No. 46: 20:00, April 8
NHK news regarding status of Fukushima Daiichi nuclear power station yesterday and today.
●Congress: US reactors may not be safe enough
A US Congressional subcommittee has warned that a nuclear power plant in the country could face the same problems as Japan's Fukushima Daiichi plant in a worst-case scenario. The House Energy and Commerce subcommittee released a study by the Nuclear Regulatory Commission about the Peach Bottom nuclear plant in Pennsylvania. The report says that if a power loss occurs for a long time, fuel rods in the reactor could be damaged, leading to the release of radioactive substances within 2 days. The reactor has the same design as the Number 1 and Number 2 reactors at the Fukushima plant. The report adds that safety equipment installed after the September 11th attacks in 2001 will prevent fuel rods from being damaged in emergencies. But the House subcommittee was not satisfied with the explanation and urged the Commission to further examine the issue.
Friday, April 08, 2011 14:14 +0900 (JST)
●Aftershock batters nuclear plants
Nuclear power plants and related facilities in the coastal areas of northeastern Japan were forced to rely on emergency power after their electricity was cut off in Thursday night's quake. Operations have been suspended at all nuclear power plants from Aomori to Ibaraki prefectures since the March 11th earthquake and tsunami
. But electricity is still crucial to keep their cooling systems operating. Japan's nuclear agency says all external power lines at Higashidori nuclear power plant in Aomori Prefecture were knocked out in Thursday's quake. The plant switched to emergency diesel power generators for some hours, but power was later restored
. The quake shut down 3 of the 4 external power lines at Onagawa nuclear power plant in Miyagi Prefecture. It is still operating on the one remaining power line. The Onagawa plant also suffered water leaks at 8 locations, including water that spilled from spent fuel storage pools at each of its 3 reactors. A device to control pressure inside a turbine building was also damaged. In addition, the quake disabled all external power lines at a nuclear fuel reprocessing plant in Aomori Prefecture. The cooling systems here are still running on emergency diesel power
Friday, April 08, 2011 14:01 +0900 (JST)
●Thursday's quake damages Onagawa nuclear plant
Tohoku Electric Power Company says Thursday night's strong earthquake caused water to overflow from spent fuel storage pools at one of its nuclear power plants. The power company reported on Friday that water had spilled onto the floor at all 3 reactors at the Onagawa nuclear power plant in Miyagi Prefecture. The amount of water spilled was 3.8 liters at the most. The utility firm also found water leaks at 5 locations in the plant, including inside buildings housing the reactors. The company added that blowout panels--devices designed to control pressure inside the buildings--were damaged at the turbine building of the Number 3 reactor. The newly reported problems add to the downing of 3 of 4 external power lines at the Onagawa plant. The plant is maintaining its cooling capabilities with the remaining power line. Tohoku Electric Power Company is continuing its efforts to determine the extent of the damage caused by the latest quake. But it says no change has yet been seen in radiation levels around the plant.
Friday, April 08, 2011 11:59 +0900 (JST)
●No. 1 reactor lost cooling function on March 11
Unreleased data obtained by NHK suggest that the failure to maintain the cooling functions of the No. 1 reactor at the troubled Fukushima Daiichi nuclear power plant possibly triggered a hydrogen explosion at an early stage. The data show that the water level inside the No. 1 reactor dropped to 45 centimeters above the fuel rods, or about one-tenth the normal level, nearly 7 hours after the March 11th earthquake and tsunami. The fuel rods become exposed 11 hours later. Water levels in the No. 2 and No. 3 reactors were kept at around 4 meters through the use of emergency generators despite the power outages. It was a day and a half to 3 days before their fuel rods were exposed. University of Tokyo Professor Naoto Sekimura says the loss of cooling functions at the No.1 reactor and the subsequent exposure of the fuel rods may have caused the hydrogen explosion as early as the next day. The plant's operator, Tokyo Electric Power Company, has so far only disclosed data from the day after the quake.
Friday, April 08, 2011 11:24 +0900 (JST)
●Work to get Fukushima plant under control goes on
Work to restore reactor cooling systems at the Fukushima Daiichi nuclear power plant will continue on Friday following a strong earthquake overnight. The magnitude 7.4 tremor was one of the largest since the devastating quake on March 11th. The plant operator, Tokyo Electric Power Company, says no new irregularities have been detected in radiation readings or the facilities. It says it will continue discharging lower-level radioactive water into the sea from a storage facility on Friday. The work is designed to make room for highly radioactive water that leaked into the basement of the turbine building next to the plant's No. 2 reactor and a concrete tunnel.
On Thursday, about 7,700 tons of lower-level radioactive water was released, and the remaining 300 tons will be discharged on Friday. TEPCO says the latest quake has not caused further leakage of contaminated water into the sea from a concrete pit outside the No. 2 reactor. The company says it will also continue work to inject nitrogen into the containment vessel of the No. 1 reactor to prevent a possible hydrogen explosion. Nearly half of the nuclear fuel rods in the reactor are feared to be exposed -- generating hydrogen that could explode if it reacts with oxygen.
Friday, April 08, 2011 11:09 +0900 (JST)
●IAEA: "Early signs of recovery" at Fukushima plant
The International Atomic Energy Agency says it has detected early signs of recovery at the crisis-stricken nuclear power plant in Japan. Speaking to reporters in Vienna on Thursday, IAEA deputy director general Denis Flory said there are early signs of recovery in some functions such as electrical power and instrumentation at the Fukushima Daiichi power station. But he added the overall situation remains very serious. Flory said 2 reactor experts from the IAEA visited the Fukushima plant on Wednesday. The experts inspected all reactors at the nuclear complex from outside and were briefed by officials in charge during their 5-hour stay
. Flory said the IAEA will continue to carefully analyze the situation based on the information obtained through the visit as well as data provided by Japanese authorities.
Friday, April 08, 2011 09:14 +0900 (JST)
●TEPCO to inspect nuclear plant after quake
The Tokyo Electric Power Company plans to resume operations to tackle safety issues at its crippled Fukushima Daiichi nuclear power plant following a powerful quake on Thursday night. The utility company says an examination immediately after the latest quake showed no ill effects on the facilities and the operation to inject water into the Number 1, 2 and 3 reactors. Radiation monitors at the plant showed no change in readings. On Friday morning, TEPCO will inspect the facility in detail and determine whether highly contaminated water has started to leak into the ocean again from a pit near the Number 2 reactor. The company plans to finish discharging the last 300 tons of relatively lightly contaminated water from a waste storage facility into the ocean on Friday. About 7,700 tons of the water containing low-level radioactive substances had been discharged by Thursday. Once the storage facility is empty, the company will pump into it highly contaminated water which flooded the turbine building of the Number 2 reactor. TEPCO also plans to finish by Saturday an operation to dump 1,500 tons of relatively-low contaminated water from drainage pits at the Number 5 and 6 reactors. The company is continuing to inject nitrogen gas into the Number 1 reactor to prevent a hydrogen explosion. It says Thursday's quake did not affect the work.
Fuel rods inside the reactor are nearly half exposed after a loss of cooling water.
Friday, April 08, 2011 08:00 +0900 (JST)
●UN expert: Fukushima worse than Three Mile Island
A senior UN scientific official says the ongoing problems at the Fukushima nuclear plant are much more serious than the Three Mile Island case in the US in 1979. The chairman of the UN Scientific Committee on the Effects of Atomic Radiation, Wolfgang Weiss, spoke at a news conference in Vienna on Wednesday. He said the Fukushima case is less serious than the accident at the Chernobyl plant in the former Soviet Union in 1986. Weiss said his organization has seen traces of iodine in the air all over the world but they are much lower than traces seen at similar distances after Chernobyl. The Japanese government is rating the Fukushima accident a "level 5" on the international scale of 7 that measures nuclear accidents. The Three Mile Island is ranked a level 5 and Chernobyl a level 7. But Weiss said although detected radiation levels around the Fukushima plant are higher than normal, they are not expected to have major impact on people's health. The UN committee is to send its experts to Japan to see the effects of radiation from the Fukushima plant, after consulting with the Japanese government.
Friday, April 08, 2011 06:15 +0900 (JST)
●TEPCO:No trouble reported
Tokyo Electric Power Company says there are no additional problems with the facilities at the crippled Fukushima Daiichi and Daini nuclear power plants due to the recent aftershock. The company says all the workers at the two plants have been evacuated to safe ground, and that there are no reports of injuries. It says electric power supply has not been cut off at the plants. TEPCO added that no injuries have been reported.
Friday, April 08, 2011 01:31 +0900 (JST)
●Aftershock puts nuclear plants on emergency power
Japan's nuclear agency says the quake that struck northeastern Japan on Thursday, disabled all but one outside power supply line at the Onagawa nuclear power plant in Miyagi Prefecture. The Nuclear and Industrial Safety Agency says 2 of the 3 power lines became unavailable and the plant is using the only remaining line to cool its nuclear reactors. It says the cooling systems of 3 spent fuel pools were disabled at one point, but had all been restored
. The agency reports no abnormal radiation readings at the plant. At the Fukushima Daiichi and Daini nuclear power plants, instrument readings and radiation monitors showed no changes following the quake. At the Higashidori nuclear power plant in Aomori Prefecture, the quake shut down all outside power lines, prompting the plant to switch on emergency diesel power generators.
The plant had shut down its reactors and was undergoing an inspection at the time of the quake. No serious effects were reported with the cooling systems of storage pools for spent fuel rods. A nuclear fuel reprocessing plant in Rokkasho, Aomori Prefecture, also lost all outside power and is operating on emergency diesel generators at the moment. No irregularities have also been reported at the Tokai Daini nuclear power plant in Ibaraki Prefecture. All these nuclear power plants had suspended power generating operations at their reactors after the March 11th earthquake and tsunami.
Friday, April 08, 2011 06:10 +0900 (JST)
●Powerful quake strikes northeastern Japan
A magnitude 7.4 quake occurred off the Miyagi coast, northeastern Japan late Thursday night. The Meteorological Agency says the quake registered 6-plus on the Japanese seismic scale of 0 to 7 in Sendai and another place in Miyagi prefecture. It says an intensity of 6-minus was registered in wide areas of Miyagi and Iwate prefectures, and that the quake was felt in many regions across Japan. The agency estimates the focus of the quake was 40 kilometers below ground. The agency issued a tsunami warning for coastal areas in Miyagi Prefecture, and tsunami evacuation advisories for Japan's northeastern seaboard from Aomori to Ibaraki prefectures. The warning and advisories were lifted about 80 minutes after the quake. It was the largest aftershock since the March 11th quake, which registered 7-minus on the Japanese seismic scale. The Meteorological Agency warned of possible strong aftershocks after last month's massive tremor. About 100 people were injured in Thursday's temblor, and fire and a gas leaks have been reported. Electricity delivery has been interrupted in Sendai.
Friday, April 08, 2011 06:10 +0900 (JST)
●Nitrogen injection ups pressure in reactor
The operator of the crippled Fukushima Daiichi nuclear power plant says pressure inside the containment vessel of the Number 1 reactor is rising following an injection of nitrogen gas. Tokyo Electric Power Company started the injection early on Thursday to prevent a possible hydrogen explosion at the reactor. Fuel rods inside the reactor are nearly half exposed after a loss of cooling water, creating a dangerous buildup of oxygen and hydrogen and fears of another explosion. The company says that after injecting 413 cubic meters of nitrogen gas until 5 PM on Thursday, the pressure reading inside the vessel was 1.76, up 0.2 from before the injection started. The company says it will continue the work for 6 more days and study a similar operation in the Number 2 and 3 reactors. Tokyo Electric also admitted that the level of highly radioactive water in a
concrete tunnel of the Number 2 reactor rose 5 centimeters in the 24 hours until 7 AM local time on Thursday. It says the rise may be a result of work on Wednesday to stop highly radioactive water leaking into the sea from a cracked concrete pit. The company says the water is about a meter below the ground level, and that it will keep monitoring it to prevent an overflow. Tokyo Electric has so far dumped about 7,300 tons of low-level radioactive wastewater into the sea from a storage facility to make room for more highly contaminated water. The company says the last 700 tons of water will be discharged by Friday.
Thursday, April 07, 2011 20:24 +0900 (JST)