NEI消息更新：
UPDATE AS OF 9:30 P.M. EDT, WEDNESDAY, MARCH 16:
NEI has updated its YouTube channel with two more videos. The first addresses the U.S. industry's response to the events in Japan and the second discusses natural, safe forms of radiation.
UPDATE AS OF 9:00 P.M. EDT, WEDNESDAY, MARCH 16:
Crews began aerial water spraying operations from helicopters to cool reactor 3 at Fukushima Daiichi shortly before 9 p.m. EDT on Wednesday, March 16. The operation was planned for the previous day, but was postponed because of high radiation levels at the plant. News sources said temperatures at reactor 3 were rising. Each helicopter is capable of releasing 7.5 tons of water.
Spokesmen for TEPCO and Japan’s regulatory agency, Nuclear and Industry Safety Agency, on March 17 Japan time refuted reports that there was a complete loss of cooling water in the used fuel pool at Fukushima Daiichi reactor 4.
The spokesmen said the situation at reactor 4 has changed little during the day today and water remained in the fuel pool. However, both officials said that the reactor had not been inspected in recent hours.
"We can’t get inside to check, but we’ve been carefully watching the building’s environs, and there has not been any particular problem," said TEPCO spokesman Hajime Motojuku.
At about 7 p.m. EDT, NISA spokesman Takumi Koyamada said the temperature reading from the used fuel pool on Wednesday was 84 degrees Celsius and that no change had been reported since then. Typically, used uranium fuel rods are stored in deep water pools at temperatures of about 30 degrees Celsius.
Recent radiation levels measured at the boundary of the Fukushima Daiichi plant have been dropping steadily over the past 12 hours, Japan's Nuclear and Industrial Safety Agency said on Wednesday night (U.S. time).
At 4 a.m. EDT on Wednesday, a radiation level of 75 millirem per hour was recorded at the plant's main gate. At 4 p.m. EDT, the reading at one plant site gate was 34 millirem per hour. By comparison, the Nuclear Regulatory Commission’s annual radiation dose limit for the public is 100 millirem. Radiation readings are being taken every 30 minutes.
Japan’s Chief Cabinet Secretary, Yukio Edano, said earlier today a radiation level of 33 millirem per hour was measured about 20 kilometers from the Fukushima Daiichi plant earlier this morning. He said that level does not pose an immediate health risk.
Edano said that TEPCO has resumed efforts to spray water into the used fuel pool at the damaged reactor 4.
TEPCO also continues efforts to restore offsite power to the plant, with up to 40 workers seeking to restore electricity to essential plant systems by Thursday morning, March 17.
UPDATE AS OF 7:30 P.M. EDT, WEDNESDAY, MARCH 16:
NEI has added a new video to its YouTube page "NEI Offers Support to Japan." Also available is an updated schematic of the reactor design at Fukushima Daiichi.
UPDATE AS OF 5:45 P.M. EDT, WEDNESDAY, MARCH 16:
U.S. Nuclear Regulatory Commission Chairman Gregory Jaczko told members of Congress today that there is no water remaining in the fuel pool at reactor 4 at Fukushima Daiichi nuclear power plant. Jaczko told members of the House Energy and Commerce Committee that “we believe that secondary containment has been destroyed and there is no water in the spent fuel pool…radiation levels are extremely high, which could impact the ability to take corrective measures.”
There is no updated information available from either Tokyo Electric Power or Japanese safety or regulatory officials on the status of the Fukushima plant. Japan's Nuclear and Industrial Safety Agency said it also is concerned about the spent fuel storage pool at reactor 3 at the Fukushima Daiichi site.
Also testifying before the House committee, Energy Secretary Steven Chu restated the administration's commitment to nuclear energy. “The American people should have full confidence that the United States has rigorous safety regulations in place to ensure that our nuclear power is generated safely and responsibly,” Chu testified. “Information is still coming in about the events unfolding in Japan, but the administration is committed to learning from Japan's experience as we work to continue to strengthen America's nuclear industry.
“Safety remains at the forefront of our effort to responsibly develop America's energy resources, and we will continue to incorporate best practices and lessons learned into that process.” Chu said. “To meet our energy needs, the administration believes we must rely on a diverse set of energy sources, including renewables like wind and solar, natural gas, clean coal and nuclear power.”
The administration and Nuclear Regulatory Commission on Wednesday said that they believe it is appropriate for U.S. residents within 50 miles of the Fukushima reactors to evacuate. In response to nuclear emergencies, the NRC works with other U.S. agencies to monitor radioactive releases and predict their path. All the available information continues to indicate Hawaii, Alaska, the U.S. Territories and the U.S. West Coast are not expected to experience any harmful levels of radioactivity.
UPDATE AS OF 4:30 P.M. EDT, WEDNESDAY, MARCH 16:
Japanese authorities have reported concerns today about the condition of the used nuclear fuel pools at Fukushima Daiichi reactor 3 and reactor 4.
Officials also are preparing to spray water into reactor 4 from ground positions and possibly later into reactor 3. Some debris on the ground from the March 14 explosion at reactor 3 may need to be removed before the spraying can begin.
Most plants store used fuel in steel-lined, concrete vaults filled with water, which acts as a natural barrier for radiation from the used fuel. The water also keeps the fuel cool while the radiation decays—or becomes less radioactive. The water itself does not leave the used fuel pool.
Used nuclear fuel at the Fukushima Daiichi plant is stored in seven pools (one at each reactor and a shared pool) and in a dry container storage facility (containing nine casks).
The used fuel pools are designed so that the water in the pool cannot drain down as a result of damage to the piping or cooling systems. The pools do not have drains in the sides or the floor of the pool structure. The only way to rapidly drain down the pool is to have structural damage of the walls or the floor.
For more information on used fuel pools, see our new fact sheet, “Used Nuclear Fuel Storage at the Fukushima Daiichi Nuclear Power Plant.”
The U.S. government on Wednesday recommended that Americans within 50 miles of the Fukushima Daiichi plant evacuate the area. The Nuclear Regulatory Commission has posted this news release on its website regarding the evacuation recommendation.
The information contained in NRC’s recent press release is new and industry is still evaluating the radiation dose calculations since there is little context for the numbers provided in the press release. On the surface, the estimated doses look to be extremely conservative, but we have no additional information on which to evaluate them.
UPDATE AS OF 4:15 P.M. EDT, WEDNESDAY, MARCH 16:
NEI has posted an updated version of its fact sheet "Used Nuclear Fuel Storage at the Fukushima Daiichi Nuclear Power Plant." Also available are updated responses to frequently asked questions on the Japan nuclear energy situation.
UPDATE AS OF 1:15 P.M. EDT, WEDNESDAY, MARCH 16:
NEI has a new fact sheet called "Industry Taking Action to Ensure Continued Safety at U.S. Nuclear Energy Plants."
UPDATE AS OF 10:00 A.M. EDT, WEDNESDAY, MARCH 16:
News reports that high radiation levels led to the evacuation of all workers from the Fukushima Daiichi nuclear power station are not accurate. Workers were evacuated for about an hour but returned to the site to continue efforts to restore safe conditions at the plant.
Restoration of electrical power to the site was under way at the Daiichi plant as of 6:00 a.m. EDT Wednesday. A temporary cable was being connected between an off-site power line and Daiichi reactor 3. Off-site power has not been available at the site since the earthquake on March 11.
Reactors 1, 2 and 3 at the plant are being cooled with seawater. There is some level of uranium fuel damage at all three units, and containment structure damage is suspected at reactor 2.
Before the earthquake, reactor 4 had been in refueling and was completely defueled. Attempts to provide cooling water to the used fuel pool at reactor 4 by helicopter were not successful. Preparations are being made to inject water into the fuel storage pool using a high-capacity spray pump. There have been two fires inside the reactor containment building at reactor 4, but they have been extinguished. Although the reactor containment building at Unit 4 was damaged, the primary containment vessel remains intact.
At the Fukushima Daini site, all four reactors are safely shut down and cooling functions are being maintained.
