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"Not only the pressure vessels, but the containment vessels of the Nos. 1 to 3 reactors at the Fukushima No. 1 nuclear power plant were probably damaged within 24 hours of the March 11 earthquake and tsunami, according to Tokyo Electric Power Co.'s analysis of the nuclear crisis. In a report on the analysis, the utility said it carried out minute calculations on internal pressure and other measurements in the nuclear reactors after the earthquake. The report was submitted to the Economy, Trade and Industry Ministry's Nuclear and Industrial Safety Agency on Monday night. TEPCO said it found that an isolation condenser, a type of emergency cooling device, did not work properly at the No. 1 reactor. This caused the core meltdown to progress until it damaged the bottom of the pressure vessel about 15 hours after the earthquake. Along with the meltdown, the temperature inside the steel containment vessel, which contains the pressure vessel, rose until it reached 300 C in 18 hours after the quake, much higher than 138 C the vessel was designed for. It is believed the internal temperature continued to rise after that. Containment vessels are designed for a much lower temperature and pressure than pressure vessels, which can be exposed to temperatures close to 300 C and pressure reaching 70 bars when a reactor is in operation."

Chugoku Electric Power Co. showed reporters Tuesday the reactor pressure vessel that will contain the nuclear fuel for a power plant in Matsue, Shimane Prefecture. News photo Heavy lifting: A pressure vessel that will contain the nuclear fuel for a power plant in Matsue, Shimane Prefecture, is removed from a plant in Kure, Hiroshima Prefecture, on Tuesday. KYODO PHOTO The 21-meter-high, 910-ton device was taken from its plant in Kure, Hiroshima Prefecture, and put on a cargo ship as reporters and photographers watched. The pressure vessel will be transported 480 km to the nuclear plant in Shimane, which is scheduled to be activated in December 2011.

"Pictured here is the stainless steel vessel of a nuclear reactor employed in a pressurized water system at commercial nuclear power plants like the Florida Power & Light Company (FPL), Turkey Point Nuclear Plant (TPN). Near the center of the nuclear reactor vessel you can see large welds which were made during the construction of this particular nuclear reactor vessel. The large weld which is near the center and extends around the vessel is called the "belt-line" weld."

Pressure within the No. 3 reactor at the Fukushima No. 1 nuclear plant was rising at one point and Tepco considered releasing more radioactive gas into the environment to avert serious damage to the containment vessel, the nuclear safety agency said Sunday afternoon. However, officials later said the pressure in the vessel, which houses lethal radioactive materials, had stabilized. They said they would observe the situation carefully and "not immediately" take the risky measure.

"Breaking News: Melt OUT was predicted on 3/11 Posted by Mochizuki on September 5th, 2011 · No Comments http://nanohana.me/?p=4545 On March 11, at 22:35, the Cabinet received advice predicting that the fuel would be damaged and the pressure vessels would be breached Forecast: exposure of top of active fuel (TAF): 21:40 (approx.) Forecast: damage to the reactor core(s) begins: 22:20 (approx.) Forecast: breaching of the pressure vessel(s) begins: 23:50 (approx.) [excerpt from source document: Cabinet briefing paper: source link] Japanese Prime Minister and Cabinet knew of melt through in MARCH"

Japan warned of a possible radiation leak on Saturday as authorities battled to contain rising pressure at two nuclear plants damaged by a massive earthquake, but said thousands of residents in the area had already been moved out of harm's way. Pressure was building in reactors of two plants at Tokyo Electric Power Co's Fukushima facility, located some 240 km (150 miles) north of Tokyo. At one of them, the Daiichi plant, pressure was set to released soon, which could result in a radiation leak, officials said. "It's possible that radioactive material in the reactor vessel could leak outside but the amount is expected to be small, and the wind blowing toward the sea will be considered," Chief Cabinet Secretary Yukio Edano told a news conference.

"The American nuclear industry, primed to begin new construction projects for the first time in 30 years, is about as eager for an operating problem at an old reactor as the oil industry was for a well blowout on the eve of opening the Atlantic coast to oil drilling. Nonetheless, a nuclear reactor where a hidden leak caused near-catastrophic corrosion in 2002 has experienced a second bout of the same problem. In 2002, the plant, Davis-Besse, in Oak Harbor, Ohio, developed leaks in parts on the vessel head, allowing cooling water from inside the vessel, at 2,200 pounds per square inch of pressure, to leak out."

"Two British nuclear submarines went to sea with a potentially disastrous safety problem that left both vessels at risk of a catastrophic accident, the Guardian can reveal. Safety valves designed to release pressure from steam generators in an emergency were completely sealed off when the nuclear hunter killers Turbulent and Tireless left port, a leaked memo discloses. The problem went undetected on HMS Turbulent for more than two years, during which time the vessel was on operations around the Atlantic, and visited Bergen in Norway, the Portuguese capital, Lisbon, and Faslane naval base near Glasgow."

Nuclear fuel inside the crippled reactors at the Fukushima Daiichi power plant has partially melted and settled at the bottom of pressure vessels in the shape of grains, according to an analysis by the Atomic Energy Society of Japan made public by Friday. The academic body's panel on nuclear energy safety has said the melted fuel at the No. 1 to 3 reactors has been kept at a relatively low temperature, discounting the possibility that a large amount of melted fuel has already built up at the bottom of their reactor vessels given the temperature readings there. A large buildup of melted nuclear fuel at th

An incident at EDF's Tricastin plant in southeast France late on Thursday forced the company to stop refuelling operations at the reactor 2, which started on Oct. 31, it said on Friday. The incident occurred during refuelling of the reactor, when a fuel assembly got stuck in the pressure vessel, EDF said in a statement. A similar incident took place in Sept. 2008 in the same reactor during refuelling operations and it took around two months for EDF to resolve the problem. "The incident took place at 2215 GMT," a source at the plant told Reuters on Friday. "We are very worried about this especially as this already happened just a year ago," he added.

An incident at EDF's Tricastin plant in southeast France late on Thursday forced the company to stop refuelling operations at the reactor 2, which started on Oct. 31, it said on Friday. The incident occurred during refuelling of the reactor, when a fuel assembly got stuck in the pressure vessel, EDF said in a statement. A similar incident took place in Sept. 2008 in the same reactor during refuelling operations and it took around two months for EDF to resolve the problem. "The incident took place at 2215 GMT," a source at the plant told Reuters on Friday. "We are very worried about this especially as this already happened just a year ago," he added.

TOKYO (Dow Jones)--Japanese authorities are facing setbacks in their battle to bring the troubled Fukushima Daiichi nuclear power plant in northeastern Japan under control as pressure builds up in one reactor while a target to supply power to another by Sunday may not be met. The Nuclear and Industrial Safety Agency said engineers will open valves inside the container vessel of the No. 3 reactor to alleviate pressure that is building up, a move that could result in the release of radioactive steam. The release of radioactive steam could also affect work being carried out in other parts of the plant, the agency said. However, it said it doesn't expect the government will have to extend the current evacuation zone around the plant as a result of the development.

"Areva SA, the French nuclear-reactor builder, took a new provision for cost overruns at a plant it's building in Finland, leaving the door open for more charges as the project is still 2 1/2 years away from completion. The company said yesterday it will book a charge of about 400 million euros ($491 million) in the first half as Finnish customer Teollisuuden Voima Oyj said this month the OL3 plant will start nuclear operations at the end of 2012 rather than by a previous June 2012 deadline. Areva "has now installed the reactor pressure vessel and continues work on piping, but history suggests further delays are very likely," Alex Barnett, an analyst at Jefferies International Ltd., who recommends buying Areva investment certificates, said in a research note today. The new charge takes total provisions for cost overruns to about 2.7 billion euros for the first-of-its-kind project, which Areva pledged in 2005 to build for 3 billion euros and complete in 2009."

"Yesterday's decision by the UK government to withdraw its proposed loan of £80m to Sheffield Forgemasters is extraordinary. No other move could have had quite so much effect on the plans for nuclear power. Forgemasters wanted the money to buy a 15,000 tonne press, a necessary piece of equipment to make the pressure vessel at the centre of a power plant. Without the money, it says it will not proceed with its expansion into the nuclear market."

In a devastating pair of financial reports that might be called "The Emperor Has No Pressure Vessel," the New York Times has blazed new light on the catastrophic economics of atomic power. The two Business Section specials cover the fiasco of new French construction at Okiluoto, Finland, and the virtual collapse of Atomic Energy of Canada. In a sane world they could comprise an epitaph for the "Peaceful Atom". But they come simultaneous with Republican demands for up to $700 billion or more in new reactor construction. The Times's "In Finland, Nuclear Renaissance Runs Into Trouble" by James Kanter is a "cautionary tale" about the "most powerful reactor ever built" whose modular design "was supposed to make it faster and cheaper to build" as well as safer to operate. But four years into a construction process that was scheduled to end about now, the plant's $4.2 billion price tag has soared by 50% or more. Areva, the French government's front group, won't predict when the reactor will open. Finnish utilities have stopped trying to guess. Finnish inspectors say Areva allowed "inexperienced subcontractors to drill holes in the wrong places on a vast steel container that seals the reactor." The Finns have also cited Areva for "the attitude or lack of professional knowledge of some persons."

If one judges by the number of requested permits, nuclear power is coming back in the United States. Companies now are asking regulators to let them build about 30 reactors for generating electricity, far more than were put into operation in the past two decades. That bodes well for one factory in Mount Vernon, Ind. Courtesy of Babcock & Wilcox Co. Courtesy of Babcock & Wilcox Co. Babcock & Wilcox came to Southwestern Indiana in the early 1960s and soon began building many of the components used in nuclear power plants. Among the factory's main products are the large pressure vessels in which uranium atoms are split to release energy. The plant's customers include both private companies and the government

"Japanese nuclear scientists say if a cooling system can be put in place at the Fukushima Daiichi plant, stabilizing its nuclear fuel could take another 3 months. The deputy head of the Atomic Energy Society of Japan, Takashi Sawada, released the projection by an informal group of 11 society members on Thursday. He said data published by Tokyo Electric Power Company shows that parts of the fuel rods in reactors 1 and 3 have melted and settled at the bottom of the pressure vessels. He said if the ongoing water injections continue, the current situation can be maintained."

70 percent of fuel rods in reactor core at Fukushima nuke plant damaged The pool for spent fuel at the No. 4 reactor of TEPCO's Fukushima No. 1 nuclear power plant is pictured in this Feb. 1, 2005, file photo. (Mainichi ) About 70 percent of the 400 fuel rods in the No. 1 reactor at the crippled Fukushima No. 1 Nuclear Power Plant are damaged, Tokyo Electric Power Co. (TEPCO) has revealed. In addition, some 30 percent of the 548 fuel rods in the No. 2 reactor core and 25 percent of those in the No. 3 reactor core are also thought to be damaged, the power company stated on April 6. The figures are based on analysis of radiation data collected from the side of the reactor pressure vessel between the March 11 earthquake and tsunami and March 15. Just after the earthquake hit, the No. 1-3 reactors were successfully shut down when control rods were inserted into the cores. However, the plant operators soon lost the ability to adequately cool the cores, and TEPCO believes it possible some of the nuclear fuel pellets inside the fuel rods may have melted and leaked from their metal sheathes. At the time of the quake the plant's No. 4 reactor was undergoing a routine inspection and had no fuel rods in its core, while reactors No. 5 and 6 were not operating.