Efforts intensified on March 17 to control the situation at the No. 3 reactor of the Fukushima No. 1 nuclear power plant, where smoke was billowing from a storage pool containing spent nuclear fuel rods.
Efforts intensified on March 17 to control the situation at the No. 3 reactor of the Fukushima No. 1 nuclear power plant, where smoke was billowing from a storage pool containing spent nuclear fuel rods.
The white smoke indicated that water in the pool has continued to evaporate, increasing the risk of damage to spent fuel rods and the release of radioactive materials into the atmosphere.
The white smoke was also observed spewing from the No. 3 reactor on March 16.
From 9:48 a.m. on March 17, two Ground Self-Defense Force helicopters made a combined four passes to drop water on the crippled No. 3 reactor.
The SDF and Tokyo Metropolitan Police Department were preparing to spray water from the ground from the afternoon of March 17.
Four GSDF helicopters departed the Kasuminome base in Sendai the morning of March 17. After a UH-60 helicopter checked on radiation levels over the nuclear power plant, the GSDF concluded that each helicopter could work for a total of 40 minutes.
With one CH-47 helicopter sending out orders to drop water, the two other CH-47 helicopters took turns scooping up seawater in buckets each with a capacity of 7.5 tons and dropping the water from between 9:48 a.m. and 10 a.m.
“We made the decision because we felt that today was the limit,” Defense Minister Toshimi Kitazawa said at a news conference from 11:30 a.m.
It was not immediately clear if the operation was successful, but Kitazawa said consideration would be given to additional water drops from the air if the need arose.
Officials of Tokyo Electric Power Co. (TEPCO), operator of the plant, later explained that they asked for the water drop on the No. 3 reactor because they had confirmed that water remained in the storage pool containing spent fuel rods in the No. 4 reactor.
The officials said they had not received any information from those at the plant about whether the white smoke had stopped.
According to an explanation by Gen. Ryoichi Oriki, chief of staff of the Joint Staff, the first water drop was made from under 300 feet, or about 90 meters. Radiation levels at 1,000 feet was 4.13 millisieverts per hour and at 300 feet it was 87.7 millisieverts per hour.
“Right now, there are no problems with the safety of GSDF members,” Oriki said.
On the afternoon of March 17, the SDF plans to gather 11 large firefighting vehicles around the Fukushima nuclear plant and spray water from the ground.
Riot police from the Tokyo Metropolitan Police Department have also deployed a high-pressure water cannon to the plant site and are preparing to spray water.
According to officials of the National Police Agency, the water cannon was handed over to TEPCO on March 15, and officials are preparing to supply the cannon with seawater. The cannon has a capacity of 4,000 liters and can only spray water for one minute at a time.
If the hose is set at a 30-degree angle, it would have to be moved within 50 meters of a building to send water to a height of 30 meters.
If the spent nuclear fuel rods in the No. 3 reactor are exposed due to a lack of water, the danger will increase that large amounts of radioactive materials will be released into the air from the damaged fuel rods. Officials of the Nuclear and Industrial Safety Agency said the outer building of the No. 3 reactor was damaged.
NISA also said the outer building of the No. 4 reactor was damaged by an explosion on March 15.
Gregory Jaczko, chairman of the U.S. Nuclear Regulatory Commission, said at a Congressional hearing March 16 as well as in an interview with ABC that he was of the understanding that there was no longer any water in the spent fuel rod pool at the No. 4 reactor.
However, TEPCO officials said the No. 4 reactor pool still contained water.
But the water levels in the pools in the No. 5 and No. 6 reactors, which had been in comparatively stable condition, were decreasing because the cooling mechanism had failed and only warm water was being pumped in.