Washington, D.C.–(ENEWSPF)–March 14, 2011 – UPDATE AS OF 5:30 P.M. EDT:
Tokyo Electric Power Co. reported at 3:00 p.m. EDT that work had resumed to pump seawater into Fukushima Daiichi 2 to maintain safe cooling water levels after the utility was able to vent steam from the pressure vessel. The fuel had been exposed for 140 minutes Monday night due to a malfunctioning pressure relief valve. Water levels later went up to cover more than half of the rods.
The U.S. Nuclear Regulatory Commission reports that the Japanese government has formally asked for assistance from the United States on nuclear power plant cooling issues triggered by the March 11 tsunami.
The agency has already sent two experts on boiling water reactor issues to Japan as part of a U.S. Agency for International Development disaster relief team. The experts now are in Tokyo providing technical assistance. The U.S. NRC is also monitoring the Japanese reactor events around the clock from its headquarters operations center in Rockville, Md.
Prior to the second exposure of the rods around 11 p.m., March 14 local time in Japan, radiation at the plant site was detected at a level twice the maximum seen so far – 313 millirem per hour, according to TEPCO.
Chief Cabinet Secretary Yukio Edano said he believes the problem at the plant ”will not develop into a situation similar to Chernobyl,” even in the worst case.
The utility said a hydrogen explosion at the nearby No. 3 reactor that occurred Monday morning may have caused a glitch in the cooling system of the No. 2 reactor.
The hydrogen explosion at reactor 3 on March 14 injured 11 people: seven TEPCO workers at the site and four members of the country’s Self-Defense Forces. The reactor’s containment vessel was not damaged and the reactor remains safely contained in its primary containment.
Administration, NRC Response to the Accident
At a White House briefing, press secretary Jay Carney said that information is still coming in on the status of nuclear plants in Japan, but that the Obama administration is committed to keeping nuclear energy as part of the U.S. energy portfolio.
Energy Department Deputy Secretary Daniel Poneman said nuclear energy “continues to play an important role in providing a low-carbon future.”
Gregory Jaczko, chairman of the Nuclear Regulatory Commission, said at the briefing that analysis of the damage, the type of reactor and the distances involved indicate a “very low likelihood” that any potential fallout from Japan might reach Hawaii or Western states.
U.S. nuclear power plants are built to endure the strain of natural phenomena like hurricanes, earthquakes and tornadoes, Jaczko said. “Right now, we continue to believe that nuclear power plants in this country operate safely and securely,” he said.
UPDATE AS OF 4:20 P.M. EDT, MONDAY, MARCH 14:
NEI has posted a new document, “Radiation in Perspective,” which describes where radiation comes from and how it is measured.
UPDATE AS OF 1:30 P.M. EDT, MONDAY, MARCH 14:
Unit 2 at the Fukushima Daiichi nuclear power plant lost a significant amount of reactor coolant for a second time on Monday. Some of the uranium fuel rods were uncovered for a period of time. A malfunctioning safety relief valve at the plant caused an increase in reactor pressure and hindered injection of coolant back into the reactor. The cause of the relief valve failure is under investigation.
The Japanese government has distributed 230,000 units of potassium iodine to evacuation centers in the area surrounding the Fukushima Daiichi and Fukushima Daini stations, according to officials. Ingestion of potassium iodine can help prevent the accumulation of radioactive iodine in the thyroid.
At the Fukushima Daini site all units have off-site power, and water levels in all units are stable. Plant operators at Daini Unit 1 were able to restore a residual heat remover system, which is now being used to cool the reactor. Work is in progress to achieve a cold shutdown. Workers at Daini Units 2 and 4 are working to restore residual heat removal systems. Unit 3 is in a safe, cold shutdown.
Radiation dose rate measurements observed at four locations around the Daini plant´s perimeter over a 16-hour period on Sunday were all normal.
UPDATE AS OF 11:00 A.M. EDT, MONDAY, MARCH 14:
Fuel rods in the reactor vessel of Unit 2 at the Fukushima Daiichi Power Plant were temporarily uncovered from cooling water today, but seawater injection has raised the water level to the halfway point, Tokyo Electric Power Co. (TEPCO) said. Seawater is now being used to cool all three Daiichi reactors that were shut down after the March 11 earthquake. Unit 2 had lost its emergency cooling capacity. Workers were preparing to remove hydrogen from the reactor building, and TEPCO has opened the steam relief valve of the reactor.
The primary containment vessels and reactor cores of reactors 1 and 3 at the Fukushima Daiichi facility are intact, following earlier hydrogen explosions in the secondary containment buildings of both reactors.
At Unit 1, seawater injection continues to cool the reactor. Safety regulators consider the reactor’s pressure an indication of a stable condition. The hydrogen explosion on March 11, which occurred between the primary containment vessel and the containment building, did not damage the primary containment vessel or the reactor core. To control the pressure of the reactor core, TEPCO has been injecting seawater and boric acid into the primary containment vessel of Unit 1 since March 12.
A hydrogen explosion Monday at Unit 3, similar to the Unit 1 explosion, did not damage the primary containment, Japan’s Nuclear and Industrial Safety Agency (NISA) said. The control room remains operational, and a government official said that pressure in the reactor vessel is stable. After the explosion, the few hundred people remaining in the 12.5-mile evacuation zone were asked to stay indoors.
At the Fukushima Daini site, cooling capability has been reestablished for Unit 4 at the reactor. Units 2 and 4 are in cold shutdown.