HIGHLY ENRICHED URANIUM COULD CAUSE CHERNOBYL DISASTER, EXPERT SAYS
RIA Novosti
KIEV, April 26 (RIA Novosti) - The accident at the fourth unit of the Chernobyl nuclear power plant could have been caused by addition of highly enriched uranium to ordinary fuel. This version was presented to Novosti-Ukraine by Sergei Chebanenko, senior fellow at the Institute of Geochemistry, Mineralogy and Oregenesis in Kiev.
"After the Chernobyl accident and fuel blowout we found uranium of a much higher degree of enrichment in the soil and hot fuel particles," he said.
One could suggest that the reactor fuel had been produced by mixing uranium "powders" of various enrichment, and we just came across the particles enriched by uranium-235 isotope. But this is impossible - fuel is produced from homogenous substances (gases or solutions) and the particles they form have a similar isotope composition," Mr. Chebanenko pointed out.
"I think the presence of highly enriched uranium can be explained as follows. Reactors are periodically shut down for routine maintenance. Their consequent start-up takes some time, and this time costs a lot of money. The start-up can be accelerated by loading fuel with higher-enriched uranium to the reactor - for instance, 80 per cent uranium assemblies like the ones used in nuclear submarines propulsion systems," he said.
"If the fuel is enriched, the neutron flux is highly intensive. To avoid reactor shutdown by protection systems, which are not designed for this kind of neutron flux, the latter were switched off," he explained.
"I am sure reactors were repeatedly started up this way. The problem is that the second - less sensitive - emergency protection system was never developed," Mr. Chebanenko noted.
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