EXPERIMENTS IN ATOMIC POWER

Press, Volume LXXXIII, Issue 25346, 20 November 1947, Page 5

EXPERIMENTS IN ATOMIC POWER

unknown elements

rtOFESSOR COCKCROFT’S REVIEW

c (From Our Own Correspondent.) LONDON, September 10. j a discussion on the peace-time ap.jations of nuclear fission, which was Lced to-day by Professor J. D. Cock2ft, the problems affecting its defgjpnient as a source of power were -nsidered, and some details were of constructional progress at the Jpiic research establishment at Hartl here were, Professor Cockcroft j three main types of nuclear rei Lors built for scientific research—graphite pile, the heavy water .jo and the reactors using pure fissile Serial, plutonium or U 235, or en--ped U 235. The graphite pile had a try simple construction, and a small -5 of this type had iust been comJted at Harwell which would be Jjd for basic measurements in nucar physics. Higher power graphite rhad a rather similar construction, the uranium rods were cooled by f at high speed. One of these, which operated at jout 1800 kw., was also being built . Harwell. Others were under conduction at the Brookhaven National jboratory on Long Island, in jnerica, and at the French atomic <ergy project. The actual power level ( all these piles would depend on the jterisity of cooling, and when cometed they would be suitable for the ioduction of radio-active isotopes for jclear experiments requiring high jutron fluxes, and for investigation io the generation of power from jclear energy. ’iles built from graphite and natur uranium had necessarily to be r her large. The minimum size reared several hundred tons of grajjte. Heavy water piles had a rather fther neutron reproduction constant, ■ 4 could therefore be smaller for a " fen power, but as the power level |vs increased more structural R jterials had usually to be introduced I f engineering reasons. A high power j pe of this type was operating at the I jgonne National Laboratory at Chalk I rer, in Canada, and another was Hng built by the French. Still smaller piles could be built if jre plutonium or uranium, highly aiched in U 235, were available. Less tin a kilogramme of fissile material dsolved in a few litres of water nuld produce a chain reacting pile. Tese had been built at Los Alamos, ad were known as “water boilers,” be they were complicated by the inUse activity of gases ph as xenon and iodine. n the conventional pile these fission pes were prevented from escaping t the sheathing of the uranium. The tense neutron and gamma radiations j water boilers also decomposed the dution rapidly and further complitted design. Power Generators Fhe natural uranium nuclear reactor cild be used in its present form as a jwer generator, and it was probable Ut experimental plants of this type vuld be built during the next five jars to obtain this country’s first derating experience of nuclear power gierators. If nature were exceptioniy kind a reactor containing 100 tons < uranium would generate IOO.OOOkw. • thermal energy for 20 years without el replacement. This would yield •out 20,000 kw. of electrical energy. It was expected, however, that the rmation of fission products would ad to poisoning of the chain reacon, due to their additional absorpon of the neutrons produced. Diffiilties might be experienced due to eterioration of materials under the itense neutron bombardment of the He. Professor Cockcroft pointed out lat upon these, and perhaps other nknown factors concerning the reurification of the elements, would deend the ultimate cost of nuclear ower. One other major uncertainty stood i the way. The safe disposal of the ery large-scale production of radioctive materials in the generation of uclear power was a major problem, nd one which would require a cautius approach. While nuclear power resented a rather dazzling prospect nd was worth a determined attack, ts future was by no means clear.