By IPS Correspondents
MOSCOW, Oct 4 1996 (IPS)

Ukraine’s environment and nuclear safety Minister Yuri Kostenko has been severely rapped by president Leonid Kuchma for his “alarmist” statements about the state of the sarcophagus encasing the shattered hulk of Chernobyl’s Reactor IV.

He had suggested that three recent rises in neutron flux inside the shelter over the crippled fourth reactor, scene of a 1984 explosion that spread nuclear debris across Europe, could signal the start of a chain reaction which might lead to another blast.

But Ukrainian national security council secretary Volodymyr Horbulin says Kostenko is mistaken while Chernobyl plant director Sergei Parashyn denies there had been any rise in radiation at the plant.

He says torrential rains had seeped under the encased reactor, causing the measuring equipment to malfunction and register a change in the density of neutron flux.

A spokesman for the International Atomic Energy Agency (IAEA) agrees with this assessment, although he admits that a full explanation may never be found. Western experts believe another explosion is unlikely.

One British specialist familiar with Chernobyl explains that although an increase in radiation (neutron flux) of over 100 times the normal level was registered earlier this month, the reading was only reported from three of the measuring instruments inside the shelter.

“If this had been the start of a chain reaction all the monitors would have responded,” he insists. This is also the view of Valery Khukhar, Kuchma’s chief adviser on nuclear policy.

He says with only three of 25 monitors registering increased activity, there was no likelihood of a sustained chain reaction.

“There was no increase in heat or gamma radiation which would have been expected in such a case,” he says.

Kostenko had initially attributed the increased radiation to faulty equipment but subsequently accepted that they were valid readings and urged the West to speed up construction of a new sarcophagus.

This view is shared by Viktor Baryakhtar, vice-president of the National Academy of Sciences of Ukraine and another adviser to the Ukrainian President on nuclear power.

However, a Russian Atomic Energy Ministry (MinAtom) official has warned that equipment for detecting gamma and neutron radiation in the sarcophagus is unreliable.

“The service life of all systems for diagnosing the gamma and neutron radiation and the temperature and humidity in the casing sealing the fourth unit of the Chernobyl nuclear power plant has expired and their readings cannot be trusted,” says MinAtom information head Georgiy Kaurov.

He explains that the Kurchatov nuclear research centre in Moscow had made regular checks on the sarcophagus up to 1991 when Ukraine stopped financing the work but had made only occasional visits since then.

Nevertheless, information available to MinAtom did not suggest that there was any danger of a chain reaction, a thermal explosion or damage to the sarcophagus, he insists. He expects the sarcophagus to survive for another 10 years.

But some Western experts say Ukraine is using the incident to press for money for a new shelter. Ukraine’s decision to close Chernobyl by 2000 were based on promises of western support for a new structure.

The aim would be to provide secure protection for more than 200 tonnes of nuclear fuel which are still inside Reactor IV in various forms until such time as its radioactivity is reduced to the point where it can be removed safely.

The present sarcophagus was constructed a decade ago as a temporary stop-gap measure with a design life of 10 years.

Valentin Kupny, Chernobyl’s deputy director in charge of the sarcophagus rejects as impractical suggestions that it is more important to remove and dispose of the fuel than to build a new shelter.

“We would need equipment able to work in high radiation fields and its development is many years away,” he says.

The present sarcophagus is a “manageable object”, although there is no knowing how long it will stand, he adds, especially as money is short for basic maintenance.

This year some 200 million dollars had been allocated for the purpose but only 60 percent has been received.

He also notes that unmelted fuel assemblies have recently been discovered inside the sarcophagus in an area known as Room 305 close to where the neutron fluxes were recorded.

Plans to build a new sarcophagus, based on a French-British design and estimated to cost 1.2 billion dollars, were finalised in 1993 as part of a series of studies financed by the European Union’s executive Commission.

However no finance was available for the construction and the plans were effectively shelved despite Ukraine’s insistence that this should be a priority.

Now the EU is revising the design criteria and is considering proposals for a cheaper version.

However the source of finance for this project has still to be decided and sources close to the current negotiations say none of the new proposals is really satisfactory.

There is growing concern that if promised western aid is not forthcoming very soon, Ukraine may choose to keep Chernobyl operating beyond the 2000 deadline.

Although Reactor I will have to close at the end of this year in any case for technical reasons, some of its equipment, such as its turbines, could be used to refurbish Reactor IV which was closed after a fire in 1992. Restarting the reactor is an option which Ukraine is unlikely to relinquish until aid promises have been fulfilled.

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