Meltdown Likely Under Way At Japan Nuclear Reactor

[bkkjames]

Interesting read if not right to the minute from TEPCO...

<A id=pressreleases>Press Releases

Press Release (Mar 13,2011)

Plant Status of Fukushima Daiichi Nuclear Power Station (as of 9am March 13th)All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down.Unit 1(Shut down)- Reactor has been shut down. However, the unit is under inspection due to the explosive sound and white smoke that was confirmed after the big quake occurred at 3:36PM. - We have been injecting sea water and boric acid which absorbs neutron into the reactor core. Unit 2(Shut down)- Reactor has been shut down and Reactor Core Isolation Cooling System has been injecting water to the reactor. Current reactor water level is lower than normal level, but the water level is steady. After fully securing safety, we are preparing to implement a measure to reduce the pressure of the reactor containment vessels under the instruction of the national government. Unit 3(Shut down)- Reactor has been shut down. However, High Pressure Core Injection System has been automatically shut down and water injection to the reactor is currently interrupted. We are examining alternative way to inject water. Also, following the instruction by the government and with fully securing safety, steps to lowering the pressure of reactor containment vessel has been taken. Spraying in order to lower pressure level within the reactor containment vessel has been cancelled.- Currently, we do not believe there is any reactor coolant leakage inside the reactor containment vessel.Unit 4 (shut down due to regular inspection)- Reactor has been shut down and sufficient level of reactor coolant to ensure safety is maintained.- Currently, we do not believe there is any reactor coolant leakage inside the reactor containment vessel.Unit 5 (outage due to regular inspection)- Reactor has been shut down and sufficient level of reactor coolant to ensure safety is maintained.- Currently, we do not believe there is any reactor coolant leakage inside the reactor containment vessel.Unit 6 (outage due to regular inspection)- Reactor has been shut down and sufficient level of reactor coolant to ensure safety is maintained.- Currently, we do not believe there is any reactor coolant leakage inside the reactor containment vessel.Casualty- 2 workers of cooperative firm were injured at the occurrence of the earthquake, and were transported to the hospital.- 1 TEPCO employee who was not able to stand by his own with his hand holding left chest was transported to the hospital by an ambulance.- 1 subcontract worker at important earthquake-proof building was unconscious and transported to the hospital by an ambulance.- The radiation exposure of 1 TEPCO employee, who was working inside the reactor building, exceeded 100mSv and was transported to the hospital.- 4 workers were injured and transported to the hospital after explosive sound and white smoke were confirmed around the Unit 1.- Presence of 2 TEPCO employees at the site are not confirmedOthers- We measured radioactive materials inside of the nuclear power station area (outdoor) by monitoring car and confirmed that radioactive materials level is higher than ordinary level. Also, the level at monitoring post is higher than ordinary level. We will continue to monitor in detail the possibility of radioactive material being discharged from exhaust stack or discharge canal. The national government has instructed evacuation for those local residents within 20km radius of the periphery because it's possible that radioactive materials are discharged.- We will continue to take all measures to restore the security of the site and to monitor the environment of the site periphery.http://www.tepco.co.jp/en/press/corp-com/release/11031305-e.html

[jfchandler]

Sounds from this latest Reuters report like they are already pumping sea water into Fukushima Daichi No. 3.

Now engineers were pumping in seawater, trying to prevent the same thing from happening at the No. 3 reactor, the government said in apparent acknowledgement that it had moved too slowly on Saturday.

"Unlike the No.1 reactor, we ventilated and injected water at an early stage," Chief Cabinet Secretary Yukio Edano told a news briefing.

Asked if fuel rods were partially melting in the No. 1 reactor, Edano said: "There is that possibility. We cannot confirm this because it is in the reactor. But we are dealing with it under that assumption. We are also dealing with the No.3 reactor based on the assumption that it is a possibility."

http://www.reuters.com/article/2011/03/13/us-japan-quake-idUSTRE72A0SS20110313

[bangkokeddy]

There are no alternatives currently. Our world needs energy to go forward. To go forward with medicine, all kind of nice things like the internet, taveling etc... nothing happens without energy.

Well, there is an option of burning coal. To understand what that means, you can go to visit some Chinese cities and ask when was the last time they saw blue sky. Or perhaps on what decade it happened.

The last nuclear plant accident was 1986. That is 25 year ago! The death toll for Chernobyl and this Japan accident has been less than people die in the traffic accidents in one year her in LOS.

Nuclear science is more challenging for the mind and therefore might scare some people. It's not that bad at all.

incorrect - a minute bit of research would so you how wrong you are. You make far too many assumptions about both the production of and future needs for energy.

Agreed with Deerai

I agree with oilinki. It seems he had thought a little bit deeper and definitely longer than the one minute some anti-nuclear scaremongers spend in google to gain 'knowledge' about the subject.

[jfchandler]

And the latest from TEPCO today on Fukushima Daichi plant radiation levels:

Furthermore, at 3:29PM, [saturday] Mar 12, radiation dose measured at site boundary

has exceeded the limiting value. Therefore, at 4:17PM, Mar 12, it was determined that a specific incident stipulated in article 15, clause 1

has occurred.

After that, the radiation dose at the monitoring post decreased once. today [sunday], the measured value revamped and the radiation dose measured at site boundary exceeded the limiting value again. As such, at 8:56AM, today, it was determined that a specific incident stipulated in article 15, clause 1 occurred.

In essence, they're saying the radiation levels at the boundary of the plant once again exceeded the regulatory limit this morning, without saying exactly what the level or limit was.

Note - the underlining in TEPCO's, as it's their way of indicating new/updated info from their prior reports.

Edited March 13, 2011 by jfchandler

[OzMick]

"One of nuclear powers big advantages is that, unlike solar, it works at night," - a wonderful comment by one of the myriad clueless posters who have posted on TV over the years.I expect he was in charge of the Irish "space ship to the sun" project????

Please have the courtesy when you quote me to include the post in its entirety. And far from being clueless, I have spent most of my working life in the power generation industry, and another 8 years on a high pressure hydrogen plant.

Most solar energy advocates I have met have no idea of grid load patterns and wouldn't know a what a MegaVar was if it bit them on the bum,

[bkkjames]

And the latest from TEPCO today on Fukushima Daichi plant radiation levels:

Furthermore, at 3:29PM, [saturday] Mar 12, radiation dose measured at site boundary

has exceeded the limiting value. Therefore, at 4:17PM, Mar 12, it was determined that a specific incident stipulated in article 15, clause 1

has occurred.

After that, the radiation dose at the monitoring post decreased once. today [sunday], the measured value revamped and the radiation dose measured at site boundary exceeded the limiting value again. As such, at 8:56AM, Today, it was determined that a specific incident stipulated in article 15, clause 1 occurred.

In essence, they're saying the radiation levels at the boundary of the plant once again exceeded the regulatory limit this morning, without saying exactly what the level or limit was.

Note - the underlining in TEPCO's, as it's their way of indicating new/updated info from their prior reports.

Not suprising John: since this happened on Friday they have been downplaying everything - the risk, the incident, and the after effects. Instead of evacuating 180,000 people from the start they decided to not risk panic, but risk lives. When all said and done - one or two Tepco officials will do the honourable thing while possibly thousands will be affected for the rest of their lives.

[bangkokeddy]

I think TEPCO is obfuscating by deliberately confusing the order of events - a fine Japanese tradition by the way, you just have to know how to spot it. ...

Haters will never miss an event to use it for their propaganda.

I haven't created past incidents and accidents of TEPCO nor have I written the text in the quote.

Look at the whole picture.

According to the "reliable" news you brought, the meltdown occurred already yesterday. 100% false.

You will get the wrong picture if some Japanese hating scaremonger brings you his selection of "news".

[dhrobertson]

So if a "bearded anorak" told you your house was on fire, you wouldn't do anything until a man in a suit told you he was right?

i think your methods of how to sift information are a bit weak.

Lighten up! It's the lack of balanced reporting at the BBC that gets to me. The problem is they never get any real engineers to speak. The dumbing down at the BBC forbids anything that's the slightest bit technical. So, it's much better to focus on scare mongering blokes with beards and anoraks (probably a vegetarian to boot!) I see Rachel Harvey has been sent so we will get the crew cut feminists' view on newcular power....

[jfchandler]

BangkokEddy, there's been no indication made publicly that a complete meltdown has occurred at the Daichi No. 1 reactor..

However, the Japanese government officially has said they presume a partial meltdown has occurred inside the No. 1 reactor, and may be occurring inside the No. 3 reactor.

They're presuming that based on the release into the environment of fission materials cesium and iodine... But they're saying they can't say for certain because they can't physically access the reactor cores...for obvious reasons.

Edited March 13, 2011 by jfchandler

[bkkjames]

And the latest from TEPCO today on Fukushima Daichi plant radiation levels:

Furthermore, at 3:29PM, [saturday] Mar 12, radiation dose measured at site boundary

has exceeded the limiting value. Therefore, at 4:17PM, Mar 12, it was determined that a specific incident stipulated in article 15, clause 1

has occurred.

After that, the radiation dose at the monitoring post decreased once. today [sunday], the measured value revamped and the radiation dose measured at site boundary exceeded the limiting value again. As such, at 8:56AM, Today, it was determined that a specific incident stipulated in article 15, clause 1 occurred.

In essence, they're saying the radiation levels at the boundary of the plant once again exceeded the regulatory limit this morning, without saying exactly what the level or limit was.

Note - the underlining in TEPCO's, as it's their way of indicating new/updated info from their prior reports.

Not suprising John: since this happened on Friday they have been downplaying everything - the risk, the incident, and the after effects. Instead of evacuating 180,000 people from the start they decided to not risk panic, but risk lives. When all said and done - one or two Tepco officials will do the honourable thing while possibly thousands will be affected for the rest of their lives.

but not surprised.... http://www.economist.com/node/1318056 from 2002

[jfchandler]

I'd second the request made above... If you guys want to have an energy methods and engineering expertise debate...can you please take it to another more appropriate place...

Meanwhile, speaking of meltdowns, from NHK on the Daichi No. 3 reactor:

Likely partial meltdown at second reactor

Chief Cabinet Secretary Yukio Edano says the level of coolant water at another reactor of the Fukushima No.1 [Daichi] nuclear power plant has decreased.

At 11 AM on Sunday, Edano told reporters that as the level of coolant at the Number 3 reactor of the Fukushima No.1 power plant has dropped, it is believed that part of the fuel rods became exposed.

This indicates the possibility that fuel rods at the reactor at the nuclear power plant may be melting, following a similar event at the Number 1 reactor on Saturday.

Edano said work was underway to ease pressure inside the reactor's container, and to pump water into it to raise the water level.

He said boric acid was added to the water to slow chemical reactions of the nuclear fuel.

Edano said radioactive materials were detected near the plant. He said the highest level of radiation recorded near the nuclear power station was 1,204.2 microsieverts per hour at 8:33 AM.

[That, I believe, is an even higher reading than the one from yesterday amid the problems with Reactor No. 1]

Edano said this was probably because the air inside the reactor's containment vessel is being discharged in an attempt to decrease the pressure.

Sunday, March 13, 2011 14:32 +0900 (JST)

http://www3.nhk.or.j...lish/13_22.html

Edited March 13, 2011 by jfchandler

[Shurup]

incorrect - a minute bit of research would so you how wrong you are. You make far too many assumptions about both the production of and future needs for energy.You also overlook that any rdiation takes 10s of thousands of years to die off- and has to be stored by man for that time.......

Radiation 'dies off' depends of the half life of the isotopes of the atoms. The half life (radiation will be half what it used to be) varies from micro or even nano seconds to years and years.

The another fact is that if the half life is short, eg it will die off fast, there will be a lot of radiation. On the other hand if the half life is long, there will be less radiation.

There are three basic type of radiations, which everybody should have learned in elementary school.

The most powerful radiation type is Alpha-radiation. These are huge helium nucleis, which even an sheet of paper can stop. If eaten or inflated to lungs, this is the worsts form.

Second radiation type is Beta-radiation which is an electron. An aluminium plate can stop the beta-radiation.

Third one Gamma-radiation, which is an photon with high frequency. This can penetrate even certain amount of lead.

In your daily life we encounter gamma-radiation, which is coming from the ground and also from the sky. This still does not kill us.

oilinki, I would just ignore him. It appears he is a specialist in all the areas of everything that's happening on the planet. Not so long ago he was trying to prove to everyone that it is divers who are to blame for the corals bleaching in the Andaman Sea, not the high water temperature that kills the corals.

I live by the principle: "Don't argue with a fool; onlookers may not be able to tell the difference" ©.

[Tywais]

Let's stop the bickering gents and keep it on topic.

[jfchandler]

but not surprised.... http://www.economist.com/node/1318056 from 2002

That's a good article James, similar to the Reuters one above recounting TEPCO's past faults and abuses...

I particularly liked this segment about the resignation of their then president back at that time, who was in charge during the period they falsfied all the reactor safety reports:

Mr Minami will oversee an internal probe, which is expected to find that a secretive corporate culture and a bureaucratic aversion to inconvenience—in other words, standard Japanese business practices—are among the chief culprits.

If that's how well the Japanese manage their nuclear power plants....gotta wonder... what would it mean for Thailand?

Quick.. the reactor's overheating... pour on the som tam???

[jfchandler]

Edano said radioactive materials were detected near the plant. He said the highest level of radiation recorded near the nuclear power station was 1,204.2 microsieverts per hour at 8:33 AM.

Tywais, I'm trying to get the hang of this, but I was an English major, and sucked at math, in university...

So does 1,204 microsieverts per hour radiation mean it was 1.2 sieverts per hour???

Edited March 13, 2011 by jfchandler

[hardy1943]

Japan is a "hi-tech" well organised country, that has spent a lot of time, thought and money on dealing with earthquakes....

Imagine if this happened in another country with nuclear power plants!

I feel sad for Japan but like you said we all should be glad it happened there.We are in the best of hands and lets hope it will not be another Chernobyl.

Even with the best organisation and planning and foresight things still can go wrong. This will be also a setback for all countries to try to shake away from the dependents on oil.

The future is at stake here too.Very sad to say the least.

[bangkokeddy]

BangkokEddy, there's been no indication made publicly that a complete meltdown has occurred at the Daichi No. 1 reactor..

That is true, i was referring to "news" by elcent posted yesterday:

that's what I wished for, but unfortunately authorities have confirmed a meltdown according to German TV station ARD.

that is 100% false.

Came from the same elcent who said: " obfuscating by deliberately confusing the order of events - a fine Japanese tradition by the way,"

There is an accident in a nuclear power plant after one of the strongest EQ ever recorded. We don't know yet how worse the accident actually is.

Some concerned anoraks with beards using the situation to propagate their "clean" green energy.

and some really disturbed minds using it to add hatemongering to scaremongering and telling "jokes" that should have no place in this topic.

In Thailand they would send an army with pat-loms (fans) to defend against nuclear radiation leakage, not to forget to consult the ghosts and fortune tellers.

[jfchandler]

Evacuations update from NHK. Not sure why these #s are quite lower than the 200,000+ ones used earlier.

The earlier numbers came from the central govt., whereas these apparently are from the local prefectural officials:

Evacuation advised for 80,0000 near nuclear plants

Fukushima prefectural government says on Sunday 70,000 to 80,000 people living near the Fukushima No.1 and No.2 Nuclear Plants are subject to an evacuation advisory.

They live in 10 cities and towns near the nuclear plants including Minamisouma-city, Tamura-city, and 8 towns.

About 62,000 people are confirmed to have already evacuated.

The prefectural authorities plan to help evacuate those remaining in the area.

Sunday, March 13, 2011 16:35 +0900 (JST)

http://www3.nhk.or.j...lish/13_25.html

Edited March 13, 2011 by jfchandler

[Tywais]

So does 1,204 microsieverts per hour radiation mean it was 1.2 sieverts per hour???

That would be 1.2 milliSieverts or .0012 Sv/hour. 1.2 Sieverts/hour would be massive.

[animatic]

There are no alternatives currently. Our world needs energy to go forward. To go forward with medicine, all kind of nice things like the internet, taveling etc... nothing happens without energy.

Well, there is an option of burning coal. To understand what that means, you can go to visit some Chinese cities and ask when was the last time they saw blue sky. Or perhaps on what decade it happened.

The last nuclear plant accident was 1986. That is 25 year ago! The death toll for Chernobyl and this Japan accident has been less than people die in the traffic accidents in one year her in LOS.

Nuclear science is more challenging for the mind and therefore might scare some people. It's not that bad at all.

incorrect - a minute bit of research would so you how wrong you are. You make far too many assumptions about both the production of and future needs for energy.

Agreed with Deerai

I agree with oilinki. It seems he had thought a little bit deeper and definitely longer than the one minute some anti-nuclear scaremongers spend in google to gain 'knowledge' about the subject.

There are alternatives and they work now, the difference is cost effectiveness vs risk aversion.

Coal is not a future alternative, it is the past and we need to look ahead not backwards.

To say that Chernoble was only 25 years ago is a red herring

the damage from Chernoble is ongoing today 25 years later.

[animatic]

BangkokEddy, there's been no indication made publicly that a complete meltdown has occurred at the Daichi No. 1 reactor..

That is true, i was referring to "news" by elcent posted yesterday:

that's what I wished for, but unfortunately authorities have confirmed a meltdown according to German TV station ARD.

that is 100% false.

Came from the same elcent who said: " obfuscating by deliberately confusing the order of events - a fine Japanese tradition by the way,"

There is an accident in a nuclear power plant after one of the strongest EQ ever recorded. We don't know yet how worse the accident actually is.

Some concerned anoraks with beards using the situation to propagate their "clean" green energy.

and some really disturbed minds using it to add hatemongering to scaremongering and telling "jokes" that should have no place in this topic.

In Thailand they would send an army with pat-loms (fans) to defend against nuclear radiation leakage, not to forget to consult the ghosts and fortune tellers.

The Japanese saying they are planing to evacuate 80,000+ people doesn't sound like

"Some concerned anoraks with beards using the situation to propagate their "clean" green energy."

Many people are quite informed on all of these subjects, and this is just an actualization of some of our worst fears.

Make it seem LESS than it is, by trite sarcastic commentary to make is seem lesser is not making your case in any way.

It does make it look like YOU have an agenda, not the inverse.

And our first priority here is to keep an eye on what is happening today in real time in japan now, and how it will affect us as well as the suffering Japanese people.

Edited March 13, 2011 by animatic

[jfchandler]

Official in protective gear scans for signs of radiation on a man who is from the evacuation area near the Fukushima Daini nuclear plant in Koriyama, March 13, 2011.

REUTERS/Kim Kyung-Hoon

Slideshow of similar photos here...

http://www.reuters.com/article/slideshow?articleId=USTRE72A0SS20110313&slide=1#a=1

[Honolulu]

I'm afraid that this nuclear emergency is unfolding very much like all of the preceeding nuclear catastrophies, ( Three Mile Island, Chernobyl). The operators and the govt. acting in concert to obfisscate, mislead, and confuse what the whole world can obviously see. The beginning of a total, uncontrolled meltdown, and another display of human error causing the sickness and death of other humans and environment on a grand scale. All to" save face".

First the Japanese operators say there is no serious risk of radiation, but evacuate over 200,000 people anyway. Then they say they have the situation under control, right before they blow the roof off the building.Now we find out that indeed significant amounts of radiation have not only been released, but 19 people have been radiated. And still they continue to downplay the situation. The amount of cowardice, thoughtlessness, and lack of responsibility would be comical if it were not so sickening.

Just now on the news, they are saying that no3 reactor is now in meltdown, in addition to no 1 reactor. If they had been more upfront and responsive in the beginning, backup generators could be helicoptered in and in place by now. The whole U.S seventh fleet is less than an hour away, for Gods sake! They could park a nuclear powered sub right off the coast and connect up to the grid and fire up the entire prefecture if they would just think ahead.God help anyone downwind from these idiots.

[animatic]

[3:46 a.m. ET, 4:46 p.m. Tokyo] A second explosion could occur at an earthquake-struck nuclear plant in northeastern Japan, a government official told reporters Sunday. Chief Cabinet Secretary Yukio Edano said an explosion could occur in the buliding housing the No. 3 reactor at the Fukushima Daiichi plant.

http://news.blogs.cnn.com/2011/03/13/japan-quake-live-blog-nine-people-test-positive-for-high-radiation-levels/

[jfchandler]

Power outages coming... says Kyodo News:

Kaieda warns of massive electricity shortage following quake TOKYO, March 13, Kyodo

Japan's eastern and northeastern areas may fall into an ''abnormal'' situation involving a shortage in electricity supply in the wake of Friday's powerful earthquake that hit Japan and crippled nuclear power plants in the northeast, industry minister Banri Kaieda said Sunday, while calling for preventive measures.

To avoid massive blackouts in the areas, Kaieda and an energy agency official said that Tokyo Electric Power Co. and Tohoku Electric Power Co. may implement planned power outages in their service areas as early as Monday, with the step likely to last more than several weeks.

''As companies and others will start economic activities...from tomorrow and afterward, there is a high possibility that the service areas of Tokyo Electric and Tohoku Electric will face an abnormal situation in which a great deal of supply shortage will occur,'' the economy, trade and industry minister said, adding that the government has urged large companies to limit electricity use.

''But if a great supply shortage is expected even if we take such measures (to limit the use), there is a possibility that Tokyo Electric and Tohoku Electric will implement planned power outages,'' Kaieda told a press conference in Tokyo.

He also said the government and utility companies will take every possible measure to minimize the impact of any planned outage on people's lives.

Tetsuhiro Hosono, head of the Natural Resources and Energy Agency, said the power suspension, if implemented, may last ''more than several weeks'' and that it may start from Monday.

http://english.kyodonews.jp/news/2011/03/77350.html

[Tywais]

Off topic/argumentative posts have been removed after my caution. Further such posts will be removed without notice. Continuing to do so will have consequences.

[jfchandler]

And an update on the Daichi No. 3 plant from Kyodo News...

Highlights below... Full article link beneath. Reactor No. 3 now officially toast.

Sea water injected into troubled Fukushima [No. 3] power plant TOKYO, March 13, Kyodo

Japanese authorities scrambled Sunday to control overheating reactors at the troubled Fukushima No. 1 [Daichi] nuclear power plant, injecting sea water into them and reducing the pressure inside, top government spokesman Yukio Edano said.

While acknowledging that the core of the No. 3 reactor at the plant may have been deformed due to overheating, the chief Cabinet secretary denied it has led to a ''meltdown,'' a critical situation where fuel rods have melted.

Edano warned, however, that a hydrogen explosion similar to one that occurred at the No. 1 reactor at the same facility nearby on Saturday could occur at the No. 3 reactor because large amounts of hydrogen were created when the water injection procedure briefly ran into trouble.

The plant's operator, Tokyo Electric Power Co., began injecting fresh water into the reactor to deal with the problem that the tops of MOX fuel rods were 3 meters above the water in the reactor following a magnitude 9.0 earthquake which hit northeastern and eastern Japan on Friday.

But it began injecting sea water after trouble developed with a fresh water pump, a step that will lead to the reactor's dismantlement.

Radiation around the reactor measured 1,557 micro sievert at 1:52 p.m., Edano said, adding the figure went down to 184 about 50 minutes later. He dismissed concerns that the radiation level would affect human health.

Meanwhile, radiation monitored at the Onagawa nuclear power plant in Miyagi Prefecture on the Pacific coast shot up on Sunday, Tohoku Electric Power Co. said, adding that it was likely caused by radioactive substances let out at the troubled Fukushima No. 1 nuclear power plant in Fukushima Prefecture.

Radiation levels were very low but about 400 times as high as in normal times, the power supplier said, dismissing the possibility that the Miyagi plant was to blame.

MORE: http://english.kyodonews.jp/news/2011/03/77339.html

[pattayasnowman]

There is no such thing as a partial Meltdown, Once the Meltdown has begun due to loss of coolant there is virtually no way to stop it. Read the 'China Syndrome"

If they try to cool it with Sea Water their will be a massive explosion as the Sea Water is immediately converted to steam causing a massive realease of Radioactive material including Plutonium the most toxic substance known.

Yes this is chernobyl all over again but located in one of the most densely popuulated places in the world. The Radiation exposure will affect millions.

[boldfj]

BTW, I believe I've seen reference to this, but it's not been addressed in a very direct way...

At Fukushima Daichi 1 reactor, once they started pumping sea water into the containment area, I'm under the impression that means that particular reactor is toast... or... to put it more scientifically...would be unable to be returned to service in the future. It's done. Never operate again...

It is interesting to note tha Fukushima Daichi 1 was initially commissioned on 26 March 1971 and was scheduled to be shut down on it's 40th birthday on 26 March 2011. So it was probably an easy decision to sacrifice the unit in an attempt to prevent a complete meltdown. However, that's not the same case with Unit 3, which still had several more years of life left, until they injected the sea water into the reactor.

Edited March 13, 2011 by boldfj

[Tywais]

There is no such thing as a partial Meltdown, Once the Meltdown has begun due to loss of coolant there is virtually no way to stop it. Read the 'China Syndrome"

Too much science fiction out there.

The China Syndrome is a hypothetical idea of an extreme result of a nuclear meltdown in which molten reactor core products breach the barriers below them and flow downwards through the floor of the containment building. The origin of the phrase is the fictional idea that molten material from an American reactor could melt through the crust of the Earth and reach China.[1]

The 'China Syndrome' refers to the most drastically severe meltdown a nuclear reactor could possibly achieve. In this case, the reactor would reach the highest level of supercriticality for a sustained period of time, resulting in the melting of its support infrastructure. The uranium in the core would behave in a similar manner to a delta-class fire, self-sustaining temperatures in excess of 2000°C. Since these temperatures would melt all materials around it, the reactor would sink due to gravity, effectively boring a hole through the reactor compartment's floor.

China Syndrome

Two meltdowns occurred at American civil nuclear power plants:

1. The partial meltdown at the Fermi 1 experimental fast breeder reactor required the reactor to be repaired, though it never achieved full operation afterward.

2. The Three Mile Island accident, referred to in the press as a "partial core melt",[3] led to the permanent shutdown of that reactor.

Nuclear Meltdown

A partial can be stopped when proper cooling is supplied. A partial refers to portions of the exposed rods being exposed. It is not necessarily a runaway action.