Tepco finds second pit leaking in Fukushima

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Seepage minor but casts doubt on radioactive storage strategy

JIJI   Apr 7, 2013 japantimes

A second underground storage pool is leaking highly radioactive water at the disaster-stricken Fukushima No. 1 power plant, operator Tokyo Electric Power Co. said Sunday.

The first pool, No. 2, was found to have leaked 120 tons on Friday. The size of the leak at the second pool, No. 3, is unknown but will probably force Tepco to review its storage strategy for the toxic water, which has become its biggest enemy.

Since the leak is apparently small, there are no plans to drain pool No. 3 into another storage area, Tepco said.

The pools are part of a group of seven vast clay-lined storage pits at the plant measuring 60 meters long, 53 meters wide and 6 meters deep. Since each is covered in three layers of protective waterproof lining, how the water escaped will remain a mystery until the faulty pits are drained and examined.

Tepco said Saturday it detected 0.11 becquerel of radioactive substances emitting beta particles, such as strontium, per cubic centimeter of groundwater on the external lining of pit No. 3 the same day. The radiation level was about double that detected Wednesday.

At that time, the utility said the water leaked by pit No. 2 may have seeped into the soil surrounding No. 3. But after detecting substances exhibiting 2,200 becquerels of radioactivity in water found between the second and third layers of lining at No. 3 on Sunday, the utility concluded that this pit was leaking as well.

The water level inside pool No. 3, however, hasn’t fallen, indicating the leak isn’t that large, Tepco said.

Tepco is transferring the remaining water in No. 2 to two other pits, but the water escaping from No. 3 is raising questions about the integrity of all of the pools and the subsequent risk to the environment.

Aside from the pools, the power plant has been building makeshift tanks to store the tainted seawater, which is perpetually needed to cool the damaged reactors’ melted fuel rods. But capacity is running out quickly.

Masayuki Ono, a senior Tepco official, said at a news conference Sunday that it is difficult for the plant to store all of the radioactive water in the temporary tanks.

On Saturday, Tepco said that around 120 tons of contaminated water with an estimated 710 billion becquerels of radioactivity probably leaked into the ground under the Fukushima No. 1 power plant. No explanation was given about where it might have ended up.

“It is the largest amount of radioactive substances that has been leaked” since the crippled facility’s cold shutdown was declared in December 2011, Tepco official Masayuki Ono said.

The utility said the remainder of the water in pool No. 2 — an enormous 13,000 tons — is being pumped into other tanks nearby — a process expected to take days.