XN000022-1986-05-11 — Page 3

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SUNDAY, MAY 11, 1986

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ANOTHER MAJOR DIFFERENCE BETWEEN THE TWO DESIGNS IS THAT THE RBMK IS A DIRECT-CYCLE SYSTEM IN THAT THE STEAM PRODUCED IN THE REACTOR DIRECTLY DRIVES THE TURBINES. THE PWR, ON THE OTHER HAND, COMPLETELY ISOLATES THE REACTOR COOLANT FROM THE STEAM DRIVING THE TURBINES, BY USING STEAM GENERATORS, THUS AVOIDING ANY COMPLICATIONS IN THIS AREA.

IN ADDITION, THE DAYA BAY PWR WILL BE HOUSED IN A THICK CONCRETE CONTAINMENT BUILDING WITH A STEEL LINER, THIS CONTAINMENT, WHICH IS NOT USED AT CHERNOBYL, IS DESIGNED TO PREVENT ANY LEAKAGE OF RADIOACTIVE MATERIAL INTO THE ENVIRONMENT IN THE UNLIKELY EVENT OF AN ACCIDENT.

MR OSBORNE SAID THE RISK INHERENT IN USING WATER-COOLED GRAPHITE REACTORS WAS CLEARLY IDENTIFIED IN 1957 WHEN A SERIOUS FIRE OCCURRED IN SUCH A PLANT IN BRITAIN. THE FIRE AT THE BRITISH ATOMIC ENERGY AUTHORITY'S EXPERIMENTAL PLANT AT WINDSCALE LED WESTERN ENGINEERS TO DRAW APPROPRIATE CONCLUSIONS AND THEY TURNED TOWARDS THE PRESSURISED WATER REACTOR.

A FEW WESTERN NUCLEAR PLANTS STILL USE GRAPHITE, BUT THE ESSENTIAL DIFFERENCE HERE IS THAT CARBON-DIOXIDE GAS IS USED AS COOLANT, NOT WATER. THIS AVERTS THE POSSIBILITY OF AN EXPLOSION OF THE SORT THAT OCCURRED AT CHERNOBYL.

GOVERNOR TO LEAVE ON TUESDAY

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THE GOVERNOR, SIR EDWARD YOUDE, WILL LEAVE FOR LONDON ON TUESDAY (MAY 13) BY FLIGHT CX 201, ÉTD 11 PM.

NOTE TO EDITORS:

A PHOTOGRAPHIC FACILITY HAS BEEN ARRANGED FOR MEDIA REPRESENTATIVES TO COVER THE GOVERNOR'S DEPARTURE. THOSE COVERING THE EVENT SHOULD ASSEMBLE IN THE AIRPORT PRESS ROOM BY 10.10 PM. GIS OFFICERS WILL BE ON HAND TO ASSIST.

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