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D'coda Dcoda

Fuku I Hydrogen Gas Update: It Was 63% Concentration [28Sep11] - 0 views

ex-skf.blogspot.com/...ogen-gas-update-it-was-63.html

shared by D'coda Dcoda on 29 Sep 11 - No Cached
  • and no need to worry, TEPCO will take care of it.TEPCO also says since there is no oxygen in the pipe that leads to the Reactor 1 Containment Vessel, there is NO DANGER of explosion.(Uh huh. "There is no danger of explosion" was what they said to the fire department and the Self Defense Force right before Reactor 1 blew up, and then before Reactor 3 blew up.)
  • From Yomiuri Shinbun (9/28/2011):
  • TEPCO announced on September 28 that the concentration of hydrogen gas in the pipe that leads to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant was 63%.
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  • TEPCO says there is no danger of explosion because no oxygen was detected in the pipe. The company will inject nitrogen in the pipe on September 29 to expel hydrogen.
  • The high concentration of hydrogen was found in the pipe that was to be used as part of the filtering system to suppress the leak of radioactive materials in the Containment Vessel. TEPCO will measure the levels of hydrogen gas in the similar pipes in Reactors 2 and 3.
  • It is considered that hydrogen gas was generated when the nuclear fuel was heated to high temperature right after the accident and the cladding and water reacted. If there are more than 4% hydrogen and more than 5% oxygen in the atmosphere, the chance of explosion increases. It is possible that there is hydrogen gas in the upper part of the Containment Vessel and in other pipes. The company says it will take measures to address hydrogen gas before proceeding on any work from now on.Looking at TEPCO's handout for the press on September 28 (Japanese only for now), all they will do is to try to expel hydrogen in the pipe alone by injecting nitrogen from the far end of the pipe. They must be operating on the assumption that all the hydrogen in the pipe is from the initial zirconium cladding and water interaction, not the recent or on-going radiolysis, and once the hydrogen currently in the pipe is expelled, that will be the end of the story.
D'coda Dcoda

VA Nuke Plant, Tritium trouble? Nuke fears rise with quake, self-policing [31Aug11] - 0 views

www.readthehook.com/...d-quake-cause-radioactive-leak

shared by D'coda Dcoda on 31 Aug 11 - No Cached
  • After the nuclear catastrophe that followed the earthquake and tsunami in Japan last spring, some Central Virginia activists cautioned that a similar nightmare could unfold right here at the Dominion-operated North Anna nuclear generating plant in Louisa County. Despite Dominion's assurances that the plant made it through the August 23 earthquake unscathed, activists contend that the quake, which measured 5.8 on the Richter Scale and had an epicenter just eleven miles from the plant, may have been more catastrophic than anyone is admitting. New information bolsters their fears.
  • On Monday, August 29, the federal Nuclear Regulatory Commission announced that the quake may, in fact, have produced force that exceeded the North Anna plant's specifications and that the Commission is sending a special Augmented Inspection Team to assess the damage.
  • Initial reviews determined the plant may have exceeded the ground motion for which it was designed," says the release, which also assures that "no significant damage to safety systems has been identified."
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  • That's small consolation to one prominent nuclear watchdog, who says it's not what's above ground that gives him the greatest concern. "Central to the issue is miles of buried pipe under the plant that carry radioactive water," says Paul Gunter, director of a nonprofit group called Beyond Nuclear.
  • unter cites recent problems with underground pipes at nuclear plants in Illinois and Vermont, where millions of gallons of water contaminated with the radioactive hydrogen isotope tritium seeped into groundwater, even as the power companies that owned the plants denied for years that it was happening.
  • The result of those leaks and their public concealment by the Exelon and Intergy power companies– at the Braidwood Station plant in Illionis and at the Vermont Yankee Nuclear Power Plant– was not additional government oversight as one might expect, says Gunter, but merely the creation of two voluntary programs that allow the power companies to inspect their own pipes and groundwater and then report the findings to the Commission.
  • Here's an industry that has hidden these leaks that is now self-reporting and overseeing itself to the NRC," says a disgusted Gunter.
  • at North Anna, newly arrived government inspectors won't be conducting their own tests of the miles of underground pipes. And the assumption that those pipes didn't sustain damage during the earthquake, which knocked two Louisa County schools out of commission and caused cracks in the Washington Monument some 90 miles away, might be laughable to Gunter if he weren't convinced of potentially grave public danger.
  • How can an uninspectable, inaccessible buried pipe have integrity?" Gunter asks. "When this Augmented Inspection Team walks onto the site, they'll be walking over the buried pipe that could be leaking." "We have a limited number of inspector resources," acknowledges Commission spokesperson Roger Hannah, who says when it comes to the pipes, inspectors will "make sure we see what [Dominion is] doing."
  • Hannah scoffs at the notion that tritium, already considered by the Commission a much lesser danger than uranium, could leak from damaged pipes into the groundwater and go unnoticed by inspectors. "If you had some issue, you'd see some leakage fairly quickly," says Hannah, noting that no tests have revealed radioactive leakage anywhere at the North Anna.
  • Dominion spokesperson Richard Zuercher also offers reassurance that all is well at North Anna, above and under-ground. "We do have ways to detect if there's any leakage in water," says Zuercher, who says the only damage at the facility was "cosmetic" and didn't affect nuclear function and who insists Dominion will "do whatever is necessary to verify that everything is intact." Gunter, however, says he believes Dominion's not going far enough to protect the public."Given the industry history and what's been done before, Dominion should be distributing bottled water to the town of Mineral and to the residents of Lake Anna," he says. "Indefinitely."
D'coda Dcoda

Tritium leaks hit three-quarters of U.S. nuclear plants [27Jun11] - 1 views

www.usatoday.com/...6-27-nuclear-plant-leaks_n.htm

shared by D'coda Dcoda on 08 Sep 11 - No Cached
  • Radioactive tritium has leaked from three-quarters of U.S. commercial nuclear power sites, often into groundwater from corroded, buried piping, an Associated Press investigation shows.
  • The number and severity of the leaks has been escalating, even as federal regulators extend the licenses of more and more reactors across America. Tritium, which is a radioactive form of hydrogen, has leaked from at least 48 of 65 sites, according to U.S. Nuclear Regulatory Commission records reviewed as part of the AP's yearlong examination of safety issues at aging nuclear power plants. Leaks from at least 37 of those facilities contained concentrations exceeding the federal drinking water standard — sometimes at hundreds of times the limit.
  • While most leaks have been found within plant boundaries, some have migrated offsite. But none is known to have reached public water supplies. STORY: Regulators weaken safety standards for nuclear reactors At three sites — two in Illinois and one in Minnesota — leaks have contaminated drinking wells of nearby homes, the records show, but not at levels violating the drinking water standard. At a fourth site, in New Jersey, tritium has leaked into an aquifer and a discharge canal feeding picturesque Barnegat Bay off the Atlantic Ocean.
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  • Any exposure to radioactivity, no matter how slight, boosts cancer risk, according to the National Academy of Sciences. Federal regulators set a limit for how much tritium is allowed in drinking water, where this contaminant poses its main health risk. The U.S. Environmental Protection Agency says tritium should measure no more than 20,000 picocuries per liter in drinking water. The agency estimates seven of 200,000 people who drink such water for decades would develop cancer.
  • The tritium leaks also have spurred doubts among independent engineers about the reliability of emergency safety systems at the 104 nuclear reactors situated on the 65 sites. That's partly because some of the leaky underground pipes carry water meant to cool a reactor in an emergency shutdown and to prevent a meltdown. Fast moving, tritium can indicate the presence of more powerful radioactive isotopes, like cesium-137 and strontium-90.
  • So far, federal and industry officials say, the tritium leaks pose no health or safety threat. Tony Pietrangelo, chief nuclear officer of the industry's Nuclear Energy Institute, said impacts are "next to zero." LEAKS ARE PROLIFIC
  • Like rust under a car, corrosion has propagated for decades along the hard-to-reach, wet underbellies of the reactors — generally built in a burst of construction during the 1960s and 1970s. There were 38 leaks from underground piping between 2000 and 2009, according to an industry document presented at a tritium conference. Nearly two-thirds of the leaks were reported over the latest five years
  • For example, at the three-unit Browns Ferry complex in Alabama, a valve was mistakenly left open in a storage tank during modifications over the years. When the tank was filled in April 2010, about 1,000 gallons (3,785 liters) of tritium-laden water poured onto the ground at a concentration of 2 million picocuries per liter. In drinking water, that would be 100 times higher than the EPA health standard. And in 2008, 7.5 million picocuries per liter leaked from underground piping at Quad Cities in western Illinois — 375 times the EPA limit.
  • Subsurface water not only rusts underground pipes, it attacks other buried components, including electrical cables that carry signals to control operations. A 2008 NRC staff memo reported industry data showing 83 failed cables between 21 and 30 years of service - but only 40 within their first 10 years of service. Underground cabling set in concrete can be extraordinarily difficult to replace.
  • Under NRC rules, tiny concentrations of tritium and other contaminants are routinely released in monitored increments from nuclear plants; leaks from corroded pipes are not permitted. The leaks sometimes go undiscovered for years, the AP found. Many of the pipes or tanks have been patched, and contaminated soil and water have been removed in some places. But leaks are often discovered later from other nearby piping, tanks or vaults. Mistakes and defective material have contributed to some leaks. However, corrosion - from decades of use and deterioration - is the main cause. And, safety engineers say, the rash of leaks suggest nuclear operators are hard put to maintain the decades-old systems.
D'coda Dcoda

TEPCO: It May Be 100% Hydrogen Gas Inside the Pipe Connecting to Reactor I Containment ... - 2 views

ex-skf.blogspot.com/...e-100-hydrogen-gas-inside.html

shared by D'coda Dcoda on 26 Sep 11 - No Cached
  • First it was reported that "over 10,000 ppm" or over 1% of hydrogen gas was detected at 2 locations in the pipe that connects to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant. Then it was allegedly "over 40,000 ppm" or 4%.According to Jiji Tsushin, TEPCO thinks the hydrogen gas concentration in the pipe may be 100%. 1,000,000 ppm.
  • Still, TEPCO says possibility of explosion is not necessarily high because there is no source nearby that could cause sparks. (Never mind that they were going to use blow torches to cut the pipes...)
  • Jiji Tsushin (12:28PM JST 6/24/2011):
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  • Concerning the detection of hydrogen gas in more than 1% concentration inside the pipe that connects to the Containment Vessel of Reactor 1 at Fukushia I Nuclear Power Plant, TEPCO announced on September 24 that it is highly probable that almost all the gas inside the pipe is hydrogen gas. TEPCO's Matsumoto said in the press conference, "Since there is no source for sparks, it cannot be said that there is a high risk of explosion immediately".
  • According to TEPCO, they measured the gas at the pipe exit several times in the afternoon of September 23. Each time, the result showed "flammable gas including hydrogen gas, over 100% ". The company plans to use the instrument that only measures hydrogen, in order to accurately measure the concentration of hydrogen.It's so TEPCO. First they used the device that could only measure up to 10,000 ppm, and that maxed out. Then they apparently used the device that could only measure up to 40,000 ppm, and that maxed out. So they brought in a bit more powerful instrument, but it measures all flammable gases including hydrogen.
D'coda Dcoda

Fukushima - Hydrogen keeps coming up [08Oct11] - 0 views

fukushima-diary.com/...-news-hydrogen-keeps-coming-up

incidents japan

shared by D'coda Dcoda on 09 Oct 11 - No Cached
  • 10/8/2011 Tepco tried to reduce hydrogen in the pipes of reactor 1 but they failed. When there is more than 1% hydrogen, it may cause hydrogen explosion. Apart from other flammable kinds of the gas, hydrogen is assumed be at 63% in the pipes. At first they managed to reduce it to be under 0.1%,but 1~2 hours later, it increased to 3.9% again. There is an explosion risk in this process. Actual worker of Fukushima tweeted like below.
  • Today we reduced the hydrogen in the pipes but it came up again.. Tomorrow we are planning to cut off the pipe but hydrogen needs to be less than 1%.
  • Tepco says extra hydrogen comes up from other pipes but I suspect it comes from underground.. We don’t have proper equipment..I wonder if they can really cut off the pipe. I’ll take a day off tomorrow but I’m worried.
D'coda Dcoda

U.S. nuke regulators weaken safety rules [20Jun11] - 0 views

www.bellinghamherald.com/...-regulators-weaken-safety.html

shared by D'coda Dcoda on 15 Nov 11 - No Cached
  • Federal regulators have been working closely with the nuclear power industry to keep the nation's aging reactors operating within safety standards by repeatedly weakening standards or simply failing to enforce them, an investigation by The Associated Press has found.Officials at the U.S. Nuclear Regulatory Commission regularly have decided original regulations were too strict, arguing that safety margins could be eased without peril, according to records and interviews.The result? Rising fears that these accommodations are undermining safety -- and inching the reactors closer to an accident that could harm the public and jeopardize nuclear power's future.
  • Examples abound. When valves leaked, more leakage was allowed -- up to 20 times the original limit. When cracking caused radioactive leaks in steam generator tubing, an easier test was devised so plants could meet standards.Failed cables. Busted seals. Broken nozzles, clogged screens, cracked concrete, dented containers, corroded metals and rusty underground pipes and thousands of other problems linked to aging were uncovered in AP's yearlong investigation. And many of them could escalate dangers during an accident.
  • Despite the problems, not a single official body in government or industry has studied the overall frequency and potential impact on safety of such breakdowns in recent years, even as the NRC has extended dozens of reactor licenses.Industry and government officials defend their actions and insist no chances are being taken. But the AP investigation found that with billions of dollars and 19 percent of America's electricity supply at stake, a cozy relationship prevails between industry and the NRC.Records show a recurring pattern: Reactor parts or systems fall out of compliance. Studies are conducted by industry and government, and all agree existing standards are "unnecessarily conservative."
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  • Regulations are loosened, and reactors are back in compliance."That's what they say for everything ...," said Demetrios Basdekas, a retired NRC engineer. "Every time you turn around, they say, 'We have all this built-in conservatism.' "The crisis at the decades-old Fukushima Dai-ichi nuclear facility in Japan has focused attention on nuclear safety and prompted the NRC to look at U.S. reactors. A report is due in July.But the factor of aging goes far beyond issues posed by Fukushima.
  • Commercial nuclear reactors in the United States were designed and licensed for 40 years. When the first were built in the 1960s and 1970s, it was expected that they would be replaced with improved models long before their licenses expired.That never happened. The 1979 accident at Three Mile Island, massive cost overruns, crushing debt and high interest rates halted new construction in the 1980s.Instead, 66 of the 104 operating units have been relicensed for 20 more years. Renewal applications are under review for 16 other reactors.As of today, 82 reactors are more than 25 years old.The AP found proof that aging reactors have been allowed to run less safely to prolong operations.
  • Last year, the NRC weakened the safety margin for acceptable radiation damage to reactor vessels -- for a second time. The standard is based on a reactor vessel's "reference temperature," which predicts when it will become dangerously brittle and vulnerable to failure. Through the years, many plants have violated or come close to violating the standard.As a result, the minimum standard was relaxed first by raising the reference temperature 50 percent, and then 78 percent above the original -- even though a broken vessel could spill radioactive contents."We've seen the pattern," said nuclear safety scientist Dana Powers, who works for Sandia National Laboratories and also sits on an NRC advisory committee. "They're ... trying to get more and more out of these plants."
  • Sharpening the pencilThe AP study collected and analyzed government and industry documents -- some never-before released -- of both reactor types: pressurized water units that keep radioactivity confined to the reactor building and the less common boiling water types like those at Fukushima, which send radioactive water away from the reactor to drive electricity-generating turbines.The Energy Northwest Columbia Generating Station north of Richland is a boiling water design that's a newer generation than the Fukushima plants.Tens of thousands of pages of studies, test results, inspection reports and policy statements filed during four decades were reviewed. Interviews were conducted with scores of managers, regulators, engineers, scientists, whistleblowers, activists and residents living near the reactors at 65 sites, mostly in the East and Midwest.
  • AP reporters toured some of the oldest reactors -- Oyster Creek, N.J., near the Atlantic coast 50 miles east of Philadelphia and two at Indian Point, 25 miles north of New York City on the Hudson River.Called "Oyster Creak" by some critics, this boiling water reactor began running in 1969 and is the country's oldest operating commercial nuclear power plant. Its license was extended in 2009 until 2029, though utility officials announced in December they will shut the reactor 10 years earlier rather than build state-ordered cooling towers. Applications to extend the lives of pressurized water units 2 and 3 at Indian Point, each more than 36 years old, are under NRC review.Unprompted, several nuclear engineers and former regulators used nearly identical terminology to describe how industry and government research has frequently justified loosening safety standards. They call it "sharpening the pencil" or "pencil engineering" -- fudging calculations and assumptions to keep aging plants in compliance.
  • Cracked tubing: The industry has long known of cracking in steel alloy tubing used in the steam generators of pressurized water reactors. Ruptures have been common in these tubes containing radioactive coolant; in 1993 alone, there were seven. As many as 18 reactors still run on old generators.Problems can arise even in a newer metal alloy, according to a report of a 2008 industry-government workshop.
  • Neil Wilmshurst, director of plant technology for the industry's Electric Power Research Institute, acknowledged the industry and NRC often collaborate on research that supports rule changes. But he maintained there's "no kind of misplaced alliance ... to get the right answer."Yet agency staff, plant operators and consultants paint a different picture:* The AP reviewed 226 preliminary notifications -- alerts on emerging safety problems -- NRC has issued since 2005. Wear and tear in the form of clogged lines, cracked parts, leaky seals, rust and other deterioration contributed to at least 26 of the alerts. Other notifications lack detail, but aging was a probable factor in 113 more, or 62 percent in all. For example, the 39-year-old Palisades reactor in Michigan shut Jan. 22 when an electrical cable failed, a fuse blew and a valve stuck shut, expelling steam with low levels of radioactive tritium into the outside air. And a 1-inch crack in a valve weld aborted a restart in February at the LaSalle site west of Chicago.
  • * A 2008 NRC report blamed 70 percent of potentially serious safety problems on "degraded conditions" such as cracked nozzles, loose paint, electrical problems or offline cooling components.* Confronted with worn parts, the industry has repeatedly requested -- and regulators often have allowed -- inspections and repairs to be delayed for months until scheduled refueling outages. Again and again, problems worsened before being fixed. Postponed inspections inside a steam generator at Indian Point allowed tubing to burst, leading to a radioactive release in 2000. Two years later, cracking grew so bad in nozzles on the reactor vessel at the Davis-Besse plant near Toledo, Ohio, that it came within two months of a possible breach, an NRC report said, which could release radiation. Yet inspections failed to catch the same problem on the replacement vessel head until more nozzles were found to be cracked last year.
  • Time crumbles thingsNuclear plants are fundamentally no more immune to aging than our cars or homes: Metals grow weak and rusty, concrete crumbles, paint peels, crud accumulates. Big components like 17-story-tall concrete containment buildings or 800-ton reactor vessels are all but impossible to replace. Smaller parts and systems can be swapped but still pose risks as a result of weak maintenance and lax regulation or hard-to-predict failures.Even mundane deterioration can carry harsh consequences.For example, peeling paint and debris can be swept toward pumps that circulate cooling water in a reactor accident. A properly functioning containment building is needed to create air pressure that helps clear those pumps. But a containment building could fail in a severe accident. Yet the NRC has allowed safety calculations that assume the buildings will hold.
  • In a 2009 letter, Mario V. Bonaca, then-chairman of the NRC's Advisory Committee on Reactor Safeguards, warned that this approach represents "a decrease in the safety margin" and makes a fuel-melting accident more likely.Many photos in NRC archives -- some released in response to AP requests under the federal Freedom of Information Act -- show rust accumulated in a thick crust or paint peeling in long sheets on untended equipment.Four areas stand out:
  • Brittle vessels: For years, operators have rearranged fuel rods to limit gradual radiation damage to the steel vessels protecting the core and keep them strong enough to meet safety standards.But even with last year's weakening of the safety margins, engineers and metal scientists say some plants may be forced to close over these concerns before their licenses run out -- unless, of course, new regulatory compromises are made.
  • Leaky valves: Operators have repeatedly violated leakage standards for valves designed to bottle up radioactive steam in an earthquake or other accident at boiling water reactors.Many plants have found they could not adhere to the general standard allowing main steam isolation valves to leak at a rate of no more than 11.5 cubic feet per hour. In 1999, the NRC decided to allow individual plants to seek amendments of up to 200 cubic feet per hour for all four steam valves combined.But plants have violated even those higher limits. For example, in 2007, Hatch Unit 2, in Baxley, Ga., reported combined leakage of 574 cubic feet per hour.
  • "Many utilities are doing that sort of thing," said engineer Richard T. Lahey Jr., who used to design nuclear safety systems for General Electric Co., which makes boiling water reactors. "I think we need nuclear power, but we can't compromise on safety. I think the vulnerability is on these older plants."Added Paul Blanch, an engineer who left the industry over safety issues, but later returned to work on solving them: "It's a philosophical position that (federal regulators) take that's driven by the industry and by the economics: What do we need to do to let those plants continue to operate?"Publicly, industry and government say that aging is well under control. "I see an effort on the part of this agency to always make sure that we're doing the right things for safety. I'm not sure that I see a pattern of staff simply doing things because there's an interest to reduce requirements -- that's certainly not the case," NRC chairman Gregory Jaczko said in an interview.
  • Corroded piping: Nuclear operators have failed to stop an epidemic of leaks in pipes and other underground equipment in damp settings. Nuclear sites have suffered more than 400 accidental radioactive leaks, the activist Union of Concerned Scientists reported in September.Plant operators have been drilling monitoring wells and patching buried piping and other equipment for several years to control an escalating outbreak.But there have been failures. Between 2000 and 2009, the annual number of leaks from underground piping shot up fivefold, according to an internal industry document.
D'coda Dcoda

Fukushima plant workers exposed to radiation [09Oct13] - 0 views

www3.nhk.or.jp/...20131009_23.html

fukushima workers

shared by D'coda Dcoda on 09 Oct 13 - No Cached
  • D'coda Dcoda on 09 Oct 13
     
    Workers at the crippled Fukushima Daiichi nuclear power plant have caused a fresh leak of contaminated water by mistakenly detaching a pipe. The plant's operator, Tokyo Electric Power Company, says 6 workers were sprayed with the contaminated water and are being checked for radiation exposure. TEPCO says the workers mistakenly detached a water pipe from a joint near a desalination device on Wednesday morning. The accident caused about 7 tons of contaminated water to leak for about 50 minutes. TEPCO says the water is contained inside a 60-meter-long, 12-meter-wide barrier that surrounds the device. The water is highly radioactive, containing 34 million becquerels of beta ray-emitting material per liter. Worker errors have been occurring frequently at the Fukushima Daiichi plant, as TEPCO struggles to keep the facility under control.
D'coda Dcoda

Leaky pipe ID'd as radioactive source at nuclear Plant Hatch, Georgia [03Oct11] - 0 views

www.ajc.com/...leaky-pipe-idd-as-1193590.html

shared by D'coda Dcoda on 03 Oct 11 - No Cached
  • Workers have identified an underground pipe leaking radioactive water beneath a nuclear power plant in Georgia
  • Southern Co. spokeswoman Amoi Geter said Monday that workers were seeking to determine if that pipe below Plant Hatch in Baxley is the sole cause of a leak of radioactive tritium that was first discovered Wednesday. Tritium is a radioactive form of hydrogen that is created inside nuclear reactors. So far, the utility and state environmental officials say the water containing tritium has not spread beyond a small area on the grounds of the nuclear power plant. They say it is not a threat to the public. Southern Co. officials have said they hope to have the leak repaired early this week.
D'coda Dcoda

Flammable gas detected in Fukushima pipe: TEPCO [24Sep11] - 0 views

www.mysinchew.com/64210

shared by D'coda Dcoda on 26 Sep 11 - No Cached
  • Flammable gas has been detected inside a pipe linked to a nuclear reactor at Japan's crippled Fukushima atomic power plant, its operator said Saturday. Tokyo Electric Power Co (TEPCO) was unable to identify the gas but nonetheless said it was unlikely there would be an explosion in the reactor. The company has been injecting nitrogen into the reactor so that the level of oxygen inside becomes low enough to prevent blasts. But a TEPCO spokesman said workers at the Fukushima Daiichi nuclear plant measured a 100-percent flammable gas in a pipe connected to the power station's reactor number one.
  • "It is not clear exactly where and how this gas was created," the spokesman told AFP. "We are considering ways to deal with it. "It is likely that we will continue the survey the gas to identify it and use nitrogen to bring its level low enough" to avoid explosions, he said. There were explosions at the reactors at the Fukushima nuclear plant after they went into meltdown following the March 11 earthquake and tsunami, which hit its cooling systems.
D'coda Dcoda

Tweets from Fukushima worker: "It's so scary" - Normal air contains enough oxygen to ca... - 0 views

enenews.com/oxygen-hydrogen-explosion-fire

shared by D'coda Dcoda on 27 Sep 11 - No Cached
  • Breaking News: High level of radiation is making hydrogen from H2O, Fukushima Diary by Mochizuki, September 26, 2011:
  • These are the tonight’s tweets of actual Fukushima worker called Happy20790 I managed to come back safely today. We couldn’t work at reactor 1 today, again. Last week, they said they detected 4% of hydrogen but it turned out to be over 100%. The current measurement tool is to detected only flammable gas, but Tepco says probably it is all hydrogen. [...] We would have been all dead if we cut of the pipe [reportedly using blow torches]. Unbelievable story, but as our original schedule, we didn’t plan to check the presence of flammable gas. The process was added the day before the day. It’s so scary. [...] [T]hen we are going to inject nitrogen to cut out to pipes. but normal air contains 18% of oxygen, which is enough to cause a hydrogen explosion even without fire. It’s so scary. Injecting nitrogen may also cause lack of oxygen. [...] It’s probably that high radiation is producing hydrogen out of H2O. [...] From his valuable statements, we can tell the hydrogen is still being produced by the very high radiation hitting H2O in the reactor. Nobody has seen it by their own eyes, but the melted fuel rods must be very active still. TEPCO: It May Be 100% Hydrogen Gas Inside the Pipe Connecting to Reactor I Containment Vessel, EX-SKF, September 24, 2011:
D'coda Dcoda

Experts split on how to decommission Fukushima nuclear plant [29Aug11] - 0 views

mdn.mainichi.jp/...20110828p2a00m0na002000c.html

shared by D'coda Dcoda on 30 Aug 11 - No Cached
  • What is actually going to take place at the Fukushima No. 1 Nuclear Power Plant, where word is that the four reactors that were crippled in the Great East Japan Earthquake and tsunami will eventually be decommissioned? The Ministry of Economy, Trade and Industry's Nuclear and Industrial Safety Agency (NISA) defines "decommissioning" as the process of removing spent fuel from reactors and dismantling all facilities. Ultimately, the site of a decommissioned reactor is meant to be reverted into a vacant lot.
  • In 1996, the then Japan Atomic Energy Research Institute (JAERI) -- now the Japan Atomic Energy Agency (JAEA) -- finished decommissioning its Japan Power Demonstration Reactor. The decommissioning process of the Tokai Nuclear Power Plant in the Ibaraki Prefecture village of Tokai began in 1998 and is set to end in fiscal 2020, while the No. 1 and No. 2 nuclear reactors at the Hamaoka Nuclear Power Plant in the Shizuoka Prefecture city of Omaezaki are slated for decommissioning by fiscal 2036. Around the world, only around 15 nuclear reactors have thus far been dismantled.
  • The standard decommissioning process entails six major steps: 1. Remove spent fuel rods, 2. Remove radioactive materials that have become affixed to reactor pipes and containers, 3. Wait for radiation levels to go down with time, 4. Dismantle reactors and other internal vessels and pipes, 5. Dismantle the reactor buildings, and 6. Make the site into a vacant lot.
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  • "Cleaning," "waiting," and "dismantling" are the three key actions in this process. Needless to say, this all needs to be done while simultaneously containing radioactive materials.
  • In the case of the Tokai Nuclear Power Plant, the first commercial plant to undergo decommissioning, spent fuel was removed over a span of three years beginning in 1998, and was transported to Britain for reprocessing. Dismantling of the facilities began in 2001, with current efforts being made toward the dismantling of heat exchangers; workers have not yet begun to take the reactor itself apart. The entire process is expected to be an 88.5-billion-yen project involving 563,000 people.
  • Hitachi Ltd., which manufactures nuclear reactors, says that it "generally takes about 30 years" to decommission a reactor. The Hamaoka Nuclear Power Plant's No. 1 and No. 2 reactors operated by Chubu Electric Power Co. are also expected to take about 30 years before they are decommissioned.
  • In the case of the Fukushima No. 1 Nuclear Power Plant, meanwhile, the biggest challenge lies in how to remove the fuel, says Tadashi Inoue, a research advisor at the Central Research Institute of Electric Power Industry (CRIEPI), a foundation that conducts research on energy and environmental issues in relation to the electrical power industry.
  • "we must deal with rubble contaminated with radioactive materials that were scattered in the hydrogen blasts and treat the radiation-tainted water being used to cool nuclear fuel before we can go on to fuel removal."
  • Currently, the Fukushima plant's operator, Tokyo Electric Power Co. (TEPCO), is desperately trying to treat the contaminated water. Huge challenges remain with regards to the contaminated rubble, as radiation levels of over 10 sieverts per hour were found near outdoor pipes on the plant grounds just the other day. Exposure to such high levels would mean death for most people.
  • Each step in the process toward decommissioning is complicated and requires great numbers of people. It's a race against time because the maximum amount of radiation that workers can be exposed to is 250 millisieverts.
  • Prefacing the following as "a personal opinion," Inoue says: "Building a car that can protect the people inside as much as possible from radioactive materials, and attaching an industrial robotic arm to the car that can be manipulated by those people could be one way to go about it."
  • Two types of fuel removal must take place. One is to take out the spent fuel in the containment pools, and the other is to remove the melted fuel from the reactor cores. Because the radiation levels of the water in the spent fuel pools have not shown any significant changes from before the crisis, it is believed that the spent fuel has not suffered much damage. However, removing it will require repairing and reinstalling cranes to hoist the fuel rods out.
  • The breached reactor core is a bigger problem. It is believed that raising water levels inside the reactor has been difficult because of a hole in the bottom of the vessel. It will be necessary to plug the hole, and continue filling the vessel with water while extracting the melted fuel. How to fill the vessel with water is still being debated. If the reactor can be filled with water, steps taken after the 1979 Three Mile Island nuclear accident can serve as a guide because in that case, in which approximately 50 percent of the core had melted, workers were able to fill the reactor with water and remove the fuel within.
  • Inoue predicts that removal of spent fuel from the containment pools will begin about five years after the crisis, and about 10 years in the case of melted fuel from the reactor core. Work on the four reactors at the Fukushima plant will probably take several years.
  • "Unless we look at the actual reactors and take and analyze fuel samples, we can't know for sure," Inoue adds. Plus, even if workers succeed in removing the fuel, reprocessing it is an even more difficult task. A review of processing methods and storage sites, moreover, has yet to take place.
  • Meanwhile, at least one expert says he doesn't believe that workers will be able to remove the melted fuel from the crippled plant.
  • "If there's 10 sieverts per hour of radiation outside, then the levels must be much higher closer to the reactor core," says Tadahiro Katsuta, an associate professor at Meiji University and an expert in reactor engineering and reactor policy who was once a member of an anti-nuclear non-profit organization called Citizens' Nuclear Information Center (CNIC). "The fuel has melted, and we haven't been able to cool it consistently. If work is begun five or 10 years from now when radiation levels have not yet sufficiently gone down, workers' health could be at serious risk."
  • Katsuta predicts that it will probably take at least 10 years just to determine whether it is possible to remove the fuel. He adds that it could very well take 50 years before the task of dismantling the reactor and other facilities is completed.
  • What Katsuta has in mind is a Chernobyl-style concrete sarcophagus, which would entail cloaking the melted tomb with massive amounts of concrete. "How could we simultaneously dismantle four reactors that have been contaminated to the extent that they have by radioactive materials?" asks Katsuta. "Japan has little experience in decommissioning reactors, and this case is quite different from standard decommissioning processes. It's not realistic to think we can revert the site back to a vacant lot. I think we should be considering options such as entombing the site with concrete or setting up a protective dome over the damaged reactor buildings
  • what we face is a great unknown to all of mankind.
D'coda Dcoda

Radioactive leaks at crippled Fukushima nuclear power plant increase two months after i... - 0 views

www.dailymail.co.uk/...ease-months-declared-safe.html

shared by D'coda Dcoda on 05 Feb 12 - No Cached
  • Less than two months ago the crippled Japanese nuclear power plant at Fukushima was declared stable.Yet now it has emerged that radioactive water is continuing to leak at the stricken site. These were spotted by workers at the reprocessing areas and were found to release enough beta rays that can lead to radiation sickness.
  • Matsumoto said TEPCO also found that 8.5 tons of radioactive water had leaked earlier in the week after a pipe became detached at Unit 4, one of the plant's six reactors. The company earlier had estimated that only a few gallons had leaked. He said officials are investigating the cause of that leak, but that it was unlikely the pipe had been loosened by the many aftershocks that have hit the plant.The structural integrity of the damaged Unit 4 reactor building has long been a major concern among experts because a collapse of its spent fuel cooling pool could cause a disaster worse than the three reactor meltdowns.
D'coda Dcoda

Major new leak at Japan's nuclear plant [01Feb12] - 0 views

www.trust.org/...-at-japans-nuclear-plant-kyodo

shared by D'coda Dcoda on 02 Feb 12 - No Cached
  • More than 8 tonnes of water have leaked from Japan's stricken nuclear power plant after a frozen pipe burst inside a reactor buiding, but none of the water is thought to have escaped the complex, Kyodo news agency said on Thursday. Kyodo, quoting the Fukushima plant's operator Tokyo Electric Power Co (Tepco), said the water had leaked from the No.4 reactor when a pipe "dropped off" but that the liquid had all been contained inside the reactor building.
  • "The total amount of leakage from the reactor was initially estimated to be 6 litres, but the utility revised the figure later Wednesday, adding that the leakage appears to have started at around 5 p.m. (0800 GMT) Monday," Kyodo said. "The utility plans to check whether there are similar cases in the other crippled reactors,"
D'coda Dcoda

#Fukushima I Nuke Plant Reactor 1: More Than 5 Sieverts/Hr Radiation on 2nd Floor [02Au... - 0 views

ex-skf.blogspot.com/...nuke-plant-reactor-1-more.html

shared by D'coda Dcoda on 03 Aug 11 - No Cached
  • It looks like the survey meter on the robot (no info on whether it was Packbot or Quince) also went overscale.From Jiji Tsushin (10:47PM JST 8/2/2011):
  • TEPCO announced on August 2 that the radiation level in the air conditioning room on the 2nd floor of the reactor building of Reactor 1 was over 5 sieverts/hr (or 5,000 millisieverts/hr). It is the highest indoor radiation ever recorded at the plant, higher than 4 sieverts/hr recorded also in the Reactor 1 reactor building on June 3. TEPCO closed off the room.
  • The vent duct that releases pressure inside the Containment vessel and the emergency gas processing pipe meet inside the room, which is upstream from the main exhaust stack where over 10 sieverts/hr radiation was measured on August 1. According to TEPCO, it is possible that the high concentration of radioactive materials got stuck inside the pipes when the venting was done on the next day after the March 11 earthquake.According to Yomiuri, 10 sieverts/hr radiation would be emitted from 2 grams of radioactive cesium.
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  • According to Kyodo News Japanese, the room is called the "train room" by TEPCO.
Jan Wyllie

Critics Question Competency Of Inspector General's Office At Nuclear Regulatory Commiss... - 0 views

www.huffingtonpost.com/...atory-commission_n_923098.html

nuclear

shared by Jan Wyllie on 12 Aug 11 - No Cached
  • Since its formation inside the NRC in 1989, the OIG has fielded thousands of whistleblower complaints and conducted a compelling list of investigations, many exposing abuse and neglect both at the NRC and within the nuclear power industry that led to Congressional investigations and subsequent agency reform. The OIG became legendary for preparing exhaustively detailed, and publicly available, reports of its investigations. Now, Mulley -- along with numerous freelance and non-profit nuclear safety advocates who for years relied on the IG's office as a vital backstop against lax nuclear oversight at the NRC -- all say that the IG's office appears to be broken.
  • At a time when the safety of the nation's nuclear power industry has come under intense scrutiny -- particularly following what investigators now say was a preventable meltdown at a Japanese nuclear facility hobbled by an earthquake and flood this spring -- the absence of a robust inspector general, say nuclear-safety advocates with organizations like the Union of Concerned Scientists, Greenpeace and the Project on Government Oversight, leaves the public more vulnerable to nuclear accidents
  • Chief among the omissions from the OIG's final report: that NRC staff had known since at least 1990 that the pipes in question inside the Byron nuclear power plant had been corroding, but had consistently failed to take steps to force the plant operator to correct the issue until the pipes ultimately sprung a leak.
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  • "I can't accept the fact of these individuals saying they don't feel comfortable," McMillan says. "Those individuals may not feel comfortable, but clearly other people feel confident enough to refer matters to this office and to ensure that they were properly investigated."
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