Saturday, April 9, 2011

Fukushima nuclear crisis news update for April 9, 2011

Japan considers wider evacuation zone, but water leak is stopped at reactor site

Fukushima_symbolThe Wall Street Journal reports that the Japanese government is considering extending the evacuation zone around the devastated Fukushima nuclear reactor complex.

According to the newspaper, the government is recalculating the risk of radioactivity that continues to be found in areas outside the plant four weeks after Japan's devastating earthquake and tsunami.

Some good news comes via NucNet which reports that workers at the Fukushima nuclear power plant have used 6,000 litres (8 cubic yards) of coagulant to stop a leak from a trench next to the unit 2 inlet point that has been causing highly radioactively contaminated water to flow into the sea since March 29th.

No decision on new evacuation limits yet

The government's top spokesman, Chief Cabinet Secretary Yukio Edano, said April 8 the current 20-kilometer (12-mile) evacuation zone around the Fukushima Daiichi plant may need to be expanded to a larger perimeter.  He said the original boundaries were set to protect against short term exposure to radiation, but with continued releases of radioactive material, the government wants a to look at a bigger protection zone.

Edano said the larger zone is expected to prevent cumulative exposure to radiation than a nuclear plant worker is limited to in a year—50 millisieverts. A one year dose clearly linked to cancer would be 100 millisieverts. At 400 millisiverts of short-term exposure, the acute symptoms of radiation poisoning can become readily apparent.

"Current evacuation orders apply to areas where people are in danger of having received 50 millisieverts [of cumulative exposure]," Mr. Edano said. "We are now looking into what to do with other areas where, with prolonged exposure, people may receive that

The WSJ also reports that two weeks ago, a Japanese government agency released a computer simulation that showed that in the first 12 days after the tsunami, some areas outside the evacuation zone exceeded Japan's recommended cumulative exposure limits.

It isn’t clear whether the government trusts the information sufficiently to make a decision.  TECPO has been plagued with reporting errors in radiation measurements.

The government is clear about local contamination problems within a few miles of the Fukushima plant.

"The [hydrogen] explosions sent radioactive materials flying to areas far outside the nuclear complex," Mr. Nishiyama, of Japan's Nuclear and Industrial Safety Agency, said at a news conference. "Radioactive materials, once spread, cannot be put back. The best we can do is to stabilize the damaged reactors and prevent further emissions of radiation."

Workers Use Coagulant To Stop Fukushima-Daiichi Leak

(NucNet): [April 6] Workers at the Fukushima-Daiichi nuclear power plant have used coagulant to stop a leak from a trench next to the unit 2 inlet point that has been causing highly contaminated water to flow into the sea since March 29th.

Tokyo Electric Power Company (Tepco) said that they used liquid tracer to find the source of the leak in the concrete utility trench and then used the coagulant to seal it. The company said the leak had stopped.

Iodine-131 and Caesium-137 were both detected in water sampled in the trench and in the sea near the water discharge. While the radioactive iodine has a half life of eight days, and degrades to background levels in a few weeks, the half life of cesium-137 is about 30 years.

The water leak was discovered on April 2nd when workers detected water releasing a radiation dose rate of more than 1,000 millisieverts per hour in the trench and found a crack about 20 cm wide on the trench’s concrete wall, from where water was thought to be flowing into the sea. Severe radiation poisoning, in some cases, fatalities, occur at 2,000 millisieverts per hour.

Meanwhile, Tepco has begun discharging into the sea low-level radioactive wastewater stored in sub-drain pits at units 5 and 6 and in a reservoir of the central radioactive waste disposal facility.

Tepco plans to discharge approximately 10,000 tonnes of low-level radioactive water and about 1,500 tonnes of the low-level radioactive subsurface water into the sea. [Water weights 8.4 pounds/gallon.  A metric tonne is 2,240 pounds. Therefore, 10,000 metric tonnes of water = 22,400,000 pounds / 8.4 equals 2.7 million gallons of radioactive water.

The discharge is necessary because workers need to use the reservoirs for storing highly radioactive water from the unit 2 turbine building, where dangerously high levels of radioactivity in water have been found in the turbine building basement. There is a risk that this radioactive water might also flow into the sea.

Tepco said it is concerned that vital equipment needed to secure the safety of the reactors might be submerged if this water is not drained.

The utility is also monitoring an accumulation of hydrogen gas in the primary containment vessel of unit 1 Measures are being taken to avoid a hydrogen explosion similar to the explosion in the primary containment vessel of unit 2.

Removing Contaminated Water Might Take Another Week, NISA Says

(NucNet): Moving highly radioactive water from a turbine building basement at the Fukushima nuclear power plant might not start for another week, Japan’s Nuclear and Industrial Safety Agency (NISA) has said.

The water needs to be moved from the turbine building basement to a storage facility. The water has been hampering work to restore the reactor's cooling systems.

NISA said the facility must be checked for cracks that might have been caused by the earthquake, and that this could take up to a week. The agency said the facility was designed to store low-level radioactive water.

The International Atomic Energy Agency said today that overall, the situation at the plant remains “very serious” although there are early signs of recovery in some functions such as electrical power and instrumentation.

Nitrogen Injection Continues At Unit 1 PCV

(NucNet): The operator of the Fukushima nuclear power plant says it is continuing to inject nitrogen gas into the primary containment vessel (PCV) at unit 1 without any problems.

Injecting nitrogen is intended to displace oxygen inside the PCV, thereby reducing the risk of explosion caused by the combustible combination of hydrogen and oxygen.

Because the containment has already been damaged and pressure inside might drop below atmospheric pressure, there is a risk that outside air containing oxygen could leak into the PCV resulting in the build-up of an explosive hydrogen-oxygen gas mix.

Tepco says it plans to continue the injection for about six days and will also consider taking similar measures at units 2 and 3.

Meltdown no longer seen as likely

The LA Times reported  April 8 that Japan's nuclear crisis ebbing.  The newspaper indicated that although the situation at the Fukushima nuclear plant is far from stabilized, evidence suggests that a complete meltdown is unlikely.

There is no evidence that overheating during the last month has resulted in any melting of the reactor vessels or their containment structures, Obama administration officials said Thursday.

The assessment, provided to The Times on background, suggests that the plant is unlikely to suffer a complete meltdown.

"We are a long way from a point where anybody would say this is stable," a senior administration official said. "But it is not a runaway. For a long time, we will be at a declining level of risk."

Separately, the La Times reported the staff of the NRC came under heavy questioning April 7 by the Advisory Committee on Reactor Safeguards, which is a panel of experts, academics and nuclear industry officials that provides guidance to the agency.

At a committee meeting, NRC officials were asked about the scientific basis for their agency's advice that Americans evacuate a 50-mile zone around the plant. According to the LA Times, NRC officials said they couldn't provide an explanation and would have to get back to the committee. 

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Friday, April 8, 2011

Cleaning up the reactor sites at Fukushima

Getting the water out is the first priority

Fukushima_symbolOver at Atomic Insights blog my friend Rod Adams asks whether the radioactive water at the devastated Fukushima nuclear site in Japan is such a big deal. He writes, “ . . . a million gallons of water is a rather modest amount of water.”

The basis for this dialog is my blog post at the American Nuclear Society blog ANS Nuclear Cafe titled Decommissioning Fukushima which was published April 6th.

Worker safety

In his blog post April 8, Rod says that I’m overly concerned about risk of exposure to the radioactive water by plant workers. Considering that TEPCO initially sent some people on to the damaged site without dosimeters, I am concerned about their safety. That doesn’t mean I am seeking perfection. The Kyodo English news wire service for April 1 reports:

“The government's nuclear regulatory agency said Friday it had issued another warning to Tokyo Electric Power Co. over the management of workers' radiation exposure at the crippled Fukushima Daiichi nuclear power plant, after it was found that there were not enough dosimeters to cover all of the workers.”

Uncontrolled water at Fukushima

The difference at Fukushima is the radioactive water is not inside a reactor cooling circuit. A lot of it is in an uncontrolled state flowing down the sides of buildings into storm drains, into the sea, etc.

Rod says that as a former nuclear submariner, he understands water and that I, as a desert rat from Idaho's Arco lava beds, do not. I agree that Rod certainly has the edge understanding water in nuclear reactors. However, even in “sun-dried Idaho,” when water shows up at a nuclear facilities in a place where it doesn’t belong, it sets off a cascade of communications.

The operator making inspection rounds notifies the shift supervisor who notifies the plant shift supervisor. Radcon is dispatched to survey the water for radioactivity. A system engineer is dispatched to evaluate the situation along with a spill response team.

That’s a summary of plant procedures at a fully staff, undamaged facility. The situation at Fukushima is anything but normal.

What to do about the water

I don’t know what TEPCO is doing about capturing radioactive waste water after fresh water is being sprayed on the spent fuel pool at Unit 4 and on Units 1-3. It seems to just about everyone that doing so would be a good idea.

The amount of fresh water being sprayed just on the spent fuel pool at Unit 4 is estimated to be in the range of 200 tons of water a day. A gallon of water weighs 8.35 pounds which yields [200 * 2000]/8.35 or about 48,000 gallons. Additional amounts of water are being sprayed on Fukushima Units 1-3.

water spraying at FukushimaSo, there is a lot of water and it is not not controlled once it leaves the spray hose from the top of the pumper boom. (see image right – the red “stick is the pumper boom taking water to the damaged secondary containment area over spent fuel pool at Unit 4)

Here are some initial thoughts about where it is going after it hits the reactors.

There is evidence from photographs that there is some loss to evaporation based on steam plumes from Units 2 & 4.

A worst case is that the water cascades to the ground running into storm drains and on to work surfaces at ground level. Also, it may be entering pits, conduit trenches, and other underground spaces. Storm water drains probably discharge into the sea which would account for radioactivity found some distance from the shoreline.

With all of these pathways to the surface, from the spent fuel pool about four stories up in the secondary containment building, it might be difficult to figure out how to curtail the various pathways to pooling on site or flowing out to sea.

Logic would suggest that getting the installed cooling systems inside the reactors working again is the fastest way to stop the uncontrolled flow of radioactive water outside them and around the site. TEPCO will have to find a way to determine the condition of the pumps and piping in order to decide if this is a feasible solution.

There is an interesting news report in the NY Times for April 8 which notes hundreds of engineers from Toshiba / Westinghouse are working on the decommissioning issue. Also, Toshiba said in a Reuters news report it thinks it can complete decommissioning of the four reactors by 2020.

Access issues

Also, Rod says that people and supplies to respond to the damaged reactors can be brought to the site by sea. He’s right about that up to a point since the docks and pilings for the plant were also damaged by the same 15 meter high tsunami that swept over the sea wall.

In that blog post, I wrote that access to Fukushima by road or rail would be a problem due to earthquake damage. The Wall Street Journal for April 6 reports on how a Japanese civil engineering firm used its most experienced crews to clear the roads. Their work started March 16. Hopefully by now some of the debris has been removed from roads. Restoring rail access could taken longer. Rebuilding railroad lines from scratch, including signal equipment, is not easy or quick.

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Thursday, April 7, 2011

Decommissioning Fukushima

It has all the challenges of Three Mile Island plus there are four damaged reactors not just one

300px-Img_kingkong1The effort to contain the nuclear reactor crisis at Fukushima brings to mind the 1933 horror movie King Kong, in which a giant ape, escaped from captivity, and perched at the top of the Empire State Building, is fatally wounded by a swarm of war planes of the era.

While fictional film character Carl Denham intones his famous last line “It was beauty killed the beast,” a less prosaic New York sanitation department might have been wondering how to remove a giant dead gorilla carcass from the corner of 5th Ave. and 34th St.  (King Kong image from Wikipedia)

Kong’s fall would have created a cleanup problem of  immense scale. It would have been “beyond the design basis” of even the entire fleet of city garbage trucks.

Six gorillas at Fukushima

This dramatic movie metaphor is relevant as a visual image of the scope of the problem faced by Tokyo Electric Power Corp. (TEPCO) with the eventual decommissioning of six reactors at Fukushima. The utility doesn’t have just one dead giant gorilla, there are six. The first three nuclear reactors are likely to be found to be fatally compromised with heat damaged fuel assemblies from loss of cooling water.  Partial melting of fuel may be part of the problem.

Massive hydrogen explosions blew the roofs off of secondary containment structures at reactors 1, 3, and 4. The fourth reactor is also likely severely damaged beyond repair. Its spent fuel pool is exposed to the open air as a result of one of the huge hydrogen explosions.

The fifth and sixth reactors, relatively undamaged, may never restart because of wrecked balance of plant infrastructure and ferocious public opposition which is leveraged by Japanese law that gives veto power over nuclear facilities to the provincial government.

BWR reactor schematic. Image from World Nuclear Association

The 15-meter high tsunami swept away the normal infrastructure of a nuclear power station which, along with rubble from the hydrogen explosions, put debris across access roads and rail sidings blocking delivery of emergency equipment.

Efforts to control leaks from buildings and trenches may go on for months or years. In short, it will be a very dangerous place to conduct cleanup work.

Read the full story exclusively at ANS Nuclear Cafe online now.

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Wednesday, April 6, 2011

NRC threat assessment of Fukushima risks

The 15 page document provides recommendations on how to mitigate them

Fukushima_symbolThe New York Times reports today that a March 26 threat assessment by the Reactor Safety Team of the Nuclear Regulatory Commission (NRC) warns that the crippled nuclear plant faces fresh threats that could persist indefinitely.

The newspaper reports that in some cases risks are expected to increase as a result of the very measures being taken to keep the plant stable, according to a confidential assessment prepared by the Nuclear Regulatory Commission.

This blog has obtained the NRC assessment from a source outside the government Click here for a copy in PDF format.

Tweet this link: http://tinyurl.com/Fuku-RPV

Note that because of the way the document was scanned it appears to be upside down. Just print out the 15 page report to read it right side up. If you are using Adobe Reader, you can rotate the image to right side up.

New threats for old

The New York Times reports that among the new threats that were cited in the assessment are new levels of stress on the containment structures as they fill with radioactive cooling water. The NRC assessment says that in a worst case scenario, the reactor primary containment structures could break open from earthquake aftershocks.

While the assessment notes that it impossible to inspect the reactor pressure vessels directly, it does not speculate that there is a breach of any of them at the time the assessment was completed (March 26).

U.S. Rep. Ed Markey is claiming in a press release April 6 that the reactor pressure vessel at Unit 1 has been breached and that melted fuel assemblies are on the floor of the primary containment building. He cites the NRC as the source of his information.

Markey said in his press statement, “The cores of at least two of the Japanese reactors are severely damaged. I have been informed by the Nuclear Regulatory Commission that the core of Unit Two has gotten so hot that part of it has probably melted through the reactor pressure vessel.”

The Wall Street Journal reported April 6 that the Nuclear Regulatory Commission disputed Markey's claim.

Martin Virgilio, deputy executive director for reactor and preparedness programs at NRC, said the regulator believes there was significant fuel damage in all three reactors and the four spent fuel pools.

"But we don't believe at this point in time that that core has left the vessel," he said. "That's not in the situation report that we have from the team in Japan, and that's as of this morning."

Update: On April 7 the New York Times in new coverage of the issue indicated there were several "speculative" scenarios of core breach for unit 2.

Control of Hydrogen

The NRC document reviewed by the New York Times also cites the possibility of new explosions inside the containment structures due to the release of hydrogen and oxygen from seawater pumped into the reactors. According to the newspaper, the document offers new details on how semi-molten fuel rods and salt buildup are impeding the flow of fresh water meant to cool the nuclear cores.

Water cooling to continue

water spraying at Fukushima According to the newspaper, experts have said the Japanese need to continue to keep the fuel cool for months.

The steps recommended by the NRC include injecting nitrogen, an inert gas, into the containment structures in an attempt to purge them of hydrogen and oxygen, which could combine to produce new explosions.

On April 6, the Tokyo Electric Power Company, which owns the plant, said it was preparing to inject nitrogen into one of the reactor containment vessels.

No new criticality incident likely

The document also recommends that engineers continue adding boron to cooling water to help prevent the cores from restarting the nuclear reaction, a process known as criticality.

According to the New York Times, the engineers who prepared the document do not believe that a resumption of criticality is an immediate likelihood, Neil Wilmshurst, vice president of the nuclear sector at the Electric Power Research Institute, when contacted about the document, told the newspaper. “I have seen no data to suggest that there is criticality ongoing.”

The newspaper reports that the document was prepared for the commission’s Reactor Safety Team, which is assisting the Japanese government and the Tokyo Electric Power Company. It says it is based on the “most recent available data” from numerous Japanese and American organizations, including the electric power company, the Japan Atomic Industrial Forum, the United States Department of Energy, General Electric and the Electric Power Research Institute, an independent, nonprofit group.

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Tuesday, April 5, 2011

Fukushima reactor status news for April 5, 2011

Update to Information Sheet Regarding the Tohoku Earthquake

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office

As of 11:30AM (EST), April 5, 2011

  • Radiation Levels
    • The concentration of radioactive nuclides from the seawater sampled at the screen device (installed to remove waste before the intake of seawater) of Unit 2 of Fukushima Daiichi Nuclear Station was as follows:

The details of this report are available at:

http://www.tepco.co.jp/en/press/corp-com/release/11040506-e.html

    • At 6:00PM on April 5, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 112 micro Sv/hour.
    • At 6:00PM on April 5, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 67.4 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 5 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
    • For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
  • Fukushima Daiichi Unit 1 reactor
    • At 6:00AM on April 5, pressure inside the reactor core: 0.308MPa.
    • At 6:00AM on April 5, water level inside the reactor core: 1.7 meters below the top of the fuel rods.
    • At 6:00AM on April 5, pressure inside the primary containment vessel: 0.15MPaabs.
    • At 6:00AM on April 5, the temperature of the reactor vessel measured at the water supply nozzle: 452.3 degrees Fahrenheit.
    • At 7:20AM on April 5, the temperature directly above the spent fuel pool by thermography measurement: 64.4 degrees Fahrenheit.
    • At 7:20AM on April 5, the temperature directly above the primary containment vessel by thermography measurement: 78.8 degrees Fahrenheit.
    • As of 7:00PM on April 5, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on April 5, preparation to recover and transfer the accumulated water at the turbine building continues.
  • Fukushima Daiichi Unit 2 reactor
    • At 6:00AM on April 5, pressure inside the reactor core: -0.018MPa.
    • At 6:00AM on April 5, water level inside the reactor core: 1.5 meters below the top of the fuel rods.
    • At 6:00AM on April 5, pressure inside the primary containment vessel: 0.10MPaabs.
    • At 6:00AM on April 5, the temperature of the reactor vessel measured at the water supply nozzle: 287.1 degrees Fahrenheit.
    • At 6:00AM on April 5, the temperature of the spent fuel pool: 159.8 degrees Fahrenheit.
    • At 7:20AM on April 5, the temperature directly above the second containment building by thermography measurement: 82.4 degrees Fahrenheit.
    • At 2:15PM on April 5, TEPCO announced that the tracer (white colored dye) was observed entering the ocean through a crack on the lateral surface of the pit (a vertical portion of an underground structure for housing electric cables) near the seawater intake.
    • At 3:07PM on April 5, TEPCO began injecting coagulator into the soil around the pit in an attempt to stop the discharge of water.
    • As of 7:00PM on April 5, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on April 5, preparation to recover and transfer the accumulated water at the turbine building continues.
  • Fukushima Daiichi Unit 3 reactor
    • At 7:20AM on April 5, the temperature directly above the spent fuel pool by thermography measurement: 132.8 degrees Fahrenheit.
    • At 7:20AM on April 5, the temperature directly above the primary containment vessel by thermography measurement: 64.4 degrees Fahrenheit.
    • At 10:20AM on April 5, pressure inside the reactor core: 0.005MPa.
    • At 10:20AM on April 5, water level inside the reactor core: 1.85 meters below the top of the fuel rods.
    • At 10:20AM on April 5, pressure inside the primary containment vessel: 0.1071MPaabs.
    • At 10:20AM on April 5, the temperature of the reactor vessel measured at the water supply nozzle: 184.5 degrees Fahrenheit. (This figure is under investigation.)
    • As of 1:30PM on April 5, approximately 4,978 tons of water in total has been shot into the spent fuel storage pool.
    • As of 7:00PM on April 5, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on April 5, preparation to recover and transfer the accumulated water at the turbine building continues.
  • Fukushima Daiichi Unit 4 reactor
    • At 7:20AM on April 5, the temperature directly above the spent fuel pool by thermography measurement: 122 degrees Fahrenheit.
    • At 5:35PM on April 5, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 6:22PM.
  • Fukushima Daiichi Unit 5 reactor
    • At 1:00PM on April 5, the temperature of the spent fuel pool: 94.6 degrees Fahrenheit.
  • Fukushima Daiichi Unit 6 reactor
    • At 1:00PM on April 5, the temperature of the spent fuel pool: 81.5 degrees Fahrenheit.
  • Fukushima Daiichi Common Spent Fuel Pool
    • At 7:10AM on April 5, the temperature of the spent fuel pool: 84.2 degrees Fahrenheit.

Our official sources are:

  • Office of The Prime Minister of Japan
  • Nuclear and Industrial Safety Agency (NISA)
  • Tokyo Electric Power Company (TEPCO) Press Releases
  • Ministry of Education, Culture, Sports, Science and Technology (MEXT)

++++++++++++++++++++++++++++++++

Taro Ishida

The Federation of Electric Power Companies of Japan
1901 L Street, NW Suite 600
Washington, DC 20036

Mobile (202) 253-2579

Phone (202) 530-0769 (Direct)
Phone (202) 466-6781
Fax (202) 466-6758

email: ishida@denjiren.com

+++++++++++++++++++++++++++++++++

Monday, April 4, 2011

Post Fukushima future of nuclear energy

Three important reasons why the U.S. new build will continue

Back by popular demand Prognosticators of financial doom and gloom for the future of construction of new nuclear power plants in the U.S. say they have plenty of evidence to bolster their case. The main Japanese utility responsible for trying to control the disaster has itself demonstrated at times confusion in resolving problems.

Financial analysts say if the leading utility in Japan, a nation strongly committed to nuclear energy, can't control its reactors, what does it say about the global industry?

Of course, they fail to mention that six reactors at Fukushima were taken out of service by the combination of a 9.0 earthquake and a 15 meter high tsunami. Is it any wonder the utility, which has asked for international help, is at times overwhelmed by the damage?

The view of naysayer groups is open to question based on three factors.

  • First, the Obama administration continues to be committed to nuclear energy. In the first week following the Fukushima accident, President Obama spoke out repeatedly on the issue.
  • Second, the Department of Energy said it would continue to evaluate new nuclear reactor projects for federal loan guarantees.
  • Third, a Gallop Poll taken in late March showed steady support for nuclear energy with little change from similar polls a decade ago.

Read the complete story exclusively at Cool Hand Nuke, a nuclear energy jobs portal and a whole lot more.

coolhandnuke

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Fukushima reactor status news for April 4, 2011

Includes press release from TEPCO on discharge of radioactive water to ocean

FukushimaFukushimaUpdate to Information Sheet Regarding the Tohoku Earthquake

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office

As of 11:30AM (EST), April 4, 2011

  • Radiation Levels
    • The level of concentration of radioactive nuclide I-131 (2.5 x 101 Bq/cm3) from the seawater sampled near the seawater discharge point of Fukushima Daiichi Nuclear Station at 1:50PM (JST) on April 3 was approximately 625 times higher than the maximum permissible water concentration (4.0 x 10-2 Bq/cm3) set by the government.
    • On April 4, TEPCO announced that it will discharge 10,000 tons of low level radioactive water stored at the Central Radioactive Waste Disposal Facility in order to accommodate higher level radioactive water. It will also discharge 1,500 tons of low level radioactive water which had accumulated at the sub-drain pits of Unit 5 and 6 in order to prevent important equipment of Unit 5 and 6 from being submerged.
    • The original TEPCO press release is attached and also available at:

http://www.tepco.co.jp/en/press/corp-com/release/11040404-e.html

(At 9:30PM on April 4, NHK reported the discharge of water from the Central Radioactive Waste Facility has commenced around 7:00PM and from the sub-drain pits at 9:00PM.)

    • At 6:00PM on April 4, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 118 micro Sv/hour.
    • At 6:00PM on April 4, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 72.1 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 4 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
    • For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
  • Fukushima Daiichi Unit 1 reactor
    • On April 2, lighting was restored at the part of the turbine building.
    • At 7:20AM on April 4, the temperature of the spent fuel pool by thermography measurement: 64.4 degrees Fahrenheit.
    • At 11:00AM on April 4, pressure inside the reactor core: 0.299MPa.
    • At 11:00AM on April 4, water level inside the reactor core: 1.65 meters below the top of the fuel rods.
    • At 11:00AM on April 4, pressure inside the primary containment vessel: 0.15MPaabs.
    • At 11:00AM on April 4, the temperature of the reactor vessel measured at the water supply nozzle: 469.0 degrees Fahrenheit.
    • As of 3:00PM on April 4, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on April 4, preparation to recover and transfer the accumulated water at the turbine building continues.
  • Fukushima Daiichi Unit 2 reactor
    • On April 2, lighting was restored at the part of the turbine building.
    • On April 2, monitoring cameras were set at the trench outside the turbine building and at the basement floor of the turbine building to monitor the water levels.
    • At 9:30AM on April 2, the accumulated water was found in the pit (a vertical portion of an underground structure for housing electric cables) near the seawater intake and the radiation level of the water was over 1,000 milli Sv/hour. In addition, the water was observed entering the ocean from a crack (about 20cm = 7.9 inches) on the lateral surface of the pit.
    • At 4:25PM on April 2, concrete was injected into the pit in an attempt to stop the discharging of water. (injected again at 7:02PM)
    • At 1:47PM on April 3, polymer absorber, sawdust, and shredded newspapers were inserted in the pit in an attempt to stop the overflow of the discharge of water, until 2:30PM.
    • At 7:08AM on April 4, tracer (white colored bath agent) was inserted into the trench outside the turbine building to determine the route of the water leakage.
    • At 11:00AM on April 4, pressure inside the reactor core: -0.018MPa.
    • At 11:00AM on April 4, water level inside the reactor core: 1.5 meters below the top of the fuel rods.
    • At 11:00AM on April 4, pressure inside the primary containment vessel: 0.10MPaabs.
    • At 11:00AM on April 4, the temperature of the reactor vessel measured at the water supply nozzle: 282.2 degrees Fahrenheit.
    • At 11:00AM on April 4, the temperature of the spent fuel pool: 122 degrees Fahrenheit.
    • As of 3:00PM on April 4, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on April 4, preparation to recover and transfer the accumulated water at the turbine building continues.
  • Fukushima Daiichi Unit 3 reactor
    • On April 2, lighting was restored at the part of the turbine building.
    • At 9:52PM on April 2, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 12:54PM (approximately 75 tons in total).
    • At 7:20AM on April 4, the temperature of the spent fuel pool by thermography measurement: 134.6 degrees Fahrenheit.
    • At 9:30AM on April 4, pressure inside the reactor core: 0.005MPa.
    • At 9:30AM on April 4, water level inside the reactor core: 1.75 meters below the top of the fuel rods.
    • At 9:30AM on April 4, pressure inside the primary containment vessel: 0.1069MPaabs.
    • At 9:30AM on April 4, the temperature of the reactor vessel measured at the water supply nozzle: 194 degrees Fahrenheit. (This figure is under investigation.)
    • As of 3:00PM on April 4, the injection of freshwater into the reactor core continues.
    • At 5:03PM on April 4, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete.
    • As of 7:00PM on April 4, preparation to recover and transfer the accumulated water at the turbine building continues.
    • As of 7:00PM on April 4, approximately 4,908 tons of water in total has been shot into the spent fuel storage pool.
  • Fukushima Daiichi Unit 4 reactor
    • On April 2, lighting was restored at the part of the turbine building.
    • At 5:14PM on April 3, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 10:16PM (approximately 180 tons in total).
    • At 7:20AM on April 4, the temperature of the spent fuel pool by thermography measurement: 86 degrees Fahrenheit.
    • As of 7:00PM on April 4, approximately 1,473.2 tons of water in total has been shot into the spent fuel storage pool.
  • Fukushima Daiichi Unit 5 reactor
    • At 2:00PM on April 4, the temperature of the spent fuel pool: 94.3 degrees Fahrenheit.
  • Fukushima Daiichi Unit 6 reactor
    • At 2:00PM on April 4, the temperature of the spent fuel pool: 70.7 degrees Fahrenheit.
  • Fukushima Daiichi Common Spent Fuel Pool
    • At 8:10AM on April 3, the temperature of the spent fuel pool: 89.6 degrees Fahrenheit.
  • Others
    • At 9:10AM on April 2, a US Military barge (No.2) carrying freshwater docked at the dedicated port at Fukushima Daiichi Nuclear Power Station, towed by a vessel of the Marine Self Defense Forces.
    • At 10:20AM on April 2, transferring freshwater from the US Military barge (No.1) to a filtrate tank resumed, until 4:40PM.
    • At 12:12PM on April 4, a US Military barge (No.2) carrying freshwater docked again at the dedicated port at Fukushima Daiichi Nuclear Power Station, after refilling the freshwater.

Our official sources are:

  • Office of The Prime Minister of Japan
  • Nuclear and Industrial Safety Agency (NISA)
  • Tokyo Electric Power Company (TEPCO) Press Releases
  • Ministry of Education, Culture, Sports, Science and Technology (MEXT)

TEPCO Press Release

Press Release (Apr 04,2011) Discharge of low level radioactive accumulated water in the Fukushima Daiichi Nuclear Power Station to the sea(2nd Release)

There is currently great amount of radioactive waste water in the turbine buildings of the Fukushima Daiichi Nuclear Power Station and especially the turbine building of Unit 2 has extremely high level radioactive waste water.

We think it is necessary to transfer the radioactive waste water to the Central Radioactive Waste Disposal Facility in order to store it in a stable condition. However, ten thousand of low level radioactive waste water has been already stored and we have to discharge the existing low level radioactive waste water to receive new liquids.

In addition, as low radioactive subsurface water is piling up in sub-drain pits of Unit 5 and 6 and a part of subsurface water is running into buildings, we are concerned that important equipment to secure the safety of reactors will be submerged.

Based on the Section 1 of the Article 64 of the Nuclear Reactor Regulation Law, we have decided to discharge to the sea approximately ten thousand tons of the accumulated low level radioactive water and a total of 1,500 tons of the low level radioactive subsurface water stored in the sub drain pits of Unit 5 and 6 as soon as we get ready.

We evaluate approximately 0.6 mSv of effective radioactive doses per year for adults as the impact on the discharge of the low radioactive waste water to the sea if they eat adjacent fish and seaweeds every day. The amount (0.6 mSv of effective radioactive doses per year) is one-fourth of annual radioactive dose to which the general public is exposed in nature.

Afterwards, we were preparing to discharge the low radioactive waste water to the sea. We intend to start to discharge the low radioactive waste water stored in the Central Radioactive Waste Disposal Facility to the sea at 7:00 pm today on April 4th. In addition, at 9:00 pm today on April 4th, we intend to start to discharge the low level radioactive subsurface water stored in the sub drain pits to the sea.

---------------------------

FEPC Transmittal 4/4/11

Dear Friends,

Please find the updated information sheet below and attached that summarizes the events from Update-18 at 11:00AM on 4/1.

For your reference, JAIF (Japan Atomic Industrial Forum) has been posting the translation of news reports on their website.

http://www.jaif.or.jp/english/

Please direct any questions regarding this document to me, Ishida@denjiren.com or Samuel Lederer, Researcher of FEPC at lederer@denjiren.com.

++++++++++++++++++++++++++++++++

Taro Ishida

The Federation of Electric Power Companies of Japan
1901 L Street, NW Suite 600
Washington, DC 20036

Mobile (202) 253-2579

Phone (202) 530-0769 (Direct)
Phone (202) 466-6781
Fax (202) 466-6758

email: ishida@denjiren.com

+++++++++++++++++++++++++++++++++

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Sunday, April 3, 2011

Impact of MOX Fuel at Fukushima

A plain English explanation

MOX fuel word cloudBased on alarms raised by scientists in Japan and elsewhere about the use of mixed oxide fuel (MOX) in the Fukushima reactor #3, the American Nuclear Society (ANS) published a technical brief on the issue on March 25, 2011. It contains factual information on the impact of mixed oxide fuel use at Fukushima Daiichi.

There are two key points that emerge from the ANS Technical Brief which was prepared by ANS members contributing their expertise as individuals and not on behalf of their respective employers. The paper is being published online by the ANS Special Committee on Nuclear Nonproliferation.

No significant impact on reactor cooling or releases of radioactivity

Mixed Oxide (MOX) fuel has been used safely in nuclear power reactors for decades. The presence of a limited number of MOX fuel assemblies at Fukushima Daiichi Unit 3 has not had a significant impact on the ability to cool the reactor or on any radioactive releases from the site due to damage from the earthquake and tsunami.

Less than 6% of fuel in core was MOX

At the time of the magnitude 9.0 earthquake, Fukushima Daiichi Unit 3 was operating with 32 mixed oxide (MOX) fuel assemblies and 516 low enriched uranium (LEU) fuel assemblies in its reactor core. In other words, less than 6 percent of the fuel in the Unit 3 core was MOX fuel. There were no other MOX fuel assemblies (new, in operation or used) at the Fukushima Daiichi plant at the time of the accident.

& & &

A summary set of talking points, based on the technical brief, is online at the ANS Nuclear Cafe which includes an extended Q&A about MOX fuel at Fukushima.

Please circulate the summary and link to the blog post to colleagues and interested persons.

Media inquiries should be directed to Clark Communications at (301) 987-7113

Questions about ANS should be directed to Laura Scheele in the ANS Outreach Dept. at (708) 579-8224

The full text of the ANS MOX paper is online at the ANS website.

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