Japan nuclear update: Repairing crack to stop radioactive water leak

The crack in a maintenance pit at the Fukushima Daiichi nuclear power plant in Japan is the source of radioactive iodine appearing in seawater near the plant for more than a week.

Tokyo Electric Power Co./AP
In this photo released by the Tokyo Electric Power Co., a TEPCO employee points at a crack newly discovered in a maintenance pit on the edge of the Fukushima Daiichi nuclear nuclear power plant in Japan. The crack was apparently caused by the March 11 earthquake and may have been leaking since then.

Japan's crisis within a crisis – severe damage to the Fukushima Daiichi nuclear plant on the country's northeast coast – may have taken a tiny step closer to resolution on Saturday with the discovery of a crack in a maintenance pit at the plant.

The crack has been identified as the source of radioactive iodine that has been appearing in seawater near the plant for more than a week, according to Japan's Nuclear and Industrial Safety Agency, which notes that workers at the stricken facility are trying to repair the crack with concrete.

But it also raises a question of how many more cracks of similar size have yet to be discovered as workers struggle to assess the full extent of damage to the plant as well as try to stem the release of radioactivity from damaged reactors and spent-fuel pools.

Japan Fukushima nuclear crisis: A timeline of key events

The discovery comes at a time of increasing frustration among some residents in areas stricken by the March 11 magnitude 9 earthquake and the resultant tsunami. They argue that while dealing with the plant is important, the government has been more focused on resolving the nuclear crisis than on dealing with the enormous number of people struggling in the aftermath of the quake and tsunami.

In an interview with the Associated Press, one woman visiting her parents in a shelter in Natori, some 50 miles north of the plant, said, "The government had been too focused on the Fukushima power plant rather than the tsunami victims. Both deserve attention."

The earthquake and tsunami have killed an estimated 11,800 people, according to emergency-management officials. The number could climb as high as 25,000, they said.

The crack likely resulted from the earthquake, specialists say. It appeared in the side of a maintenance pit associated with the plant's Unit 2 reactor – one of six reactors at the site. The pit is near an inlet that brings seawater into the plant to act as a coolant for steam the reactor produces to turn the plant's generators. The steam runs through a seawater-cooled condenser, where it cools, becomes liquid again, and then is sent back to the reactor for reuse.

The pit had filled with water contaminated from efforts to keep the Unit 2 reactor and its partially uncovered core cool using a portable pump brought in after the quake to supply fresh-water coolant.

The quake and tsunami knocked out all emergency power at the plant, as well as power coming in from off-site. That power is needed to operate the cooling systems designed to keep the reactor cores from overheating and melting.

Some of the spent-fuel pools at the plant also have lost water that cools the spent-fuel assemblies and acts as a radiation shield. Problems with at least two of the pools have contributed to the release of radiation into the environment.

In its latest assessment of the plant's condition, the International Atomic Energy Agency says that the plant's condition "remains very serious."

Japan Fukushima nuclear crisis: A timeline of key events

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