#2 seawater pump has malfunctioned and they are warning of a complete meltdown

[kristopher]

They say there is a possibility the rods are completely exposed because the pump has failed. They also warn of potential containment failure.

Keeping containment vessel capped is key.

Adjusting pressure is key to preventing breach and they will use a valve (on what i think is an electric conduit?) to bleed pressure.

Same problem with hydrogen buildup is facing them.

He keeps saying what *needs* to be done (inject water/cool core, preserve integrity of containment, vent pressure) but they've said they can do nothing but perhaps bleed the pressure.

[muriel_volestrangler]

1. 'They' and 'he'?

Spokesman for TEPCO, the Japanese government, an independent nuclear expert, a reporter? It would help to know.

[tekisui]

3. So far, all I see is a line from Reuters on AJ.

Reuters - Nuclear fuel rods now fully exposed at Reactor No.2 at the Fukushima nuclear plant.

http://blogs.aljazeera.net/live/asia/disaster-japan-live-blog#update-11811

[kristopher]

4. It was repeated at least 3 times by 3 different people on NHK

One announcer said it then a Prof. Sekimura from Univ of Tokyo and then yet anoother announcer repeated it. I'm a bit distracted as the weather report immediately preceding this segment is calling for winds to shift tomorrow to come out of the north with light rain and I'm concerned the effect that we might see in Tokyo if this were to line up. I used to be on a Hzmat decon team when I was young and I don't like the way this is shaping up.

So far luck has not been our friend.

Sorry I didn't include that in the OP.

[GliderGuider]

7. Stay safe, kristopher.

We've had our disagreements in the past, but this isn't just talking trash on the internet. I'm glad you're keeping an eye on the weather.

We'll talk more when this settles down - I expect a number of us on the other side of the fence have changed our minds about a lot of things as a result of this disaster.

[tekisui]

2. Shit. From bad to worse.

[leveymg]

5. How do you say "shit" in Japanese?

[FBaggins]

6. "Fukushima"?

[necso]

8. I've been watching NHK World

and the statement was (loosely) something to the effect that "The {operating} company cannot deny that the fuel rods may have been completely exposed."

Someone (didn't recognize) just stated that the rods may have been completely exposed for 2-2.5 hours (I dunno).

(Although sometimes when speakers use the word vessel, I'm not sure whether they mean reactor vessel or containment vessel. There's also a containment building that houses the containment vessel (and the reactor vessel within), and some of these buildings (1, 3) have apparently been damaged.)

But supposedly seawater is being pumped in again (to both the reactor and containment vessels, but there may be a leak in the reactor vessel), and the fuel covered.

Has anyone calculated the amount of heat that may be generated (given various assumptions), and how much seawater may have to be cycled through the various vessels.

...

Latest statement: the rods have been covered to a depth of two meters; so apparently pumping is working (I dunno).