UPDATE AS OF 4 P.M. EDT, TUESDAY, MAY 24:
Tokyo Electric Power Co. (TEPCO) said today that fuel damage likely occurred in reactors 2 and 3 of the Fukushima Daiichi nuclear energy facility in the first few days after the March 11 earthquake and tsunami. Both reactors are now reported to be stable and at relatively low temperatures. The extent of the fuel damage is unknown. If the water gauges inside the two reactors are accurate, there was sufficient water in the reactors to prevent damage to all the fuel, the company said.
Most of the fuel damage that occurred in reactor 2 is believed to have taken place within 100 hours of the earthquake. TEPCO believes fuel was damaged in reactor 3 within 60 hours. The company previously confirmed that fuel was damaged in reactor 1.
TEPCO plans to install two heat exchangers today to lower the temperature of the used reactor fuel at reactor 2
UPDATE AS OF 1:30 P.M. EDT, FRIDAY, MAY 20:
Below is a round-up of noteworthy news that happened this week with regard to the Fukushima Daiichi nuclear plant and the U.S. nuclear industry's response.
Tokyo Electric Power Co. (TEPCO) workers entered reactor buildings 2 and 3 Wednesday for the first time since explosions at the facility. Radiation levels in building 2 peaked at 5 rem per hour. Facing high heat and humidity, the workers remained in the building for only 15 minutes. In reactor 3, radiation peaked at 17 rem per hour near a pipe connected to the reactor. TEPCO employees first entered the reactor 1 building on May 5.
TEPCO is looking at how to begin nitrogen injection into reactors 2 and 3 to further stabilize them. The company has been injecting nitrogen into reactor 1 for several weeks. High humidity in building 2 is hampering operations. In building 3, high radiation levels must be reduced before workers can begin efforts to inject nitrogen. TEPCO announced plans to install new cooling systems for fuel pools in four of the six reactors at the site. It is believed the new systems will reduce the high humidity in the reactor buildings.
TEPCO provided a new timeline for recovery of the damaged reactors, recognizing challenges the company has encountered are slowing progress on certain activities. The company reaffirmed that the target timeframe for stabilizing the plant-between October and January-remains unchanged.
Radiation levels in the ocean near the Fukushima Daiichi facility increased again on Thursday, but overall radiation is decreasing in seawater and other areas around the facility.
Mitsubishi Heavy Industries has created two radiation-proof forklifts to assist TEPCO workers in removing debris from the Fukushima Daiichi site. TEPCO has been using robotic and remote-controlled equipment for clean-up activities. The forklifts, with cabins sealed by 10 centimeter-thick steel plates and more than 20 centimeter-thick lead-glass, have filters that keep out radioactive dust.
Industry consultant Lake Barrett told the House Science, Space and Technology Committee on May 13 that the tsunami, not the earthquake, caused most of the damage at the Fukushima Daiichi nuclear power plant.
A blue ribbon commission studying U.S. used fuel policies heard briefings May 13 on the Fukushima Daiichi accident from the Nuclear Regulatory Commission and the Energy Department. The NRC representative summarized agency activities since the earthquake and tsunami damaged the facility. The DOE spokesman also discussed his agency's activities, including a workshop scheduled for June 6-7 that will bring the nuclear energy community together to discuss lessons learned from the Japan event and potential actions that could further enhance nuclear safety.
TEPCO had a net loss of $15.4 billion for the fiscal year that ended March 31, and the company's president has announced his resignation, CNN reports.
Japan will continue to use nuclear power plants "that are deemed safe," Prime Minister Naoto Kan said in a Reuters report
, but "we need to fully consider what needs to be done to enhance the safety of nuclear power."
TEPCO said the earthquake that struck Fukushima Daiichi March 11 exceeded design specifications at three of the site's six reactors, Reuters reported. "This was clearly a larger earthquake than we had forecast," said Junichi Matsumoto, a TEPCO spokesman. "It would have been hard to anticipate this."
Operators of nuclear energy facilities have fixed or scheduled for correction all the issues NRC inspections found in post-Fukushima inspections, The New York Times reports.
Five tons of seawater may have flooded a reactor at the Hamaoka nuclear energy site, Japan Today reports. The site closed last week at the request of Japan's prime minister for fears of a possible earthquake.
Japan's utilities could have trouble meeting summer electricity demand, unless nuclear reactors-including those unaffected by the earthquake and tsunami but were shut down for maintenance at the time-are restarted, Reuters reports.
The Week Ahead
The Nuclear and Radiation Studies Board of the National Academy of Sciences will discuss the aftermath of Fukushima, beginning at 12:30 p.m. EDT May 26 at the Keck Center, 500 5th St., NW, Washington, D.C.
The NRC's Advisory Committee on Reactor Safeguards will review events at Fukushima, beginning at 1 p.m. EDT May 26 at NRC headquarters, Room T-2B1, 11545 Rockville Pike, Rockville, Maryland.