Burial of Japan reactors trickier than Chernobyl: pump firm

AICHTAL, Germany (Reuters) - Encasing reactors at Japan's Fukushima nuclear plant in concrete would present much more of a challenge than Chernobyl, according to an executive of the firm whose pumps are helping cooling efforts there.

"In Chernobyl, where a single reactor was encased, 11 trucks were in action for a number of months. In Fukushima we're talking about four reactors," Gerald Karch, chief executive of the technical business of unlisted machinery maker Putzmeister, said in an interview with Reuters.

He said that while no decision had been made in Japan, concrete encasing would be the most sensible solution once the crippled Fukushima Daiichi plant has cooled down.

"In my opinion, when a closed-circuit cooling system has been developed and successfully set up, there will be no other option but to encase the reactors in concrete," he said.

He added, however, that the logistics of such an operation -- getting all the necessary trucks on site, for example -- would present a real challenge for plant operator Tokyo Electric Power Co (TEPCO).

On Tuesday, Japanese authorities put the nuclear calamity on a par with the 1986 disaster in Chernobyl after new data showed that more radiation leaked from the power plant in the early days of the crisis than first thought.

"Yes, there are certain similarities between the two events, but at the same time I think that we can't really draw comparisons," Karch said.

"There is still a high chance that the situation (in Fukushima) can be stabilized," he said.

The Chernobyl nuclear disaster was the result of a single explosion, he said. That meant that in contrast to Japan the reactors did not have to be cooled and could be encased in concrete soon after the explosion.

EMERGENCY COMMISSIONS

Putzmeister, which makes colossal bright red truck-mounted cranes with arms up to 70 meters in length, delivered 11 vehicles after an explosion and fire at the nuclear reactor in present-day Ukraine released large quantities of radioactive contamination into the atmosphere in 1986.

Almost exactly 25 years later, Putzmeister, which translates to "Plaster Master," is aiding efforts in Japan by supplying equipment to pump millions of liters of water over hot reactors damaged by a 9.0 magnitude earthquake and tsunami that hit the region on March 11.

Putzmeister, founded in 1958 and headquartered in sleepy Aichtal, on the outskirts of the Baden-Wuerttemberg capital of Stuttgart, has sold five vehicles to TEPCO, the operator of the Fukushima Daiichi power plant.

Karch declined to indicate how much TEPCO paid for the trucks, which have also been used in firefighting, but said that each costs "well over a million dollars."

"The transportation costs alone -- in an Antonov aircraft -- of a Putzmeister machine from Germany to Japan, are close to a million dollars."

The trucks themselves, which are usually only built when commissioned, were made available at extremely short notice after last month's earthquake, thanks to customers willing to give up their vehicles.

"We quickly located a truck that was on its way to a customer in Vietnam. By March 18, we had been able to transport that truck to Fukushima, where we trained members of TEPCO to operate it," Karch said.

Among the other four trucks, some had previously been in Spain, but had returned to Putzmeister -- largely unused -- when building projects were terminated or postponed during the credit crisis.

(Editing by Robert Birsel)