US Experts: Breach in Spent Fuel Pool may doom repair effort – Also, Add Volcano to list

March 18, 2011


Fukushima Unit number 4

US experts now believe that the spent fuel pond at the badly damaged Fukushima number 4 reactor is breached, and may be difficult or impossible to fill with badly needed new cooling water.

LA Times had it first:

U.S. government nuclear experts believe a spent fuel pool at Japan’s crippled Fukushima reactor complex has a breach in the wall or floor, a situation that creates a major obstacle to refilling the pool with cooling water and keeping dangerous levels of radiation from escaping.

Unlike the reactor itself, the spent fuel pool does not have its own containment vessel, and any radioactive particles and gases can more easily spew into the environment if the uranium fuel begins to burn. In addition, the pool, which contains 130 tons of uranium fuel, is housed in a building that Japanese authorities say appears to have been damaged by fire or explosions.

A breach in the pool would leave engineers with a problem that has no precedent or ready-made solution, said Edwin Lyman, a physicist with the Union of Concerned Scientists.

“My intuition is that this is a terrible situation and it is only going to get worse,” he said. “There may not be any way to deal with it.”

NYTimes was also reporting the story:

..a senior Western nuclear industry executive said that there also appears to be damage to the floor or sides of the spent fuel pool at Reactor No. 4, and that this is making it extremely hard to refill the pool with water. The problem with No. 4 was first reported by The Los Angeles Times.

Engineers had said on Thursdaythat a rip in the stainless steel lining of the pool at Reactor No. 4 and the concrete base underneath it was possible as a result of earthquake damage. The steel gates at either end of the storage pool are also vulnerable to damage during an earthquake and could leak water if they no longer close tightly. The senior executive, who asked not to be identified because his comments could damage business relationships, said Friday that a leak had not been located but that engineers had concluded that it must exist because water sprayed on the storage pool has been disappearing much more quickly than would be consistent with evaporation.

“They have to figure out what to do, and certainly you can’t have No. 2 going haywire or No. 3 going haywire at the same time you’re trying to figure out what to do with No. 4,” said the executive, who said he had learned of the problem from industry contacts in Japan.

The Union of Concerned Scientists has this graphic of the amounts of spent fuel on site, – which lists the Number 4 reactor as having 250 tons – at variance with the LA Times story and other reporting.

Meanwhile, in other news, a volcano in southern Japan erupted.

The volcano last erupted Jan. 19 after remaining dormant for two years. Volcanologists had warned that a “lava dome” was growing inside the volcano’s crater, although it was uncertain when or if the volcano would erupt.

Sunday’s eruption, which was the biggest volcanic activity in Shinmoedake in 52 years, caused widespread destruction and panic. The blast could be heard for miles, and shattered windows four miles away, the BBC reported. Hundreds of people fled the area as the volcano spewed debris, including hot ash and rocks, more than 6,000 feet in the air, according to BBC reports.

(The current eruption has no impact on the evolving nuclear situation. – PS)

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