Mar 22, 2011 11:41 AM by CNN Wire Staff
TOKYO (CNN) -- Workers at Japan's Fukushima Daiichi nuclear power plant have been scrambling to cool down fuel rods and prevent the release of additional radioactive material since a 9.0-magnitude earthquake and tsunami hit the area on March 11.
Here are the latest developments.
Technicians restored power to the control room of the No. 3 reactor at the quake-damaged Fukushima Daiichi nuclear power plant, the station's owner reported late Tuesday. Tokyo Electric Power Company said it was able to confirm power by turning the control room's lights on. The next step, the company said, is to get air conditioning in the room so workers can enter and work there.
Water was sprayed on the damaged housing of reactor No. 3 for about 50 minutes on Tuesday, and seawater was still being injected into the reactor core, Japan's Nuclear and Industrial Safety Agency said. Workers plan to spray water over reactor No. 4 for three hours on Tuesday as well.
CONDITIONS AT THE PLANT
Reactors 1 and 2 at Japan's earthquake-stricken Fukushima Daiichi nuclear power plant suffered more damage from seawater than originally believed and will take more time to repair, the plant's owner said Tuesday. The tsunami that followed the 9.0-magnitude earthquake March 11 damaged electrical components and coolant pumps in units No. 1 and 2. Those are two of the three units now believed to have suffered damage to their reactor cores, said Sakae Muto, vice president of the Tokyo Electric Power Company.
Reactor No. 2 suffered more damage than No. 1, and the earliest those parts can be replaced is Wednesday, Muto said. The cause of the damage was unclear, but seawater was pumped in previously to cool the reactors as an emergency measure after the earthquake.
Reactors No. 3 and 4 were still being evaluated to determine which parts need repair or replacement, he said. The first priority is to work on the lighting and air conditioning in the central control room so crews can work from inside and gather further data.
Workers were continuing efforts to restore power at the plant Tuesday -- a key step that officials hope will allow them to bring cooling systems back online. Tokyo Electric hoped to provide power to systems and equipment in reactors No. 2 and No. 4 by the end of the day, the non-profit Japan Atomic Industrial Forum said.
But while work to reconnecting cooling systems continued, workers and firefighters resumed spraying water at the buildings housing the No. 3 reactor Tuesday afternoon, Tokyo Electric said.
About 660 workers were at the site Tuesday, Tokyo Electric said. About 330 of those were employees of the power company.
Toshiba has sent more than 100 engineers to help resolve the crisis at nuclear plants in northeastern Japan, the company said in a statement Tuesday. The company said more than 100 engineers were "providing vital support and resources" at the Tokyo Electric's Fukushima Daiichi and Fukushima Daini plants after requests from the power company and the Japanese government.
"Toshiba will reinforce these resources as required," the company said, noting that 700 engineers at other facilities were also analyzing the Fukushima Daiichi plant's situation. Toshiba supplied four of the reactors at the Daiichi plant, according to the World Nuclear Association.
Crews also began using concrete pumps to pour water on the No. 4 reactor building, the company said.
Tokyo Electric said it has no plans to use a concrete pump engine to place a mixture of mortar and water into the containment vessel and spent nuclear fuel pool at the No. 4 reactor. Instead, the pump would be used to pour only water.
Smoke began spewing from adjacent reactors at the Fukushima Daiichi plant Monday. White smoke coming from the No. 2 reactor Monday evening followed gray smoke coming from the No. 3 reactor in the afternoon. It wasn't immediately clear what was causing the smoke or what was burning, but measurements taken shortly after the first smoke plume was spotted Monday afternoon did not indicate a radiation spike. As the smoke billowed from the No. 3 reactor, officials evacuated those who had been working near it. An official with Japan's nuclear safety agency said no one was injured and that no one heard any sound like an explosion.
Before the smoke was seen, the nuclear agency estimated that, between roughly 9 p.m. Sunday to 4 a.m. Monday, 1,170 tons of water were sprayed on the reactor and its fuel pool. Cooling down and replenishing that fuel pool had been a priority in an effort to prevent overheating, the exposure of fuel rods and the release of more radioactive material into the atmosphere.
Prior to the appearance of smoke, authorities had said they are ready to begin supplying electricity into the Nos. 3 and 4 reactors at the plant, a Tokyo Electric official told CNN.
The official said the power supply is set up but isn't flowing because cooling pumps broke during the earthquake and tsunami. Authorities on Monday are switching out some of the equipment and plan to restart the power, once that process is complete.
CONDITIONS OUTSIDE THE PLANT
A faint trail of white smoke rose above the damaged plant Tuesday. Officials have not said what caused the smoke. Tokyo Electric Power Company said in a statement that the smoke was decreasing and barely visible.
Japanese authorities were scheduled to measure radioactivity in waters around the plant on Tuesday and Wednesday after tests found radioactive substances in seawater, the International Atomic Energy Agency said.
Japanese Chief Cabinet Secretary Yukio Edano said authorities had detected radiation in spinach and milk, but not in any other crops.
He urged consumers to "try not to panic," noting that the government had stopped shipments of any farm products they believed could be contaminated.
The U.S. military is considering the mandatory evacuation of thousands of American troops and their families in Japan out of concern over rising radiation levels, a senior defense official tells CNN.
An air monitor in Seattle has detected trace levels of radiation in connection with the nuclear emergency in Japan, the Washington State Department of Health reported Monday. Officials said the levels do not pose a health risk.
The USS George Washington pulled out of its port in Yokosuka, about 28 miles (45 kilometers) south of Tokyo, "as a precaution," according to a posting on the ship's Facebook page. The ship will remain off the coast of Japan, the posting said. Last week, the U.S. Navy repositioned the USS Ronald Reagan after radiation detectors found minute traces of contamination on sailors and equipment.
Short-term exposure to food contaminated by radiation from the damaged nuclear plant poses no immediate health risk, a spokesman for the World Health Organization said Monday. The United Nations organization initially said the food-safety situation was "more serious" than originally thought. But spokesman Peter Cordingley said Monday that the assessment was based not on the levels of contamination but that radioactivity was found in food beyond the 12.4-mile (30-kilometer) evacuation zone.
On Monday, authorities in the village of Iitake urged residents to avoid drinking tap water that tests showed contained more than three times the maximum standard of radioactive iodine. Measurements in Iitake showed 965 becquerels per kilogram of radioactive iodine in the water, which is well above the 300 becquerels per kilogram maximum standard. Cabinet Secretary Edano said that "there is no problem to use this water for non-drinking purposes," such as bathing. He added, "This level is reportedly going down now."
On Sunday, a government ban on the sale of raw milk from Fukushima Prefecture and spinach from neighboring Ibaraki Prefecture became public.
Japanese officials reported levels of radioactive iodine in milk from four locations in Fukushima that ranged from about 20% over the acceptable limit to more than 17 times that limit. Testing at one location also found levels of cesium about 5% over the acceptable limit, the health ministry reported Sunday.
In Ibaraki, a major center of vegetable production, tests at 10 locations found iodine levels in spinach that ranged from 5% over acceptable limits to more than 27 times that ceiling. At seven sites, levels of cesium grew from just above 4% to nearly four times the limit.
Edano stressed that he believed the levels of radiation in food -- while above the legal standards -- do not pose any immediate health risk, saying they were mostly dangerous only if consumed repeatedly over one's lifetime.
Potassium iodide pills were made available Monday to U.S. military families and their dependents at four locations around Japan, according to the U.S. Navy's commander in Japan.
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