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INTERNATIONAL GR UP W RESEARCH REACt' 1£5 NOVEMBER 4- 5- 6 1996 AIX- EN- PRO VENL'E / FRANCE III h. ~tec nlcatome INTERNATIONAL GROUP ON RESEARCH REACTORS 5th MEETING NOVEMBER 4-5-6;1 1996 AIX-EN-PROVENCE / FRANCE GRAND HOTEL ROI RENE PROCEEDINGS PREFACE Overview The fifth meeting of the International Group on Research Reactors (lOORR-V) was held in Aix en-Provence, France, on November 4-6, 1996. Attendance was excellent (between 70 and 80 participants from 21 countries). Thirty-one papers were presented in four sessions over the two day meeting, and written versions of the papers or hard copies of the viewgraphs used are published in these Proceedings. A book of abstracts was published and handed out at the beginning of the meeting, which proved to be very useful to the participants. The meeting was a huge success, and we look forward with much anticipation to lOORR-VI. I should like to congratulate Klaus Boning on his election to Chairman of lOORR. I am certain that he and his colleagues will do an excellent job. It has been my pleasure to be associated with - the IGORR membership, and I hope to meet you all again some day. Kathy F. Rosenbalm OPENING SESSION Colin D. West - ORNL Yannick Le Corre - Technicatome Rene Ginier - CEA Welcome to the fifth meeting of the International Group on Research Reactors (lGORR). I should like first to thank our French colleagues, and the Commissariat A l'Energie Atomique (CEA) for their splendid efforts on organizing this meeting, which has a very strong international participation. I should also like to thank our Technical Program Coordinator, Kathy Rosenbalm, whom most of you know but who, unfortunately, could not be present. IGORR has become stronger, over the years since it was founded. Clearly, our organization has a useful role to play within our community of people working on new and improved research reactor facilities. Its' vitality is evidenced by the increased number of participants in this meeting and by the continued evolution and changes in our agenda. For example, in making the preparations for this meeting we found so much interest in and so many contributions concerning cold neutron sources that we have included for the first time a whole session devoted to papers on that topic. In addition, this year there are reports on two separate surveys that were initiated by the last IGORR meeting: one, 1;>y Albert Lee, on containment design criteria and one, by Doug Selby, on cold neutron cross sections. Another innovation this year, thanks to the CEA organizers, is the preparation, before the meeting, of a book of abstracts of the talks: I think we will all find this helpful in the next couple of days. Of course, the full Proceedings will be produced and published as soon after the meeting as practicable: please submit your contributions to the organizers on time. I should particularly like to welcome, for the first time, representatives of some of the institutes in former Eastern European countries. I am sure their experiences and ideas will be interesting and helpful to us all. Mter the technical sessions, there is to be a visit to Cadarache, which I know will be a new experience for many of us. In addition, I should like to thank very much the mayor of Abc, who has kindly and graciously invited us to a reception on Monday evening: a very nice welcome and gesture from our host city. The agenda is a full one, and full of interesting papers. The session chairmen have been instructed to keep speakers strictly to the time limit, so that their colleagues later in the session will not be deprived of their fair share of timel Let us begin IGORR-V. .;1 h. &itec nlcatome 1 IGORR 5 MEETING NOVEMBER 4, 1996 f?! WELCOME ADDRESS ~ M. YANNICKLE CORRE (TECHNICATOME Chairman) Dear Colin WEST, Dear Bertrand BARRE, Dear audience, I am really happy to welcome you for the 5th meeting of the International Group on Research Reactors : I am really happy because it's the second time since the creation of IGORR in Nineteen Ninety (1990), that TECHNICATOME has the pleasure to organise in a a close collaboration with the Commissariat I 'Energie Atomique the IGORR meeting in France. In Paris in June Nineteen Ninety Two (1992) IGORR Two (2) gathered Forty Five (45) participants. Today, in Aix-en-Provence, we are more than Eighty (80), including for the first time new representatives of some Eastern Europe countries. This shows the interest of the Research Reactor Community for lGORR activities. Thanks to Colin WEST for having created this group. I am also happy because many of you, coming from foreign countries will have the opportunity to discover the fascinating city of Aix-en-Provence, the «City of Arts ». Ilitechnicatome 2 The Nuclear Research Reactors have also an important past. They have played a key role in the history of the Nuclear Energy and my opinion is that they will still play an important part. More than Three Hundred and Seventy (370) Research Reactors and critical mock ups were erected during the past Fifty (50) years in the world. More than Two Hundred and Eighty (280) are still in operation, and among them Eighteen (18) in France. Let me remind you some aspects of their contribution to the Nuclear Energy development: • with the first critical mock-ups, the feasibility of the fission nuclear chain reaqtion announced in August Nineteen Thirty Nine (1939) by Albert EINSTEIN to Franklin ROOSEVELT, on the basis of the work performed by Frederic JOLIOT, Enrico FERMI and Leo SZILLARD was demonstrated: the first reactor CPl went on criticality in Chicago on December Nineteen Forty Two (1942) . In France, ZOE started on December Nineteen Forty Eight (1948) ; It was the beginning of French Nuclear Reactor history which led to celebrate in Nineteen Ninety Five (1995) the Fifty (50) years of existence of the «Commissariat it l'Energie Atomique» with the background of one of the world biggest nuclear programs and a major contribution to the independence of our Nation. • The first generation of Research Reactors enabled the determination of numerous physical parameters and gave the confirmation of the behaviour of fission Nuclear Reactors, therefore giving the basis for the development of large nuclear power plants. • Afterwards many irradiation programs had to be performed in Research Reactors to qualify fuel and material technology for the future reactors. For this purpose sophisticated in core loops were also introduced in Research Reactors allowing fuel testing in representative thermodynamic conditions. • Up to now in the world, Research Reactors have demonstrated their extended possibilities : o in the field of fundamental and applied research, o in the field of material, component and fuel testing, o in the field of radioisotope production, o in the field of teaching and training. Ilitechnicatome 3 • Very early safety aspects have also arisen, leading to specific programs on dedicated facilities, like CABRI and PHEBUS in France. CABRI allowed the study of the cinetics of cores in case of sudden reactivity introductions. On PHEBUS, the consequences of severe degradations of fuel are studied under an international collaboration. I know that you will visit these facilities in Cadarache on November Six (6). • For the scientific community, Research Reactors appeared to be also powerful tools for fundamental research and medicine applications. In the Nuclear developed countries, the high level of demands led to the specialization of the Research Reactors. In France, it's the reason why after the first generation of multipurpose reactors like MELUSINE, SILOE and then OSIRIS, specialized high flux reactors were built, in Nmeteen Seventy Two (1972) the RHF in Grenoble, and in Nineteen Eighty (1980) the ORPHEE reactor in Saclay. In a complementary way, OSIRIS and SILOE activities were focused on irradiation experiments and radioisotope production; both still operate with heavy programs. What's future for the Research Reactors? Today we have to acknowledge than most of existing Research Reactors are of pool type. They proved their versatility and their easy adaptability to new irradiation programs. High flux reactors obtain higher fluxes with the help of an additional reflector made of Beryllium or heavy water. Pool type Research Reactors appear to be a good investment on the condition that enough attention is payed to their design, taking into account the experience acquired by the years of operation of the previous Reactors. In the countries who developed for many years a nuclear program, a high level of demand exists with a resulting specialization of the research facilities and with even more high neutron flux requirements. There are needs for: • on one hand, irradiation reactors for qualification of fuel and materials including fast reactors and fusion programs, and radioisotope for medicine and industry, • on the other hand, reactor for neutron beam delivery with a growing demand for cold neutrons. , In a complementary way, safety assessment studies will certainly need the continuation of ongoing programs on dedicated facilities. III h. mcatome ~tec 4 For the countries who recently decided to develop a Nuclear Research or Energy program, a multipurpose pool type Research Reactor is certainly a good choice if it is done in association with a coherent development policy for the national scientific community. This kind of Research Reactor will allow access to most of the applications I mentioned before. The France who successfully managed a huge electronuclear program has developed the highest level of expertise in Research Reactor design, as well in CEA as in the associated industrial partners. Numerous collaborations with nuclear developing countries are on the way now and will benefit from this high skill level. TECHNICATOME, with CEA, is willing to contribute to this effort. Mister Chairman, I do believe that Nuclear Energy will remain a key technology for the future. Research Reactors can be in the next decades useful and versatile tools, contributing to this future in the frame of qualification programs for fission and fusion energy. The Reducing Enrichment in Research and Test Reactors program, I mean RERTR program, aiming at demonstrating that most of existing Research Reactors can be converted to low enriched uranium silicide fuel, with a comparable level of performances, is of a great interest, opening the field for wide peaceful applications. New projects will of course benefit from this new fuel technology. In France, we are preparing the necessary renewal of the existing irradiation Research Reactors. Mister Chairman, dear audience, there are still a lot of things to do ; doubt and humility are necessary in any scientific approach. After years of success the major error would be to believe that all technical aspects have been solved. Chemobyl and TMI are here to remind us this reality. Fighting against high economical constraints, our countries need to maintain for the future a scientific and engineering community with the highest skill level in the nuclear field. I am sure that lGORR, facilitating exchanges between countries, is working in that direction for the world scientific development. I wish you three interesting working days of technical debates and visits.