asked the Secretary of State for Education and Science what proportion of the total effort of the Atomic Energy Authority is in work on graphite moderated reactors; and whether he will direct the Authority to pay greater attention to other reactor systems, in view of the doubt as to whether this type of reactor, especially on account of its high capital cost, is best suited for electricity generation in this country.

One third of the Authority's current effort on civil reactor development is on graphite moderated reactors, including participation in the international "Dragon" Project. As regards the second part of the Question, we have not yet the necessary information to compare the suitability of different reactor systems for electricity generation in this country. The Authority's current development effort on the advanced boiling water reactor is comparable with that on the graphite moderated advanced gas-cooled reactor.

Is it not a little disquieting that one public corporation appears to take a different view from another public corporation which is its chief customer? Is it not possible that we have taken the wrong turning by specialising so much in graphite-moderated reactors, and might it not be well to have a general review of this question?

There is no question yet of having taken a wrong turning. It is desired as a result of tendering inquiries that we should make a clear and fair comparison between the cost of an A.G.R. and of a B.W.R. built to the same standard and specification. We must await the decision which will be made after tenders have been received before considering this matter finally. There is no question of having taken a decision yet

In making a comparison between the A.G.R. and the other systems which would have to be imported from abroad, will development costs which have already been incurred by the Atomic Energy Authority be spread over the likely number of stations which will be ordered, or would they be written off altogether?

These are precisely the matters that we want to consider further, but I can assure the hon. Gentleman that the capital cost and the fuelling costs of all existing expenditure on development will be taken into account.

Would my right hon. Friend be prepared to consider again the inevitable emphasis which there must be on policy resulting from the fact that there is really only one customer for the Atomic Energy Authority here in the shape of the Central Electricity Generating Board? Bearing in mind the very considerable potential market which there may be abroad for atomic reactors, would he consider consulting his right hon. Friend the Minister of Power and possibly his right hon. Friend the President of the Board of Trade to see whether or not we can work out a system which ensures at least that the single customer factor does not result in our losing overseas markets?

That raises rather wider considerations, but I can assure my hon. Friend that this comparison will be a very important one and will require very skilled work, and the Government are determined that it should be done fairly and thoroughly.