Nuclear events taking place in Japan. / General Chatting / Forums

Forums

4hv.org :: Forums :: General Chatting

« Previous topic | Next topic »

Nuclear events taking place in Japan.

first previous 2 3 4 5 next last

Move Thread

LAN_403

Chris Russell

Sun Mar 13 2011, 04:02AM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

Patrick wrote ...

No panic is underway on my part. There has been water-soluable release of radioactive chemistry, I will respectfully remind you that the consequences and potential for the pressure vessel to fail are not trivial, and please show me any nations' official emergency documents, that say: "add sea water here". If they are adding sea water to the primary cooling circuit they are at least in fear of total loss of core containment.

Pure speculation at this point. The fact that they're using seawater now more likely reflects the fact that this reactor is now considered a total loss, and fresh water is best retained for the reactors that do have a chance of being used again; up until recently it was hoped that the reactor could be brought under control without damage to the core. Total loss of core containment remains quite unlikely. Poisonous death clouds of radioactive cesium remain even more unlikely. Being vigilant is wise at this point; claiming that you need thyroid protection at this point is at best irresponsible. There's enough to worry about right now without throwing more FUD into the mix.

Patrick wrote ...
I dont know that anyone can be sure that bulk fission has been stopped, and the cesium is a potential sign that fuel rods are damaged/destroyed. If the fuel melts/breaks away from the control rods, then they can pile up at the bottom of the reactor assume different geometry and begin heating again.

I was specifically responding to your concerns about void coefficients; that implies that the core was still fissioning after the shutdown. That's not the case. The control rod insertion essentially stopped the fission, dropping the reactor's thermal output by 90%. The residual heat in the reactor is the result of many radioactive byproducts that cool off much more gradually. If the core has undergone a meltdown, fission may have resumed, but that's got little to do with whether the reactor was shut down in the first place.

Let's keep it civil, folks. I'd hate to have to lock an important thread like this one because tempers couldn't be kept in check.

Nah

Sun Mar 13 2011, 04:25AM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

I would like to apologize for offending anyone. This is a major crisis and I am sorry if it seemed like I wasn't taking it seriously. Also, you know I'm asian. I have family living in Korea.

Chris Russell

Sun Mar 13 2011, 04:32AM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

Nah wrote ...

I would like to apologize for offending anyone. This is a major crisis and I am sorry if it seemed like I wasn't taking it seriously. Also, you know I'm asian. I have family living in Korea.

No worries. I think everyone's just a little on edge right now. The bad news just seems to keep coming, and we're all left trying to sort the useful information from the noise so we can make some sort of sense out of it all. It's very easy at times like this to accidentally convey the wrong idea, or to misinterpret someone else's intent. Hopefully we can keep that in mind so that our discussion of these events remains open, honest, and productive.

Proud Mary

Sun Mar 13 2011, 10:58AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Ash Small wrote ...

Apparently radiation levels near the reactor are such that one hour's exposure is equivalent to the normal exposure in a year. Is anyone able to interpret anything from this? (around 9000 times normal levels)

In the UK, a working figure of 2.5 mSv is generally given as the annual individual exposure from all sources, including cosmic rays, K40 ingested in food, radon exposure from local geology, living in brick or stone built houses, diagnostic X-rays, and proximity to nuclear power stations. In some parts of the UK, especially in Devon and Cornwall, where there is significant uranium mineralisation, radon radiation exposure can be as high as 6 mSv per year.

So if we are conservative in interpreting the journalistic 'one hour's exposure is equivalent to the normal exposure in a year,' we can suppose it to mean an hourly dose of 5 mSv.

To put this in perspective, each incremental increase of 100 mSv is reckoned to increase the probability of devoloping cancer by 1%. If 1 million people are exposed to 5 mSv/hr for 20 hrs, then 10,000 of them will develop cancer as a result.

A single dose of 1 Sv will cause radiation sickness, and 4 - 5 Sv will kill 50% of those exposed to it.

IntraWinding

Sun Mar 13 2011, 02:38PM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

Hearing they've used sea water as coolant worries me. It's possibly a previously assessed safe emergency action but instead, they might have acted in haste to prevent an imminent disaster with a method that has 'untold' consequences.

Salt water is renowned for its corrosive properties: Whilst Google shows zirconium is resistant.

there will likely be lots of other materials exposed to it.
Another possibility is, sea water contains a wide range of elements which exposed to radiation in the core may transmute to radioactive isotopes not usually encountered in a reactor accident.

Conundrum

Sun Mar 13 2011, 03:44PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Using sea water is far better than letting the core melt.
Yes its a last resort method of cooling the hot core but it does work at least for cooling the exterior of the pressure vessel to reduce the pressure inside to safer levels and reduce the chances of a complete meltdown and subsequent breaching of the pressure vessel.

Either way reactor *1's power generating days are over no matter what they do as the turbines and surrounding infrastructure are gone so at this point its all about containment not what can be salvaged.

Flash news, depending on which reports you read the overheating at Reactor 1 is barely under control despite the salt water + boron flooding and Reactor 3 is experiencing a similar hydrogen build-up to the one which caused the explosion in *1.

Also another reactor at Onagawa is experiencing difficulties, possibly the start of a LOCA.

Worst case scenario, if they can't control the hydrogen build-up there could be a similar explosion as happened at *1.

EDIT 2:- Yup, another hydrogen explosion, looks like *3 is now in numerous fragments and despite what the news is saying I can see that the damage is far, far worse than at reactor *1.

Is it just me or does this almost look like a design flaw, surely emergency venting even of hydrogen should not cause such a massive blast?

-A

"Botheuuuurgh" said Pooh, as he contracted radiation sickness...

Dr. Drone

Mon Mar 14 2011, 12:08AM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Marko

Mon Mar 14 2011, 11:46AM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

The unit 3 blows:

Looks like it's "lid" was thrown at least a hundred meters into the air.

Marko

Dr. Drone

Mon Mar 14 2011, 06:24PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Coronafix

Mon Mar 14 2011, 10:25PM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Japan was moved by 8 feet after this quake.

Dr Spark, your Arizona water frontage may not be worth the memory of the cleanup.

,000-bodies-found-on-Japan-shore%27

first previous 2 3 4 5 next last

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob