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back to article Threat to third Fukushima nuke reactor

The Tokyo Electric Power Co (TEPCO) is pumping seawater through two ailing reactors at the Fukushima Daiichi (Fukushima No 1) nuclear plant in an attempt to cool radioactive materials in the plant, while simultaneously attempting to prevent an explosion in a third. Cooling of the reactors was disrupted by Friday's 9.0 earthquake …

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Flame

Bad publicity for nukes

The anti-nuke lobby will be having a field day.

Though if the 3rd goes "china", they might have just concerns. Uncoolable Nukes? In an earthquake zone? Doesn't look so clever now; the design should have been able to cope.

Feel sorry for the civilians though - they were probably assured it was totally safe, and now they're living in a stadium because it's....errrr....not.

Flames...because it hopefully won't happen.

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Something I only just found out

I had a look on Google maps for the location of Fukushima - people do know these things were built on the coastline right? I'd like to see any building survive a 9.0 megaquake *and* a 33ft tsunami and escape without massive damage. It's also worth remembering that these reactors were of a much older design than some of the ones we have in the UK and that retooling a full installed and functioning reactor with the latest safety features is not an undertaking to be done quickly.

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Silver badge
Stop

by design

reactors are often on the coast precisely because of access to vast quantities of cooling water. I think the reactor is a testament to good design. No malfunction of the pressure containment vessel (yet) and a limited release of radioactive material.

More leaked out of sellafield over a number of years *undetected* than this incident.

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Silver badge

*undetected*

Indeedy -- more like 'unannounced' until those pesky protesters began sampling the waters.

I do love the pro-nuke lobby here becoming more and more hesitant in thier 'It won't happen, it can't happen' as it turns in to 'I hope it doesn't happen' and a creeping 'Oh, shit'.

So, here we are, waiting for Yellowstone Park to go skywards or a lump of the Canary Islands to slip gracefully in to the sea or one mother of a sun spot . . .

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RE: *undetected*

'I do love the pro-nuke lobby here becoming more and more hesitant in thier 'It won't happen, it can't happen' as it turns in to 'I hope it doesn't happen' and a creeping 'Oh, shit'.'

Yeah, isn't it great when loads of people die so you can say 'I told you so' on some internet forum.

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Flame

"Nuclear safety" is a numbers game

It would be even greater if we didn't lobby for and build more nuclear power stations, thereby ensuring those "loads of people" don't have to die in the inevitable catastrophes.

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Anonymous Coward

My original point was...

...that whether you consider the reactors to be safe or not, the press and the anti-nuke lobby's will have a field day.

Joe Public fears the nuke (partly because he doesn't understand it), and this incident provides justification for his beliefs. The facts are irrelevant.

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Anonymous Coward

yeah because

The UK had a magnitude 9.0 earthquake just the other... o wait...

And I'm ignoring most of the media coverage as you can almost visualise them fapping so hard just hoping the reactors meltdown so they can climax and gush all over the camera crews. They're all waiting for their "ooo the humanity" moment.

The reactors have survived, a m9.0 earth quake, a tsunami, and at the moment 3 days of cooling system failures, and they're 30 years old.

Willing to wager the refinery that exploded has done more environmental damage.

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Silver badge

Eh?

I'm not referring to the small number of people affected so far, we usually get, 'OOH, it's not so bad, no-one's died yet so it must be safe.' It's the pro's who rely on a low casualty count.

I'm not saying 'told you so' - that's your stupid game and I'm not playing.

I was referring to the apparent lack of leaks at the place with such an awful reputation they change the name twice to try and disguise how bad things have got. A place that had a 'D' notice on it.

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RE: Eh?

Yeah, we really need something like that to happen over here. That'll show the pro-nuke lobby.

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Anonymous Coward

not that

Not that a meltdown matters due to the third containment layer, but whatever. The main reason to not just let the thing meltdown is that it'll render it useless.

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Already done

Dumping seawater into the reactor to keep it cool and thus prevent a further meltdown has already rendered it useless.

For that matter, if it's had a partial meltdown it's a moot point.

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Anonymous Coward

Meh

http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

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Dead Vulture

Sensationalist

From what I've heard - not from sensationalist media (Yes, you included El Reg) , this has no threat to the reactor.

An eyewitness Nuclear engineer reported (On Sky News 08:20AM) that the explosion barely moved the building and just took off the cladding.

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Anonymous Coward

Praise be! It must be true

If its on Sky News, it must be true, I mean they're never given to selectively presenting the facts in a way pleasing to His Rupertness now, are they?

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Go

no the point is...

Yes, I would be mad to believe Sky News.

But the point is that the presenters etc. were trying to make out it was a terrible situation, this Nuclear engineer wasn't and destroyed their point.

The presenter kicked him off as soon as he said that. Lots of interviews with those in Japan - when the said the situation is not as bad as the media make out then the kick the interviewee for the excuses of time.

Just heard Eamon Holmes respond "You don't know, it's invisible, isn't it?" to a caller saying that the reports were exaggerated.

Point Proven.

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WTF?

Two questions,

what are they doing with this radioactive seawater, what is the effect of seawater on the steel containment vessel/metal fuel rods?

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Boffin

well

1) the excess seawater goes either into the damaged closed loop system (to be flushed later) or into a cooling pond as appropriate. Eventually it will be evaporated and combined with other low level contaminated products to be recycled.

2) short term - very little, they are designed with sea water emergency cooling in mind. Long term is not good but the thinking is that in such an event the reactor is almost scrap anyway.

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Boffin

Also note...

The half-life on the contamination is measured in hours, or even minutes. This isn't a long-term contamination.

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Anonymous Coward

Were is this H2 coming from?

2(H2O) to 2(H2)+O2 is a reversible reaction but requires/releases a lot of bond energy and (normally) a Catalyst, doesn't it? I can't recall from my Physical Chemistry knowledge what energy is required but it I suspect it is more than you would get from recirculating cooling water.

Any scientists amongst you care to comment/guide?

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Boffin

indeed

catalyst is required at room temperature.

Not at high temperature, it is enough to excite polar bonds into buggering off and combining elsewhere. 2273K should be enough (at 1 atm). In fact, at high temperature the process is even more efficient. Higher pressures could increase the temperature threshold but then if it does build up then you suddenly get an overpressure of more H2 gas which is even worse.

Sometimes it is better to vent the slush steam H2 mix and light it controlled, at least you dont take the cooling circuit with you - they may even have done this as there is talk of pumping more water through the system - so the primary cooling pumping system is still working else it would be dump the core in concrete and hope for a controlled explosion..

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Anonymous Coward

H2 comes from..

The zircaloy fuel casings react with steam at high temps to make hydrogen. Most reports claim its due to the casings melting but it happens about 1000degC before the casings melt.

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H2 origin

The excess heat is providing the energy, and I suspect the zirconium cladding of the fuel rods may act as a cataylst

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Silver badge

It's not just dissocation of water.

The equilibrium even at 2000 C is ~3% hydrogen 97 % water. Catalysts don't affect equilibria only rate. The hydrogen is being produced in a chemical reaction - probably zirconium fuel rod components reacting at high temperatures with water/steam

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Bronze badge

Oxidisation of the metal cladding

The bit that is missing from your formula is the the metal in the ziconium alloy cladding. The oxygen combines with that thereby releasing the hydrogen. There should be no free oxygen inside the containment vessel.

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Flame

Re: Were is this H2 coming from?

I believe it's the zirconium cladding of the fuel rods that is responsible for the hydrogen isn't it?

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LDS
Silver badge
WTF?

If they were shutdown, why they overheated?

Is there something the Japanese are not telling? If the reactor was properly shutdown (stopping the nuclear reaction by absorbing the neutrons that keep the reaction going on) from where does the heat comes? Was it the heat produced before the shutdown? If so why it doesn't decrease now? Ok, if the cooling system failed there could be a lot of heat to dissipate, but there should not be more produced. Or the reactors actually didn't stop?

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Silver badge

why they overheated? → #

The primary reaction has shutdown but highly radioactive waste products with very short-half-lives generate a considerable amount of heat as they decay. Without cooling, depending on the reactor design this can lead to overheating and potentially melting

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Boffin

Read this:

http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

Basically, the main reaction is uranium being split. Uranium naturally has a very long half life, (even U235) but it's fission products have very short half lives. Thus, once you've stopped the main reaction (by absorbing the energetic neutrons), these derivative atoms further decay all on their own, giving off heat (up to 10% or the reactor's rating, I believe).

But not for very long...

Personally, I'd like to see more of the thorium reactors reported on a few weeks ago. They don't suffer the same problems, as their safety system is entirely passive. See here:

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

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Grenade

I'd like to comment.

But I'm sure the butt-hurt tree-hugging moderator who deleted my post on the previous thread will censor this one too.

Funny how that comment got deleted but hate-filled racist rants by the likes of Obviously! seem to be acceptable.

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FAIL

Boo Hoo!

"I swore at people who disagree with me and my comment got deleted!"

Grow up Norkolk, El Reg are in now way tree huggers, (I know because I am). You were just offensive.

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Silver badge

We have the technology?

Now that they have killed off the reactors by flooding with seawater, where will they build the replacements?

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# We have the technology?

Same sites most likely. Energy company owns the land and has the infrasturcture there already (albeit damaged). Hopefully any future reactors will be designed to withstand mag 9+ earthquakes with backup generators placed out of the way of any tsunamis

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Boffin

More likely

Modern reactor designs have entirely passive cooling systems which do not require power in the event of a shutdown. They'll probably just build a more modern design of reactor on the same site, after burying the existing cores in concrete.

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Go

"withstand mag 9+ earthquakes"

If the lifetime of the reactor is planned to be 50y, that will not be needed.

Earthquake energy gone now, we hope.

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# withstand mag 9+ earthquakes

Probably right. but....

1). I can't see new designs passing without the integrity in its vital systems being able to withstand such a quake better even if such a quake is exceedingly rare. The public and hence the politicians will demand that.

2). Now you have that design there on paper, it makes sense to build it en masse rather than design each individual ractor seperately.

3). The tectonic pressure was only released on a 200km stretch of the subduction zone. The tension has just been passed elsewhere along the plate boundary. Further big quakes might well happen along japan's western coast in the next 50 years.

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Good /bad publicity

I think this could be good publicity. Think about how well these reactors have performed in the light of a massive earthquake and then a tsunami. And these are fairly old reactors.

It's testament to the skill of the engineers that worked on them that they have withstood so much. Respect has to go to those people.

Here's hoping for a safe shut-down of the remaining reactors. The Japanese people have enough on their plates without having to worry about radiation leaks.

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Unhappy

# Good /bad publicity

You know it'll never be seen that way.

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Unhappy

I'm sure that these were marvels of engineering,

and I'm sure that the people who built them to stay mostly intact after the punishment they sufferered did a great job. I just think it was a bad idea to build them in the first place......

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Same old rubbish 25 years on

It's pleasing to note that the people of Japan don't have a large scale nuclear accident to deal with on top of the catastrophic tsusami, however -

"The maximum potential radiation dose received by any ship's force personnel aboard the ship when it passed through the area was less than the radiation exposure received from about one month of exposure to natural background radiation from sources such as rocks, soil, and the sun."

Why do they always spout such rubbish? You may as well say "a soldier operating in Helmand Province was briefly exposed to the same degree of cranial pressure as is exerted by wearing a hat for a year" (in other words he took a 7.62 to the head and died). It's *exactly* the lies they told the poor souls they sent into Chernobyl post-explosion - "oh you'll be fine as long as you're not in there for any longer than 30mins; that's your lifetime limit". Doesn't really work like that does it?

I'm not saying those sailors are at immediate risk of a very nasty death, but it's not exactly comforting to see our own officials spouting the same rubbish that the Ruskies did 25 years ago. The same rubbish that killed hundreds of workers.

Just be honest with folk - they were exposed to 30-60x the usual dose for a period of 12-24 hours. I know - that doesn't sound quite as cuddly as "from sources such as rocks, soil, and the sun".

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Grenade

Re: Same old rubbish 25 years on

""The maximum potential radiation dose received by any ship's force personnel aboard the ship when it passed through the area was less than the radiation exposure received from about one month of exposure to natural background radiation from sources such as rocks, soil, and the sun."

Why do they always spout such rubbish?"

Because radiation kills everything it touches and the only safe about is zero!

Combine that with the heady heights of mathes/science reached by mainstream journalists and scare stories selling more contnet and you've probably got the reason.

Perhaps TheReg should standard on BED's?

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

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Bronze badge
FAIL

Pump stopped when its fuel ran out?

understand it's touch-and-go, but that seems like a big mistake to make at this point

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Yes

because a 30' high tsunami is unlikely to have damaged their fuel supply, or the communication infrastructure to get more there....

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But there is an even bigger risk, than "just" meltdowns:

Did you ever ask yourself what they do with the spent fuel?

--> They just have to store it forever. And the "cosmetic" explosion of the roofs of several buildings lead to a quite dangerous situation.

Read this article:

A 1997 study by the Brookhaven National Laboratory on Long Island described a worst-case disaster from uncovered spent fuel in a reactor cooling pool. It estimated 100 quick deaths would occur within a range of 500 miles and 138,000 eventual deaths.

http://www.nytimes.com/2011/03/15/world/asia/15fuel.html?_r=2&partner=rss&emc=rssThe

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