icon incredibly appropriate
Mar. 13th, 2011 01:57 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
lexRight, speaking as someone who couldn't sleep (literally) due to fear over the reactors in Japan? AMERICA: STFU. THEY'RE STABLE. jfc.
Let's talk about meltdown. Everyone goes HOMG CHERNOBYL ADKFHSDKFHSKDJHFSDKJFSKJD but hold your horses, meltdown isn't called explosionapalooza. Heat damage to the rods, aka melting, is called meltdown. If left exposed/unsubmerged for hours, they will melt totally and the remains will melt down into the earth until they cool on their own. In this scenario there could be contaminants in the water table, but not in the air. If there were, for some absurd reason, a fiery explosion that ruptured the core containment (and I sincerely doubt it, since we've already proved that even a 40-yr-old plant on its last legs can withstand a hydrogen explosion, which is the only probable cause of such a thing in these plants) it would expose the rods to air, probably cause uncontrolled meltdown, and could carry contaminants into the air. It would not necessarily carry them into the upper atmosphere, which is where they'd need to go for other countries to be affected. So, there are your worst-case scenarios. I don't even have any idea how that last one could happen in these circumstances, so if you must go WHARRGARBLE at this then go with the first scenario.
Okay so. First it was just Daiichi 1. Daiichi unit 1 is the one with the HOMG EXPLOSION. What happened: water was superheated, split into hydrogen and oxygen, and THAT exploded. This is an anticipated event that is designed into reactors. As you may have noticed, the core containment was not breached. The outer shell that broke apart is just a regular building, not meant to withstand anything but the weather. Submerging and cooling the rods is not as easy as it sounds - I believe they're at about 600F. As you probably know, water boils a few hundred degrees below that. Steam and vapor pressure is an issue. Due to pump failure, the rods were not completely submerged, and the exposed sections did melt a bit. This caused the release of radioactive cesium and iodine as the cladding on the rods melted. Steam pressure is being carefully controlled with periodic releases, which does release some radioactive contaminants as well. This is why radiation readings rise and fall in that area. However, the rods are submerged and cooling and under control now. The use of seawater rather than freshwater means that Unit 1 will be a write-off, but it would be anyway due to the meltdown.
Daiichi 3 is now having pump problems. We may see a similar scenario to Unit 1; buuuuut there are now pumps in place at the facility and they are clearly willing to write off damaged reactors, so I expect Unit 3 will come under control quickly.
There's like two other reactors that are also having pump issues, last I checked. Those ones are still under control, not experiencing meltdown (as far as I know), and efforts to cool them with fresh water (and thus preserve them for future use) are underway.
Cooling these reactors is a delicate balance of steam and pressure. It's not simple, it's not easy, but it's being done and done well. The only troubles encountered are facets of engineering that have already been phased out of modern reactor designs. Should we panic? No. Should we consider updating our ancient reactors? Hell yes.
OKAY DONE RANT NOW. AS YOU WERE.
Let's talk about meltdown. Everyone goes HOMG CHERNOBYL ADKFHSDKFHSKDJHFSDKJFSKJD but hold your horses, meltdown isn't called explosionapalooza. Heat damage to the rods, aka melting, is called meltdown. If left exposed/unsubmerged for hours, they will melt totally and the remains will melt down into the earth until they cool on their own. In this scenario there could be contaminants in the water table, but not in the air. If there were, for some absurd reason, a fiery explosion that ruptured the core containment (and I sincerely doubt it, since we've already proved that even a 40-yr-old plant on its last legs can withstand a hydrogen explosion, which is the only probable cause of such a thing in these plants) it would expose the rods to air, probably cause uncontrolled meltdown, and could carry contaminants into the air. It would not necessarily carry them into the upper atmosphere, which is where they'd need to go for other countries to be affected. So, there are your worst-case scenarios. I don't even have any idea how that last one could happen in these circumstances, so if you must go WHARRGARBLE at this then go with the first scenario.
Okay so. First it was just Daiichi 1. Daiichi unit 1 is the one with the HOMG EXPLOSION. What happened: water was superheated, split into hydrogen and oxygen, and THAT exploded. This is an anticipated event that is designed into reactors. As you may have noticed, the core containment was not breached. The outer shell that broke apart is just a regular building, not meant to withstand anything but the weather. Submerging and cooling the rods is not as easy as it sounds - I believe they're at about 600F. As you probably know, water boils a few hundred degrees below that. Steam and vapor pressure is an issue. Due to pump failure, the rods were not completely submerged, and the exposed sections did melt a bit. This caused the release of radioactive cesium and iodine as the cladding on the rods melted. Steam pressure is being carefully controlled with periodic releases, which does release some radioactive contaminants as well. This is why radiation readings rise and fall in that area. However, the rods are submerged and cooling and under control now. The use of seawater rather than freshwater means that Unit 1 will be a write-off, but it would be anyway due to the meltdown.
Daiichi 3 is now having pump problems. We may see a similar scenario to Unit 1; buuuuut there are now pumps in place at the facility and they are clearly willing to write off damaged reactors, so I expect Unit 3 will come under control quickly.
There's like two other reactors that are also having pump issues, last I checked. Those ones are still under control, not experiencing meltdown (as far as I know), and efforts to cool them with fresh water (and thus preserve them for future use) are underway.
Cooling these reactors is a delicate balance of steam and pressure. It's not simple, it's not easy, but it's being done and done well. The only troubles encountered are facets of engineering that have already been phased out of modern reactor designs. Should we panic? No. Should we consider updating our ancient reactors? Hell yes.
OKAY DONE RANT NOW. AS YOU WERE.
