Atomic Energy of Canada Limited OUTLOOK FOR CANDU REACTORS PART 1: TECHNICAL PART 11: ECONOMIC by D.G. HURST Papers presented at the IAEA International Survey Course on Economic and Technical Aspects of Nuclear Power, Vienna, September 1-12, 1969. Chalk River, Ontario Januory 1970 AECL-3553 ATOMIC ENERGY OF CANADA LIMITED Chalk River Nuclear Laboratories OUTLOOK FOR CANDU REACTORS PART I : TECHNICAL PART II : ECONOMIC by D. G. Hurst Papers presented at the International Survey Course on Economic and Technical Aspects of Nuclear Power, sponsored by the IAEA at Vienna, September 1-12, 1969. AECL-3553 OUTLOOK FOR CANDU REACTORS PART I : TECHNICAL PART II : ECONOMIC by D. G. Hurst ABSTRACT The CANDU reactor system, established at NPD and Douglas Point, is the basis for two of the world's large nuclear generating stations - Pickering and Bruce - now under construction. Further evolution of the system will result from materials development, fusl modifications, and higher thermodynamic efficiency, but with firm guidance by cost evaluations that are kept fully up-to-date. Significant reduction of capital cost should be attainable without seriously affecting the already low fuelling cost. Papers presented at the International Survey Course on Economic and Technical Aspects of Nuclear Power, sponsored by the IAEA at Vienna, September 1-12, 1969. Chalk River Nuclear Laboratories January 1970 AECL-3553 Perspective d'avenir pour les réacteurs CANDU 1 Partie: Aspects techniques 2 Partie: Aspects économiques par D.G. Hurst Mémoires présentés au Colloque international sur les aspects économiques et techniques des réacteurs de puissance organisé à Vienne par l'Agence internationale de l'énergie atomique, du Ie* au 12 septembre 1969. Résumé La filière CANDU, employée dans le NPD et à Douglas Point, sert de base à deux centrales nucléaires - Pickering et Bruce - actuellement en construction qui compteront parmi les plus grandes du monde. La filière CANDU va connaître une évolution résultant du développement de certains matériaux, de modifications apportées au combustible, d'un rendement thermodynamique accru, mais tenant compte des évaluations de coût tenues constamment à jour. Une réduction importante des investissements devrait être possible sans augmentation du coût de l'approvisionnement en combustible qui devrait rester bas. L'Energie Atomique du Canada, Limitée Chalk River, Ontario Janvier 1970 AECL-3553 -1- OUTLOOK FOR CANDU REACTORS PART I: TECHNICAL by D. G. Hurst 1. 1 Introduction I am very pleased to have this opportunity to discuss once again the outlook for CANDU reactors, which are heavy-water moderated pressure tube reactors without restriction on the fuel and coolant con- tained in the pressure tubes. It is ten years or more since I was pub- licly involved in discussions of this topic. At that time the operation of any power reactor using heavy water was some years away - the commis- sioning of the NPD reactor took place in 1962. We, the proponents of heavy-water, gave theoretical proof of a promising outlook and others gave theoretical proof of failure. Today we no longer rely on theory; we have a major heavy-water power reactor program underway. 1. 2 Survey of Operating and Committed CANDU Reactors On Figure 1 are shown the operating and committed CANDU nuc- lear power plants representing an investment of more than lj billion dollars. Note that the word CANDU is followed by PHW (Pressurized Heavy Water) or BLW (Boiling Light Water) signifying the coolant and a number giving the electrical output. The first three stations, NPD, Douglas Point, Gentilly, although operated by electric utilities, are owned by AECL. The Pickering and Bruce stations on the other hand, which together require an investment of about 1. 4 billion âollars, are wholly utility owned. The utility, Ontario Hydro Electric Power Commission, is a provincial organization in no way controlled by AECL or the Federal -2- 6000 BRUCE 4 x CANDU - PHW - 750 — 5000 PICKERING 4000 1 4 x CANDU- PHW-500 .r GENTILLY 3000 CANDU-BLW - 250 DOUGLAS POINT CANDU - PHW - 200 2000 - P n \ \ N. s- CANDU-•PHW-25 \ 1000 - \CANDU •BHW-25-^ \ \ \ 1 V i i i i i 1 i i i i . i , N 0 960 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 1979 IN SERVICE DATE Figure 1. Nuclear Power Commitment in Canada -3- Government and its decisions to proceed with Pickering and Bruce removes the sometimes implied criticism that the power reactors in Canada are D2O because AECL blindly follows its owr. predilection. Utilities make investments of this magnitude only after hard-headed scrutiny of all alter- natives. Not included on this figure are the commitments of India to 800 MWe from similar reactors, the 137 MWe KANUPP plant being built in Pakistan by Canadian General Electric, and the plans of other countries for heavy- water reactors. Tvluch information on CÀNDU reactors is in the literature, for example, the Canadian contributions to the Agency "Symposium on Heavy Water Power Reactors" September 1967. Let us look in more detail at the solid prospects for CANDU shown on Figure 1. NPD NPD has been in operation since 1962 and the details up to September 1967 are given in (1). Its success has been one of the factors leading to the major commitments. It has fulfilled its primary purpose but is continued in operation as a training centre and a test bed for new equipment and operating methods. During the summer of 1968 changes were made to per- mit net boiling and throughout the 1968-69 winter run it operated smoothly in the boiling mode with net exit quality of 13% and an output of 25 MWe (gross). Douglas Point The 200 MWe Douglas Point reactor is still in its "shakedown" stage which the operations staff expect to see last for 5 years, i.e. they do not feel that a meaningful on-line capability figure can be expected for -4- another year or so. This is in line with experience elsewhere. Although Douglas Point was planned as a "full-scale" power station under the cond- itions existing in the Ontario system and taking into account available turbine sizes, these conditions have changed so much that 200 MWe is no longer "full-scale" and 500 MWe and 750 MWe are more appropriate. The scaling-up is also advantageous economically. The history of Douglas Point is checkered. During the crucial winter periods when full system capability is required it has come through adequately, but there were early problems with purnp seals and bearings (now hopefully solved) and teething problems with the fuelling machines which are of a somewhat different design from NPD. Experience with NPD and Douglas Point has been published and reference may be made to some of the more recent papers (1, 2, 4). Gentilly With one exception the committed CANDU reactors are cooled by heavy water. Other coolants have been kept in mind and development effort has been expended on the more promising. A comprehensive review (3) was made in 1962 of CANDU variations from which four coolants - heavy-water, light water fog, boiling light water, and organic - were selected for quantitative comparison. Cost studies gave organic coolant a slight economic edge with boiling light water next. However, the economic assessment of organic involved some parameters which had not been fully substantiated and accordingly the committee did not give organic top priority but recommended vigorous development of fog and boiling light water and also continued development of organic coolant. As a result of further studies, construction was authorized in 1966 of a 250 MWe BLW (Boiling Light Water) prototype at Gentilly in the Province of Quebec as a -5- joint project of AECL and Hydro-Quebec. The design and construction have progressed well, in spite of early labour difficulties not arising locally. The predicted cost appears to be a good estimate. The BLW reactor, as represented at Gentilly, is an advance but it contains greater promise still with higher steam quality. The current value of 16. 5% exit quality is imposed by the decision to avoid dryout with a 50% margin, i.e. the critical power ratio is 1.5. As heat trans- fer data accumulate it should be possible to operate much closer to 1. The result will be a higher exit quality with accompanying higher burnup which, together with smaller reactivity hold-up, higher efficiency, and elimination of high temperature D,O, will keep BLW in the competition. 1. 3 Industrial Participation From the early days of the Canadian power program the intent has been to involve industry to the maximum extent possible. Through design and construction of NPD, the Canadian General Electric Co. Ltd. (CGE) acquired the necepsary know-how to enable them to bid successfully on the KANUPP power reactor in Pakistan and the WR-1 research reactor in Canada. The power reactor design group is at present merged with AECL, providing a coordinated organization for supply of reactors. Canadian design and consulting firms have been active in a number of nuclear projects throughout the world using experience gained in Canadian work. All reactor components are obtained from industry. Because of their specialized technology and the small volume to date, the pressure tubes and sheaths have been obtained from the USA, but with the large reactors now committed the market will support Canadian production, -6- and at least two companies will shortly be qualified to produce pressure tubes. Eldorado Nuclear Ltd. has set up a zirconium billet production plant. The fuel program has been most successful. Close liaison was maintained among the design group, the two manufacturers who set up production shops, and the fuel development group at Chalk River which had the use of fuel testing loops.