Tokyo (CNN) -- Workers began to see some success in their battle to cool down reactors at the quake-damaged Fukushima Daiichi nuclear plant Sunday, but Japanese officials said they may need to release additional radioactive gas into the air.
The plant's owner, Tokyo Electric Power Co., said electricity was being supplied to a switchboard in reactor No. 2.
But officials said they were monitoring reactor No. 3 to determine whether to release gas to reduce mounting pressure in the containment vessel -- the steel and concrete shell that insulates radioactive material inside.
Power company officials said pressure was higher than previous readings -- but stable -- Sunday afternoon. And Chief Cabinet Secretary Yukio Edano said the pressure increase did not require "an immediate release of the air at this moment."
Still, "even in the best scenario, there will be a lot of bumps ahead," Edano told reporters as he assessed the situation at the plant in a briefing Sunday.
There are six reactors at the nuclear plant, where workers have been struggling to stave off a full meltdown since a 9.0-magnitude earthquake and ensuing tsunami knocked out cooling systems.
Workers have injected steam to release pressure in previous operations.
The dual disasters, which struck March 11, devastated much of northeastern Japan. On Sunday, the country's national police said 8,277 people were confirmed dead and more than 12,722 remained missing as search efforts continued. In Miyagi prefecture -- one of the hardest hit areas -- police said the death toll could climb to 15,000 there alone.
Authorities have evacuated about 200,000 people from a 20-kilometer (12-mile) area surrounding the plant, but the crisis there has sparked concern across the country.
Very small amounts -- far below the level of concern -- of radioactive iodine have been detected in tap water in Tokyo and most prefectures near the Fukushima plant.
And on Sunday, Edano said authorities were still analyzing data after finding abnormally high levels of radiation in milk and spinach.
The government hopes to decide Monday whether to ban consumption and shipment of food from farms near the plant, he said.
The contaminated milk detected in Fukushima prefecture had not been distributed or sold, he said.
On Saturday, officials said tainted milk was found 30 kilometers (18 miles) from the plant, and spinach was collected as far as 100 kilometers (65 miles) to the south, almost halfway to Tokyo.
A person who consumed the tainted food continuously for a year would take in the same amount of radiation as a single CT scan, Edano said Saturday. That's about 7 millisieverts, or double what an average person in an industrialized country is exposed to in a year, according to the U.S. Food and Drug Administration.
"Even if you consume the spinach in question for a long time, it will not pose an immediate threat to your health," Edano said Sunday.
At the plant itself, workers from the power company and firefighters helping douse reactors with water are taking on the risk of far greater radiation exposure.
Firefighter Yasuo Sato told reporters his family was well aware of the risk -- and proud that he was taking it.
When he sent a text message to his wife telling her he was heading to the troubled nuclear plant, he said her reply was simple: "Please become a savior for Japan."
Six members of an emergency crew working to restore electricity at the plant have been exposed to more than 100 millisieverts of radiation per hour.
Officials say regaining electrical power could bring cooling systems back online -- a key step in curbing the further emission of radioactive material and preventing a full nuclear meltdown. A meltdown occurs when nuclear fuel rods get so hot that they melt the steel and concrete structure containing them, spilling out into the air and water with potentially deadly results.
The earthquake and tsunami Friday knocked out regular and backup cooling systems at the plant.
It was unclear whether the cooling system in reactor No. 2 was working after power was restored Sunday.
The plan is to get power up and running for the Numbers 1, 3 and 4 reactors soon. Cooling systems at the Numbers 5 and 6 reactors -- the least-troublesome of the group -- have already been restored, Kyodo News said.
Japan's nuclear agency said workers were spending about five hours installing electrical cables Sunday before water spraying operations resumed. Radiation levels at the plant declined during that operation, Japanese public broadcaster NHK reported.
On Saturday, authorities set up a new system to spray seawater continuously on the troubled reactors for extended periods of time. Previously, firefighters, soldiers and electric company workers had manually done the same in brief intervals to avoid prolonged radiation exposure.
Water was directed at the No. 3 reactor's spent fuel pool on Saturday in order to cool it and prevent the emission of more radioactive material into the atmosphere. Authorities have also started spraying the No. 4 reactor and continued efforts there Sunday.
The plant's owner, Tokyo Electric Power Co., said electricity was being supplied to a switchboard in reactor No. 2.
But officials said they were monitoring reactor No. 3 to determine whether to release gas to reduce mounting pressure in the containment vessel -- the steel and concrete shell that insulates radioactive material inside.
Power company officials said pressure was higher than previous readings -- but stable -- Sunday afternoon. And Chief Cabinet Secretary Yukio Edano said the pressure increase did not require "an immediate release of the air at this moment."
Still, "even in the best scenario, there will be a lot of bumps ahead," Edano told reporters as he assessed the situation at the plant in a briefing Sunday.
There are six reactors at the nuclear plant, where workers have been struggling to stave off a full meltdown since a 9.0-magnitude earthquake and ensuing tsunami knocked out cooling systems.
Workers have injected steam to release pressure in previous operations.
The dual disasters, which struck March 11, devastated much of northeastern Japan. On Sunday, the country's national police said 8,277 people were confirmed dead and more than 12,722 remained missing as search efforts continued. In Miyagi prefecture -- one of the hardest hit areas -- police said the death toll could climb to 15,000 there alone.
Authorities have evacuated about 200,000 people from a 20-kilometer (12-mile) area surrounding the plant, but the crisis there has sparked concern across the country.
Very small amounts -- far below the level of concern -- of radioactive iodine have been detected in tap water in Tokyo and most prefectures near the Fukushima plant.
And on Sunday, Edano said authorities were still analyzing data after finding abnormally high levels of radiation in milk and spinach.
The government hopes to decide Monday whether to ban consumption and shipment of food from farms near the plant, he said.
The contaminated milk detected in Fukushima prefecture had not been distributed or sold, he said.
On Saturday, officials said tainted milk was found 30 kilometers (18 miles) from the plant, and spinach was collected as far as 100 kilometers (65 miles) to the south, almost halfway to Tokyo.
A person who consumed the tainted food continuously for a year would take in the same amount of radiation as a single CT scan, Edano said Saturday. That's about 7 millisieverts, or double what an average person in an industrialized country is exposed to in a year, according to the U.S. Food and Drug Administration.
"Even if you consume the spinach in question for a long time, it will not pose an immediate threat to your health," Edano said Sunday.
At the plant itself, workers from the power company and firefighters helping douse reactors with water are taking on the risk of far greater radiation exposure.
Firefighter Yasuo Sato told reporters his family was well aware of the risk -- and proud that he was taking it.
When he sent a text message to his wife telling her he was heading to the troubled nuclear plant, he said her reply was simple: "Please become a savior for Japan."
Six members of an emergency crew working to restore electricity at the plant have been exposed to more than 100 millisieverts of radiation per hour.
Officials say regaining electrical power could bring cooling systems back online -- a key step in curbing the further emission of radioactive material and preventing a full nuclear meltdown. A meltdown occurs when nuclear fuel rods get so hot that they melt the steel and concrete structure containing them, spilling out into the air and water with potentially deadly results.
The earthquake and tsunami Friday knocked out regular and backup cooling systems at the plant.
It was unclear whether the cooling system in reactor No. 2 was working after power was restored Sunday.
The plan is to get power up and running for the Numbers 1, 3 and 4 reactors soon. Cooling systems at the Numbers 5 and 6 reactors -- the least-troublesome of the group -- have already been restored, Kyodo News said.
Japan's nuclear agency said workers were spending about five hours installing electrical cables Sunday before water spraying operations resumed. Radiation levels at the plant declined during that operation, Japanese public broadcaster NHK reported.
On Saturday, authorities set up a new system to spray seawater continuously on the troubled reactors for extended periods of time. Previously, firefighters, soldiers and electric company workers had manually done the same in brief intervals to avoid prolonged radiation exposure.
Water was directed at the No. 3 reactor's spent fuel pool on Saturday in order to cool it and prevent the emission of more radioactive material into the atmosphere. Authorities have also started spraying the No. 4 reactor and continued efforts there Sunday.
