Meltdown Likely Under Way At Japan Nuclear Reactor

[Jdietz]

I find it rather curious in a country that has a wide use and long history of solar energy why this wasn't also in place as an additional back up to continue the batteries recharge of the cooling systems??

A reactor cooling system is not like your regular aquarium pump you can run off a Nokia cell phone battery and a couple of garden lamp variety solar cells. Do the math:

- Main coolant pump BWR. Impeller: axial or semi-axial. Head: 50-70 m. Flow rate: 800-4000 m³/h. Power: 250-750 kW

- A single loop may use 1 or 2 reactor coolant pumps per loop

So let's take the 'best case' scenario. 1 Coolant loop, 1 pump running at almost idle (250 kW)

- Solar panels convert sunlight directly into electricity with an efficiency of about 13%. The earth's surface receives close to 1000 watts per square meter

- Let's say the sun shines for 8 full hours a day at this full strength.

- Let's assume charging / conversion loss for the 16 dark hours of 30%

So every hour in the sun we need to make around 1MW of power to keep the backup battery charged.

That amounts to around 7,500 m2 of solar panels for each reactor. And this is the "best case" scenario.

While currently solar cells are great for lighting a led lamp or small fluorescent tube and a radio at night, they are no replacement for even a small diesel generator, unless you have land to spare (and LOTS of it)

[MJP]

I find it rather curious in a country that has a wide use and long history of solar energy why this wasn't also in place as an additional back up to continue the batteries recharge of the cooling systems??

A reactor cooling system is not like your regular aquarium pump you can run off a Nokia cell phone battery and a couple of garden lamp variety solar cells. Do the math:

- Main coolant pump BWR. Impeller: axial or semi-axial. Head: 50-70 m. Flow rate: 800-4000 m³/h. Power: 250-750 kW

- A single loop may use 1 or 2 reactor coolant pumps per loop

So let's take the 'best case' scenario. 1 Coolant loop, 1 pump running at almost idle (250 kW)

- Solar panels convert sunlight directly into electricity with an efficiency of about 13%. The earth's surface receives close to 1000 watts per square meter

- Let's say the sun shines for 8 full hours a day at this full strength.

- Let's assume charging / conversion loss for the 16 dark hours of 30%

So every hour in the sun we need to make around 1MW of power to keep the backup battery charged.

That amounts to around 7,500 m2 of solar panels for each reactor. And this is the "best case" scenario.

While currently solar cells are great for lighting a led lamp or small fluorescent tube and a radio at night, they are no replacement for even a small diesel generator, unless you have land to spare (and LOTS of it)

They don't work at night.

[WarpSpeed]

I find it rather curious in a country that has a wide use and long history of solar energy why this wasn't also in place as an additional back up to continue the batteries recharge of the cooling systems??

A reactor cooling system is not like your regular aquarium pump you can run off a Nokia cell phone battery and a couple of garden lamp variety solar cells. Do the math:

Really?????? When you start off with a disrespectful, patronizing response like that you loose all credibility.

As for not enough land the entire area around this reactor like all reactors is restricted for nothing more then safety and security as a buffer zone, a solar tower could well fulfill the needs and then some what you mentioned is NOT the best case scenario, far from it..

Edited March 14, 2011 by Mario2008
flame removed, keep it civil

[WarpSpeed]

I find it rather curious in a country that has a wide use and long history of solar energy why this wasn't also in place as an additional back up to continue the batteries recharge of the cooling systems??

A reactor cooling system is not like your regular aquarium pump you can run off a Nokia cell phone battery and a couple of garden lamp variety solar cells. Do the math:

- Main coolant pump BWR. Impeller: axial or semi-axial. Head: 50-70 m. Flow rate: 800-4000 m³/h. Power: 250-750 kW

- A single loop may use 1 or 2 reactor coolant pumps per loop

So let's take the 'best case' scenario. 1 Coolant loop, 1 pump running at almost idle (250 kW)

- Solar panels convert sunlight directly into electricity with an efficiency of about 13%. The earth's surface receives close to 1000 watts per square meter

- Let's say the sun shines for 8 full hours a day at this full strength.

- Let's assume charging / conversion loss for the 16 dark hours of 30%

So every hour in the sun we need to make around 1MW of power to keep the backup battery charged.

That amounts to around 7,500 m2 of solar panels for each reactor. And this is the "best case" scenario.

While currently solar cells are great for lighting a led lamp or small fluorescent tube and a radio at night, they are no replacement for even a small diesel generator, unless you have land to spare (and LOTS of it)

They don't work at night.

That's what batteries are for..And before you answer that is the third level of redundancy on these plants but they only get 8 hours run time.. So obviously several back up supplies would be required and that's what they've been doing but a problem with recharger capacity due to no power available which is why I posed the statement..

In essence a recharge capacity to the back up batteries sets..

Edited March 13, 2011 by WarpSpeed

[MJP]

I find it rather curious in a country that has a wide use and long history of solar energy why this wasn't also in place as an additional back up to continue the batteries recharge of the cooling systems??

A reactor cooling system is not like your regular aquarium pump you can run off a Nokia cell phone battery and a couple of garden lamp variety solar cells. Do the math:

- Main coolant pump BWR. Impeller: axial or semi-axial. Head: 50-70 m. Flow rate: 800-4000 m³/h. Power: 250-750 kW

- A single loop may use 1 or 2 reactor coolant pumps per loop

So let's take the 'best case' scenario. 1 Coolant loop, 1 pump running at almost idle (250 kW)

- Solar panels convert sunlight directly into electricity with an efficiency of about 13%. The earth's surface receives close to 1000 watts per square meter

- Let's say the sun shines for 8 full hours a day at this full strength.

- Let's assume charging / conversion loss for the 16 dark hours of 30%

So every hour in the sun we need to make around 1MW of power to keep the backup battery charged.

That amounts to around 7,500 m2 of solar panels for each reactor. And this is the "best case" scenario.

While currently solar cells are great for lighting a led lamp or small fluorescent tube and a radio at night, they are no replacement for even a small diesel generator, unless you have land to spare (and LOTS of it)

They don't work at night.

That's what batteries are for..

Are you talking about a solar powered torch? Because that always bothered me.

(A little levity in these dark times helps).

[jfchandler]

the nuclear agency says fukushima daiichi reactor no. 3 fuel rods are half exposed/RT@felix85

That's another very bad sign...and this one of course is a more confirmed report...

They've supposedly been pumping sea water into No. 3 all day... and now tonight they're saying the fuel rods are half exposed???

PS - Guys, we're getting off topic again in some of the posts above... Please try to keep mostly on point, re the troubled reactors in Japan.

[powderpuff]

Yeah so it's all about "defective valves". I wonder if these guys could tell the truth if they wanted to?

They want us to accept that ALL the safety valves were defective. Well that absolves them of responsibility.

I bet if you took 500 Japanese nuclear engineers & asked them what happened you would get 500 different stories.

[jfchandler]

The latest from NHK (8:35 pm Thai time):

Problems still plague Fukushima nuclear plants

Cooling system problems continue to plague two nuclear plants in earthquake-hit Fukushima Prefecture.

The level of coolant water in the Number Three reactor at the Fukushima Number One [Daichi] power plant dropped on Sunday, leaving the fuel rods exposed by two meters. The situation continued for at least until 3pm, possibly causing a partial melting of the rods.

As a result, masses of hydrogen gas have accumulated in the inside top of the reactor building. The gas may cause an explosion similar to that which occurred at the Number One reactor on Saturday.

Tokyo Electric Power Company, also known as TEPCO, is considering ways to remove the hydrogen from the structure.

The Number One reactor and its containment structure are being pumped with seawater in an effort to secure cooling.

The Nuclear and Industrial Safety Agency says the amount of seawater should entirely fill the reactor structure, and that the building should be safe as long as the water flow continues.

At the Number Two reactor, the amount of coolant continues to be lower than usual, and the pressure within the containment vessel is above normal.

TEPCO attempted to restore the functioning of an electrical pressure-relief device by connecting a generator, but has not succeeded.

The company is considering other means to relieve the reactor pressure, such as releasing air from the containment vessel.

Inadequate cooling is also occurring at the Fukushima Number Two (Daini) power plant, where the pumps to send seawater to cool the Number One, Two and Four reactors have failed due to the tsunami.

TEPCO says it will try to restore the cooling systems by replacing the pump motors overnight.

Sunday, March 13, 2011 22:35 +0900 (JST)

Edited March 13, 2011 by jfchandler

[WarpSpeed]

the nuclear agency says fukushima daiichi reactor no. 3 fuel rods are half exposed/RT@felix85

That's another very bad sign...and this one of course is a more confirmed report...

They've supposedly been pumping sea water into No. 3 all day... and now tonight they're saying the fuel rods are half exposed???

PS - Guys, we're getting off topic again in some of the posts above... Please try to keep mostly on point, re the troubled reactors in Japan.

It is all on topic about nuclear reactors in Japan and elsewhere and the need for greater redundancy on them..Or does it need to simply be reporting and no debate nor discussion?

Edited March 13, 2011 by WarpSpeed

[WarpSpeed]

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

That is a pretty horrendous radiation reading if taken outside the fence of the site - 1.204 mSv per hour would exceed your annual healthy dose limit within a day. I'd strongly recommend not standing at that fence on the downwind side.

For GeriatricKid who was worried about his flight plans - I shouldn't worry if I were you: You can divide the radiation you will be exposed to into three categories

Alpha particles, which can cause cancer or burns if you ingest radioactive material and it sits in your tissues for some time, but which are effectively stopped by a sheet paper; your aeroplane will not draw in so much fresh air, and any contamination will be so diluted that I would recommend you avoid the risk of ulcers from worrying about this

Beta particles: which can penetrate greater distances, but you will be pretty well shielded by the skin of the aeroplane, I believe, and similarly, any contamination drawn in through the air intakes will be so diluted as to be minimal

gamma rays: You will be exposed to a much higher gamma ray exposure from extraterrestrial sources due to reduced protection by having several kilometres less atmosphere above you; the additional gamma ray exposure from the 'radiation cloud' will not be large in comparison.

You might want to think about the gamma rays next time that you fly, though, whenever and wherever.

SC

That all applies while on the plane but once disembarking may be a problem due to it being "hot" unless they take precautions and give it a significant wash down away from the point of disembarking prior..

I'm more concerned with the masses of naval and other ships off shore loaded with aid and assistance who may be in range of potential exposure if the winds blow their way, a likely scenario I'm afraid ..

I'd recommend against licking the outside of the aeroplane...

Yes very clever, but it is termed "radiation" because it "radiates" so that level if intimacy is not necessary to get exposed, these are past incorrect assumptions that have caused masses of people predominantly service men to be needlessly and carelessly exposed....

[Maestro]

Translation from the news ticker of German-language online newspaper in Switzerland:

2011-03-13 14:06 UTC

The pressure in reactor 3 is rising steadily, the government warns about a new explosion. "If there is a meltdown in reactor 3 the worst can happen because because the special rods in this reactor contain the highly toxic Plutonium", wrote Greenpeace.

[jfchandler]

Radiation screening to start

(posted 4:59 pm Thai time) -- from NHK

Health authorities in the Japanese prefecture of Fukushima will conduct radiation screening for residents who lived near the prefecture's quake-hit nuclear plant.

It has been confirmed that 22 people were exposed to radiation following the hydrogen explosion at the plant's No.1 reactor building.

Health authorities will conduct screenings at evacuation shelters across the prefecture, and also provide testing to other residents who desire it.

If the levels of exposure are confirmed to require decontamination, residents will be advised to dispose of their clothing and to shower.

Officials are now deciding where to establish decontamination facilities.

On Sunday the prefecture confirmed 19 people had suffered radiation exposure, bringing the total to 22. Authorities deny the victims' health is at risk.

Sunday, March 13, 2011 18:59 +0900 (JST)

http://www3.nhk.or.j...lish/13_28.html

Edited March 13, 2011 by jfchandler

[jfchandler]

Mayors call for safer nuclear facilities

NHK -- A group of municipalities that host nuclear power plants in Japan have urged the central government to do all it can to ensure the safety of the facilities.

The statement came after a radiation leak forced residents to evacuate the area in a 20-kilometers radius around the Fukushima Number One nuclear power plant.

The head of the group, Tsuruga City Mayor Kazuharu Kawase, met the Director-General of the Nuclear and Industrial Safety Agency Nobuaki Terasaka on Saturday evening.

Mayor Kawase said that the municipalities were shocked that residents living near the damaged power plant were ordered to evacuate.

Kawase strongly demanded the agency look into the cause of the incident and boost disaster preparedness for the safety of the residents.

The mayor says that municipalities across the country are worried that a similar accident may occur at a plant near them.

He says that the group will closely watch how the government will try to improve nuclear power plant quake resistance based on the lessons from the latest accident in Fukushima.

Sunday, March 13, 2011 07:09 +0900 (JST)

[Maestro]

Translation from the news ticker of German-language online newspaper in Switzerland:

2011-03-13 14:53 UTC

Russia announced they will supply more liquid gas to Japan. The news agency Itar-Tass reported that a tanker wit 19,500 cubic metres is on its way to Hiroshima. A further 100,000 cubic metres are scheduled for next week.

[jfchandler]

This is the first reference I've seen to this, so I thought it was worth noting... in a recent NHK report:

Edano said the company is mixing boric acid with the water to help absorb neutrons to slow nuclear fission.

Edano added that government's Nuclear and Industrial Safety Agency has endorsed the procedure.

Self-Defense Force troops, who are actually in charge of the cooling process, are using pump trucks and other methods to inject the sea water. They say the work started on Saturday evening will be completed on early Sunday.

[WarpSpeed]

Translation from the news ticker of German-language online newspaper in Switzerland:

2011-03-13 14:06 UTC

The pressure in reactor 3 is rising steadily, the government warns about a new explosion. "If there is a meltdown in reactor 3 the worst can happen because because the special rods in this reactor contain the highly toxic Plutonium", wrote Greenpeace.

And if the wind shifts south west for any length of time ?

[jfchandler]

And a bit of clarification from NHK on just what the Japanese regulation is on reporting radiation leaks:

The report pertains to Fukushima Daichi Reactor No. 1:

The company says radiation levels near the front gate of the plant gradually went down after rising to 1,015 microsieverts per hour on Saturday afternoon. But levels rose again to 882 microsieverts [per hour] on Sunday morning. Radiation levels above 500 microsieverts must be reported to the government by law.

[jfchandler]

Translation from the news ticker of German-language online newspaper in Switzerland:

The pressure in reactor 3 is rising steadily, the government warns about a new explosion. "If there is a meltdown in reactor 3 the worst can happen because because the special rods in this reactor contain the highly toxic Plutonium", wrote Greenpeace.

I think people are mixing up a bit two very different issues...

One issue is a hydrogen explosion like yesterday at Reactor No. 1, where the exterior building was damaged but the reactor supposedly remained intact... That's not good...but apparently not a huge disaster.

A separate issue is if there was an explosion that ruptured or emanated from the reactor vessel itself, which would then directly spread highly radioactive materials all over the place...

Both explosions, but the first is a very different matter from the second.

[jfchandler]

Factbox: Experts on explosion at Japan nuclear plant

Sun Mar 13, 2011 11:38am EDT

(Reuters) - Japan was fighting to stop fuel rods in three earthquake-damaged reactors at the Fukushima Daiichi plant from overheating after some controlled leaks of radioactive steam into the air to relieve pressure.

The fear is that if the fuel rods do not cool, they could melt the container that houses the core, or cause an explosion, and in a worst case scenario, release radioactive material into the wind.

Here are comments from experts:

MORE: http://www.reuters.com/article/2011/03/13/us-japan-quake-experts-idUSTRE72C2M020110313

[jfchandler]

Factbox: Timeline of Japan's unfolding nuclear crisis

Sun Mar 13, 2011 11:00am EDT

TOKYO (Reuters) - Japan is under global scrutiny over the handling of its nuclear crisis after a huge earthquake crippled three reactors at a nuclear power complex, raising fears of an uncontrolled radiation leak.

Below is a timeline of statements made by Japanese authorities and the complex's owner, Tokyo Electric Power (TEPCO), after the quake struck on Friday, the strongest tremor ever recorded in Japan at a magnitude of 8.9.

[The info posted in this link is a pretty detailed timeline of what's occurred with the reactors...]

MORE: http://www.reuters.c...E72C2DH20110313

Edited March 13, 2011 by jfchandler

[Jdietz]

Reposting link straight from the source, as it will be buried in the history now. They're still posting regular updates:

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

[Tanaka]

where is the radiation going? Is it blowing towards North America?

My question then is, will it be safe to fly? If one looks at the air routes, they seem to fly over Japan and through the radiation cloud.

Please, someone tell me I am wrong.

WIND

CNN just had a professor on who explained that there is no melt dow... reactors are build failure-proof... the radiation from a scan are 100-1,000 times more than standing next to the reactor for an hour...

In other words: Carry on, don't worry be happy. Nothing to see here folks, move along.

Reactors failure-proof? What a load of ignorant, complete and utter bullshit!

[jfchandler]

Wind direction monitored near quake-hit Japan nuclear plant

Sun Mar 13, 2011 10:38am EDT

TOKYO (Reuters) - The wind over Japan's earthquake-damaged nuclear complex will remain blowing from the west during the night on Sunday, pushing any radioactivity toward the ocean, an official at Japan's Meteorological Agency said.

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

Earlier in the day, the wind was blowing from the south, raising concerns radioactivity could affect residential areas.

"The wind is expected to blow westerly during the night, in the direction where there are no residents," the official said.

MORE: http://www.reuters.c...E72C27A20110313

Edited March 13, 2011 by jfchandler

[jfchandler]

Reposting link straight from the source, as it will be buried in the history now. They're still posting regular updates:

http://www.tepco.co....se/index-e.html

Jd, I'm not sure what point you're trying to make... We've been posting TEPCO's links and/or their actual English updates from that site regularly for the past two days...

[Jdietz]

Relax, just reposting the link Reuters is apparently using as one of its sources so we all can stay up to date without having to wade through 10 pages of history.

Site is a bit overloaded at the moment though.

[jfchandler]

This is the first reference I've seen to this. Prior TV posters here have been saying the plant was due to be closed... Apparently not.

Stricken Japan nuclear reactor past due date

Sun Mar 13, 2011 8:31am EDT

TOKYO (Reuters) - A 40-year-old nuclear reactor facing a possible meltdown in northeastern Japan was originally scheduled to go out of commission in February but had its operating license extended another 10 years.

The earthquake-stricken No. 1 reactor operated by Tokyo Electric Power Co's Fukushima Daiichi power plant is the utility's oldest atomic core.

It was originally scheduled to operate only 40 years.

But the Japanese government's Nuclear and Industrial Safety Agency approved TEPCO's application to keep it hot after inspecting the facility, according to a statement on the Ministry of Trade Economy Industry's website.

MORE: http://www.reuters.com/article/2011/03/13/us-japan-quake-reactor-idUSTRE72C1FT20110313

[harrycallahan]

I've been doing some reading.

Once the control rods are inserted which happens immediately when shutdown is initiated the main uranium reaction comes to a halt. After that it takes time for the residual isotopes to decay sufficiently for the core to reach a cool state. That's about 2-3 days.

Expect this to be a non-story by about Tuesday. (catatrosphic meltdown concerns)

Edited March 13, 2011 by harrycallahan

[jfchandler]

Don't worry... Be happy....

No danger of major Japan radiation leak: UK expert

LONDON | Sun Mar 13, 2011 10:10am EDT

(Reuters) - Frantic efforts in Japan to cool three nuclear reactors may avert a collapse of the radioactive cores and a more costly clean-up, but there is no risk of an extensive radiation leak, a top UK academic said.

Engineers fought on Sunday to avert a meltdown at earthquake-crippled nuclear reactors by pumping in cooling seawater after Tokyo said it was assuming partial damage had already happened.

The risk is that uranium and plutonium fuel may fall in on itself, as their metal sheaths melt, creating a molten deposit at the bottom of the reactor which may be impossible to remove, as happened at Three Mile Island in Pennsylvania in 1979.

"Because of the way the core was destroyed (there) it meant that even after it cooled down they couldn't take the fuel out," said Robin Grimes, director of the Center for Nuclear Engineering at Imperial College London.

"They had a load of rubble at the bottom of a metal pot."

MORE: http://www.reuters.com/article/2011/03/13/us-japan-quake-nuclear-interview-idUSTRE72C1MI20110313?pageNumber=1

[jfchandler]

That kind of addresses a question I had posed earlier... once they start using sea water and boron, then what? Jdietz posted a couple days more... You're saying 2-3 days....

Let's hope you're right...and the Japanese can keep things in hand for that much longer.

Unfortunately, the risk, I gather, is that when things like today happen where the rods of Reactor No. 3 are significantly exposed and not covered in coolant, there's the potential risk of a reactor explosion... That's what the scientists have been warning.

I've been doing some reading.

Once the control rods are inserted which happens immediately when shutdown is initiated the main uranium reaction comes to a halt. After that it takes time for the residual isotopes to decay sufficiently for the core to reach a cool state. That's about 2-3 days.

Expect this to be a non-story by about Tuesday. (catatrosphic meltdown concerns)

Edited March 13, 2011 by jfchandler

[Jdietz]

while this is true, there are a number of slightly worrying observations:

- During these 3 to 4 days (and up to a week or so) there need to be water cooling as well

- The fact that they are adding Boron to the water may point to the fact that the reaction is ongoing / maybe the control rods haven't been fully inserted due to warping of the structure by the quake

- They can't confirm on their instruments that the water they are pumping in is actually raising the level in the reactor. Not sure at this time if it is an instrument failure or something else. I don't think they are willing to go in and have a look...