HWR PROGRAMMES (Session 1) The AECL reactor development programme 49 D.A. Meneley Main objectives of Romanian HWR programme 57 C. Minqiuc. A. Panait, S.N. Rapeanu, M.T. Chirica Progress of China's nuclear power programme 67 Jianping Cai The pressurized heavy water reactor programme in the Republic of Korea 75 Young Eeek Jung ADVANCES IN PLANT DESIGN (Session 2) Development of the advanced heavy water reactor 87 H.P. Vyas, M.L. Dhawan, K., Balakrishnan, D. Saha, K. Anantharaman CANDU improvements 99 S.K.W. Yu SAFETY AND LICENSING ASPECTS (Session 3) Trends in CANDU licensing Ill V.G. Snell, S.D. Grant Safety and licensing issues for Indian PHWRs 121 G.R. Srinivasan, M. Das ADVANCES IN SYSTEM DESIGN (Session 4, Part 1) Passive heat removal in CANDU 137 R.S. Hart Emergency core cooling system simplification 151 R.S. Hart, D.B. Rhodes Development of a secondary shutdown system for the 500 MW(e) PHWR 165 K. Belakrishnan, U. Kannan, S. Nawathe, S.C. Mahajan, A. Kakodkar ADVANCES IN SYSTEM DESIGN (Session 4, Part 2) Computer based C&I systems in Indian PHWRs 181 G. Govindarajan, M.P. Shartna The higher order flux mapping method in large size PHWRs 197 A.K. Kulkarni, V. Balaraman, H.D. Purandare NEW PLANT FEATURES (Session 5) CANDU design options with detritiation 211 D.J. Wren, R.S. Hart A passive emergency heat sink for water cooled reactors with particular application to CANDU reactors 225 N. J. Spinks CANDU PRESSURE TUBES: ASSESSMENT AND IMPROVEMENT OF SERVICE LIFE (Session 6) Improving the service life and performance of CANDU fuel channels 233 A.R. Causey, B.A. Cheadle, C.E. Coleman, E.G. Price Methodologies for assessment of the service life of pressure tubes in Indian PHWRs 247 R.K. Sinha, A. Sharma, K. Madhusoodanan, S.K. Sinha, U.D. Malshe FUEL AND FUEL CYCLE OPTIONS (Session 7) A PHWR with slightly enriched uranium about the first core 261 C. Notari Slightly enriched uranium fuel for a PHWR 269 C. Notari, A. Marajofsky Synergistic fuel cycles of the future 275 D.A. Meneley, A.R. Dastur COMPUTER CODE DEVELOPMENT AND VERIFICATION (Session 8) Validation of computer codes used in safety analyses of CANDU power plants 285 E.O. Moeck, J.D. Luxat, L.A. Simpson, M.A. Petrilli, P.D. Thompson Computer codes for safety analysis of Indian PHWRs 297 S.S. Bajaj, P.K. Malhotra, N. Mohan, H.P. Rammohan, M. Singhal Development and validation of computer codes for analysis of PHWR containment behaviour 313 S.G. Makandeya, S.K. Haware, A.K. Ghosh, V. Venkat Raj REACTOR ACCIDENT ANALYSIS (Session 9) A study of the Indian PHWR reactor channel under prolonged deteriorated flow conditions 331 S.K. Gupta, B.K. Dutta, V. VenkatRaj, A. Kakodkar Coolant void reactivity behaviour in pressure tube type plutonium fuel lattices of ATR 361 N. Fukumura, Y. Kowata, T. Ihara PROBABILISTIC SAFETY ANALYSIS (Session 10) Application of PSA level 1 for the FUGEN prototype ATR plant 377 H. Ikeda, Y. Iguchi, M. Sotsu, O. Seki, S. Satou OPERATING EXPERIENCE OF HWRs (Session 11) Operational experience with the first eighteen slightly enriched uranium fuel assemblies in the Atucha-1 nuclear power plant 391 M. Higa, R. Perez, J. Pineyro, J. Sidelnik, J.A. Casario, L. Alvarez, J. Fink Operating experience of the FUGEN HWR in Japan 401 H. Ikeda, T. Hayashi, T. Iijima Fault diagnosis through wear particle analysis (ferrography in Indian PHWRs and BWRs 415 AX. Sinha, V.N. Konda, M.D. Soman Pillai, V.S. Srinivasan APPENDIX: International advances in design, manufacture, testing, operation and maintenance of fuelling machines and fuel handling equipment for heavy water reactors 427 A.B. Ghare LIST OF PARTICIPANTS 471 NEXT PAGE(S) laf t BLANK SUMMARY INTRODUCTION At the beginning of 1996, worldwide there were 33 heavy water moderated reactors (HWRs)1 with a total capacity of 18.6 GW(e) providing about 5.5% of the world's current nuclear electrical capacity, and 10 more HWRs were under construction2. HWR technology has proven to be economic, safe and reliable, and there is a mature infrastructure and regulatory base in several countries. The experience from development, licensing, construction, and, from the approximately 430 reactor-years of operation, forms a sound basis for the programmes underway in several countries to advance HWR technology. The very good neutron economy of HWRs allows fuelling with natural uranium thereby requiring no investment in uranium enrichment, while also providing flexibility for the use of different fuel options which would result in increased utilization of fissile materials. The IAEA, following the recommendation of the International Working Group on Advanced Technologies for Water Cooled Reactors (IWGATWR), convened a Technical Committee meeting on Advances in Heavy Water Reactors, at Homi Bhabha Centre for Science Education, Mumbai, India, from 29 January to 1 February 1996. The meeting was organized in co-operation with the Bhabha Atomic Research Centre (BARC) and the Nuclear Power Corporation India Limited (NPCIL). The Technical Committee meeting focused on technologies aimed at improvements in currently operating HWRs, design and development for future plants, and development and evaluation of fuelling options. This was the third Technical Committee meeting on Advances in Heavy Water Reactors. The previous meetings in this series were held in Toronto, Canada in 1993 [1] and in Montreal, Canada in 1988 [2]. This IAEA meeting addressed both the status of national programmes and technical topics including advances in plant and system design and new plant features, development of pressure tube technologies, fuel and fuel cycle options, computer code development and verification, and safety and accident analysis. An important area of HWR technology which was not addressed at this Technical Committee meeting, but which was addressed in depth during an international conference in May 1996 organized by the Canadian Nuclear Society [3] is the topic of advances in fuelling machines and fuel handling equipment for heavy water reactors.