Nuclear reactor
May 5, 2011
On Thursday, Japanese workers entered the No. 1 reactor building at the crippled Fukushima nuclear plant for the first time since a hydrogen explosion after the devastating March 11 earthquake and tsunami ripped off its roof.
A dozen engineers - two TEPCO staff and 10 contractors - equipped with protective suits, masks and air tanks started moving in and out in small groups connecting duct pipes to ventilators that are expected to filter out 95 percent of the radioactive material in the air.
"We will operate the ventilators for about two or three days," a TEPCO spokesman said. "After that we plan to start work on actually installing the cooling system."
But high radiation levels inside the building, which has leaked continuously since the disaster, prevented the staff from starting on installing a new cooling system to bring the plant under control.
TEPCO says installation could take all year
No member of staff spent more than 10 minutes inside the building on Thursday. TEPCO said it hoped that radiation levels after three days of operating the ventilating system would be low enough for workers to remain inside for longer periods to start installing the substitute cooling system.
But the plant operator also said it could take all year.
The company spokesman said he could not give details of the 10 contractors' employment conditions, but added that they were bound by the same 250-millisievert limit for exposure to radioactivity as all other staff at the beleaguered plant.
Under Japanese law, nuclear plant workers cannot be exposed to more than 100 millisieverts over five years. However, to cope with the Fukushima crisis, the Health Ministry raised the legal limit on March 15 to 250 millisieverts in an emergency.
Radiation of up to 49 millisieverts per hour was detected inside the building on April 17 when TEPCO sent in a robot to survey conditions.
No new explosion
TEPCO also said in a report issued to the government's Nuclear and Industrial Safety Agency on Thursday that there was no possibility of another explosion at the reactor. It said there had been progress in filling the containment vessel, an outer shell of steel and concrete that houses the reactor vessel, with water.
Workers have been trying to fill the reactors with enough water to bring the nuclear fuel rods inside to a "cold shutdown," in which the water cooling them is below 100 degrees Celsius and the reactors are considered stable.
TEPCO said that if the nuclear safety agency approved the report, it would increase the rate at which it was pumping in water to speed up the process.
The government and TEPCO have come under fire both at home and abroad for their handling of the crisis. Tens of thousands were made homeless after the disaster.
The magnitude 9.0 quake and the following massive tsunami killed about 14,800 people. Some 11,000 are still missing.
Author: Sherpem Sherpa/Reuters/dpa
Editor: Anne Thomas