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Meltdown Likely Under Way At Japan Nuclear Reactor

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Time to update the Safe Nuclear Reactor Design Handbook?

"Make sure your coastal reactor plant is located at an altitude where it can't be reached by a tsunami."

50 metres would be fine.

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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.

Actually, Three Mile Island was a partial meltdown:

The Three Mile Island accident was a partial core meltdown in Unit 2 (a pressurized water reactor manufactured by Babcock & Wilcox) of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg in 1979. The plant was owned and operated by General Public Utilities and the Metropolitan Edison Co. It was the most significant accident in the history of the American commercial nuclear power generating industry, resulting in the release of up to 481 PBq (13 million curies) of radioactive gases, but less than 740 GBq (20 curies) of the particularly dangerous iodine-131.[1]

http://en.wikipedia.org/wiki/Three_Mile_Island_accident

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Snowman, that's the problem they've been dealing with..

They're having to use water and sea water now to keep the reactors cooled...and that's creating steam and pressure inside the units...as well as hydrogen... And then that has to be vented outside to reduce interior pressure, leading to the release of radiation in some levels.

Yet the reactors keep cooking... I haven't seen any explanation of HOW LONG they'll have to keep doing so before the boric acid mixture or other factors cause the fission activity to lessen.

The sea water presumably is part of what led to yesterday's explosion at Reactor 1, and is why the govt. was warning earling today of a possible explosion today at Reactor 3, potentially caused by exactly the same factors.

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.

Edited by jfchandler

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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.

I believe, Tywais, that is exactly what the Japanese govt. has said happened yesterday at Reactor 1, and they believe may be happening today at Reactor 3... Parts of the fuel rods being exposed and their casing potentially melting.

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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.

Are you administrating or contributing?

You may consider my posts trite (you probably don't understand the humour) but I was trying to make a real point.

There are two many posts from people who don't understand the facts.

There are too many pundits on the BBC who clearly do not understand the engineering or the physics involved.

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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.

The China Syndrome was a work of fiction.

Japanese reactors are not the type (breeder) which produce plutonium.

There has so far been no breech of reactor shell as happened at Chernobyl, nor does it seem likely.

As long as the continue to pump in water and allow the steam produced to vent, there should not be an explosion within the reactor.

The explosion reported, and another expected, is most likely hydrogen vented inside the building; a quite small explosion would blow off the roof sheeting, and there have been no reports of injuries from it AFAIK.

A small quantity of radioactive material may be carried over with the vented steam, and will end up in the north Pacific, population close to zero.

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Time to update the Safe Nuclear Reactor Design Handbook?

"Make sure your coastal reactor plant is located at an altitude where it can't be reached by a tsunami."

50 metres would be fine.

And to have an elevated/uphill water reservoir to use when the pumps fail

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Japan, neighbors anxiously watch wind

Sun Mar 13, 2011 4:35am EDT

TOKYO (Reuters) - The wind over Japan's earthquake-damaged nuclear complex will continue blowing from the south, putting residents north of the facility in the path of any radiation, a weather official said on Sunday.

The Fukushima Daiichi plant, operated by Tokyo Electric Power Co (TEPCO), is located about 240 km (150 miles) north of Tokyo on the country's northeast coast.

The wind will keep blowing from the south in the area from noon until early evening, the Japan Meteorological Agency official said.

The direction of the wind is a key factor in judging possible damage to the environment from radiation leaking from the plant, which was devastated on Friday by Japan's biggest earthquake on record and a subsequent tsunami.

Officials are working desperately to prevent fuel rods from overheating in a first reactor after some radiation leaked into the air. The government said on Sunday that a building housing a second reactor was at risk of exploding.

South Korea, to the west of Japan, saw little chance of any radiation blowing across its territory.

"We see no impact (from Japan's radiation) so far as the current winds are westerlies," said Lee Durk-hun, head of operational safety analysis at the Korea Institute of Nuclear Safety.

"However, if the winds change, it could affect us, and according to our close monitoring systems, we will prepare measures to prevent any damage."

Authorities in China's northeastern province of Liaoning have begun monitoring for possible radiation from Japan, but have not yet detected any, Xinhua news agency reported.

"At present the figures are normal and Liaoning has not been affected," it quoted nuclear safety official Gao Kui as saying.

http://www.reuters.com/article/2011/03/13/us-japan-quake-wind-idUSTRE72C0G420110313

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Clicking on here every nowan'again it's amazing to see how many people have suddenly become experts on nuclear science. :rolleyes:

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Anxiety, fatigue grow among evacuated citizens near nuclear plant

Kyodo News

SENDAI, March 13, Kyodo

Anxiety and distress was growing among evacuees near the Fukushima No. 1 [Daichi] nuclear power plant Sunday, a day after a blast occurred and fears increased over possible radioactive leaks from the plant that was hit by Friday's massive earthquake.

''What's going to happen, and when...?'' a local town official said in expressing concerns, although he noted that people are not panicking. He evacuated from the Fukushima Prefecture town of Okuma, where the plant is located, to the city of Tamura in the same prefecture, farther away from the plant.

Noting that some of the evacuees have also fallen ill because of fatigue and anxiety about the future three days after evacuation, the official said, ''There are calls for information about hospitals. There is also a need for medicine.''

As the government expanded from 10 kilometers to 20 km the radius of the evacuation area for residents living near the plant, where one of the reactors partially melted Saturday and the blast occurred, another 180,000 residents were forced to seek refuge.

Another resident from Okuma tweeted, ''I want to go back to Okuma, which I love.'' Another woman from the town, who was rescued by the Japan Self-Defense Forces, tweeted, ''I hope to return to Okuma soon.''

A woman who evacuated to neighboring Yamagata Prefecture from the coastal city of Minamisoma tweeted that there is no more gasoline in Fukushima and called for help, saying ''Supply gasoline to Fukushima.''

In another elementary school in the town of Kawamata, around 500 people newly arrived by car or bus from another coastal town, Namie. Electricity is down in Kawamata and there is no heating in the area where temperatures have fallen to as low as minus 1 C.

A male worker from Namie said, ''Some are flustered because their evacuation centers have been changed. Some are getting nervous as they can't foresee what is going to happen.''

''It is extremely cold. Supplies of blankets and food are short,'' the worker added.

As of Saturday night, around 1,800 residents had evacuated to nine asylums located at school gymnasiums and other facilities in the town of Miharu. One town worker said, ''The facilities are full, and we cannot accept any more evacuees.''

In the town of Kagamiishi, where around 10 people evacuated, a town worker said, ''What will happen if more come to take refuge here? We have little knowledge about nuclear power.''

http://english.kyodo...1/03/77360.html

Edited by jfchandler

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Reply to post in other thread:

Thanks, I understand this point of view, but cooling it with sea-water would have the same effect as boric acid. - The reactor would never be up again. This is talked about since more than 12 hours.

The problems seem to be with the injection of sea-water and boric acid.

Although Boric acid isn't a standard regulating compound in a BWR, it is just an additive to the coolant, and does no harm to the reactor. It regulates the reaction in much the same way as the control rods do. When flushed out again, reaction starts back up.

Sea water however is messily corrosive crap, will clog up pipes and destroy pumps and seals etc.

The main problem seems to be that without power, there is not enough water pressure to overcome the reactors pressure, so you don't get any water in. This causes the water inside the reactor to boil off, increasing the pressure even more.

Releasing this pressure means releasing lightly radioactive water to the atmosphere (and maybe causing another explosion just like in #1, as hydrogen may have formed).

So basically what they will be doing is choosing between evils, carefully weighing:

- Scrapping the reactor / Trying to salvage it

- Venting radioactive steam / keep trying to keep enough water in the reactor

- Explosion risks / Radiation risks

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I asked yesterday if the control rods were lowered into the core.

Guess no one cares about that. Distraction.

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Clicking on here every nowan'again it's amazing to see how many people have suddenly become experts on nuclear science. :rolleyes:

Yes I agree. But,careful, Taiwais will start removing your posts if you use sarcasm or any other form of wit to make the point.

I hope he does, some of us want to read what's happening instead of reading this nonsense.

My apologies for contributing to said nonsense.

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jQuery().ready(function() { initServiceInstanceId('1.348809'); });

  • Published 02:11 13.03.11
  • Latest update 02:11 13.03.11

Japan nuclear blast could be more deadly than Chernobyl, experts fear

Experts in Israel and abroad divided on scope of disaster at Japan's nuclear plants, as Japanese government hasn't provided accurate information regarding threat posed by explosions at Fukushima nuclear power plant.

By Yossi Melman Since the Japanese government has not provided accurate information regarding the possible threat posed by the explosion at the Fukushima nuclear power plant, experts in Israel and abroad are divided on the scope of the disaster and the ramifications for the environment.

It appears that immediately after earthquake warnings were first heard, the Japanese authorities shut down all six reactors located in the affected region, which lies 250 kilometers north of the capital Tokyo, by cutting off the flow of electricity to the reactors. But the emergency generator, whose function is to provide power to the pump responsible for cooling the reactor, did not activate. As a result, the reactor's core began to heat up.

</IMG>At the same time, radioactive materials and gases were emitted into the air, but measurements taken indicate that the amount was relatively minimal. The most dangerous elements discharged were iodine and cesium, two by-products of the nuclear fission process that takes place in nuclear plants. These are two relatively volatile compounds that can easily spread into the atmosphere.

Professor Uzi Even of Tel Aviv University, who in the past worked for the Israel Atomic Energy Commission, told Haaretz that these two compounds are extremely dangerous, which is why the Japanese government yesterday began distributing iodine tablets, which neutralize the threat of radioactive poisoning that primarily affects the thyroid gland.

Even recalled that several years ago, Israel had distributed such tablets to residents living in the vicinity of the nuclear reactor in Dimona in the event that dangerous materials leaked into the air. He also noted that another potential source of danger is the possibility that the measuring equipment used to gauge the heat levels in the reactor core could spin out of control as a result of a cut in power. In such a scenario, Japanese experts working to prevent a nuclear disaster would have trouble ascertaining the core's situation.

Hebrew University Professor Menachem Luria, an expert on air quality and poisoning, told Channel 2 on Saturday: "This is very worrying. There is no doubt that we have not seen anything like this in years, perhaps ever since nuclear experiments were conducted in the atmosphere in the 1950s. From what we can gather, this disaster is even more dangerous than Chernobyl, both from the standpoint of the population's exposure to radioactive material and the spread of radioactive contamination in the area."

Luria continued: "Once there is an uncontrollable heating up, the nuclear fuel undergoes a metamorphosis into the gaseous phase. Since we are talking about metals and solid items, they turn into particles that are capable of traveling great distances. They can wander thousands of kilometers."

If these gases are indeed emitted into the atmosphere in large quantities, the wind regime could carry them all the way to China, South Korea, and eastern Russia, or in the other direction, toward Hawaii and the west coast of the United States. The likelihood of this happening, though, is not high.

Experts are now positing two possible scenarios. This first scenario is a disaster on the scale of Chernobyl, where the reactor core melted and enormous quantities of radioactive fallout were discharged into the air before being propelled by the wind and harming civilians living at a relatively great distance from the reactor. Because the core melted, the steel and concrete seal, which was meant to protect the core and prevent dangerous material from being emitted into the air, could not withstand the pressure and collapsed. As a result, thousands of people were killed, though the exact number of deaths remains unknown to this day.

http://www.haaretz.com/print-edition/news/japan-nuclear-blast-could-be-more-deadly-than-chernobyl-experts-fear-1.348809

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Nice to hear somebody who knows that they are talking about!

Although the Japanese are attempting to be creative, adding sea water is incredibly dangerous to this operation.

It has been covered via the media that the rods have already been exposed to the air and local environment, within the facility. It would appear that access has now become somewhat risky.

Sea water will indeed, if not destroy the pumping systems and cooling systems, leave salt deposits that are destructive to the whole process (which must be clinically clean and purified).

If pumped into the system, and surrounding the cores, it will be incredibly complex to remove and permit functional use of the reactor cooling system for good.

That in itself lends itself to massive risk in plunging the rods back to where they belong, if at all possible, after events have stabilised.

The Japanese, may indeed send in Kamikaze engineers to work for as long as possible to clean matters,(in order to save face).

AS for reactor 3 melting down - um - I hazard a guess at Chernobyl repeated, unless the Kamikaze guys do their job. Pity them.

-m.

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