DISASTER Fukushima Reactor Disaster: MAIN THREAD - Five Year Anniversary
- Thread starter Red Baron
- Start date
Japan earthquake: Footage of blast at nuclear plant
http://www.bbc.co.uk/news/world-asia-pacific-12721498
Note the supersonic shockwave from this greatly slowed down video.
I believe this was a hydrogen explosion due to the core overheating.
Big fear during Three Mile Island actually happened in Japan this morning.
I think it is fair to say that the situation is out of control at this facility.
http://www.bbc.co.uk/news/world-asia-pacific-12721498
Note the supersonic shockwave from this greatly slowed down video.
I believe this was a hydrogen explosion due to the core overheating.
Big fear during Three Mile Island actually happened in Japan this morning.
I think it is fair to say that the situation is out of control at this facility.
BertaBurtonLake
Inactive
Well, this is going from bad to worse pretty damn quickly.
Here we go sports fans, strap on your hernia belts.
10:59pm Of 90 people from within the 10km exclusion zone around Fukushima nuclear power plant tested, three have given positive results for radiation exposure, says Japanese public broadcaster NHK. That's just over three per cent.
10:54pm Japanese authorities are making plans to distribute iodine to residents near the Fukushima nuclear plant. This helps to protect against radiation poisoning of the thyroid gland.
http://blogs.aljazeera.net/live/asia/live-blog-japan-earthquake
.
10:59pm Of 90 people from within the 10km exclusion zone around Fukushima nuclear power plant tested, three have given positive results for radiation exposure, says Japanese public broadcaster NHK. That's just over three per cent.
10:54pm Japanese authorities are making plans to distribute iodine to residents near the Fukushima nuclear plant. This helps to protect against radiation poisoning of the thyroid gland.
http://blogs.aljazeera.net/live/asia/live-blog-japan-earthquake
.
Z28Camaro6D9
Veteran Member
Thought to be hydrogen explosion. Heavily fortified reactor vessel inside believed to be still intact (for now.) Fuel rods were already slightly exposed from water. Media stating radiation level has actually decreased since explosion, however container building explosion likely took out cranes and other devices necessary to manipulate core material and/or manipulate emergency cooling methods. Evacuation zone moved out to 20 Km. Sea water now being considered for emergency cooling
The area near the plant has just sustained a 6.4 earthquake and now white smoke is being observed coming from a reactor building.
Press Release (Mar 12,2011)
White smoke around the Fukushima Daiichi Nuclear Power Station Unit 1
On March 11, 2011, turbines and reactors of Fukushima Daiichi Nuclear
Power Station Unit 1(Boiling Water Reactor, Rated Output 460 MW) and
Unit 2 and 3 (Boiling Water Reactor, Rated Output 784 MW) that had been
operating at rated power automatically shutdown due to the
Tohoku-Chihou-Taiheiyou-Oki Earthquake.(already announced)
Today at approximately 3:36PM, a big quake occurred and there was a big
sound around the Unit 1 and white smoke.
Our two employees and two subcontract workers working for the safety of
the plant were injured and transported to the hospital.
We are presently checking on the site situation of each plant and effect
of discharged radioactive materials.
We will endeavor to restore the units and continue monitoring the
environment of the site periphery.
http://www.tepco.co.jp/en/press/corp-com/release/11031225-e.html
Press Release (Mar 12,2011)
White smoke around the Fukushima Daiichi Nuclear Power Station Unit 1
On March 11, 2011, turbines and reactors of Fukushima Daiichi Nuclear
Power Station Unit 1(Boiling Water Reactor, Rated Output 460 MW) and
Unit 2 and 3 (Boiling Water Reactor, Rated Output 784 MW) that had been
operating at rated power automatically shutdown due to the
Tohoku-Chihou-Taiheiyou-Oki Earthquake.(already announced)
Today at approximately 3:36PM, a big quake occurred and there was a big
sound around the Unit 1 and white smoke.
Our two employees and two subcontract workers working for the safety of
the plant were injured and transported to the hospital.
We are presently checking on the site situation of each plant and effect
of discharged radioactive materials.
We will endeavor to restore the units and continue monitoring the
environment of the site periphery.
http://www.tepco.co.jp/en/press/corp-com/release/11031225-e.html
mt4design
Has No Life - Lives on TB
Thanks Red.
I went to bed and woke up to news of the quake. Last night, I didn't want to go to sleep fearing the worst with the nuke plants. Woke up to this news...
If momentum was a factor, then it seems all the momentum is going toward the negative. There hasn't been any positive news yet regarding the nuke situation and it seems to get worse and worse as moments pass. It really doesn't look good, does it?
Mike
-----------------------------------------------------------------------------------------
12 March 2011 Last updated at 08:44 ET
Huge blast at Japan nuclear power plant
http://www.bbc.co.uk/news/world-12723092
Richard Black By Richard Black Environment correspondent, BBC News
The word "meltdown" goes to the heart of the big nuclear question - is nuclear power safe?
The term is associated in the public mind with the two most notorious accidents in recent memory - Three Mile Island, in the US, in 1979, and Chernobyl, in Ukraine, seven years later.
You can think of the core of a Boiling Water Reactor (BWR), such as the ones at Fukushima Daiichi, as a massive version of the electrical element you may have in your kettle.
It sits there, immersed in water, getting very hot.
The water cools it, and also carries the heat away - usually as steam - so it can be used to turn turbines and generate electricity.
If the water stops flowing, there is a problem. The core overheats and more of the water turns to steam.
The steam generates huge pressures inside the reactor vessel - a big, sealed container - and if the largely metal core gets too hot, it will just melt, with some components perhaps catching fire.
In the worst-case scenario, the core melts through the bottom of the reactor vessel and falls onto the floor of the containment vessel - an outer sealed unit.
This is designed to prevent the molten reactor from penetrating any further. Local damage in this case will be serious, but in principle there should be no leakage of radioactive material into the outside world.
But the term "in principle" is the difficult one.
Reactors are designed to have "multiply redundant" safety features: if one fails, another should contain the problem.
However, the fact that this does not always work is shown at Fukushima Daiichi.
The earthquake meant the three functioning reactors shut down. But it also removed the power that kept the vital water pumps running, sending cooling water around the hot core.
Diesel generators were installed to provide power in such a situation. They did cut in - but then they cut out again an hour later, for reasons that have not yet been revealed.
In this case, redundancy did not work. And the big fear within the anti-nuclear movement, as used in the film The China Syndrome, is that the multiple containment of a molten core might not work either, allowing highly radioactive and toxic metals to burrow into the ground, with serious and long-lasting environmental impacts - total meltdown.
However, the counter-argument from nuclear proponents is that the partial meltdown at Three Mile Island did not cause any serious effects.
Yes, the core melted, but the containment systems held.
And at Chernobyl - a reactor design regarded in the West as inherently unsafe, and which would not have been sanctioned in any non-Soviet bloc nation - the environmental impacts occurred through explosive release of material into the air, not from a melting reactor core.
To keep things in perspective, no nuclear accident has caused anything approaching the 1,000 fatalities stemming from Friday's earthquake and tsunami.
'Subcritical' reactors
Whether a partial meltdown is under way at Fukushima Daiichi is not yet clear.
The most important factor is summed up in a bulletin from the Tokyo Electric Power Company (Tepco) that owns the facility: "Control rods are fully inserted (reactor is in subcritical status)."
Smoke billowing from Fukushima nuclear plant A large explosion was seen at the plant with debris blow out from the building
Control rods shut off the nuclear reaction. Heat continues to be produced at that stage through the decay of radioactive nuclei - but that process in turn will begin to tail off.
Intriguingly, Ryohei Shiomi, an official at Japan's Nuclear Safety Commission, is widely quoted as having said a meltdown was possible and that officials were checking.
Meanwhile, a visually dramatic explosion in one of the reactor buildings has at least severely damaged the external walls.
In principle, this should not cause leakage of radioactive material because the building is just an outside shell; the job of keeping dangerous materials sealed in falls to the the metal containment vessel inside.
Chief cabinet secretary Chief Yukio Edano confirmed this was the case, saying: "The concrete building collapsed. We found out that the reactor container inside didn't explode."
He attributed the explosion to a build-up of hydrogen, related in turn to the cooling problem.
Under pressure
The only release of any radioactive material that we know about so far concerns venting of the containment vessel.
When steam pressure builds up in the reactor vessel, it stops some of the emergency cooling systems working, and so some of the steam is released into the containment vessel.
However, according to World Nuclear News, an industry newsletter, this caused pressure in the containment vessel to rise to twice the intended operating level, so the decision was taken to vent some of this into the atmosphere.
In principle, this should contain only short-lived radioactive isotopes such as nitrogen-16 produced through the water's exposure to the core. Venting this would be likely to produce short-lived gamma-ray activity - which has, reportedly, been detected.
One factor that has yet to be explained is the apparent detection of radioactive isotopes of caesium.
This is produced during the nuclear reaction, and should be confined within the reactor core.
If it has been detected outside the plant, that could imply that the core has begun to disintegrate.
"If any of the fuel rods have been compromised, there would be evidence of a small amount of radioisotopes in the atmosphere [such as] radio-caesium and radio-iodine," says Paddy Regan, professor of nuclear physics at the UK's University of Surrey.
"The amount that you measure would tell you to what degree the fuel rods have been compromised."
It is an important question - but as yet, unanswered.
Cover-ups and questions
In fact, the whole incident so far contains more questions than answers.
Parallels with Three Mile Island and Chernobyl suggest that while some answers will materialise soon, it may takes months, even years, for the full picture to emerge.
How that happens depends in large part on the approach taken by Tepco and Japan's nuclear authorities.
As with its counterparts in many other countries, Japan's nuclear industry has not exactly been renowned for openness and transparency.
Tepco itself has been implicated in a series of cover-ups down the years.
In 2002, the chairman and four other executives resigned, suspected of having falsified safety records at Tepco power stations.
Further examples of falsification were identified in 2006 and 2007.
In the longer term, Fukushima Daiichi raises several more very big questions, inside and outside Japan.
Given that this is not the first time a Japanese nuclear station has been hit by earthquake damage, is it wise to build such stations along the east coast, given that such a seismically active zone lies just offshore?
And given that Three Mile Island effectively shut down the construction of civilian nuclear reactors in the US for 30 years, what impact is Fukushima Daiichi likely to have in an era when many countries, not least the UK, are looking to re-enter the nuclear industry?
I went to bed and woke up to news of the quake. Last night, I didn't want to go to sleep fearing the worst with the nuke plants. Woke up to this news...
If momentum was a factor, then it seems all the momentum is going toward the negative. There hasn't been any positive news yet regarding the nuke situation and it seems to get worse and worse as moments pass. It really doesn't look good, does it?
Mike
-----------------------------------------------------------------------------------------
12 March 2011 Last updated at 08:44 ET
Huge blast at Japan nuclear power plant
http://www.bbc.co.uk/news/world-12723092
Richard Black By Richard Black Environment correspondent, BBC News
The word "meltdown" goes to the heart of the big nuclear question - is nuclear power safe?
The term is associated in the public mind with the two most notorious accidents in recent memory - Three Mile Island, in the US, in 1979, and Chernobyl, in Ukraine, seven years later.
You can think of the core of a Boiling Water Reactor (BWR), such as the ones at Fukushima Daiichi, as a massive version of the electrical element you may have in your kettle.
It sits there, immersed in water, getting very hot.
The water cools it, and also carries the heat away - usually as steam - so it can be used to turn turbines and generate electricity.
If the water stops flowing, there is a problem. The core overheats and more of the water turns to steam.
The steam generates huge pressures inside the reactor vessel - a big, sealed container - and if the largely metal core gets too hot, it will just melt, with some components perhaps catching fire.
In the worst-case scenario, the core melts through the bottom of the reactor vessel and falls onto the floor of the containment vessel - an outer sealed unit.
This is designed to prevent the molten reactor from penetrating any further. Local damage in this case will be serious, but in principle there should be no leakage of radioactive material into the outside world.
But the term "in principle" is the difficult one.
Reactors are designed to have "multiply redundant" safety features: if one fails, another should contain the problem.
However, the fact that this does not always work is shown at Fukushima Daiichi.
The earthquake meant the three functioning reactors shut down. But it also removed the power that kept the vital water pumps running, sending cooling water around the hot core.
Diesel generators were installed to provide power in such a situation. They did cut in - but then they cut out again an hour later, for reasons that have not yet been revealed.
In this case, redundancy did not work. And the big fear within the anti-nuclear movement, as used in the film The China Syndrome, is that the multiple containment of a molten core might not work either, allowing highly radioactive and toxic metals to burrow into the ground, with serious and long-lasting environmental impacts - total meltdown.
However, the counter-argument from nuclear proponents is that the partial meltdown at Three Mile Island did not cause any serious effects.
Yes, the core melted, but the containment systems held.
And at Chernobyl - a reactor design regarded in the West as inherently unsafe, and which would not have been sanctioned in any non-Soviet bloc nation - the environmental impacts occurred through explosive release of material into the air, not from a melting reactor core.
To keep things in perspective, no nuclear accident has caused anything approaching the 1,000 fatalities stemming from Friday's earthquake and tsunami.
'Subcritical' reactors
Whether a partial meltdown is under way at Fukushima Daiichi is not yet clear.
The most important factor is summed up in a bulletin from the Tokyo Electric Power Company (Tepco) that owns the facility: "Control rods are fully inserted (reactor is in subcritical status)."
Smoke billowing from Fukushima nuclear plant A large explosion was seen at the plant with debris blow out from the building
Control rods shut off the nuclear reaction. Heat continues to be produced at that stage through the decay of radioactive nuclei - but that process in turn will begin to tail off.
Intriguingly, Ryohei Shiomi, an official at Japan's Nuclear Safety Commission, is widely quoted as having said a meltdown was possible and that officials were checking.
Meanwhile, a visually dramatic explosion in one of the reactor buildings has at least severely damaged the external walls.
In principle, this should not cause leakage of radioactive material because the building is just an outside shell; the job of keeping dangerous materials sealed in falls to the the metal containment vessel inside.
Chief cabinet secretary Chief Yukio Edano confirmed this was the case, saying: "The concrete building collapsed. We found out that the reactor container inside didn't explode."
He attributed the explosion to a build-up of hydrogen, related in turn to the cooling problem.
Under pressure
The only release of any radioactive material that we know about so far concerns venting of the containment vessel.
When steam pressure builds up in the reactor vessel, it stops some of the emergency cooling systems working, and so some of the steam is released into the containment vessel.
However, according to World Nuclear News, an industry newsletter, this caused pressure in the containment vessel to rise to twice the intended operating level, so the decision was taken to vent some of this into the atmosphere.
In principle, this should contain only short-lived radioactive isotopes such as nitrogen-16 produced through the water's exposure to the core. Venting this would be likely to produce short-lived gamma-ray activity - which has, reportedly, been detected.
One factor that has yet to be explained is the apparent detection of radioactive isotopes of caesium.
This is produced during the nuclear reaction, and should be confined within the reactor core.
If it has been detected outside the plant, that could imply that the core has begun to disintegrate.
"If any of the fuel rods have been compromised, there would be evidence of a small amount of radioisotopes in the atmosphere [such as] radio-caesium and radio-iodine," says Paddy Regan, professor of nuclear physics at the UK's University of Surrey.
"The amount that you measure would tell you to what degree the fuel rods have been compromised."
It is an important question - but as yet, unanswered.
Cover-ups and questions
In fact, the whole incident so far contains more questions than answers.
Parallels with Three Mile Island and Chernobyl suggest that while some answers will materialise soon, it may takes months, even years, for the full picture to emerge.
How that happens depends in large part on the approach taken by Tepco and Japan's nuclear authorities.
As with its counterparts in many other countries, Japan's nuclear industry has not exactly been renowned for openness and transparency.
Tepco itself has been implicated in a series of cover-ups down the years.
In 2002, the chairman and four other executives resigned, suspected of having falsified safety records at Tepco power stations.
Further examples of falsification were identified in 2006 and 2007.
In the longer term, Fukushima Daiichi raises several more very big questions, inside and outside Japan.
Given that this is not the first time a Japanese nuclear station has been hit by earthquake damage, is it wise to build such stations along the east coast, given that such a seismically active zone lies just offshore?
And given that Three Mile Island effectively shut down the construction of civilian nuclear reactors in the US for 30 years, what impact is Fukushima Daiichi likely to have in an era when many countries, not least the UK, are looking to re-enter the nuclear industry?
Folks, this is a desperate last ditch effort to prevent a full scale meltdown of the stricken reactor.
They are attempting to scuttle the reactor by any means possible. This may result in another hydrogen explosion and also greatly increases the risk of additional radiation leakage.
This is a true emergency as they have to do -anything- right now to prevent a core meltdown. RB
-------
10:29pm The operator of the Fukushima nuclear power plant, Tokyo Electric Power Co, will fill the leaking reactor with sea water to cool it down and reduce pressure in the unit, a government spokesman says. Cabinet secretary Yukio Edano said:
The nuclear reactor is surrounded by a steel reactor container, which is then surrounded by a concrete building.
The concrete building collapsed. We found out that the reactor container inside didn't explode.
Authorities earlier warned of a reactor meltdown at the reactor, damaged when a massive earthquake and tsunami struck the northeast coast, but said the risk of radiation contamination was small.
We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside.
At this point, there has been no major change to the level of radiation leakage outside, so we'd like everyone to respond calmly.
We've decided to fill the reactor container with sea water. Trade minister Kaieda has instructed us to do so. By doing this, we will use boric acid to prevent criticality.
It is expected to take between five and ten hours to fill the reactor core with sea water - and around ten days to complete the process.
Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there.
http://blogs.aljazeera.net/live/asia/live-blog-japan-earthquake
They are attempting to scuttle the reactor by any means possible. This may result in another hydrogen explosion and also greatly increases the risk of additional radiation leakage.
This is a true emergency as they have to do -anything- right now to prevent a core meltdown. RB
-------
10:29pm The operator of the Fukushima nuclear power plant, Tokyo Electric Power Co, will fill the leaking reactor with sea water to cool it down and reduce pressure in the unit, a government spokesman says. Cabinet secretary Yukio Edano said:
The nuclear reactor is surrounded by a steel reactor container, which is then surrounded by a concrete building.
The concrete building collapsed. We found out that the reactor container inside didn't explode.
Authorities earlier warned of a reactor meltdown at the reactor, damaged when a massive earthquake and tsunami struck the northeast coast, but said the risk of radiation contamination was small.
We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside.
At this point, there has been no major change to the level of radiation leakage outside, so we'd like everyone to respond calmly.
We've decided to fill the reactor container with sea water. Trade minister Kaieda has instructed us to do so. By doing this, we will use boric acid to prevent criticality.
It is expected to take between five and ten hours to fill the reactor core with sea water - and around ten days to complete the process.
Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there.
http://blogs.aljazeera.net/live/asia/live-blog-japan-earthquake
Fukushima Daiichi
Unit 1
- 439 MWe BWR, 1971
- Automatically shut down
- Water level decreasing
- Pressure release implemented
- Explosion observed with unknown
effect
- Containment believed intact
- Seawater injection has started
Unit 2
- 760 MWe BWR, 1974
- Automatically shut down
- Water level lower but steady
- Preparations for pressure release
Unit 3
- 760 MWe BWR, 1976
- Automatically shut down
- Preparations for pressure release
Unit 4
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 5
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 6
- 1067 MWe BWR, 1979
- Shut for periodic inspection
Battle to stabilise earthquake reactors
12 March 2011
UPDATE 8: 1.35 pm GMT
Attention is focused on the Fukushima Daiichi and Daini nuclear power plants as Japan struggles to cope in the aftermath of its worst earthquake in recorded history. An explosion has been seen at the site and seawater is now being injected to the plant.
Three of Fukushima Daiichi's six reactors were in operation when yesterday's quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. These suddenly stopped about an hour later, and this has been put down to tsunami flooding by the International Atomic Energy Agency (IAEA).
The loss of the diesels led the plant owners Tokyo Electric Power Company (Tepco) to immediately notify the government of a technical emergency situation, which allows officials to take additional precautionary measures.
For many hours the primary focus of work at the site was to connect enough portable power modules to fully replace the diesels and enable the full operation of cooling systems.
Pressure and releases
Without enough power for cooling systems, decay heat from the reactor cores of units 1, 2 and 3 has gradually reduced coolant water levels through evaporation. The consequent increase in pressure in the coolant circuit can be managed via pressure release valves. However, this leads to an increase in pressure within the reactor building containment. Tepco has said that the pressure within the containment of Fukushima Daiichi 1 has reached around 840 kPa, compared to reference levels of 400 kPa.
The company has decided to manage this "for those units that cannot confirm certain levels of water injection" by means of a controlled release of air and water vapour to the atmosphere. Because this water has been through the reactor core, this would inevitably mean a certain release of radiation. The IAEA said this would be filtered to retain radiation within the containment. Tepco has confirmed it was in the process of relieving pressure at unit 1 while preparing to do the same for units 2 and 3
Explosion
Television cameras trained on the plant captured a dramatic explosion surrounding unit 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to know the extent of the damage. The external building structure does not act as the containment, which is an airtight engineered boundary within. According to reported comments attributed to chief cabinet secretary Yukio Edano, the containment has not been comprimised.
Monitoring of Fukushima Daiichi 1 had previously shown an increase in radiation levels detected emerging from the plant via routes such as the exhaust stack and the discharge canal. Tepco have said that the amount of radioactive material such as iodine it is detecting have been increasing. The amount of radiation at the site boundary now exceeds a regulatory limit triggering another set of emergency precautions.
To protect the public from potential health effects of radioactive isotopes of iodine that could potentially be released, authorities are preparing to distribute tablets of non-radioactive potassium-iodide. This is quickly taken up by the body and its presence prevents the take-up of iodine should people be exposed to it.
The injection of seawater into the building followed 8.20pm and this will be followed by addition of boric acid, which is used to inhibit nuclear reactions.
Over the last several hours evacuation orders for local residents have been incrementally increased and now cover people living within 20 kilometres of the power plant.
Raised temperatures
Meanwhile at adjacent Fukushima Daini, where four reactors have been shut down safely since the earthquake hit, Tepco has notified government of another emergency status.
Unit 1's reactor core isolation cooling system had been operating normally, and this was later supplemented by a separate make-up water condensate system. However, the latter was lost at 5.32am local time when its suppression chamber reached 100ºC. This led Tepco to notify government of another technical emergency situation.
Tepco has announced it has decided to prepare for controlled releases to ease pressure in the containments of all four units at Fukushima Daini.
A three kilometre evacuation is in progress, with residents in a zone out to ten kilometres given notice of potential expansion.
Workers
A seriously injured worker was trapped within Fukushima Daiichi unit 1 in the crane operating console of the exhaust stack and is now confirmed to have died. At Fukushima Daiini unit 3 one worker received a radiation dose of 106 mSv. This is comparable to levels deemed acceptable in emergency situations by the UK Health and Safety Executive, for example.
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html
Unit 1
- 439 MWe BWR, 1971
- Automatically shut down
- Water level decreasing
- Pressure release implemented
- Explosion observed with unknown
effect
- Containment believed intact
- Seawater injection has started
Unit 2
- 760 MWe BWR, 1974
- Automatically shut down
- Water level lower but steady
- Preparations for pressure release
Unit 3
- 760 MWe BWR, 1976
- Automatically shut down
- Preparations for pressure release
Unit 4
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 5
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 6
- 1067 MWe BWR, 1979
- Shut for periodic inspection
Battle to stabilise earthquake reactors
12 March 2011
UPDATE 8: 1.35 pm GMT
Attention is focused on the Fukushima Daiichi and Daini nuclear power plants as Japan struggles to cope in the aftermath of its worst earthquake in recorded history. An explosion has been seen at the site and seawater is now being injected to the plant.
Three of Fukushima Daiichi's six reactors were in operation when yesterday's quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. These suddenly stopped about an hour later, and this has been put down to tsunami flooding by the International Atomic Energy Agency (IAEA).
The loss of the diesels led the plant owners Tokyo Electric Power Company (Tepco) to immediately notify the government of a technical emergency situation, which allows officials to take additional precautionary measures.
For many hours the primary focus of work at the site was to connect enough portable power modules to fully replace the diesels and enable the full operation of cooling systems.
Pressure and releases
Without enough power for cooling systems, decay heat from the reactor cores of units 1, 2 and 3 has gradually reduced coolant water levels through evaporation. The consequent increase in pressure in the coolant circuit can be managed via pressure release valves. However, this leads to an increase in pressure within the reactor building containment. Tepco has said that the pressure within the containment of Fukushima Daiichi 1 has reached around 840 kPa, compared to reference levels of 400 kPa.
The company has decided to manage this "for those units that cannot confirm certain levels of water injection" by means of a controlled release of air and water vapour to the atmosphere. Because this water has been through the reactor core, this would inevitably mean a certain release of radiation. The IAEA said this would be filtered to retain radiation within the containment. Tepco has confirmed it was in the process of relieving pressure at unit 1 while preparing to do the same for units 2 and 3
Explosion
Television cameras trained on the plant captured a dramatic explosion surrounding unit 1 at around 6pm. Amid a visible pressure release and a cloud of dust it was not possible to know the extent of the damage. The external building structure does not act as the containment, which is an airtight engineered boundary within. According to reported comments attributed to chief cabinet secretary Yukio Edano, the containment has not been comprimised.
Monitoring of Fukushima Daiichi 1 had previously shown an increase in radiation levels detected emerging from the plant via routes such as the exhaust stack and the discharge canal. Tepco have said that the amount of radioactive material such as iodine it is detecting have been increasing. The amount of radiation at the site boundary now exceeds a regulatory limit triggering another set of emergency precautions.
To protect the public from potential health effects of radioactive isotopes of iodine that could potentially be released, authorities are preparing to distribute tablets of non-radioactive potassium-iodide. This is quickly taken up by the body and its presence prevents the take-up of iodine should people be exposed to it.
The injection of seawater into the building followed 8.20pm and this will be followed by addition of boric acid, which is used to inhibit nuclear reactions.
Over the last several hours evacuation orders for local residents have been incrementally increased and now cover people living within 20 kilometres of the power plant.
Raised temperatures
Meanwhile at adjacent Fukushima Daini, where four reactors have been shut down safely since the earthquake hit, Tepco has notified government of another emergency status.
Unit 1's reactor core isolation cooling system had been operating normally, and this was later supplemented by a separate make-up water condensate system. However, the latter was lost at 5.32am local time when its suppression chamber reached 100ºC. This led Tepco to notify government of another technical emergency situation.
Tepco has announced it has decided to prepare for controlled releases to ease pressure in the containments of all four units at Fukushima Daini.
A three kilometre evacuation is in progress, with residents in a zone out to ten kilometres given notice of potential expansion.
Workers
A seriously injured worker was trapped within Fukushima Daiichi unit 1 in the crane operating console of the exhaust stack and is now confirmed to have died. At Fukushima Daiini unit 3 one worker received a radiation dose of 106 mSv. This is comparable to levels deemed acceptable in emergency situations by the UK Health and Safety Executive, for example.
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html
As I posted on another thread!
They have the wrong people in charge and they do not take this seriously enough. They needed to get generators to the plants no matter what, what ever it takes including running over anyone the won't get out of the way of a giant pay-loader pushing its way to the power plant with a generator.
They have the wrong people in charge and they do not take this seriously enough. They needed to get generators to the plants no matter what, what ever it takes including running over anyone the won't get out of the way of a giant pay-loader pushing its way to the power plant with a generator.
They waited too long to get outside help, tried to "internalize" the problem and it appears to have gotten literally out of control.
The loss of back-up power is going to be a huge scandal.
I also read where the water intake screens may have been clogged from the tsunami and confused efforts to diagnose the problem.
We'd been getting slammed all yesterday, now orders coming in on-line at rate of one per minute or more.
Will be sold out of current KI shortly and shifting to Plan 'B', our emergency back-up supply of 6.2 million doses, soon.
I won't be on-line much anymore till things cool down.
Best info we have for this developing Japan situation, especially for those in U.S., is our 'When An Ill Wind Blows From Afar' guide...
www.ki4u.com/illwind.htm
Pointing others to it in my absence, will be helpful to many trying to sort this all out and help avert panic amongst some others.
- Shane
Will be sold out of current KI shortly and shifting to Plan 'B', our emergency back-up supply of 6.2 million doses, soon.
I won't be on-line much anymore till things cool down.
Best info we have for this developing Japan situation, especially for those in U.S., is our 'When An Ill Wind Blows From Afar' guide...
www.ki4u.com/illwind.htm
Pointing others to it in my absence, will be helpful to many trying to sort this all out and help avert panic amongst some others.
- Shane
erichtmobile
Senior Member
This could turn into a real full blown sh*t sandwich if they don't get this under control
Ravekid
Veteran Member
I have a very limited understanding of nuclear power plants. I know that the nuclear materials get hot and cause steam which turns turbines and makes the electricity. I know that control rods between the rods are used to attract particles to prevent collisions of certain particles. The collisions are what make the heat, right?
So, what exactly is a "melt down?" I'm taking that it means things get so hot, that the melting point of every material in the reactor is reached at some stage, thus everything "melts?" I'm all guessing fires will start due to the intense heat? So after things start melting...that is what I want to know. What happens then? What is the danger, if any, to the US? Do the nuclear reactions continue to take place in some sort of melted glob of metal? Is the melt down material so hot that it melts down to the center of the Earth?
So, what exactly is a "melt down?" I'm taking that it means things get so hot, that the melting point of every material in the reactor is reached at some stage, thus everything "melts?" I'm all guessing fires will start due to the intense heat? So after things start melting...that is what I want to know. What happens then? What is the danger, if any, to the US? Do the nuclear reactions continue to take place in some sort of melted glob of metal? Is the melt down material so hot that it melts down to the center of the Earth?
In a nutshell, the fuel rods melt into a lava-type material and the reactor core itself is compromised. At that point, an intact containment structure might keep the reaction mass contained for a time, but the fear would be that the mass would eventually burn through the structure, into the environment, where it could hit groundwater; radioactive sludge hitting H2O leads to steam type explosions, with fallout being blown into the atmosphere.
The fear for us would be the fallout making in into the jetstream and then falling on us - "fallout". We've taken fallout from foreign nuclear tests, but there's never been a full-out "China Syndrome" so results might well be different. IIRC Chernobyl was different - there was a fire from the outside air hitting the exposed reactor core that spread the contamination, not the fuel elements interacting with groundwater. So, we're going ever farther into unknown territory.
The fear for us would be the fallout making in into the jetstream and then falling on us - "fallout". We've taken fallout from foreign nuclear tests, but there's never been a full-out "China Syndrome" so results might well be different. IIRC Chernobyl was different - there was a fire from the outside air hitting the exposed reactor core that spread the contamination, not the fuel elements interacting with groundwater. So, we're going ever farther into unknown territory.
Excellent questions.....anyone know the answers?
Sysman
Old Geek <:)=
Yup. I heard they had 13 backup generators that all failed when the flood hit.
Gotta wonder about some of the design decisions. I mean the plant is on the coast, what did they expect. Japan has more Tsunamis than anyplace on Earth I believe. Sure, this was a big one, but when you're talking about nuke plant safety, you've got to consider everything, including "once in a lifetime" events...
Why didn't they have a couple generators on the roof, or someplace else above any "potential" hi-water mark???
Yea, I know, 20-20...
.
The Temperature inside the reactor core is about 3000. Degrees and it will melt cement and steel and once containment is breached the will start put out radiation particulate into the atmosphere and radiate in evey direction also. Anyone that gets close to it at that point tying to contain it will likely die days later if not the next day, anyone within a mile or two of the plant will likely die in months or a year later and the land around will uninhabitable for maybe 100 to 200 years or more.
Cascadians
Leska Emerald Adams
The airport there is the only one operational and where the rescue and relief efforts are being staged.
Talking head from the Heritage Foundation talking down the situation, saying the Japanese have it in hand, and this shows how "robust" their system is. I would argue that the exact opposite is happening; 24 hours ago, we were just getting hints that there were troubles, and right now there's a wrecked containment building, and they're trying to scuttle the reactor with seawater to prevent a meltdown, if there hasn't been a partial one already. Best at this point to assume that the Japanese gov is not letting the full story out, and that the situation is probably progressing to a worse case scenario, although I hope not for the residents around there.
xtreme_right
Veteran Member
For those that didn't order any KI tablets, here is the next best thing. I'd get to the pharmacy before it gets sold out. This is from Shane's site.
http://www.ki4u.com/illwind.htm
http://www.ki4u.com/illwind.htm
Scary before and after images of the containment building:
http://en.wikipedia.org/wiki/File:2011-03-12_1800_NHK_Sōgō_channel_news_program_screen_shot.jpg
http://en.wikipedia.org/wiki/File:2011-03-12_1800_NHK_Sōgō_channel_news_program_screen_shot.jpg
xtreme_right
Veteran Member
I don't believe what the Japanese officials are telling the public. How do I know when to start taking KI tablets? I don't want to take longer than necessary. Here's a snip from Shane's site that gives the FDA's recommendations on taking KI.
lafrteacher
Inactive
From what I have read, Pure Prussian Blue (a pigment- make sure it's 100%!) used to make Radiogardase is effective for many forms of radiation poisoning.It binds to the ions so they can be excreted from the body.
Remember, KI does not prevent radiation sickness; it only fills up the thyroid so one doesn't get thyroid cancer later.
Eating a diet rich in fruits and veggies can help speed recovery to lower doses of radiation. My guess is that it increases the speed of elimination from the body.
And another thing about the thyroid: it's most critical to "fill it up" for children and young adults. Us older people aren't nearly as susceptible to that form of radiation uptake.
lafrteacher
Inactive
The Traveler
Veteran Member
Fox news just reported that over 190 people have signs of radiation sickness.
Marthanoir
TB Fanatic
bought my KI from Shane years ago + i have some that the .govt sent to everybody as a proactive measure some years ago, shame the Japanese didn't do the same, it would have been easier than trying to distribute it now
Cascadians
Leska Emerald Adams
Reading from another forum, translation, that the USA is evacuating all its citizens from Japan. Is this true?
http://babelfish.yahoo.com/translat...-milieu/4669.html&lp=nl_en&btnTrUrl=Translate
Also that the USA now is planning to distribute KI also?
http://en.rian.ru/natural/20110312/162973901.html
http://babelfish.yahoo.com/translat...-milieu/4669.html&lp=nl_en&btnTrUrl=Translate
Also that the USA now is planning to distribute KI also?
http://en.rian.ru/natural/20110312/162973901.html
willowlady
Veteran Member
Looking at the two photos carefully, they don't appear to be of the same location. Very similar, but not the same. Perhaps it's just different angles..... Whether the same or not, the devastation to the containment building is near total. Anything that would blast all that concrete out from the steel frames has to have damaged anything left inside the building, like the cores. Just IMO.
VesperSparrow
Goin' where the lonely go
Well OF ALL THE DANGED TIMES TO START BEING FAIR!!! TAKE IT BACK, RIGHT NOW MR.!!!!!
GOD LORD MAKE THIS JUST GO AWAY...
I notice that the unit having problems is the oldest at this site, in service 1971, forty years old? ETA: a friend has sent me a note that this reactor was built by US company General Electric GE. Let's hope they did a good job.
Fukushima Daiichi
Unit 1
- 439 MWe BWR, 1971
- Automatically shut down
- Water level decreasing
- Pressure release implemented
- Explosion observed with unknown
effect
- Containment believed intact
- Seawater injection has started
Unit 2
- 760 MWe BWR, 1974
- Automatically shut down
- Water level lower but steady
- Preparations for pressure release
Unit 3
- 760 MWe BWR, 1976
- Automatically shut down
- Preparations for pressure release
Unit 4
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 5
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 6
- 1067 MWe BWR, 1979
- Shut for periodic inspection
Fukushima Daiichi
Unit 1
- 439 MWe BWR, 1971
- Automatically shut down
- Water level decreasing
- Pressure release implemented
- Explosion observed with unknown
effect
- Containment believed intact
- Seawater injection has started
Unit 2
- 760 MWe BWR, 1974
- Automatically shut down
- Water level lower but steady
- Preparations for pressure release
Unit 3
- 760 MWe BWR, 1976
- Automatically shut down
- Preparations for pressure release
Unit 4
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 5
- 760 MWe BWR, 1978
- Shut for periodic inspection
Unit 6
- 1067 MWe BWR, 1979
- Shut for periodic inspection
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Countrymouse
Country exile in the city
Iirc, I read elsewhere that the fuel rods are encased in some sort of other metal (zinc-based?) called "cladding"--I suppose it acts as sort of an "insulator" to hold the rods in?--and of course I know it's the "control" rods were (supposedly) inserted fully, thus preventing the fuel rods from coming into contact with one another and re-starting the fission process. HOWEVER--what I read, was that "if" the core overheated, the cladding itself would melt, and THAT would put the fuel rods back into contact with one another, re-starting the fission process and leading to full meltdown.
Can you tell me if I'm understanding this correctly, and if that is indeed a possible scenario?
Jeffrey Thomason
Veteran Member
Pretty sure this is the after effects of the explosion at Daiichi #1:
via http://www.yomiuri.co.jp/national/news/20110312-OYT1T00519.htm?from=navr
If you look at the before and after posted earlier, you can see the steel girders exposed above.
Largely intact actually, i'd imagine containment is not compromised at this point.
via http://www.yomiuri.co.jp/national/news/20110312-OYT1T00519.htm?from=navr
If you look at the before and after posted earlier, you can see the steel girders exposed above.
Largely intact actually, i'd imagine containment is not compromised at this point.