Earthquake/Tsunami in Japan

[Babel-17]

http://twitter.com/Joi

1. I feel sorry for the 50 TEPCO staff who were left behind while the others evacuated - #TEPCOpressconf less than a minute ago via Seesmic Web
2. chikawatanabe @miyagawa I think JP media has gone insane to think it's their job to make others apologize. 5 minutes ago via Echofon in reply to miyagawa Retweeted by Joi and 9 others
3. teni Reporter to spokesman: "We don't want to know how you FEEL; tell us what's going on. How was today's explosion different from earlier ones?" 7 minutes ago via Seesmic twhirl Retweeted by Joi and 30 others
4. Another TEPCO press conference coming up soon... 13 minutes ago via Seesmic Web
5. mizuko NHK now giving detailed reports of wind flows and direction after explosion and damage of containment pool i… (cont) http://deck.ly/~xGkJW 21 minutes ago via TweetDeck Retweeted by Joi and 28 others
6. Bottom of second containment chamber so can leak and hard to fix RT @Lawnmowercutter: @Joi what happens with the suppression pool? 21 minutes ago via Seesmic Web
7. Let me qualify: NHK expert saying possibly worst JAPANESE nuclear failure ever - waiting for more info 24 minutes ago via Seesmic Web
8. NHK expert saying that possibly the worst nuclear failure in history - urging officials to release more information ASAP 28 minutes ago via Seesmic Web
9. NHK: explosion, suppression pool pressure drop, 10,000X increase (over normal) radition levels, partial evac of TEPCO staff - reactor 2 29 minutes ago via Seesmic Web

http://www.nhk.or.jp/nhkworld/

 

[tongue_of_colicab]

That doesn't sound good...hope it doesn't get too bad. Not only for the people in Japan, but also for me. I'll be there 10 days from now!

 

[Mize]

This is why the newer designs (where rod shields have to be lifted, rather than rods lowered are so much safer. Power loss? Gravity stops the reaction.

Anyway, I'm due to change planes in Narita on Saturday. I sure hope all goes well.

 

[Kaotik]

This is why the newer designs (where rod shields have to be lifted, rather than rods lowered are so much safer. Power loss? Gravity stops the reaction.

Anyway, I'm due to change planes in Narita on Saturday. I sure hope all goes well.

Gravity doesn't stop the reaction any beter than they did at Fukushima.

All 3 problematic reactors had their control rods inserted normally, without any issues, the same moment as the earthquake hit 'em.
The problem is, even with control rods the power capacity (and thus heat) only drops to 10% first, which means for reactors 2 & 3 depending on their efficiency around 150-200 MW of heat, and from there it needs to be cooled down over time, first 24h drop it to 2%, which is still 3-4 MW's of heat, and then the following 24h's each drop it by 0.5% or so if my memory serves me right.

 

[Gubbi]

Fire at a storage pond at reactor 4 (which is shut down) releases massive amount of radioactivity. The fire is extinguished, but apparently the pond is boiling, indicating loss of cooling there too, with falling water levels as a consequence.

Situation seems out of control.

In other news: Political capital for nuclear power is eroding fast.

Cheers

 

[Kaotik]

In other news: Political capital for nuclear power is eroding fast.

Cheers

Which is just retarted, sure, if you're at coastal area which is also very seismicly unstable, this should give you concerns etc, but most nuclear plants, planned or already in use, aren't.

 

[pcchen]

Which is just retarted, sure, if you're at coastal area which is also very seismicly unstable, this should give you concerns etc, but most nuclear plants, planned or already in use, aren't.

It seems to be a bit naive to assume that only tsunami and earthquake can do such damage to a nuclear reactor.

 

[cjo]

It seems to be a bit naive to assume that only tsunami and earthquake can do such damage to a nuclear reactor.

By all accounts, the reactors + assoociated infrastructure survived the quake intact (even though it was 7x more powerful than the plant was designed to withstand). It was the tsunami which crippled the cooling efforts, which was triggered by a once-in-a-millennium scale earthquake.

If it takes a once-in-a-millennium event to put a nuclear plant in to a state where it *might* have a full meltdown (it hasn't happened yet) in a 40-year-old station, their safety systems / design must be pretty good going.

The odds of Japan experiencing another disaster of this magnitude within 1 or 2 lifetimes are slim.

 

[MfA]

Can someone explain to me how it's a good idea to store used fuel on an elevated floor?

 

[Kaotik]

Can someone explain to me how it's a good idea to store used fuel on an elevated floor?

For whatever reason it apparently is, since it's common practice in nuclear plants.
Most likely due ease of moving them from the reactor.

 

[Mariner]

Which natural disasters other than earthquake and tsunami could damage a nuclear reactor? I presume that they are designed to be 'Typhoon-proof' so the only other thing I can think of would be a direct or near hit by meteor bombardment, in which case damage to a nuclear reactor would be the last of our worries...

 

[MfA]

For whatever reason it apparently is, since it's common practice in nuclear plants.
Most likely due ease of moving them from the reactor.

If you do get into a situation where you want to simply cover it in sand&cement and let it meltdown into the earth you're making it much harder on yourself.

 

[Bouncing Zabaglione Bros.]

In other news: Political capital for nuclear power is eroding fast.

It's a necessary stepping stone to fusion power, without which our civilisation cannot continue in it's present form once the oil runs out. Still, I'd like to see us switch to something more stable like thorium plants in the meantime.

 

[GZ007]

Can someone explain to me how it's a good idea to store used fuel on an elevated floor?

Maybe because the fact that they dont want to get it washed into sea or something like that.

If they would place the whole complex on a higher ground than there wouldnt be such problems now. I heard that the reactor was designed against 6m tsunami.
Its more of the japanese fault than the nuclear reactors.

 

[KimB]

This is a good article about the unreasonable fears regarding the nuclear plant:
http://online.wsj.com/article/SB10001424052748704893604576198421680697248.html

Basically, modern nuclear reactors just don't suffer from the same design flaws that, for instance, caused the Chernobyl disaster, and known improvements to the design of this reactor can prevent even its problems from recurring. There will be some damage from the reactor, but the nuclear reactor will turn out to be a tiny, tiny blip on top of the overall disaster of the tsunami. There is no way the damage it causes will come anywhere close to comparing to the thousands who are already confirmed dead.

 

[MfA]

If it can wash away a ground floor or underground storage facility it can wash away the foundation of the pool ... silly argument.

 

[Gubbi]

Can someone explain to me how it's a good idea to store used fuel on an elevated floor?

Same reason having your backup diesel reactors in the basement of your coastally situated power station. Lack of foresight I guess.

Or, the structures are designed to withstand a certain amount of stress. If the stresses exceed this design limit, all bets are off wrt. risks.

The Fukushima disaster evolved like this:
1. Quake triggers automatic shutdown.
2. Power grid dies, cooling at Fukushima switches to emergency cooling.
3. Tsunami arrives, washes over the anti-tsunami seawall and kills the diesel generators in the basement.
4. Cooling runs off an emergency battery pack.
5. After eight hours emergency battery pack is exhausted, cooling stops.
6. Havok

All the safety systems worked as designed. The failure is a result of failing to anticipate a scenario that exceed the design limits.

Cheers

 

[MfA]

This is a good article about the unreasonable fears regarding the nuclear plant:
http://online.wsj.com/article/SB10001424052748704893604576198421680697248.html

Basically, modern nuclear reactors just don't suffer from the same design flaws that, for instance, caused the Chernobyl disaster, and known improvements to the design of this reactor can prevent even its problems from recurring. There will be some damage from the reactor, but the nuclear reactor will turn out to be a tiny, tiny blip on top of the overall disaster of the tsunami. There is no way the damage it causes will come anywhere close to comparing to the thousands who are already confirmed dead.

In a modern reactor sure ... in these Japanese reactors?

- Blow the top of the lackluster containment building -> done.
- Get a leak in a storage pond containing the dirtiest radioactive material creating a fire -> done.

You wouldn't want to combine the two with a significant amount of spent fuel. I think a Chernobyl grade disaster was pretty close actually, we got lucky.

 

[Grall]

This is a good article about the unreasonable fears regarding the nuclear plant:

You may think it's unreasonable, but when we've had giant explosions in three nuclear reactors in quick succession and a serious fire in a fourth along with ongoing cooling issues in another two, hundreds of thousands of people evacuated along with hazardous levels of radiation released, I'm not so sure most people would agree with you there.

There will be some damage from the reactor, but the nuclear reactor will turn out to be a tiny, tiny blip on top of the overall disaster of the tsunami.

Again that may be your opinion, but the nuclear aspect of this disaster might well end up occupying the majority of public mindshare.

 

[Gubbi]

In a modern reactor sure ... in these Japanese reactors?

- Blow the top of the lackluster containment building -> done.

To my knowledge the secondary containment buildings haven't failed.

The outer structures was blown away by the big hydrogen explosions in yet another instance of "unforseen consequences": The zirconium tubes holding the nuclear fuel reacted with the super heated steam to form zirconium-oxide and hydrogen. When the steam was vented to lower the pressure in the reactor to try injection of water, the hydrogen was vented along with it, then detonating.

Cheers