Japan Strains to Fix a Reactor Damaged Before Quake

The Monju prototype fast-breeder reactor — a long-troubled national project — has been in a precarious state of shutdown since a 3.3-ton device crashed into the reactor’s inner vessel, cutting off access to the plutonium and uranium fuel rods at its core.

Engineers have tried repeatedly since the accident last August to recover the device, which appears to have gotten stuck. They will make another attempt as early as next week.

But critics warn that the recovery process is fraught with dangers because the plant uses large quantities of liquid sodium, a highly flammable substance, to cool the nuclear fuel.

The Monju reactor, which forms the cornerstone of a national project by resource-poor Japan to reuse and eventually produce nuclear fuel, shows the tensions between the scale of Japan’s nuclear ambitions and the risks.

The plant, a $12 billion project, has a history of safety lapses. It was shuttered for 14 years after a devastating fire in 1995, one of Japan’s most serious nuclear accidents before this year’s crisis at the Fukushima Daiichi Nuclear Power Station. Prefecture and city officials found that the operator had tampered with video images of the fire to hide the scale of the disaster. A top manager at the plant recently committed suicide, on the day that Japan’s atomic energy agency announced that efforts to recover the device would cost almost $21.9 million. And, like several other reactors, Monju lies on an active fault.

Even if the device can be removed, restarting the reactor will be risky, given its safety record and its use of highly toxic plutonium as fuel, said Hideyuki Ban, co-director of the Citizens’ Nuclear Information Center, a watchdog group, and a member of an advisory government committee on Japan’s long-term nuclear energy policy. The plant is 60 miles from Kyoto, a city of 1.5 million people, and the fast-breeder design of the reactor makes it more prone to Chernobyl-type runaway reactions in the case of a severe accident, critics say.

“Let’s say they make this fix, which is very complicated,” Mr. Ban said. “The rest of the reactor remains highly dangerous. And an accident at Monju would have catastrophic consequences beyond what we are seeing at Fukushima.”

Japan badly needs sources of energy. By closing the loop on its nuclear fuel cycle, Japan aims to reuse, recycle and produce fresh fuel for its 54 reactors.

“Monju is a vital national asset,” said Noritomo Narita, a spokesman here in Tsuruga for the reactor’s operator, the government-backed Japan Atomic Energy Agency. “In a country so poor in resources, such as Japan, the efficient use of nuclear fuel is our national policy, and our mission.”

Critics have been fighting the project since its inception in the 1970s. “It’s Japan’s most dangerous reactor,” said Miwako Ogiso, secretary general of the Council of the People of Fukui Prefecture Against Nuclear Power. “It’s Japan’s most nonsensical reactor.”

After promises of safety upgrades, as well as lavish subsidies and public works, the government has wooed local officials into allowing a restart of the reactor. In Fukui, the government had ready allies: with 14 nuclear reactors, it is Japan’s most nuclear-friendly prefecture. (Fukushima, in second place, has 10 reactors.)

Monju was reopened in May 2010, and just three months later, the 3.3-ton fuel relay device fell into the pressure vessel when a loose clutch gave way. In the two decades since the reactor started tests in 1991, the atomic energy agency has managed to generate electricity at the reactor only for one full hour.

In Monju, Japan is pursuing a technology that most countries have long abandoned. Decades ago, a handful of countries, including the United States, started exploring similar programs. But severe technical difficulties, as well as fears about the weapons-grade plutonium that the cycle eventually produces, have led most countries to scrap their programs.

But Japan has remained staunchly committed to the Monju project. The government of Prime Minister Naoto Kan has shielded it from the deep cuts in spending that it has required of other national projects since it came to power in September 2009.

Under a government plan, Japan would use technology developed at Monju to commercialize fast-breeder reactors by 2050.

Mr. Kan has recently hinted at an overhaul of Japan’s nuclear policy, though he has not commented specifically on the fate of the Monju reactor.

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Workers Enter Japan’s Crippled Reactor Building

TOKYO — Workers entered a damaged reactor building at the Fukushima Daiichi nuclear plant on Thursday for the first time since explosions crippled the Japanese power plant two months ago.

The plant’s operator, the Tokyo Electric Power Company, said the workers were trying to install a ventilator to help lower radiation levels in the reactor building.

If all goes according to plan, the reduced radiation should allow workers to enter the plant for short periods to begin the critical task of installing a new cooling system. It will also reduce the chance that radiation will be released into the environment, said Michael Friedlander, a former senior nuclear power plant operator in the United States.

“In general, it’s all positive,” he said.

The power company said a dozen workers in antiradiation suits entered the outer rooms of Unit 1 to begin installing the system for filtering out radioactive particles in the air. Last month, robots found dangerously high radiation levels in the building, which was damaged by a hydrogen explosion after the March 11 earthquake and tsunami in northeastern Japan.

The filter will act like a vacuum cleaner, absorbing radioactive particles from the building’s air.

Tokyo Electric officials said the ventilator should lower radiation levels enough that workers would be able to enter the rest of the building within three days.

The company can then begin replacing the cooling system to regain control of the overheated reactor, which has partly melted down.

Tokyo Electric must install cooling systems at three of the Fukushima plant’s six reactors to stay on its current timetable of stabilizing the plant within six to nine months.

The cooling systems were knocked out, and storage pools for spent fuel rods compromised, by the earthquake and tsunami.

The workers were sent into the plant after robots found that radiation levels in the building had dropped from last month, though they are still high.

To limit exposure, the workers were split into four groups of three. Each group entered in 10-minute shifts, the company said. The workers also carried their own oxygen tanks to reduce risk, the company said.

The workers are installing large ducts that will be used to filter the air inside the building.

If the air purification system is properly set up and running, it is reasonable to assume that workers can move to the next step of installing a cooling system by early next week, Mr. Friedlander said.

Kevin Drew contributed reporting from Hong Kong.

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Water Pumping Begins at Japan Nuclear Reactor

 

The Japanese government, meanwhile, said it was considering a plan to further restrict access to the evacuated area within 12 miles of the plant, the Fukushima Daiichi Nuclear Power Station. Some families have been re-entering the area to remove belongings, and dozens of people have never left.

At the plant itself, the Tokyo Electric Power Company said that it planned to pump 10,000 metric tons of water into a storage building at a rate of 480 tons a day, which would take nearly three weeks. The company is still working on ways to remove an additional 57,500 tons of heavily contaminated water at the same building, next to Reactor No. 2, and at other nearby buildings.

The cautious pace of the pumping and the volume of water to be moved are further signs of the complexity of the undertaking that faces Tokyo Electric. Removing the water is one of the 63 tasks that the company outlined Sunday in its plan to fully shut down the stricken reactors, halt all releases of radioactive material and restore reliable cooling and electricity roughly by the end of the year.

Michael Friedlander, a former senior nuclear power plant operator in the United States, said that while the pumping might be proceeding slowly, a faster pace could prove dangerous.

“If a pipe breaks and you’re pumping hundreds of gallons a minute, you’re going to make a huge mess,” he said.

Hidehiko Nishiyama, the deputy director general of Japan’s Nuclear and Industrial Safety Agency, said that the heavily contaminated water that had accumulated in basements and trenches at the site is two million times as radioactive as the less contaminated water that workers pumped into the ocean from April 4 to April 10. Workers pumped 10,393 tons of the less contaminated water into the ocean in order to make room in storage areas for the far more highly radioactive water from inside the reactor buildings.

Pumping contaminated water into the ocean has provoked considerable dismay from Japanese fishermen and from nearby countries, particularly South Korea and China. Mr. Nishiyama said Tuesday that Japan had no plans and no need to do so anymore.

Plans are being made for the installation of water-purification equipment and heat exchangers so that the same water can be pumped repeatedly through the reactors.

Anne Lauvergeon, the chief executive of Areva, France’s nuclear-power equipment provider, said at a news conference in Tokyo on Tuesday evening that it would probably take until the end of May to set up a water treatment station at the plant. Once running, she said, it should be able to handle 50 metric tons of water an hour and should almost entirely remove the radiation.

The technology, called “co-precipitation,” uses chemical agents to remove radioactive elements from water. The treatment station itself will be provided by Veolia Water, a British water and waste management service. Areva and Tokyo Electric have not discussed the cost of the services, Ms. Lauvergeon said.

Areva, together with Veolia Water, will also provide three lines of desalination equipment to enable Tokyo Electric to convert seawater into fresh water for cooling the reactors. Fresh water provides better cooling; the spaces between the fuel rods have started to become congested with salt from seawater.

She also said that Areva was not preparing an overall plan to decommission the troubled plant, though she said the company was prepared to cooperate with any long-term process to eventually dismantle Fukushima Daiichi. Toshiba and Hitachi have submitted competing plans to dismantle the plant; the work could take decades.

In a further effort to improve cooling, Mr. Nishiyama said Tuesday that a decision had been made to flood the primary containment vessels of the No. 1 and No. 3 reactors with enough water to cover up the sides of the reactor pressure vessels up to the level of the uranium fuel rods.

This was not done sooner because only now have workers been able to determine that the primary containment vessels are sufficiently watertight. The vessel at the No. 2 reactor is damaged and leaking gases, and the leak or leaks need to be plugged before it can be flooded, Mr. Nishiyama said.

The No. 2 reactor has posed some of the greatest challenges in recent days, including another leak that spewed radioactive water until plugged two weeks ago.

Robots entered Reactors Nos. 1 and 3 on Sunday and measured the radiation inside. But when two robots entered Reactor No. 2 on Monday, the steam inside was so dense that a robot mounted with a camera was unable to get a clear image of a radiation sensor carried by the other robot, Japanese officials said.

Ken Ijichi, Moshe Komata and Kantaro Suzuki contributed reporting.