Merged nuclear power safe?

[BenBurch]

Consider the amount of mixing. The total volume of gas that is going to be evolved mixed with cubic miles of air. And it's all short-half-life gas unless there are processes at work I don't know about. ¹³⁵Xe has a half life around ten hours.

 

[pipelineaudio]

Consider the amount of mixing. The total volume of gas that is going to be evolved mixed with cubic miles of air. And it's all short-half-life gas unless there are processes at work I don't know about. ¹³⁵Xe has a half life around ten hours.

Lets say that some sort of other factor, like hydrogen or some such explodes the core into the air and atomizes it, what could the possibilities be then?

 

[BenBurch]

Lets say that some sort of other factor, like hydrogen or some such explodes the core into the air and atomizes it, what could the possibilities be then?

I can't imagine that happening. However, metal oxides don't tend to remain Aerosols all that long. Remember that there were HUNDREDS of above ground nuclear tests that put vaporized Uranium and Plutonium and other stuff into the air quite efficiently. It was not a huge disaster even if it was most unwise.

 

[Hindmost]

Lets say that some sort of other factor, like hydrogen or some such explodes the core into the air and atomizes it, what could the possibilities be then?

Then it becomes a fairly major release...not like chernobyl, but fission products will be sent into the atmosphere. The core wouldn't be atomized--but there would be significant release of noble gases and other fission products. This is not good--but not enough details yet.

glenn

 

[pipelineaudio]

Thank you for helping assuage my fears. Hopefully mattus and other nuclear types will add in as well

 

[MattusMaximus]

Thank you for helping assuage my fears. Hopefully mattus and other nuclear types will add in as well

I'm trying to follow the latest developments via the World Nuclear News website. Here are some of the most recent updates...

(Breaking News) Loss of coolant at Fukushima Daiichi 2

... The Japan Atomic Industry Forum reported back statements from the Nuclear and Industrial Safety Agency (NISA) saying that Tepco made a notification at 8.50pm that some fuel rods were presumed broken, based on radiation detected.

I wonder if that last paragraph is in reference to the latest discussion about a spike in radiation levels? Anyone?

(Some Good News ) Cold shutdowns at Fukushima Daini

Two more reactors at Fukushima Daini have now achieved cold shutdown with full operation of cooling systems. Engineers are working for the same at the last unit. ...

I would hope the news media picks up on this last one. It'd be nice to see some kind of good news from them amidst all of the hysterical yammering

 

[MattusMaximus]

why don't they just dump a few million cubic yards of concrete onto all 4 cores?

That's probably what they'll end up doing eventually, but the cores have to cool down first.

 

[LoudHoward]

Well, news.com.au, possibly the most unreliable source in history (swinging towards the hysterical side) just posted this on their live disaster blog:

And just in: the company that runs the facility says the seal around the reactor does not appear to have been damaged.

Sounds promising?

 

[MattusMaximus]

How do you propose they get the rods out if they're buried in concrete?

You don't. The reactor core material is probably a total write-off by this stage. Once the immediate situation is stabilized, these reactors will be scrapped, and that is going to be expensive

 

[Kestrel]

The problem with the press is not a lack of critical thinking. They know damned well what is really going on. They also know that so long as they keep people scared of nuclear Armageddon they will keep watching. Ratings take precedence over facts.

PBS had a short segment on the reactor problems. Two real experts and clear explanations of what has already happened and what could happen. Unfortunately, only a small segment of TV viewers get their news from PBS.

ETA: One of the experts said the fuel for the diesel generators was stored in above ground tanks. This may have been why the emergency power failed.

 

[Kestrel]

You don't. The reactor core material is probably a total write-off by this stage. Once the immediate situation is stabilized, these reactors will be scrapped, and that is going to be expensive

They wrote off the cores when they dumped the boron solution and followed up with seawater.

 

[qarnos]

Just a quick question for the nuclear gurus. Given that the main problem here seems to be loss of coolant due to lack of electrical power to pump the water, is it wise to automatically shut down the reactor in the event of an earthquake, regardless of any reactor damage?

Yes - I know - hooray for hindsight, but it seems the reactors themselves held up just find to the quake and tsunami, but were let down by the power system.

 

[PhantomWolf]

Good reason to start migrating reactors from conventional rod to pebble bed.

 

[Hindmost]

Just a quick question for the nuclear gurus. Given that the main problem here seems to be loss of coolant due to lack of electrical power to pump the water, is it wise to automatically shut down the reactor in the event of an earthquake, regardless of any reactor damage?

Yes - I know - hooray for hindsight, but it seems the reactors themselves held up just find to the quake and tsunami, but were let down by the power system.

The reactors did shutdown automatically. It only takes a few seconds to shut down a reactor. Unit 2: The diesels started like they were supposed to and actually were keeping the reactor in safe shutdown....then the Tsunami it and took the diesels off line. This is a station blackout and becomes a problem because even though the reactor is shutdown, the fisson products will produce about 5% of the total reactor heat and decay exponentially to less than 1% after about 10 days--decay heat is still about 2% of total reactor power about now...going on memory...so I may be off a bit. That fission product heat is still quite a few MW of power must be cooled...which was difficult without electrical power to the emergency cooling pumps. Hence the last ditch effort to use sea water to keep the core covered. If it doesn't stay covered...then mechanical failure and partial meltdown can occur...and has a bit.

Now,this is not like Chernobyl because that reactor was full critical and probably prompt critical when it had its explosion...full power ripping apart of the reactor like that is NOT what is happening here.

glenn

 

[Kestrel]

Good reason to start migrating reactors from conventional rod to pebble bed.

Any of the small modular reactor designs that don't require an active cooling system would get around this problem.

 

[bobdroege7]

http://www.guardian.co.uk/world/2011/mar/14/fukushima-nuclear-power-plant-japan


Perhaps an explosion at the number 2 plant now.

Radiation levels 680 usieverts or 68 mrem at a monitoring station north west of the plant.

It is the Guardian, so I would look for other sources to confirm.

 

[MattusMaximus]

They wrote off the cores when they dumped the boron solution and followed up with seawater.

This ^^^

Boy, this mess is going to cost somebody a helluva lot of money

 

[Sword_Of_Truth]

Law enforcement in hawaii is claiming that radioactive clouds are coming to hawaii in two days and law enforcement is to be wearing NBC suits

This isnt public info but I'm spilling what I heard

Is there any chance of truth to this?

Tell them to take that stuff off or they'll be at risk of a solar radiation overdose.

 

[Travis]

The reactors did shutdown automatically. It only takes a few seconds to shut down a reactor. Unit 2: The diesels started like they were supposed to and actually were keeping the reactor in safe shutdown....then the Tsunami it and took the diesels off line. This is a station blackout and becomes a problem because even though the reactor is shutdown, the fisson products will produce about 5% of the total reactor heat and decay exponentially to less than 1% after about 10 days--decay heat is still about 2% of total reactor power about now...going on memory...so I may be off a bit. That fission product heat is still quite a few MW of power must be cooled...which was difficult without electrical power to the emergency cooling pumps. Hence the last ditch effort to use sea water to keep the core covered. If it doesn't stay covered...then mechanical failure and partial meltdown can occur...and has a bit.

Now,this is not like Chernobyl because that reactor was full critical and probably prompt critical when it had its explosion...full power ripping apart of the reactor like that is NOT what is happening here.

glenn

He was asking if the reactors would have survived if they had not been shutdown automatically. I'm curious myself as it now seems like they would still be operating normally if they hadn't been SCRAMed.

 

[MattusMaximus]

According to this report - not sure how reliable it is - there was a brief leak of radiation from one of the reactors after another explosion. However, as is stated in the last paragraph...

... Detectors showed 11,900 microsieverts of radiation three hours after the blast, up from just 73 microsieverts beforehand, Kinjo said. He said there was no immediate health risk because the higher measurement was less radiation that a person receives from an X-ray. He said experts would worry about health risks if levels exceed 100,000 microsieverts.

I expect the media and scare-mongers to scream long & loud about this one, though