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Fast Breeder
Alistair Fraser has used the notes of Dr Lorna Arnold, UKAEA
historian, and trawled the minutes of
the Fast Reactor Design Committee (FRDC: 1951-1958) held in the National
Archives for this article.
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UKAEA At Dounreay
Dounreay Picture Gallery Aspects Of The
Dounreay Site Early History On The Site |
FAST REACTOR
A British think-tank, the Maud Committee, reported in 1941 that following a chain reaction it would be possible to separate fissile uranium 235 from non-fissile uranium 238 by a system called gaseous diffusion. Such a plant would cost £3 million and could be producing U235 by the end of 1945. Importantly, the Maud report also examined the long-term possibilities of a ‘uranium boiler’ in which a slow, controlled chain reaction could be used in the production of power. There was a further possibility it would produce a new element of mass 94, later to be called plutonium, which was expected to have properties similar to U235. This report was seen by Winston Churchill, the prime-minister, who agreed that its contents be further developed and, under strict secrecy, a small organisation code-named Directorate of Tube Alloys (DTA) was set up as part of the Department of Scientific and Industrial Research (DSIR). With the support of DTA, important research work was carried out by a number of universities and by commercial companies, including ICI. Information gathered during this research was conveyed to the American government through the scientific exchange agreement set up between both countries in 1940. This report gave renewed impetus to America’s own research programme culminating in the setting up of the Manhattan Project, costing some $2 billion. This project team, which included a number of British scientists, produced the first atomic bombs that were exploded over Hiroshima and Nagasaki in 1945. This defining event, together with the climate prevailing in the post-war period when the super powers were obsessed with developing bombs, has been seen by many as a hindrance to the civil nuclear industry because of the inevitable linkage.
Within government there was a feeling that this developing industry should be transferred from being part of the Ministry of Supply and become a stand-alone public corporation, wholly funded by the Treasury. Thus, the United Kingdom Atomic Energy (UKAEA) came into being on 19 July 1954, with Sir Edwin Plowden as its first chairman. UKAEA retained the Ministry of Supply’s three divisions, including the Industrial Group, based at Risley, under Sir Christopher Hinton. This group was to play a vital role in the development of Dounreay over the next four decades. However, three years before UKAEA was set up, the first steps had been taken to develop a fast reactor programme. On 9th October 1951, the first meeting of the Fast Reactor Design committee took place in Christopher Hinton’s Risley office. A total of eight people were present although its number and personnel would change over the years. Among those who served on the committee were Sir John Cockcroft, Sir William Penney, R R Matthews, who became Dounreay’s second director, and C R Tottle, who later became head of reactors at Dounreay. Except when unavoidably absent Hinton remained throughout. This committee would meet sixty-five times in total over a seven-year period. They scrutinised 277 papers, reports and drawings, mostly all written in great scientific and engineering detail, many accompanied by bewildering equations and formulae. Every aspect of the reactor design was scrutinised, and despite the careful wording of the minute-taker, it is very clear there were many heated debates and that little went through ‘on the nod’, recommendations were frequently challenged and the authors invited to re-visit their conclusions. Many authors, and indeed some members, mindful of the experimental nature of their task, were clearly anxious to push things to the limit. Notwithstanding his great belief in nuclear power, Hinton was not prepared to take risks. At one point during discussion on the reactor design and the possibility of an explosion, and the consequential fission product hazard, Hinton said: “The only safe design, is one on which on failure becomes less critical. I will not take a decision which could imperil the livelihoods of a large section of the population.” The type of containment for the reactor exercised the committee’s minds for some time because the type chosen would greatly influence where eventually the reactor would be sited. The three types of containment considered were an underground cavern, a concrete igloo, and a steel sphere. Over the course of the next two years the committee gradually favoured the idea of a sphere. As their understanding of fast reactor technology grew, their fears of an explosion diminished, although they never dismissed the possibility, or the danger associated with a release of radiation. By the spring of 1953 the committee were becoming concerned at the lack of progress on identifying a site. The minutes tend to suggest that the committee favoured a new site. Hinton expressed his opposition to the new reactor being built at Windscale, Drigg, or at a new site in the Isle of Man. Mindful of safety factors, and in particular the remote possibility of an explosion, population density and its proximity to any proposed site weighed heavy upon their deliberations. The committee was anxious that the site chosen should be outwith a radius of five miles from centres of population greater than 2,500. During the summer of 1953, the proposed locations were narrowed down to Wigtown, Kirkcudbright, Banff, the western highlands and the north and north-east coasts of Scotland. The complete coastline of Ireland, and the ‘useful’ coastline of England were completely removed from the equation. Hinton favoured a site in the western highlands or the north of Scotland, and at their meeting on 30 July 1953, he advised the committee that a site ‘at Thurso’ had been considered’. Hinton had made a visit to the north in May 1953 when he visited sites in both Caithness and Sutherland. This fact is not reported in any minute. One of the members, Professor Skinner, did not favour a Scottish site because it would be ‘very difficult to recruit staff to a Scottish site’. The chosen site required its height above sea-level to be ‘about fifty feet’, close proximity to the sea for intake of sea-water for cooling purposes and where discharges could me made, and where a fresh water supply was readily available on a daily basis. It now appeared that the proposed location had been narrowed down to two sites, Golspie in Sutherland and ‘a site near Thurso’. In September 1953 Hinton reported that the Golspie site, which was suitable in most respects, was not to be considered further due to its close proximity to the village. He told the committee that a site ‘near Thurso’ was identified and an estimate for its development had been prepared for submission to the Atomic Energy Council (AEC). Whilst not identifying the exact location, Hinton said the site was some thirty miles from Wick airfield and the site contained an old naval camp, in good condition. Hinton reported that the estimate for the project was £15 million with, and £14 million without a power plant. Included in both estimates were the plants for the final fabrication of fuel elements and for chemical separation of irradiated material. The inclusion of the two plants was queried by the AE C. However, Hinton was adamant they should be built on the same site as the reactor. He argued it was vital, for safety reasons, that the manufacture of elements should be under the control of the same person who controlled the reactor. He also pointed out it was undesirable to transport new and irradiated elements several hundred miles. Despite opposition from Sir John Cockroft the committee agreed, subject to Treasury approval, that the one-site principle should be approved. At the end of March 1954, Hinton reported that the Dounreay project had received Treasury approval, initial site preparation would commence towards the end of the year, with construction work scheduled for March 1955. With a site fixed and construction just a year away, the committee concentrated on finalising the technical detail of the reactor. They discussed at great length the intricacies of the control equipment, the fuel to be used, the core design, the type of coolant and shielding to be used. The committee was advised in September 1954, that a team from the Ministry of Works, led by Frank Brockelsby, was designing the sphere. It would be approximately 135 feet in diameter formed by welding together steel plates with an average thickness of one inch. One of the few Fast Reactor Design committee meetings where Christopher Hinton was absent was the meeting of 5 January 1955. The previous evening he addressed a packed Thurso town hall when his audience of some five hundred people heard at first hand details of the fast reactor project planned for Dounreay. Within two months construction work had commenced and by late autumn of 1955 a giant ‘bowl’ had taken shape as the skilled platers and welders of Motherwell Bridge & Engineering Co Ltd completed the bottom half of the sphere, which contained the shielding. Another Lanarkshire firm, Alexander Findlay & Co Ltd., were erecting the internal structural steelwork.
With the sphere watertight, contractors commenced the intricate task of installing the various components, firms like James Scott & Co. and Reyrolle Ltd., electrical engineers, Thomas Ward of Sheffield and John Thompson and Henry Hargreaves, mechanical engineers, Honeywell Controls, Crossley Engineering of Manchester, Carruthers of Glasgow, installer of the 25-tonne rotating crane, and many more, working round the clock to achieve the dream of limitless energy. Throughout the site there was a high level of construction activity as offices, workshops, plants, laboratories, and a variety of support and ancillary facilities were being built. Whilst all this was taking place, the fast reactor design committee continued to meet monthly, fine tuning design and details, and making amendments on the basis of feed-back from their engineers on site. On the 6th of November 1958, the committee met for the last time. Reviewing the situation, the chairman Christopher Hinton said that the committee started out with light hearts and high hopes. Would these hopes be justified? They would not have long to wait to find out. At the end of 1958 the plant was handed over to operations and the necessary preparatory start-up work commenced. By November 1959, DFR was operating on low power, and in October 1962 it fed electricity into the national grid. The hopes of Christopher Hinton and his colleagues were realised. It is not clear how history will finally judge the fast reactor concept. What is not in doubt is the vision of the engineers and scientists behind the concept. When they started out they had no detailed template for the design of a 60MW reactor. All they had to guide them was their brilliant engineering and scientific design intuition and, in the words of Hinton, ‘high hopes’. On the north coast of Caithness, overlooking the Pentland Firth, these hopes took shape. |
