Posts Tagged ‘Fukushima Dai-ichi nuclear plant’

Fukushima radioactive water leakage now stopped

April 5, 2011

Update! BBC:

A leak of highly radioactive water into the Pacific Ocean from Japan’s crippled Fukushima Daiichi nuclear plant has been stopped, its operator reports. Tepco said it had injected chemical agents to solidify soil near a cracked pit, from where the contaminated water had been seeping out.

TEPCO reports the first signs that at least one of the leaks has been found and that preventive measures seem to be having some effect according to NHK:

TEPCO has injected a hardening agent beneath a leaking concrete pit in a bid to stem the flow of highly radioactive water into the sea. The firm says the leakage seems to be decreasing, following the infusion of the hardening agent.

The utility showed reporters a photo of the leak on Tuesday evening, saying it indicates such a decrease. TEPCO said it will infuse another 1,500 liters of liquid glass. Tokyo Electric Power Company started infusing liquid glass into gravel below the pit near the Number 2 reactor at 3 PM on Tuesday.

Leakage - before and after: screen shot from NHK

TEPCO spotted a crack in the pit 3 days ago while trying to find the source of the leakage of contaminated water into the Pacific Ocean. Since then, the utility has tried in vein to seal the pit with concrete, or to plug piping leading into it with a polymer mixture. A test using a dye agent showed the possibility that the radioactive water is leaking from a cracked pipe, and then seeping through gravel into the concrete pit.

TEPCO is planning to board up the breached sections of an offshore dike to prevent the tainted water from spreading further into the sea. It is also considering building underwater barriers at 3 locations, including one near a water intake for the Number 2 reactor

Fukushima Dai-ichi – Tracing the leaks

April 4, 2011

Fukushima Dai-ichi reactors #1 to 4 will never operate again. Politically, it is difficult to see how reactors #5 and 6 could be brought back into operation though technically it may well be feasible. But right now the focus is on finding where exactly the radiation leaks are coming from. The process of tracing all leaks and gradually bringing them all under control is likely to take months rather than weeks.

Some of the nuclear hysteria is dying down and some media attention is returning to the people affected by the quake and the tsunami. And nobody has received anything like a fatal dose of radiation from Fukushima.

And mentioning Fukushima in the same breath as Hiroshima and Nagasaki (which our instant media pundits are inclined to do) is obscene.

TEPCO seems to be getting its house in order and perhaps the efforts of Chairman Tsunehisa Katsumata are having some effect.

Update from NHK:

TEPCO, is continuing its efforts to identify the exact route of the highly radioactive water flowing into the Pacific from its damaged Fukushima Daiichi nuclear power complex.

TEPCO poured a white liquid into a tunnel leading to a concrete pit where the contaminated water is leaking through a crack. This operation was undertaken to determine the exact route the water is taking to the ocean from the pit, located near the plant’s Number 2 reactor.

Monday’s work follows a failed attempt on Sunday to stop the flow of contaminated water by injecting a polymer absorbent into a duct connecting the tunnel with the pit. TEPCO says it will inject the chemical again to block the duct as soon as it has identified the leakage route.

The utility company has also been working on removing radioactive water from the basements of the turbine buildings for two of the plant’s reactors.

The radioactive water in the condensers for the two reactors is being transferred to storage tanks. As soon as the condensers are emptied, the water from the reactor will be drained into them to allow work to begin to restore the reactors’ cooling systems.

Work to remove the water was begun on Sunday at reactors Number 1 and 2. A similar operation will start at the Number 3 reactor on Monday.

As a temporary measure, the Nuclear and Industrial Safety Agency is considering setting up silt barriers near a water intake for the Number 2 reactor.

Fukushima reactors coped with the massive quake but were overwhelmed by the tsunami wave

April 2, 2011

It is becoming increasingly clear that the Fukushima nuclear plant successfully withstood quake accelerations which were somewhat higher than had been designed for but the real damage came from the tsunami which overwhelmed the defences of the plant and then knocked out all the emergency generators (13 of them in the basement apparently). That in turn knocked out all cooling pumps and cooling functions and then the die was cast…..

Latest IAEA updates on the Fukushima nuclear accident.

image IAEA - credit Google Earth

From JAIF:

The chief executive of General Electric has stressed that the GE reactors at the Fukushima Daiichi nuclear plant have no structural problems. Jeff Immelt spoke to NHK and other media outlets on Thursday. Some observers say the No. 1 and 2 reactors, the oldest types at the plant, have a flaw in their designs. He said the GE reactor has been in service for more than 40 years and is well tested and well-designed and has been upgraded over time. Immelt said in Washington on Thursday that he was aware of the doubts expressed about nuclear power plants. But  he said it is necessary to diversify energy sources at a time of rising oil prices. In the United States, more than 20 reactors are in use that have similar structure to the Fukushima No. 1 and 2 reactors. Questions were raised about their safety after the Fukushima reactors were damaged last month.

Meanwhile TEPCO released further information about the forces measured during the quake:

TEPCO says 3 of the plant’s 6 reactors were shaken on March 11th by tremors exceeding forces they were designed to withstand. Reactor No.2 suffered the largest horizontal ground acceleration of 550 gals, which is 26 percent stronger than the reactor’s design limit.

(A gal – is named after Galileo Galilei (1564-1642) – and is a unit of acceleration equal to 1 centimetre per second per second – 1 cm /s/s)

TEPCO says the readings were 548 gals at the No.5 reactor, about 21 percent higher than its design limit; and 507 gals at the No.3 reactor, topping the capacity by about 15 percent. The power company says the strength of ground motions were close to or within the design parameters at the remaining 3 reactors, and at all 4 reactors of the nearby Fukushima Daini nuclear plant.
The utility says it had been planning to reinforce the reactors so they could withstand horizontal shaking of 600 gals, after the government reviewed their quake-resistance standards 5 years ago. But the work was not finished.

In the event strengthening the earthquake resistance would not have helped. By all accounts the tsunami wave was more than twice the height of the existing wall defences.

Reactors 3 and 4: image TEPCO

TEPCO stocks are on their way to losing all value

March 30, 2011

Shares in Tokyo Electric, commonly known as TEPCO, dropped another 17.7 percent on Wednesday to 466 yen and trading was later stopped.

Chart: tepco stock 20110330

It seems inevitable that TEPCO stocks will lose all their value and will be driven to zero – unless nationalisation comes first. Now even the largest shareholders are being hit:

Shares in TEPCO’s main bank, Sumitomo Mitsui Financial Group , which is also a large shareholder with a 2.7 percent holding, fell 2.1 percent.
Dai-ichi Life Insurance , which is the second-largest shareholder in TEPCO with 4.1 percent stake, rose 3 percent after Deutsche Securities said the impact of TEPCO stock price fall is limited on its embedded value, a measure of an insurer’s worth that includes the present value of future earnings from life insurance contracts.  However, Dai-ichi shares have fallen 18 percent compared with a 10.3 percent decline in the benchmark Nikkei 225 index .

There is a vacuum in the leadership of TEPCO. The President of TEPCO Masataka Shimizu has been hospitalized for high blood pressure and dizziness. Chairman Tsunehisa Katsumata will take over operation of the power company. He is 70 years old and faces an unenviable task.

Tsunehisa Katsumata: kyoto photo

Tsunehisa Katsumata served as President of Tokyo Electric Power Co., Inc., from October 2002 to June 2008. Mr. Katsumata has been the Chairman of Tokyo Electric Power Co. Inc., since June 2008. Mr. Katsumata serves as Chairman of the Board of Federation Of Electric Power Companies of Japan. He has been an Outside Director of Sompo Japan Insurance Inc. and NKSJ Holdings, Inc. since April 1, 2010. Mr. Katsumata has been a Director of Tokyo Electric Power Co., Inc. since June 1996. He serves as an Outside Director at KDDI Corp. He serves as Chairman of Evaluation Committee at Japan Finance Corporation.

TEPCO leadership in disarray as share price drops to 47 year low and Government considers nationalisation

March 29, 2011

TEPCO staff along with SDF forces, police and firefighters at the Fukushima Dai-ichi nuclear plant are making heroic efforts to get the radiation leakages under control. But they are being let down by the leadership of TEPCO. And the performance of their President  Masataka Shimizu has particularly come in for much criticism.

The company’s stock price dropped 18 % today as shares reached their lowest level in 47 years. TEPCO has dropped to about 20% of the value it had a few weeks ago. The total liabilities that TEPCO may have to face are a long way ftom being known and could exceed $25 billion. As a corporation they could not survive and the Japanese government is considering the nationalisation of just the Fukushima Dai-ichi plant as well as the nationalisation of the entire company as possible options. In any event there is little chance of the current stock holders of TEPCO  ever getting any return or even of holding on to any significant value in their ownership.

BBC reports:

Speculation is growing that the Japanese government may start talks to nationalise Tokyo Electric Power, which owns the Fukushima nuclear plant.

The company has said it will need to raise about $25bn (£15.6bn) to shore up its finances. The talk of Tepco being nationalised has been fuelled by a statement from cabinet minister Koichiro Gemba to the Reuters news agency that a discussion about bailing out Tepco was possible.

But Chief Cabinet Secretary Yukio Edano said the government was not currently considering a nationalisation. “Although details cannot be seen such as how exactly the government is going to nationalise the company, as long as there are concerns that Tepco may be nationalised, investors don’t want to hold the stock,” said Hajime Nakajima of Cosmo Securities.

On Tuesday a flood of sell orders caused Tepco shares to stop being traded temporarily. A day earlier, the shares dropped to their lowest level in three decades.

Tepco shares have dropped to 566 Yen from a 52 week high of 2,500 Yen.

related: TEPCO was ready to give up and abdicate on 14th March

Fukushima Dai-ichi: Reactor No.2 suppression pool leaking highly radioactive water

March 27, 2011


Very high levels of radiation have been measured in water leaking from reactor #2. It is thought that the breach is in the suppression pool.

TEPCO, says it has measured radiation levels of 2.9 GBq/cc in water from the basement of the turbine building attached to the Number 2 reactor. The level of contamination is about 1,000 times that of the leaked water already found in the basements of the Number 1 and 3 reactor turbine buildings. The measurements indicated 2.9 GBq/cc iodine-134, 13 MBq/cc of iodine-131, and 2.3 MBq /cc for each of cesium 134 and 137. This is clear evidence that fission is continuing.

University of Tokyo graduate school professor Naoto Sekimura says the leak may come from the suppression chamber of the Number 2 reactor, which is known to be damaged. The chamber is designed to contain overflows of radioactive substances from the reactor.

All workers have been evacuated from the reactor #2 building.

Fukushima Dai-ichi nuclear plant: Reactor vessel integrity may be compromised

March 26, 2011

Leakage of water with high levels of radioactivity  raise the possibility that there may be cracks in the reactor containment vessels of Reactors #1,2 and 3.  One saving grace is that the pressure in the vessels remains high and would argue against a breach. However cracks below the water level that permit some water seepage  cannot be ruled out. It is also possible that the leakage of radioactive water is not from the vessel itself but from some of the surrounding valves or piping.

The Guardian:

A suspected break in the core of a nuclear reactor could have been responsible for a leak of large amounts of radioactive contamination at the Fukushima Daiichi power plant, Japanese nuclear safety officials said on Friday, in another setback to efforts to avert disaster at the stricken facility.

In the latest developments, officials have said seawater outside one of the units has registered 1,250 the normal level of radiation, while efforts are under way to pump radioactive water that has pooled around the reactor turbines into safe storage. The BBC has reported that short-term radioactive iodine has been detected at very high levels in the Pacific Ocean near the plant.

US naval barges have started rushing in supplies of fresh water amid concerns the seawater being used to cool down the reactors might be causing corrosion. …

On Thursday three workers were exposed to unusually high levels of radiation after stepping in contaminated water in the turbine building of the crippled No. 3 reactor, which they were trying to cool.

Two received possible beta ray burns to their legs. All three have been transferred to a special radiation treatment facility. Kyodo news reported that the two more seriously injured workers could have suffered internal radiation exposure.

“The contaminated water had 10,000 times the amount of radiation as would be found in water circulating from a normally operating reactor,” said Hidehiko Nishiyama, a spokesman for Japan’s nuclear safety agency.

Nishiyama said it was unlikely that the reactor had cracked, but conceded that the unusually high levels of radiation appeared to have originated from its core. “It is possible there may be damage somewhere in the reactor,” he said, adding that a leak in the plumbing or the vents could also be to blame.

GE BWR cutaway : image

NHK World reports:

A high level of radioactive iodine has been detected in seawater near Japan’s troubled Fukushima Daiichi nuclear power plant. The facility was hit by the March 11th earthquake and tsunami.

The Nuclear and Industrial Safety Agency said on Saturday that iodine 131 in excess of 1,250 times regulated standards was found in seawater collected 330 meters south of a plant water outlet at 8:30 AM on Friday.

The agency says there is no immediate threat to people within the 20-kilometer evacuation zone. The agency adds that as seawater is dispersed by ocean currents the contamination level will decline.

Iodine 131 at146.9 times regulated standards was detected in seawater in the area on Wednesday.

Saturday, March 26, 2011 12:44 +0900 (JST)

Kyodo News:

TEPCO, is currently injecting fresh water into the No. 2 reactor core to prevent crystallized salt from seawater already injected from forming a crust on the fuel rods and hampering the smooth circulation of water, thus diminishing the cooling effect. It has begun injecting fresh water into the No. 1 and No. 3 reactor cores.

At the same time, the firm is trying to remove pools of water containing highly concentrated radioactive substances that may have seeped from either the reactor cores or the spent fuel pools, while also trying to restore power at the No. 2 reactor.

On Thursday, three workers were exposed to water containing radioactive materials 10,000 times the normal level at the turbine building connected to the No. 3 reactor building. On Friday, a pool of water with similarly highly concentrated radioactive materials was found in the No. 1 reactor’s turbine building, causing some restoration work to be suspended.

Similar pools of water were also found in the turbine buildings of the No. 2 and No. 4 reactors, measuring up to 1 meter and 80 centimeters deep, respectively. Those near the No. 1 and No. 3 reactors were up to 40 cm and 1.5 meters deep. ..

The U.S. Department of Energy said in its radiological assessment released Friday that by comparing aerial measurement data from Thursday with previous measurements, the data indicate peak exposure rates in the western side of the Fukushima plant are lower.


Radioactive water leaks from 3 reactors – fresh water cooling started

March 25, 2011

The path to complete cooling and stability will not be smooth or easy at Fukushima Dai-ichi nuclear plant. New complications and setbacks in Reactors #1,2 and 3 are leading to new strategies and actions. There will no doubt be many more such challenges in the days and weeks ahead.

Update 25th March midnight JST (1600 CET):

TEPCO said Friday it has begun injecting freshwater into the No. 1 and No. 3 reactor cores at the crisis-hit Fukushima Daiichi nuclear plant to enhance cooling efficiency, although highly radioactive water was found leaking possibly from both reactors as well as the No. 2 reactor.

The latest efforts to bring the troubled reactors at the plant under control are aimed at preventing crystallized salt from seawater already injected from forming a crust on the fuel rods and hampering smooth water circulation, thus diminishing the cooling effect, the plant’s operator said.

A day after three workers were exposed to water containing radioactive materials 10,000 times the normal level at the turbine building connected to the No. 3 reactor building, highly radioactive water was also found in the turbine buildings of the No. 1 and No. 2 reactors.

Early Friday, concern grew that the high-level radiation leak detected with the workers’ exposure Thursday could indicate possible damage to the No. 3 reactor vessel, but the government’s nuclear safety agency later denied the possibility, saying no data, such as on the pressure level, have suggested the reactor vessel has cracked or been damaged. The No. 3 reactor used plutonium-uranium mixed oxide fuel for so-called ”pluthermal” power generation.

While the high-level radiation is suspected to have come from the reactor, where overheating fuel rods are believed to have partially melted, it remains uncertain how the leak occurred, said Hidehiko Nishiyama, spokesman for the government’s Nuclear and Industrial Safety Agency.

He said further verification is needed to find out how the radioactive water reached the underground site where the workers were exposed. Huge volumes of water have been poured into the reactor as well as its apparently boiling spent fuel pool since they lost their cooling functions.

In addition to the infusion of freshwater to the No. 1 and No. 3 reactors, it injected seawater to the spent fuel pools of the No. 2 and No. 4 reactors through pipes, and firefighters sprayed a massive amount of seawater onto the No. 3 fuel pool, the utility said.

The government, meanwhile, encouraged residents within 20 to 30 kilometers of the plant to leave voluntarily, citing concerns over access to daily necessities, while maintaining its directives for them to remain indoors and for residents within 20 km of the plant to evacuate.

Fukushima Dai-ichi nuclear plant: Status on March 25th

March 25, 2011

It is 2 weeks today since the quake and Tsunami struck. The toll of dead and missing exceeds 27,000.

Progress continues steadily but painfully slowly at the Fukushima Dai-ichi nuclear plant. The radiation levels are fluctuating but pose no health hazard to the general public. Containment vessel at Reactor #3 is damaged and may be causing radiation spikes.


  • The work to restore external AC power for units-1, 2, 3 and 4 is in progress. External AC power to the main control room at unit-2 will be available today. According to TEPCO, the reactor surface temperature at unit-1 increased to  approx. 400 ° C once (design assumption maximum 302 ° C).  Now it has dropped to 204.5 ° C (as of 06:00 on March 25).
  • Meanwhile,  in the turbine building at unit-3, drainage work is also in progress. (10:45, March 25)
  • On March 24, 2 workers, who were working to lay electrical cables in turbine building at unit-3, were sent to the hospital. TEPCO suspected that the nuclear fuel in the reactor or spent nuclear fuel at the pool was damaged and water contaminated with high radioactivity was leaked  to the workspace. Further investigation is now carrying on. These 2 workers were not wearing boots. Another worker wearing boots is safe. (07:15, March 25).
  • As for the coolant of reactors at Fukushima Daiichi, TEPCO would like to switch from seawater to fresh water as fast as possible. The first switch will be carried out at unit 3. (04:30, March 25)
  • Ministry of Defense announced that the Self-Defense Force helicopter measured the surface temperatures of Fukushima Daiichi units-1, 2, 3 and 4 from the air by using infrared rays and  found that the temperature of each units is below 20 ° C. Unit-1:17 ° C; Unit-2: 13°C; Unit-3: 11 °C; Unit-4: 17 °C (as of the morning on March 24). Especially, the surface temperature of the spent fuel pool at unit-3 dropped significantly to 31 °C, compared to 56°C on the previous day. (21:15, March 24)

From IAEA:

Unit 1: Workers have advanced the restoration of off-site electricity and lighting in the Unit’s main control room was recovered as of 24 March, 11:30 UTC. They are now checking the availability of the cooling system. While the pressure in the reactor vessel remains high, Japanese authorities are reporting that it has stabilized.

Unit 2: Engineers are working for the recovery of lighting in the main control room, and the instrumentation and cooling systems.

Unit 3: Around 120 tonnes of seawater was injected in the spent fuel pool via the cooling and purification line. The operation was carried out between 23 March, 20:35 UTC and 24 March, 07:05 UTC. Work was under way for the recovery of the instruments and cooling systems. However, it had to be suspended because three workers were exposed to elevated levels of radiation on 24 March.

Unit 4: The spent fuel pool was sprayed with around 150 tonnes of water using concrete pump truck. The operation was carried out between 24 March, 05:36 UTC and 06:30 UTC of the same day.

Units 5 and 6: Repair of the temporary pump for Residual Heat Removal (RHR) was completed as of 24 March, 07:14 UTC, and cooling started again 21 minutes later.

At the Common Spent Fuel, the power supply was restored as of 24 March, 06:37 UTC and cooling started again 28 minutes later. Work is now under way for the recovery of the lighting and instrumentation systems. As of 24 March, 09:40 UTC, the water temperature of the pool was around 73 °C.

As of 24 March, 10:30 UTC workers continue to inject seawater into the reactor pressure vessels of Units 1, 2 and 3 and are preparing to inject pure water.


Fukushima Dai-ichi nuclear plant: Reactor #3 control room powered up and cooling pumps to be switched on tomorrow

March 23, 2011

Progress at the Fukushima Dai-ihi nuclear plant continues steadily but slowly.External power is now available to all 6 reactors. Highlights today:

  • A high-powered water cannon truck has arrived from Australia at a US base in Tokyo to help recovery efforts at the Fukushima Daiichi nuclear power plant. The water cannon can shoot 150 liters of water per second at a target 150 meters away. It can also operate unmanned for 2 to 3 days while pumping seawater. It will be sent o Fukushima if needed.
  • A vehicle with a long spraying arm injected water into the No.4 reactor at the troubled Fukushima Daiichi nuclear power plant for about 3 hours on Tuesday. The vehicle, owned by a construction firm in Mie Prefecture in central Japan, began the operation at 5:17 PM Tuesday at the request of the Tokyo Electric Power Company. The vehicle is used in construction of high-rise buildings, and is capable of extending its arm more than 50 meters to pour concrete. The operation ended at about 8:30 PM.

Water spraying into Reactor #4: image nhk

  • Tokyo fire department started operation of spraying water to Unit-3 through cooperation with Osaka fire department. Water spraying  was conducted for one hour and finished around 16:00. Total amount of water sprayed is more than 3 times the pool capacity.
  • TEPCO said on Tuesday that it will restore power to the control rooms of No.3 and No.4 reactors as soon as water-spraying operations are completed to cool down fuel storage pools.
  • Defense Minister Kitazawa announced  that surface temperature measurement by helicopter will be conducted everyday, weather permitting, and not just twice a week in view of the smoke and steam that has been observed.

NHK World:

TEPCO has restored the electricity supply to the control room of the Number 3 reactor at the quake-damaged Fukushima Daiichi nuclear plant. Lights in the control room were switched on again on Tuesday night.
Eleven days have passed since the massive earthquake devastated northeastern Japan and cut off external power to the Fukushima Daiichi nuclear plant.
TEPCO reconnected power cables to the Number 3 and Number 4 reactors earlier on Tuesday.
TEPCO will now try to reactivate vital monitoring systems in the control rooms, such as those for measuring temperatures inside the reactors and water levels in the spent fuel storage pools. TEPCO says it will transmit electricity to the cooling pump for the Number 3 reactor on Wednesday. The company says if the pump functions normally, it will begin cooling the reactor and the spent fuel storage pool

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