Japanese earthquake / tsunami discussion

maquiladora

Anyone know why the rods are fully exposed again, only a few hours ago they had the water back up to a depth of 2 metres?

kona

Rob A. Bank wrote: »

Are these nuclear clowns still saying this is less severe than the Three Mile Island nuclear disaster ?

Only one reactor was involved in Three Mile Island without the release of radioactive gasses into the atmosphere.

The (reliable) evidence from non-Japanese sources is that radioactive Cesium-137 and Iodine-131 have been detected 160 km away.

Will you please read the facts before you call qualified people clowns?

TMI was a pressurised water reactor rated at 800Mw

The plants in fukushima are Boiling water reactors, a totally different design.

The Unit 1 is 350 Mw and 3rd is 750 Mw.

Both are smaller than the Three mile Island Plant, The incident at TMI didnt emit radiation because the cooling system is seperate to the water used to work the Turbines to produce power.
The Steam in a BWR is radioactive unlike TMI , and has been vented, this will cause radiation.


Stop posting ****e you have no clue about, pasted from some random source you googled, to anybody who understands whats going on, your embarrasing yourself.

JONJO THE MISER

Why the hell isnt the Irish government telling Irish people to get out of Japan, with the wind expected to change tomorrow and rain it could rain down radioactive on Tokyo.

Whahey!

Think its to do with the pressure from the steam - that its too powerful to get the water into the vessel.

kona

maquiladora wrote: »

Anyone know why the rods are fully exposed again, only a few hours ago they had the water back up to a depth of 2 metres?

Could be a leak, also some will flash off as steam and evaporate, maybe the pumps have failed or stopped.

ScumLord

maquiladora wrote: »

New York Times quoting a Pentagon source.

Neither of which are known for their reliability when it comes to information. IE, Iraq's WMD, and a news for profit paper can never be truthful in my opinion they're to biased towards controversy.

Turtwig

Well if people can get themselves off the panic bus for a moment.

Cold Shutdowns have been achieved at Fukushima Daini which had also declared a State of Emergency. Units 1, Units 2, and 3 are now shutdown with temperatures not exceeding 100ºC. Unit four is well on target. Effectively the evacuation zone around Fukushima Daini is expected to be rescinded.

Radiation levels in Fukushima Daichi today at 13:55 GMT were 15 m Sv /hr. Comparably less to the figure 50 mSv/hr after the second hydrogen explosion rocked unit 3 early this morning GMT time.

maquiladora

BULLETIN: Fuel rods fully exposed again at Fukushima nuclear power plant: TEPCO

TOKYO, March 15, Kyodo

Tokyo Electric Power Co. said Monday fuel rods were fully exposed again in the No. 2 reactor of the Fukushima No. 1 nuclear power plant as of 11 p.m.

TEPCO said a steam vent of the pressure container of the reactor that houses the rods was closed for some reason, leading to a sudden drop in water levels inside the reactor.

Stevek101

kona wrote: »

The Unit 1 is 350 Mw and 3rd is 750 Mw.

Isn't Unit 1 is actually 460 and both 2 and 3 784 Mw? All of which are having difficulties. Unit 3 is using MOX fuel which is a cause for greater concern.

geetar

JONJO THE MISER wrote: »

Why the hell isnt the Irish government telling Irish people to get out of Japan, with the wind expected to change tomorrow and rain it could rain down radioactive on Tokyo.

i think its pretty obvious to leave. especially in the affected areas. its not really necessary

Whahey!

How long can the fuel rods be fully exposed before they heat up to the point of melting?

maquiladora

NHK says TEPCO say they are doing eveything they can think of to try and stop the fuel from melting but they cannot release air or inject water now...

kona

Stevek101 wrote: »

Isn't Unit 1 is actually 460 and both 2 and 3 784 Mw? All of which are having difficulties. Unit 3 is using MOX fuel which is a cause for greater concern.

You could be right, I didnt check up on it, its just off the top of my head from info i read on friday, Unit 1 is considerable smaller than the rest, and indeed unit3 used MOX, regardless of the fuel its not going to go into meltdown IMO.

For all the lunatics out there, Nuclear Fission can occur in nature too, maybe check a few caves in Donegal

Turtwig

Whahey! wrote: »

How long can the fuel rods be fully exposed before they heat up to the point of melting?

Above 1000 º C they start to deform, above 1300 ºC there's a strong possibility they have melted. 1400 ºC Melting is pretty much underway.

kona

Whahey! wrote: »

How long can the fuel rods be fully exposed before they heat up to the point of melting?

Melting point of Uranium is around 1000 C, Usually in normal conditions the reactors is around 500 C , Now fission isnt taking place so, there are no Neutrons to cause further fission and heat, so its just residual heat, thats been cooling for 3 days.

You would need proper figures to work it out exactley, but Id guess it wouldnt be too long if there isnt cooling, a matter of hours.

maquiladora

TOKYO — Japanese officials say the nuclear fuel rods appear to be melting inside all three of the most troubled nuclear reactors.

Chief Cabinet Secretary Yukio Edano said Monday: "Although we cannot directly check it, it's highly likely happening."

Some experts would consider that a partial meltdown of the reactor. Others, though, reserve that term for times when nuclear fuel melts through a reactor's innermost chamber but not through the outer containment shell.

http://www.chron.com/disp/story.mpl/ap/top/all/7471312.html

Sierra Oscar

3.29pm: Japanese officials say the nuclear fuel rods appear to be melting inside all three of the most troubled nuclear reactors, according to Associated Press.

Chief Cabinet Secretary Yukio Edano said: "Although we cannot directly check it, it's highly likely happening."

http://www.guardian.co.uk/world/blog/2011/mar/14/japan-tsunami-nuclear-alert-live

Not out of the woods yet.

The plant workers attempting to avert disaster must be a bag of nerves at this stage considering they have been at it since Friday and have seen two explosions occur. Lets all keep them in our minds.

opinion guy

OK something I don't get.

I get that the water is needed for cooling. But are there not control rods that can be raised and lowered in order to control the rate of reaction ? And aren't they not dropped into the 'off' position by the failsafes ?

Then why are the reactors still generating heat in the first place ?

Forgive I'm a bit rusty. Its been at least 13 or 14 years since I studied any of this

digme

irelands over run with nuclear experts from county clare
bunch of parrots

Morlar

digme wrote: »

irelands over run with nuclear experts from county clare
bunch of parrots

And begrudgers from where ?

If their information is accurate who cares where they are from or where they got it from ?

Do you really think we should all sit around and wait for some stray nuclear physicist to wander into the thread ?

Turtwig

opinion guy wrote: »

OK something I don't get.

I get that the water is needed for cooling. But are there not control rods that can be raised and lowered in order to control the rate of reaction ? And aren't they not dropped into the 'off' position by the failsafes ?

Then why are the reactors still generating heat in the first place ?

Forgive I'm a bit rusty. Its been at least 13 or 14 years since I studied any of this

Controls rods control the rate of reaction within the reactor, once they are fully inserted the chain reaction is stopped. However, there is still radioactive decay happening within the reactor and as a result heat continues to build up in the core. This heat build up is enough to cause a meltdown if it is not stopped.

opinion guy

OSI wrote: »

The control rods did indeed deploy exactly as intended and all nuclear reaction within the reactors stopped at that point. However the fuel is still extremely hot and will continue to be so for a good while.

Yes that makes sense to me. But if no further reaction were occurring then the fuel would not heat up in the absence of coolant - it would only cool less quickly. So it can't be as simple as that.


Edit: Ok Malty_T cleared it up for me. THanks dude

digme

Morlar wrote: »

And begrudgers from where ?
Do you really think we should all sit around and wait for some stray nuclear physicist to wander into the thread ?

no no we have many of them right here it seems on boards.

opinion guy

Malty_T wrote: »

Controls rods control the rate of reaction within the reactor, once they are fully inserted the chain reaction is stopped. However, there is still radioactive decay happening within the reactor and as a result heat continues to build up in the core. This heat build up is enough to cause a meltdown if it is not stopped.

Hmm so does that mean nuclear fuel rods always have to stored in water or some coolant ?

kona

Some lad on BBC just gave the most accurate information on this Nuclear Issue Ive heard all weekend, He explained it perfectly, even had a diagram.

Fallschirmjager

i think there is a lot of confusion out there:

it appears the aircraft carrier was not affected, a chopper flying relief missions from it were and a scrubbed shower later and the equivalent exposure of an xray (if i read that correctly) they are back in operation so its not exactly you growing 2 heads or shoveling waste from a reactor ala chernobyl. the aircraft carrier then moved as a precaution, i think people are getting flashes of information and adding it all up and i think the media is hyping it up.

having a discussion about the nuclear industry is a bit like the abortion debate, everyone reverts to sides and finger pointing.

i would just once like to have a rational debate on it without the screeching from either side, but to be realistic, i am asking this on after hours

Turtwig

opinion guy wrote: »

Hmm so does that mean nuclear fuel rods always have to stored in water or some coolant ?

Yep, even spent fuel from reactors is usually kept in water coolant.

edit : Confab said it better.

Mr Benevolent

opinion guy wrote: »

Hmm so does that mean nuclear fuel rods always have to stored in water or some coolant ?

Live ones, yes. Spent ones, no. At least not after they've cooled down.

maquiladora

Kyodo : Radiation twice the maximum seen so far detected at nuke plant.

opinion guy

Confab wrote: »

Live ones, yes. Spent ones, no. At least not after they've cooled down.

Makes sense