I've been talking with folks who are certified nuke engs. This event has been rated a 4 on the 7 point scale (TMI was a 3 (correction - 5), Chernobyl a 7)

Backup gens are on site, and are running for reactors 2,3,4

No1 they are pumping seawater and boron in, which will "posion" the reactor.

The explosion was from them venting the gasses - because there IS at least some melting of the rods in No1, there was a mix of hydrogen and oxygen vented - it went "bang" - outside the containment

In the machine spaces (aka where the generators and the like are) the rad levels WERE up to .67 Rem/hr - not great (fairly normal is .007)

Remember, "western' design reactors all have a negative 'radioactivitiy defecit' - basically, they way they are designed and built, the hotter they get, the less well they react - aka they tend to be self slowing (in fact, it is possible to build a reactor that is fail SAFE - turn off the cooling, when the heat gets high enough, it turns off - basically it stabilizes at a very HIGH temp, but a temp that is safe for the design - see the idea of PBRs). Anyway, chernobyl (and that whole series of graphite moderated reactors) had a POSITIVE defecit in certain operating ranges - aka, when they got hot, they got more radioactive, so they got hotter, so they got more radioactive, etc - so you can guess what happened

Graphite reactors have one HUGE advantage (well, two) - fairly cheap, and if you're looking to make plutonium for weapons, it's a great design.....

Nothing in the links I hadn't run into earlier. My point remains unchanged.

From the information available, the core may be (heck I'll play pessimist), is probably melting inside the primary reactor containment vessel. The outer building structure has been blown off, most likely due to the vented steam having a high concentration of hydrogen which ignited. The outer structure for this facility was not designed as a pressure containment vessel so the wall got blown off while the steel structure remains (clearly visible in some BBC photos).

At this time there is no indication of a nuclear burn through of the primary reactor containment vessel and if the local team working on it can keep cooling water (sea water at last report) flowing around the RCV this mess will be mostly contained. It sounds like a similar chain of events is playing out at the other reactor.

Radiation releases so far have been very small, due mainly to planned venting of pressure from the RCV. NHK is saying that a sensor within 5km of the plant is detecting radiation levels approaching 1015 microsieverts. For perspective that is about the same as eating 30 bananas or having 10% of a CT Scan. Nothing to ignore but not the end of all life in the neighborhood either.

I'm not saying this isn't serious but I am asking for a bit of perspective. Japan has just suffered one of the biggest earthquakes ever. Hundreds were killed by horrific tsunamis. Thousands are homeless. Despite this the hysteria is over a power plant that is still contained.

-Eric

My sources say TMI was rated a 5 on the INES. That makes TMI worse than Fukushima (so far). Lets all hope it stays that way.

-Eric

You're correct - I meant to say 5

People don't realize exactly HOW bad things were inside containment at TMI

From circa 1982 to 1992, the company I worked for was a customer of a lab that also tested a LOT of 'stuff' for nuke plants, so I got to see a LOT of what was going on, plus I got to read a LOT of the trade magazines and NRC reports (the testing process often goes 24x7, and you have to be there, with nothing to do for 4-6 hours at a time). The core at TMI was slagged - about 70% of it was 'rubble' down at the bottom. Now here is the fun. The building was hot as heck inside, with radioactive water inside, and now you have to very carefully defuel the reactor, but it's not nice and ordinary, and electronices wouldn't last do to the radiation levels

Before digging deeper the video I saw seemed to be a chemical explosion. Certainly doesn't look nuclear, no flash, and it doesn't look like a diesel tank going up, which would produce a rich red flame and thick black smoke. The later thick black smoke may be indeed coming from diesel tanks afire but they don't seem to be the point of origin, or of immediate concern.

Knowing a little about reactors, I'll have to refresh my memory and knowledge base, much of it from researching TMI, I'm leaning toward a hydrogen buildup and explosion in the containment as the cause. Which would cause the surrounding building, but not necessarily the reactor vessel or plumbing, to disintegrate.

A large volume of hydrogen and air going up would look like that, a colorless blast with a moderately soft brissance. Looking at the video I note that the ability to see materials near the blast center moving makes me think neither conventional or nuclear explosive are involved. both them move so fast that the human eye, even most cameras, can't catch the action. Going off you see it as things being there, then not. Not like in the movies, which tend to be the special effects fallback, small charges under bottles of naphtha.

The question is; how much damage was done to the reactor vessel, plumbing, pumps? The reactor itself isn't capable of creating a true nuclear explosion but a meltdown isn't impossible and, based on TMI and several other explosions at nuclear plants, a hydrogen explosion, isn't improbable.

Given the Japanese engineers at the site were talking about releasing 'vapor' I don't think it is unlikely that the vapor was, at least in part, hydrogen gas and that they released it, hoping to limit the spread, into the surrounding building, which isn't designed to absorb the abuse of an explosion, where it was sparked by some unknown source. The frame of the building remaining supports this and is, to my way of thinking, a good sign.

In these cases it is always better to get information from credible sources, even outside my own brilliant analysis, and avoid pronouncements that are not clearly backed up by evidence.

I'll go back to my main point ...

Why are they not simply telling people the truth - or at least the facts as they have them? We have gone through the progression" "No problem" ... "Some radiation release but OK" ... "Outside wall has been broken by chemical explosion but reactor OK" ... "Plant on fire but no meltdown" ... "Maybe a partial meltdown". Along the way we first hear that background radiation has increased, but is not serious. Now we hear that maybe some cesium contamination has escaped the plant (but this is unconfirmed).

I really don't mind if this incident is 1 on a scale of 7, or 7 on a scale of 7. It would just be nice if someone would give the actual FACTS as they know them. It now seems obvious that people have been measuring radiation levels for a long time and have that data, and quite possibly they even have chemical species breakdowns for some of the atomic species in the released material.

This whole incident has been handled a lot like the initial steps of the BP oil disaster in the Gulf of Mexico. Layers and layers of denial. It's just not a good way to handle information related to a public safety hazard.

other Pete

To be geeky...It wouldn't end up in China. Japan's antipode is off the coast of Chile and Peru. So, that would make it an "Off the coast of Chile and Peru Syndrome".

(I couldn't help myself)

Just a head's up for those of you who might be in the path of wind-borne radioactive particles, normally blue spiderwort flowers will turn pink when exposed to radiation. Spiderwort is a very common, easy to identify, and edible weed.


Dayflower1 by merriwether, on Flickr


Dayflower2 by merriwether, on Flickr

-Blast

Thanks Blast ....

<< hoping that's the only blast I deal with!

Any information on what level of radiation exposure causes this change? Are we talking in the range of an Xray, CT scan or higher.

-Eric