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Japan:TEPCO to attach hoses to improve water filter flow + More Related News

Thursday, August 4, 2011

Laaska News  August 4,2011

The operator of the Fukushima Daiichi nuclear plant will attach makeshift hoses to its wastewater filtering system to help improve the water flow.

Tokyo Electric Power Company has been filtering highly contaminated wastewater to remove radioactive material and salt, and then pumping the water back into the reactors as coolant.

But the filters have been working at about 35 percent below capacity, likely because metal piping connecting the tanks has been narrowed by mud.

The utility therefore plans to stop the system for nearly 12 hours on Thursday and attach bypass hoses at 2 locations.

TEPCO has also installed a new device to remove radioactive cesium, in addition to the one currently in use.

It plans to start test-running the device on Saturday, and begin full operation next Monday.

TEPCO aims to improve the efficiency of its water filtering system to lower wastewater pooled in facility basements to safe levels as soon as possible.

The utility says it plans to achieve this for the No.1 and No. 2 reactors in early September.

Evacuation orders to be lifted in late August

The government says it wants to lift evacuation advisories in a few weeks for areas 20 to 30 kilometers from the Fukushima Daiichi nuclear power plant.

A recovery timetable released on Wednesday proposes lifting the evacuation notice later this month or early next since the situation at the plant has improved.

The plan covers areas between 20 and 30 kilometers from the plant. Residents there are currently advised to stay indoors and prepare for emergency evacuation.

Many residents there have been forced to evacuate, and schools and hospitals are closed.

The government says it will begin negotiations with local municipalities later this week and ask them to draw up reconstruction plans.

The measures are expected to include reopening hospitals and other public services and decontaminating schoolyards.

The government says it will support each local government to help them bring residents back home.

TEPCO reports cooling system’s reliability

 

The operator of the Fukushima power plant says it could restart injecting water into its crippled reactors within 3 hours after mechanical problems or power failure halt the plant’s cooling system.

Tokyo Electric Power Company made the claim in a report to the industrial ministry’s Nuclear and Industrial Safety Agency on Wednesday.

The agency asked TEPCO to report how it will deal with the failure of the cooling system, which recycles decontaminated radioactive water as coolant for reactors.

The report says TEPCO could restart the system within 30 minutes of a loss of power or the water pumps breaking down by using extra pumps and emergency generators.

If problems occur simultaneously, TEPCO says it will use fire engines to restart injecting coolant water within 3 hours.

The report admits that if the circulation of coolant water is suspended for several hours, temperatures in the reactors could climb high enough to cause radioactive releases, or another hydrogen explosion.

The company says it would increase the amount of coolant water to the maximum levels in such an emergency.

TEPCO’s report is expected to help the government review an emergency evacuation advisory for local residents.

Discussions begin on how to scrap Fukushima plant

A government-appointed panel has begun discussing the timetable for decommissioning the reactors at the Fukushima Daiichi nuclear plant.

About 30 people, including members of the Atomic Energy Commission and officials from the plant’s operator, Tokyo Electric Power Company, took part in the panel’s initial meeting on Wednesday.

Yuichi Hayase, who joined US researchers in studying the accident at Three Mile Island in 1979, briefed the participants on how that plant was brought under control.
Hayase explained that it took 11 years to extract all the fuel rods, as workers were coping with the world’s first nuclear meltdown. It was also necessary to develop remote-controlled robots and technology to process contaminated wastewater.

Panel members discussed middle- and long-term challenges in the decommissioning process, such as how to repair the reactor containment vessels and decontaminate the buildings by remote control to enable extraction of the fuel rods.

One expert cited the need for long-term training of specialized personnel, while another said international expertise is essential in drawing up the timetable.

Kyoto University Professor Hajimu Yamana, who heads the panel, said he expects longer preparations for extracting the fuel rods, because the reactor cores at Fukushima are more badly damaged than at Three Mile Island.

The panel plans to finalize the timetable by early next year, at the end of the second stage of the process to bring the plant under control.

NHK.

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