§ 53. Mr. Pentland
asked the Parliamentary Secretary for Science why Her Majesty's Government have given permission to the United Kingdom Atomic Energy Authority to proceed with the building of a prototype steam generating heavy water reactor; and what is the estimated cost of the project.
§ Mr. Denzil Freeth
The Atomic Energy Authority development on thermal reactors has up to now been concentrated on one basic system—the gas cooled, graphite moderated reactors—and improvements on that system. The power stations built in this country are of this type. The Advanced Gas-Cooled Reactor at Windscale, which is now running at power, is an advanced version of the same family of reactors, providing higher gas temperatures and reduced capital costs. The high-temperature reactor under development in collaboration with the O.E.C.D. countries at Winfrith is a still further advance of the same type of reactor.
Both my noble Friend and the Atomic Energy Authority have been concerned for a considerable time about the narrow technical base on which our reactor development rests. We have kept in as close touch as possible with developments abroad, notably those in Canada, Sweden and the U.S.A., on a variety of water moderated reactors. For some five years the Atomic Energy Authority has inten- 24W sively studied water moderated reactors in order to evolve a design which would achieve good neutron economy allied to low capital costs. The type designated S.G.H.W. (Steam Generating Heavy Water), the outcome of these studies, is a heavy water moderated reactor, with boiling light water coolant and a potential capacity for superheating the steam. The reactor employs pressure tubes as distinct from the pressure vessels of the gas-cooled, graphite reactors. For the past two years, a design and research and development programme has been undertaken to ensure that feasibility and design problems could be solved. I am confident that this type shows promise as an advanced water reactor and will enable the basis of reactor technology in this country to be broadened in the way required. There has been close collaboration and agreement with the nuclear consortia in the assessment and design of this reactor.
The capital cost of the prototype is £16 million and this sum includes the cost of built-in experimental facilities and a contingency against the uncertainties in estimating.