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D'coda Dcoda

Shutdown of Fukushima Reactors Is Ahead of Schedule [Nov11] - 0 views

spectrum.ieee.org/...-reactors-is-ahead-of-schedule

shared by D'coda Dcoda on 28 Oct 11 - No Cached
  • Editor's Note: This is part of the IEEE Spectrum special report: Fukushima and the Future of Nuclear Power.
  • This past April, when the Japanese government and Tokyo Electric Power Co. (TEPCO) jointly unveiled their plan to bring the damaged reactors of the Fukushima Dai-ichi nuclear power plant to a cold shutdown and gain control of the release of radioactive materials, they set a tentative completion date for mid-January 2012. And "tentative" had to be the operative word, for the obstacles TEPCO faced—and to some extent still does face—are challenging in the extreme. They include:
  • Fuel rod meltdowns in reactors 1, 2, and 3 due to loss of cooling systems following the 11 March earthquake and tsunami; Severe damage to the upper levels of reactor buildings 1, 3, and 4 and slight damage to building 2, stemming from hydrogen explosions; High levels of radiation and contaminated rubble, making working conditions hazardous and difficult; Thousands of metric tons of contaminated water accumulating on the site and leaking out of the reactors.
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  • Critics, however, were quick to question the stability of the system and its ad hoc design. The combination of filtering and decontamination technologies—mainly from the French nuclear giant Areva and the U.S. nuclear waste management company Kurion—includes some 4 kilometers of piping. The critics have a point. Even with the addition of a reportedly more robust system (to be used in parallel or as backup as needed) from Toshiba and IHI Corp., TEPCO admits the system underwent 39 disruptions between 10 July and 8 September. One consequence is that roughly 100 000 metric tons of water still need to be decontaminated.
  • It appears, however, that the process is now ahead of schedule. Environment Minister Goshi Hosono, who is also in charge of the Fukushima nuclear accident recovery, told the International Atomic Energy Agency's annual general conference in Vienna on 19 September that Japan was now aiming to complete a cold shutdown of the Fukushima plant by December 2011, instead of mid-January 2012. Progress was already evident in July, when Hosono announced that workers had completed step 1 of the two-step road map on schedule, reducing radioactive emissions and starting to bring down the core temperatures in reactors 1, 2, and 3. Hosono attributed the success to the construction of a new cooling system, which had begun pumping water into all three damaged reactors. In addition to cooling, the system also decontaminates the water accumulating in the basements of the reactor and turbine buildings. The contamination is the result of injected water coming into contact with the molten fuel in the pressure vessels.
  • Disruptions and remaining challenges notwithstanding, TEPCO has been making progress toward step 2 of the road map: a cold shutdown. According to TEPCO, that means achieving and maintaining a temperature of less than 100 °C as measured at the bottom of a reactor pressure vessel—the steel vessel containing the fuel rods—which itself is enclosed inside a protective containment vessel. A major advance came at the beginning of September, when TEPCO was able to start up the core spray lines to cool reactors 1 and 3. The core spray lines apply water directly to the cores from above, while the system installed in July has been cooling the cores by injecting water from the bottom. TEPCO has also begun increasing the amount of water being injected into reactor 2. The core spray line could not be used until recently because TEPCO first had to survey the subsystem's piping and valves. Given the high radiation in the area, this was difficult, but workers completed the job in July and confirmed the system's operability in August.
  • By late September, as a result of these efforts, the temperatures in all three reactors had dropped below 100 °C for the first time since the accident. As of 29 September, the temperatures for reactors 1, 2, and 3, respectively, were 77.5 °C, 99.7 °C, and 78.7 °C. "We are steadily bringing the postaccident situation under control," says Hosono. "To achieve step 2 this year, we'll move the schedule forward and do our best." But Yoshinori Moriyama, deputy director-general of Japan's Nuclear and Industrial Safety Agency (NISA) is cautious. "We need to maintain this state over the midterm," he says. "Temporary lower temperatures and the nonrelease of radioactive substances do not immediately mean that this is a cold shutdown." In order for NISA to declare a cold shutdown, the temperatures must remain stable and below 100 °C into December. So NISA won't officially declare a cold shutdown until near the end of 2011.
  • Despite these positive developments, nuclear experts point out that achieving a cold shutdown does not make the troubled plant completely safe, given that even spent fuel continues to generate heat for years after use. And upon achieving a cold shutdown, TEPCO must take on a new series of challenges. These include finding where the injected water is escaping, stopping those leaks, dealing with the accumulated contaminated water, removing and storing the thousands of spent fuel rods from the pools in reactors 1 to 4, and then figuring out a way to remove the melted fuel. The last is a task that could take a decade or more, according to experts.
D'coda Dcoda

Actions speak louder than words over cold shutdown goal for Fukushima nuclear reactors ... - 0 views

mdn.mainichi.jp/...20110921p2a00m0na002000c.html

shared by D'coda Dcoda on 22 Sep 11 - No Cached
  • Achieving a "cold shutdown" of a nuclear reactor is not difficult as long as the reactor is not broken. A cold shutdown is defined by experts as a situation in which nuclear reactors whose operations are suspended are being stably cooled down and the temperatures in them are kept below 100 degrees Celsius. However, it is no easy task to achieve a cold shutdown at the tsunami-hit Fukushima No. 1 Nuclear Power Plant where fuel has melted and holes have developed in damaged reactors.
  • Goshi Hosono, state minister for the prevention of nuclear accidents, told the International Atomic Energy Agency (IAEA) annual general meeting under way in Vienna that Tokyo will do its best to achieve a cold shutdown of the stricken reactors at the plant by the end of this year. His remark suggests that the government intends to bring forward its target of achieving a stable cool-down of the troubled reactors and of substantially reducing the amount of radioactive substances released from the plant by January 2012.
  • The temperature at the bottom of the No. 1 reactor's pressure vessel has been stabilized at less than 100 degrees Celsius, and that of the No. 3 reactor has recently been kept below that level. Hosono appears to have made the remark at the IAEA conference while keeping in mind these positive signs. It is a matter of course for the government to try its utmost to bring the crippled reactors under control as soon as possible, and it is important for it to show its determination to achieve this goal to the international community.
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  • At the same time, however, it is notable that the government has failed to clarify what a cold shutdown at the Fukushima plant specifically means. Currently, water contaminated with radioactive materials is purified and reused to cool down reactor cores as a last-ditch measure, and plant operator Tokyo Electric Power Co. (TEPCO) is unlikely to be able to use a conventional cooling system in the foreseeable future.
  • If the cooling system with a total extension of four kilometers develops trouble, the temperatures of the reactor cores could rise again. Since it remains unclear where the melted fuel is situated in the troubled reactors, the temperatures of the pressure vessels alone are far from convincing. Under these circumstances, the phrase, "cold shutdown," should not be used in a casual manner without clearly defining it. It is important to grasp the actual conditions of the reactors and fuel as accurately as possible and take appropriate countermeasures in a well-organized manner.
  • The lifting and reviewing of evacuation advisories depends largely on whether the cold shutdown of the stricken nuclear reactors can be achieved. Therefore, the government should specifically explain the conditions of the reactors and risks involving them to the public. In anticipation that the reactors will be stabilized in a relatively short period, the government is set to lift its designation of areas 20-30 kilometers from the nuclear power station as "emergency evacuation preparation zones" as early as this month. In these areas, residents are allowed to stay in their neighborhoods, but kindergartens and schools remain closed. Such a contradiction should be eliminated according to the circumstances of each of these areas.
  • On the other hand, it is indispensable to regularly measure the precise levels of radiation and decontaminate areas tainted with radioactive substances so that residents can return to their neighborhoods without worries about being exposed to radiation. Moreover, it is necessary to speed up efforts to repair and build public infrastructure in the affected areas.
  • Hosono has sought cooperation from the IAEA to share its expertise in decontamination. It is an important task to bring together the knowledge of the international community to revive crisis-hit Fukushima.
D'coda Dcoda

Criteria for 'cold shutdown' of Fukushima nuclear plant remain vague and ambiguous [18O... - 0 views

australiancannonball.com/...ant-remain-vague-and-ambiguous

shared by D'coda Dcoda on 19 Oct 11 - No Cached
  • The government and Tokyo Electric Power Co. (TEPCO) unveiled a revised roadmap to contain the crippled nuclear reactors at the Fukushima No. 1 Nuclear Power Plant on Oct. 17, clearly stipulating that they would aim for a stable condition called a “cold shutdown” of the reactors by the end of this year, but the criteria used to thrash out the work schedule are vague and ambiguous. It is still not clear whether they can judge that they have achieved a cold shutdown only by checking the temperatures of the bottoms of reactor pressure vessels. On the assessment of the amounts of radioactive substances being released from the nuclear reactors, the government and TEPCO, the operator of the troubled Fukushima nuclear complex, must come up with more detailed data than “provisional figures” in order to say definitely that they have “achieved” a cold shutdown. Furthermore, the government and TEPCO failed to show any direction on the timing of lifting of evacuation advisories — the final goal of the nuclear disaster response roadmap, let alone prospects for measures that should be taken after a cold shutdown is achieved.
D'coda Dcoda

Michigan nuclear plant releasing radioactive steam into environment after unexpected sh... - 0 views

enenews.com/nment-after-unplanned-shutdown

shared by D'coda Dcoda on 27 Sep 11 - No Cached
  • Nuclear Event in USA on Tuesday, 27 September, 2011 at 03:09 (03:09 AM) UTC, RSOE EDIS [Hungarian National Association of Radio Distress-Signalling and Infocommunications (RSOE) operates Emergency and Disaster Information Service (EDIS)]:
  • Entergy’s Palisades nuclear plant near South Haven is venting radioactive steam into the environment as part of an unplanned shutdown triggered by an electrical accident. This shutdown, which began Sunday evening, came just five days after the plant restarted from a shutdown that was caused by a leak in the plant’s cooling system. “The steam that would normally go to the generators, that steam is now going into the environment … through the steam stack [...] This would have very low levels of tritium.” -Nuclear Regulatory Commission spokeswoman Prema Chandrithal h/t Anonymous tips, mooter, Sue-Ellen Campbell
D'coda Dcoda

Plugging leaks will end crisis, not cold shutdown: analysts [12Sep11] - 0 views

search.japantimes.co.jp/...nn20110911f1.html

shared by D'coda Dcoda on 12 Sep 11 - No Cached
  • Ever since the nuclear crisis erupted six months ago, the public has been clamoring to know when the damaged reactors at the Fu ku shi ma No. 1 power plant will be brought under control and when the nightmare will end. The government and Tokyo Electric Power Co., which runs the crippled plant, are working to bring the three reactors into cold shutdown by mid-January.
  • Cold shutdown means the temperature at the bottom of the pressure vessel, which holds the core, has been lowered to less than 100 degrees. This critical milestone, known as "Step 2" in Tepco's road map for containing the crisis, would limit the release of radioactive materials from the plant to less than 1 millisievert per year, a level that poses no health risks.
  • Since work at the plant is proceeding relatively smoothly, it appears likely the mid-January target will be met. But Fukushima No. 1 will still have a long way to go before the flooded plant's reactors are stable enough to be considered safe, experts warn. The main reason is the abundance of highly radioactive water.
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  • "There are about 110,00 tons of contaminated water (in the plant) and the situation is still not completely under control because coolant water is leaking from the containment vessels. There is no guarantee that the irradiated water won't leak from the plant (and contaminate the environment)" if another natural disaster strikes, said Hisashi Ninokata, a professor of reactor engineering at the Tokyo Institute of Technology.
  • After achieving cold shutdowns of reactors 1, 2 and 3, the government may declare parts of the 20-km no-go zone around the plant safe. It may even let the evacuees return, as long as the area is decontaminated and crucial infrastructure restored.
  • But the longer the tainted water leaks, the more the radioactive waste will grow, leaving the Fukushima plant vulnerable to further disasters, Ninokata said. Before the Fukushima crisis can be said contained, the holes and cracks from which the water and fuel are escaping must be located and sealed. But this extremely difficult task could take years because the radiation near the reactors is simply too high to let workers get near them.
  • "It'll be too early to say that the situation has reached a stable phase even after Step 2 is completed," said Chihiro Kamisawa, a researcher at Citizens' Nuclear Information Center, a nonprofit group of scientists and activists opposed to nuclear power. When a reactor is in cold shutdown, the water cooling its fuel is still hot but no longer boiling, which significantly reduces the amount of radioactive emissions.
  • In late July, the temperature in reactor No. 1's pressure vessel fell below 100 degrees. On Monday, the same thing was achieved in reactor 3 after Tepco activated a system that pumps water deep into the containment vessel. But on Friday, reactor No. 2 was still boiling away with a reading of 112.6. "Efforts seem to be making smooth progress, and I think Step 2 is likely to be achieved by mid-January," said Shinichi Morooka, a Waseda University professor and reactor expert.
  • Another reason for optimism is the progress being made with the water decontamination system. The cleaning rate has greatly improved in the past few weeks and exceeded 90 percent of capacity last week. If the decontamination system ever reaches its full potential, it will allow Tepco to inject coolant at a higher rate and bring the melted cores to lower and stabler temperatures.
  • The government also plans to start decontaminating soil in various hot spots so the evacuees can return once the second step is completed. But some experts are questioning whether residents should be allowed to return so soon. The cracks and holes in the leaking reactors haven't even been pinpointed yet, let alone fixed, they say.
  • "As an engineer, I am worried (about the plan to let residents return) when it is still unclear what is really going on inside the reactors," said Morooka. For the time being, Tepco can only guess where the water is leaking from and which parts need repair, because radiation has prevented workers from fully exploring the buildings.
  • Spokesman Junichi Matsumoto said that since no extensive damage to the reactors was found during inspections of the first and second floors of the buildings, any holes or cracks are probably at the basement level. But with the basement floors flooded, Tepco's top priority is just to get the water out. Plans to fix the reactors aren't even being discussed yet, Matsumoto said.
  • Asked if the containment vessels can take another quake, the Tokyo Institute of Technology's Ninokata said he believes the impact would likely be distributed evenly through the structure without widening existing cracks or holes. But if the impact somehow focuses on parts damaged by the March 11 disasters, there could be further damage, he said. "The containment vessel is what really ensures the safety of a nuclear reactor," Ninokata said, warning that if radioactive materials are still leaking out, allowing residents to return would risk harming their health.
D'coda Dcoda

State of Cold Shutdown: Hosono Says "No One Knows Where the Fuel Is, But I'm Confident ... - 0 views

ex-skf.blogspot.com/...d-shutdown-hosono-says-no.html

shared by D'coda Dcoda on 18 Dec 11 - No Cached
  • In a typical display of utter disregard for the general public, the Noda administration announced last night that there would be no more joint press conference where reporters could meet with TEPCO people and the government officials from the Cabinet Office and other relevant ministries and agencies, receive updates and ask questions.The last night's joint press conference is to be the last one, now that Fukushima I Nuclear Power Plant is officially in a "state of a cold shutdown" and the accident has been decreed by the government to be "over".Here's what Minister in charge of the accident and Minister of the Environment Goshi Hosono had to say last night in the last joint press conference, as reported by Nifty News (12/16/2011):
  • Minister of the Environment Hosono expressed some concern that "No one knows where the fuel is until we open the reactors", but he reaffirmed the cold shutdown, following the lead of his prime minister. He said, "No matter where the fuel is, it is being cooled".
D'coda Dcoda

TEPCO revises timetable to cold shutdown for seventh time in eight months [20Nov11] - 0 views

enformable.com/...r-seventh-time-in-eight-months

shared by D'coda Dcoda on 21 Nov 11 - No Cached
  • The government and Tokyo Electric Power Co. have revised the timetable for the seventh time in the eight months since the crisis began. Data suggests the reactors and radioactive material are under control, and the power plant will achieve a cold shutdown once required conditions are confirmed.
  • The situation at the nuclear plant does not meet this definition. Is it appropriate for the government and TEPCO to call the current status nearly a cold shutdown?
  • the status of the molten nuclear fuel is unclear. It is not known how the fuel, believed to have partially melted through pressure vessels of the reactors and into containment vessels, has dispersed and how much lies in water. On Nov. 2, TEPCO said a small-scale recriticality incident–in which nuclear fuel achieves a fission chain reaction–may have taken place at the No. 2 reactor of the power plant.  TEPCO should have been able to coolly handle the detection of xenon, but it failed to do so as it had not properly prepared necessary data.
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  • There are many other unsolved issues, including how to cope with contaminated water said to be accumulating at a rate of 200 to 500 tons a day in underground areas of the reactor buildings. The government and TEPCO must thoroughly solve these issues without being bound by their timetable. Source: Yomiuri Online
D'coda Dcoda

Fukushima Update | No end in sight for nuclear crisis[23Oct11] - 0 views

fukushimaupdate.com/for-nuclear-crisis-japan-times

shared by D'coda Dcoda on 23 Oct 11 - No Cached
  • Tokyo Electric Power Co. and the government on Oct. 17 released a newly revised a road map to bring the stricken Fukushima No. 1 nuclear power plant under control. It shows that a “cold shutdown” of the Nos. 1, 2 and 3 reactors at the plant will be achieved by the end of the year. The reactor cores suffered meltdowns after the March 11 earthquake and tsunami inflicted severe damage, but the temperature in the lower part of the pressure vessels has now fallen below 100 C. As of Oct. 15, it was between 73 C. and 83 C. The amount of radioactive substances released from the reactors has been halved from the level in September when the road map was earlier revised. It is estimated that the three reactors are now releasing radioactive substances at the rate of about 100 million becquerels per hour maximum, about one-eighth of a millionth the level immediately after the nuclear crisis started.
  • Tepco and the government said that with this rate, the annual exposure to radiation in the Fukushima No. 1 compound will be around 0.2 millisieverts maximum, lower than the goal of one millisievert. They also said that the level of contaminated water in the reactor building basements has stabilized. In view of those factors, Tepco and the government said in their newly revised road map that the “cold shutdown” will be achieved by the end of this year. But it must be emphasized that the state of “cold shutdown” that Tepco and the government speak of does not meet the true definition of a cold shutdown — when the temperature inside the pressure vessel is below 100 C and the reactors no longer release radioactive substances. Therefore, achieving this state would not mean that the nuclear crisis has been brought under control.
D'coda Dcoda

N-fuel conditions unclear [18Nov11] - 0 views

www.yomiuri.co.jp/...T111118006066.htm

shared by D'coda Dcoda on 19 Nov 11 - No Cached
  • The latest timetable for bringing a nuclear fuel meltdown at the Fukushima No. 1 nuclear power plant under control shows the situation is no longer in the critical condition it was immediately following the accident, but many issues remain unsolved
  • the status of the molten nuclear fuel is unclear. It is not known how the fuel, believed to have partially melted through pressure vessels of the reactors and into containment vessels, has dispersed and how much lies in water. It is questionable to assess the situation as nearly a cold shutdown. Usually, to achieve a cold shutdown, all fuel rods should be cooled under water, and nuclear fuel, pressure and containment vessels should be intact and in good condition.
  • The situation at the nuclear plant does not meet this definition. Is it appropriate for the government and TEPCO to call the current status nearly a cold shutdown?
D'coda Dcoda

Recent US nuke headlines: Problems at nuke plants in Vermont, Michigan, South... - 0 views

enenews.com/ermont-michigan-south-carolina

shared by D'coda Dcoda on 03 Oct 11 - No Cached
  • Vt. nuke reduces power after pump fails -BusinessWeek Entergy faces another special investigation over malfunction at Palisades -Michigan Messenger Officials investigate reactor shutdown at Robinson plant -SCNOW False alarm sounds as Robinson Nuclear Plant goes back on line in Hartsville -The Republic NRC Tells Dominion It Plans More Inspections at North Anna – Businessweek Will recent earthquake affect plans for third nuclear reactor at North Anna? -Times-Dispatch Kucinich joins protesters at Toledo anti-nuke rally -Toledo Blade N.M. Senators Push For Increased Funding For Nuclear Waste Cleanup -Talk Radio News Servicea 1,389 CPM Peak Geiger Counter Reading, rain sample, Taos County, NM, Sept 07, 2011 -YouTube 800+ CPM Geiger Counter Reading, Sun Sept 4, 2011 -YouTube MORE: Advocates shocked at names used in federal claim manual -The News Tribune PNNL technology detects radioactive materials from the sky -KNDO
D'coda Dcoda

TEPCO redefines "cold shutdown" - Only bottom of pressure vessel has to be under 100 de... - 0 views

enenews.com/s-celcius-reactor-core-coolant

shared by D'coda Dcoda on 05 Sep 11 - No Cached
  • Plugging reactors no longer stated goal for Tepco, Japan Times, July 20, 2011: [...] A cold shutdown is usually defined as bringing the temperature of the reactor-core coolants to below 100 degrees. But this has been redefined as bringing the temperature at the bottom of the pressure vessels to below 100 degrees and reducing the release of radioactive materials from the reactors [...]
D'coda Dcoda

Hurricane Irene shuts down US nuclear reactors [29Aug11] - 0 views

www.guardian.co.uk/...ane-iren-shuts-nuclear-reactor

shared by D'coda Dcoda on 30 Aug 11 - No Cached
  • A nuclear reactor in Maryland has been shut down because of wind damage, while others were either taken offline or operating at reduced capacity as precautionary measures before the arrival of hurricane Irene on Sunday.A reactor at the Calvert Cliffs nuclear plant in Lusby, Maryland, remained off-line on Sunday, after going into automatic shutdown when a piece of aluminum siding ripped from a nearby building damaged a transformer.Constellation Energy, which operates the Lusby plant, said the facility was safe and that a second reactor was operating at full capacity. No power outages were expected because of the shutdown.
  • Maryland state emergency agency said the plant would reopen after inspection. "Number one will stay offline until they have folks that will crawl over every inch of it," its spokesman, Quentin Banks said.It was the second complete shutdown caused by Irene, after authorities took a plant offline in New Jersey as a precaution before the storm.Exelon Corporation decided on Saturday afternoon to take its Oyster Creek generator offline as Irene blew in. "It's really as a precaution, a conservative action, because we do expect hurricane force winds," Marshall Murphy, an Exelon spokesman, told reporters.
  • Fourteen nuclear plants from North Carolina to New Hampshire were in Irene's path
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  • Progress Energy powered down its reactors in Brunswick, North Carolina, and Dominion Resources cut production at one reactor at its Millstone plant in New London, Connecticut, by 70%. Another Dominion plant in Virginia, which had gone down because of last week's earthquake, remained offline for Irene.
D'coda Dcoda

Radiation expert says outcome of nuke crisis hard to predict, warns of further dangers ... - 0 views

mdn.mainichi.jp/...20110909p2a00m0na016000c.html

shared by D'coda Dcoda on 10 Sep 11 - No Cached
  • As a radiation metrology and nuclear safety expert at Kyoto University's Research Reactor Institute, Hiroaki Koide has been critical of how the government and Tokyo Electric Power Co. (TEPCO) have handled the nuclear disaster at the Fukushima No. 1 nuclear plant. Below, he shares what he thinks may happen in the coming weeks, months and years. The nuclear disaster is ongoing. Immediately after the crisis first began to unfold, I thought that we'd see a definitive outcome within a week. However, with radioactive materials yet to be contained, we've remained in the unsettling state of not knowing how things are going to turn out.
  • Without accurate information about what's happening inside the reactors, there's a need to consider various scenarios. At present, I believe that there is a possibility that massive amounts of radioactive materials will be released into the environment again. At the No. 1 reactor, there's a chance that melted fuel has burned through the bottom of the pressure vessel, the containment vessel and the floor of the reactor building, and has sunk into the ground. From there, radioactive materials may be seeping into the ocean and groundwater.
  • The use of water to cool down the reactors immediately after the crisis first began resulted in 110,000 cubic meters of radiation-tainted water. Some of that water is probably leaking through the cracks in the concrete reactor buildings produced by the March 11 quake. Contaminated water was found flowing through cracks near an intake canal, but I think that's just the tip of the iceberg. I believe that contaminated water is still leaking underground, where we can't see it. Because of this, I believe immediate action must be taken to build underground water barriers that would close off the nuclear power plant to the outside world and prevent radioactive materials from spreading. The important thing is to stop any further diffusion of radioactive materials.
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  • The government and plant operator TEPCO are trumpeting the operation of the circulation cooling system, as if it marks a successful resolution to the disaster. However, radiation continues to leak from the reactors. The longer the circulation cooling system keeps running, the more radioactive waste it will accumulate. It isn't really leading us in the direction we need to go.
  • It's doubtful that there's even a need to keep pouring water into the No.1 reactor, where nuclear fuel is suspected to have burned through the pressure vessel. Meanwhile, it is necessary to keep cooling the No. 2 and 3 reactors, which are believed to still contain some fuel, but the cooling system itself is unstable. If the fuel were to become overheated again and melt, coming into contact with water and trigger a steam explosion, more radioactive materials will be released.
  • TEPCO says it is aiming to bring the No. 1, 2 and 3 reactors to cold shutdown by January 2012. Cold shutdown, however, entails bringing the temperature of sound nuclear fuel in pressure vessels below 100 degrees Celsius. It would be one thing to aim for this in April, when the government had yet to confirm that a meltdown had indeed taken place. But what is the point of "aiming for cold shutdown" now, when we know that fuel is no longer sound?
  • In the days ahead, the storage of enormous quantities of radiation-contaminated waste, including tainted mud resulting from the decontamination process, will become a major problem.
  • When the Three Mile Island accident took place in 1972, the melted nuclear fuel had stayed within the pressure vessel, making defueling possible. With Fukushima, however, there is a possibility that nuclear fuel has fallen into the ground, in which case it will take 10 or 20 years to recover it. We are now head to head with a situation that mankind has never faced before.
D'coda Dcoda

LNG Market May Tighten on Japanese Nuclear Shutdown, SocGen Says [05Oct11] - 0 views

washpost.bloomberg.com/Story

alternatives natural gas

shared by D'coda Dcoda on 05 Oct 11 - No Cached
  • Kyushu Electric Power Co.’s nuclear shutdown may exacerbate tightness in the global liquefied natural gas market as demand for the fuel used in electricity generation has exceeded estimates, Societe Generale SA said. Kyushu’s 1,180-megawatt No. 4 reactor at its Genkai atomic plant shut down automatically yesterday after a malfunction, according to the Ministry of Economy, Trade and Industry. Global LNG supply rose 14 percent in the first seven months of this year to about 140 million metric tons, compared with the bank’s full-year forecast of more than 10 percent growth, Thierry Bros, a Paris-based analyst for the bank, said. “The closure is more bad news for the Japanese nuclear industry which looks to face even more difficulties restarting reactors after planned maintenance and/or automatic shutdowns,” Bros said. “Without approval to restart reactors down for maintenance, all of Japan’s reactors could be shut by May.”
Dan R.D.

TEPCO aims to stabilize Fukushima plant in six months - RT [17Apr11] - 0 views

rt.com/...kushima-shutdown-resign-robots

japan nuclear consequences TEPCO strategy shutdown fukushima

shared by Dan R.D. on 29 Oct 11 - No Cached
  • The operator of Fukushima-1 nuclear power plant aims to restore the cooling systems of the reactors at the troubled facility within three months and achieve “cold shutdown” of the plant in six to nine months.
  • ''We will do our utmost to curb the release of radioactive materials by achieving a stable cooling state at the reactors and spent fuel pools,'' said TEPCO’s Chairman Tsunehisa Katsumata at a news conference on Sunday, as cited by Kyodo news agency.
  • The water, which has been pumped into the reactors to cool them down, started leaking into the basements of the facility’s buildings through the cracks that appeared as a result of the earthquake. The level of water reached 85cm below ground level on Sunday in reactor 2 and threatens to overflow into the ocean. It happened despite the efforts to decant some of the water to a condenser tank at the premises of the reactor.
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  • In a week’s time, the company plans to transfer the contaminated water from reactor 2 to a nuclear waste facility that can store some 30,000 tons of such water.
Jan Wyllie

Japan makes breakthrough in nuclear crisis - FT.com - 0 views

www.ft.com/...c8-11e1-a4c4-00144feabdc0.html

shared by Jan Wyllie on 17 Dec 11 - No Cached
  • Japan has succeeded in bringing its tsunami-stricken atomic power station to a safe “cold shutdown”, the government said on Friday, concluding the most dangerous phase of its nuclear crisis after a nine-month struggle.
  • Cold shutdown is a technical term meaning temperatures inside the reactors’ cores are stably below the 100-degree centigrade boiling point. It indicates that a nuclear chain reaction is highly unlikely to recur, though Fukushima Daiichi’s damaged units remain highly radioactive at close range and will remain so for years.
  • A side effect of their early efforts was that tens of thousands of tonnes of contaminated water built up at the site, some of which leaked into the sea.
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  • A government-appointed panel estimated in October that sealing or dismantling the site’s four ruined reactors could cost Y1,100bn, but some government officials and outside experts argue that the true amount could be several times higher.
D'coda Dcoda

Japan heads back to nuclear zero for reactor checkups [02Sep13] - 0 views

www.japantoday.com/...ing-just-one-online-nationwide

japan nuclear power'

shared by D'coda Dcoda on 02 Sep 13 - No Cached
  • D'coda Dcoda on 02 Sep 13
     
    Workers will switch off one of Japan's two working reactors Monday, with the other set for shutdown later this month and no restarts in sight amid continued public hostility to nuclear power.
D'coda Dcoda

The NRC and the 2013 Shutdown - Next Steps [04Oct13] - 0 views

public-blog.nrc-gateway.gov/...d-the-2013-shutdown-next-steps

nuclear energy NRC USA

shared by D'coda Dcoda on 09 Oct 13 - No Cached
  • D'coda Dcoda on 09 Oct 13
     
    U.S. Nuclear Regulatory Commission about to stop operating - Will run out of funds this week - "We sincerely regret these actions are necessary" - Scientist: "Yes, I'm worried"
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