[en] The paper reports on France's experience in the development of power reactors.

[en] The Vulcain programme has been set up with the aim of developing a water reactor type specially designed to be attractive in the range of small and medium power outputs, especially in view of its application in developing countries. There is a market on economic grounds for small and medium size nuclear power stations whose specific investment cost is below a threshold. Extra-economic considerations may also justify the erection of small and medium size nuclear power stations. We believe that nuclear power stations of the Vulcain type are an interesting proposal for these markets.

[en] The Atomic Energy Commission of India has so far approved setting up of three nuclear power stations. The first nuclear station which has recently gone into operation, is located at Tarapur, about 60 miles north of Bombay on the western coast of India. The second nuclear station which is in an advanced stage of construction is located at Rana Pratap Sagar in Bajasthan; and the third station on which work has recently started is located at Kalpakkam, about 55 miles south of Madras on the eastern coast of India.

[en] The dramatic growth of the nuclear power industry in the United States during the period 1965 to 1968 is illustrated. As can be seen, more than 72,500 Mw(e) of nuclear capacity were in operation, ordered or announced as of September 1968. Surprisingly, at the present time, one year later the chart looks essentially the same. Only two new plants have been announced in the interim. In fact, a number of companies cancelled plans for previously announced nuclear plants and turned back to fossil fueled units.

[en] Nuclear power is now being accepted as a fully competitive source of electric power in large sized units in many industrialized countries. If we examine growth of nuclear capacity in recent years, we find that there has been a steady increase in unit sizes and this trend is likely to continue. Under these circumstances countries which are unable to use large plants may find it increasingly difficult to benefit from cheap nuclear power until their grids become extensive enough to absorb such large units. This paper examines the prospects of intermediate size power reactors (200 - 500 MW), by reviewing the problems associated with their availability and competitiveness and suggests how some of these problems could be met.

[en] Swedish model reactor development work has already reaped rewards in the. form of four sales of BWR's (without foreign license). Now the time for marketing decision on BHWR's with their allied technology is approaching. The simplicity and safety of the natural circulation BHWR's with concrete pressure vessels of integral design and the attractive fuel cycle could open a market for this type. Next year, results from Marviken BHWK operation and the Scandinavian model concrete pressure vessel testing will provide residual technology demonstration, and this and the results of a current evaluation study of a 750 MWe natural uranium version are expected to prove the viability of the concept. Experience, designs characteristics, and economy are reviewed. (author)

[en] The High Temperature Gas-Cooled Reactor (HTGR) has now reached the stage of a practical operating power reactor system in the U.S. One HTGR plant, the 40-MW(e) Peach Bottom Atomic Power Station, has been in successful commercial operation on the system of the Philadelphia Electric Company since June 1967. A second, larger HTGR plant, the 330-MW(e) Fort St. Vrain Nuclear Station of the Public Service Company of Colorado, is well along in construction, with commercial operation scheduled for early 1972. Development and design work is also proceeding rapidly for HTGRs in the 1100-MW(e) range, These larger HTGR plants use the fundamental principles, demonstrated by the Peach Bottom prototype and the component and systems technology being employed in the Colorado plant.

[en] The High Temperature Gas-Cooled Reactor (HTGR) is particularly suited to accommodate a variety of fuel cycles because of its core characteristics. Specific qualities such as the inherently low neutron losses, the high specific power, the high burnup capabilities and the high thermal efficiency result primarily from the type of fuel element used. Graphite serves as structural material, moderator, and fission product barrier and with its low capture cross section assures a low level of parasitic neutron absorption. The excellent material properties of graphite at elevated temperatures permit high gas outlet temperatures which lead to compact, high-efficiency plants.

[en] Two different fuel cycles are possible in all types of high temperature gas-coole reactors: • the thorium-uraniusv cycle and • the uranium-plutonium cycle with low enrichment. Originally only the thorium cycle was considered, because ef its excellent conversion ratios. In this case comparatively highly enriched uranium is needed. Economically the optimum enrichment is between 80 and 93% of U²³⁵ if the uranium-Plutonic cycle is adapted, enrichments between 4 and 8% U²³⁵ can be adapted. In both cycles U²³⁵ can be replaced by plutonium. This can. be economical only if the plutonium prices are comparatively low.

[en] The design construction and operation of the Ågesta and the Marviken nuclear power plants have been and are indispensable parts in the Swedish development of large size, heavy water power reactors. Both reactors are based on the use of pressure vessels, the Ågesta reactor giving experience of pressurised water cooling and the Marviken reactor being aimed for demonstrating the heavy water boiling reactor in a direct cycle. It is obvious that the main body of the knowledge and the experience gathered is in the hands and in the mind of each individual who has participated in the development and the operation of the reactors and it should be clear that the major part of this store of knowledge can never be made available by words - but better by deeds. The questioner can, however, share some glimpses of this by studying the available statistics, and by investigating the more spectacular occurrences. It is intended that this report should give the reader an appreciation of such records.