Massive quake hits off the coast of japan, causing tsunamis accross the pacific

[red]

Things could change, but it sounds like the precautionary features of the Japanese nuclear power plants are much better than Chernobyl.

http://www.nytimes.com/2011/03/14/wo...=3&ref=science

not only that, but they were able to evacuate everyone that lived within like 15 miles of the place before anything serious happened. at chernobyl it happened in the middle of the night and the population had no idea the plant was about to blow

[HarveyWallbangers]

Didn't the Russian government try to hide what was going on? Unlike the Japanese government.

This picture is amazing.

[red]

yes, they try and hide everything in russia. i think we detected all the radiation in the air with a satellite and called them to ask what was going on or else they never would have acknowledged it

[Scott Campbell]

i don't think it was the water supply, its the pumping system that recirculates the water and keeps it cool. the pumps run of the regular energy that the plant supplies, they shut that down after the quake. then they went to the backup diesel generators to run the pumps, those were knocked out by the tsunami. they had a 3rd backup, batteries, but those only had a life of 8 hours.

my thinking is that in the future they should put those diesel generators way the hell up in some tower, so they are far away from any flooding risk. if those diesel generators had survived none of this would have happened i think

That's exactly the kind of engineering design type stuff you learn in a disaster like this.

Though generators in a tower might be more susceptible to hurricanes and tornadoes. Maybe you need 2 sets of generators.

[pbmax]

Sounds like the risk to the general public is being a bit overblown. Some by people that are opposed to nuclear energy.

http://online.wsj.com/article/SB1000...680697248.html

Except that your excerpt fails to account for the melted fuel rods descending into the ground. Where radiation will be more problematic, localized and severe than steam.

Chernobyl, if I recall correctly, was an experimental design. This design is old and highly tested. Three Mile Island had a partial meltdown where partially liquefied fuel material collected in the bottom of the containment structure. A full meltdown, might compromise that structure more than occurred Three Mile Island.

And its worth noting that two of the external containment structures have already been damaged by explosions, so they are already partially compromised in the event of more steam release.

[pbmax]

Allow me to paraphrase from respected media industry leader The Hindustan Times:

http://www.hindustantimes.com/Japan-battling-chain-reaction/Article1-673474.aspx

Reactor #2 now has a fully exposed core and the pump system failed. They are working to restore presently.

EDIT: I am way behind. NYTimes has Tokyo Electric saying that they got seawater back in. Fuel rods were exposed for several hours.

http://www.nytimes.com/2011/03/15/world/asia/15nuclear.html?hp

[pbmax]

People within a 20 km radius of the reactors are being told to stay indoors with a/c and ventilation off.

Dental X-Ray indeed (from Times story above), but still basically good news:

By Monday night, officials said that radiation readings around the plant reached 3,130 micro Sievert, the highest yet detected at the Daiichi facility since the quake and six times the legal limit. Radiation levels of that magnitude are considered elevated, but they are much lower than would be the case if one of the container vessels had been compromised.

[pbmax]

3rd explosion reported, Reactor 2, now they are three for three. This link makes a leap to worse than Three Mile Island, but its unclear how they confirmed a total meltdown other than a comment that it was impossible to rule it out. Haven't seen word whether the explosion was expected as part of a pressure release. Also unsure if water is still getting to the fuel rods.

http://www.telegraph.co.uk/news/worldnews/asia/japan/8382139/Japan-crisis-third-explosion-raises-spectre-of-nuclear-nightmare.html

Water is being pumped in to No. 2, lending plausible that the steam release and subsequent explosion were planned.

http://www.nationalpost.com/news/explosion+rocks+Japanese+nuclear+plant/4438546/story.html

[Scott Campbell]

I thought they could have a relatively safe "meltdown" as long as the containment facility wasn't breached.

[Patler]

i don't think it was the water supply, its the pumping system that recirculates the water and keeps it cool. the pumps run of the regular energy that the plant supplies, they shut that down after the quake. then they went to the backup diesel generators to run the pumps, those were knocked out by the tsunami. they had a 3rd backup, batteries, but those only had a life of 8 hours.

my thinking is that in the future they should put those diesel generators way the hell up in some tower, so they are far away from any flooding risk. if those diesel generators had survived none of this would have happened i think

That's exactly the kind of engineering design type stuff you learn in a disaster like this.

Though generators in a tower might be more susceptible to hurricanes and tornadoes. Maybe you need 2 sets of generators.

These are 40 year old reactors built with 50 year old technology. Current state of the art doesn't require pumps in the backup cooling systems. Cooling is based on convection flow, so will keep circulating without any source of external power at all.

[Scott Campbell]

These are 40 year old reactors built with 50 year old technology. Current state of the art doesn't require pumps in the backup cooling systems. Cooling is based on convection flow, so will keep circulating without any source of external power at all.

Outstanding.

They've proposed a nuke plant here in UT.

[pbmax]

I thought they could have a relatively safe "meltdown" as long as the containment facility wasn't breached.

Well, that is a matter of some conjecture. Chernobyl was entirely different and Three Mile Island has a partial meltdown. A full meltdown, fuels rods and control rods liquefied, burn very hot without cooling. Harv's article pointed out that a normally functioning reactor operates just over 500 degrees. But an uncooled one can get well past 1000.

A liquefied fuel source could, under the right conditions, get even hotter as the control rods would likely not be as effective once the pellets melt. It would still take a tremendous amount of energy to get through the main containment fixture (made of steel and concrete), but its theoretically possible. No one has tested the possibility live before. The good news is that it seems all three reactors are still being fed seawater (a technique called feed and bleed).

There Mile Island had a shorter period of time with one reactor with exposed fuel, suffered a partial meltdown and was found to have some fuel collected at the bottom of the containment structure.

If the main containment structure hasn't been compromised (and radiation levels seem to indicate it hasn't) they stand a far better chance.

[Scott Campbell]

I thought they'd conceded the meltdown a while ago now. Breach of containment would be the only really bad surprise at this point.

But I'm not following it that closely.

[pbmax]

They conceded that a partial meltdown had probably happened. But there was no way to be sure.

However, bad news on the containment front. The last explosion has been discovered to have damaged the main steel containment structure of Reactor 2. They are evacuating the site.

http://www.nytimes.com/2011/03/15/world/asia/15nuclear.html?hp

[pbmax]

Not a bad read for the basics:

http://allthingsnuclear.org/

Worrisome point: Reactor 3 has MOX fuel, which is recycled Uranium Oxide plus Plutonium. Plutonium and its heavier cousins are far more lethal in the radioactivity released than uranium. If workers need to leave the entire facility, the Reactor 3 sea water operations would stop. If the MOX melts, its the most dangerous should any radioactivity from it be released. Only a percentage of the fuel in 3 is MOX though.