CNN: Cooling system fails in another reactor at Japanese nuclear plant

[jaxx]

(03-15-2011 06:30 AM)There Is No Spoon Wrote:  Bunch of Tweets seem to be saying that this nuclear crisis is now rated at a level 6 of 7 which would make it the 2nd worst nuclear event to date.

WSJ is reporting that radiation levels are stabilized and that they seem to have things under control for the time being. Fingers crossed.

I saw that too, thinking it is coming from France.

[sandnsea]

(03-15-2011 05:04 AM)jaxx Wrote:  I remember watching Life After People on the History Channel. One thing that stuck with me was showing a huge pool of spent rods....and them starting to cook after the electricity to cool them was stopped.

Found this about the scene:

Nuclear Meltdown - Super-heated steam pours out of nuclear power plants as spent nuclear fuel boils the water in cooling tanks. Buildings buckle under the intense heat. As radioactive fallout spreads, nearby forests are decimated. Pine trees turn red as chlorophyll is damaged.

Read more: http://ngccommunity.nationalgeographic.c...z1GfIWcNJ1

Don't know why, but I have remembered this, and the pool of rods.

Aw geez, I never even thought of that. It's always those spent fuel rods that are the final no-go for me though. Thinking about the lack of electricity to keep them safe though, something I never thought of. I just don't see how we can be so self-centered and short-sighted. Somebody needs to make a movie, that's the only way people ever understand anything anymore.

[A Fool and his Money]

To Jaxx --

I believe that summary is about right, with a few points to clarify.

Here's MY UNDERSTANDING -- and I'd welcome any further clarifications ...

Re: cooling of the 4, 5 and 6 -- which were offline -- my understanding is that the overheating (and fire) at #4 involved SPENT fuel, not core fuel. SPENT fuel can be cooled just by sitting in a pond of water. Some of that water had evaporated off at #4, exposing the spent fuel to air. Once exposed, the spent fuel heated up and started the fire.

CORE fuel remains extremely hot for weeks to months after "shut down" (which happened at the time of the quake) -- still dissipating "decay heat" -- and the cooling water needs to be continually circulated (and ideally cooled.) If core fuel sits in stagnant water for very long, the water heats up very rapidly and begins to boil.

This is when problems begin -- pressure builds up, water boils off, fuel rods are exposed, melting begins, hydrogen is created that can cause explosions ... all the major problems that 3 Dai-ichi reactors 1, 2 and 3 have experienced.

The good news is that reactors 1, 2 and 3 ARE cooling down, albeit slowly. Each day that passes without a serious meltdown brings us closer to a much safer situation, described next.

At a certain point, enough heat dissipates that even a full meltdown would become much less dangerous. That's because the core -- while still hot enough to melt -- no longer gets hot enough to burn thru the containment structure floor (aka "The China Syndrome.")

I believe we're several days away from that essential threshold.

If crews can stabilize things and get us beyond that threshold, cooling and venting would continue for several months.

Does this description capture things accurately? Anybody?

re: RE: CNN: Cooling system fails in another reactor at Japanese nuclear plant
I am trying to piece information together.
#'s 1 2 & 3 have had explosions.
#4 (which was "down" when the crisis hit) had a fire in the concrete that has been put out.
#4 is overheating...so down is never down, and cooling it becomes necessary.
#'s 5 & 6 are in the same position as #4 (they were also "down") but need cooling.

Anyone keeping up....is this where we are at the moment?

[jaxx]

Thanks AFAHM, that is good information.

#
2314: A spokesman for the Tokyo Electric Power Company (Tepco) has said: "At around 0545 today, our employee carrying batteries to the control room discovered smoke billowing from the building of reactor 4 [at Fukushima Daiichi]."

Reactor building....or spent rods building?

[yowzayowzayowza]

(03-15-2011 04:15 PM)A Fool and his Money Wrote:  That's because the core -- while still hot enough to melt -- no longer gets hot enough to burn thru the containment structure floor (aka "The China Syndrome.")

Melted material will first pool in the reactor vessel, failing that the containment vessel, failing that the concrete structure. Each layer is more open to the environment. Three Mile Island's fuel melted, but did not breach the reactor vessel. I would not be betting for a similar outcome X 3 from this situation, so far.

Least thatz my arithmetic.

[jaxx]

#
0003: A new fire that broke out inside reactor 4 at the Fukushima Daaichi nuclear plant, which was damaged in Friday's earthquake and tsunami, appears to be out. This was the second time in two days that the reactor where spent nuclear rods were being kept caught fire. Workers at the plant are pumping sea-water through several of the plant's reactors in an effort to cool and stabilise them. Japanese media reports say radiation levels at the reactors remain too high for workers there to approach them. Japan's Prime Minister, Naoto Kan, and the International Atomic Energy Agency (IAEA) have expressed concern and called for the provision of more timely, and accurate information.


So it was the spent rods again. I'm glad the fire is out, for now.

edit to add:
#
2359: Back to the ongoing crisis at the Fukushima Daiichi nuclear plant: the Kyodo news agency reports that engineers are spraying boric acid to prevent "recriticality" - presumably, the resumption of a self-sustaining nuclear chain reaction - at reactor 4.

[There Is No Spoon]

(03-15-2011 05:52 PM)jaxx Wrote:  Thanks AFAHM, that is good information.

#
2314: A spokesman for the Tokyo Electric Power Company (Tepco) has said: "At around 0545 today, our employee carrying batteries to the control room discovered smoke billowing from the building of reactor 4 [at Fukushima Daiichi]."

Reactor building....or spent rods building?

I think they're storing spent rods in reactor building #4.

[yowzayowzayowza]

n/t..

[jaxx]

I'm trying to remember if #4 has spent rods on the ground level or above the reactor level. It's different for each of the reactors.

[jaxx]

Just reported:

#
0146 : Tepco says the reactor 3 at Fukushima Daiichi nuclear power plant has been emitting white smoke for about 45 minutes, Kyodo News reports. The plant's reactor 4 was the one where a fire broke out earlier this morning, Tepco said.

Crap!

[There Is No Spoon]

(03-15-2011 08:01 PM)jaxx Wrote:  Just reported:

#
0146 : Tepco says the reactor 3 at Fukushima Daiichi nuclear power plant has been emitting white smoke for about 45 minutes, Kyodo News reports. The plant's reactor 4 was the one where a fire broke out earlier this morning, Tepco said.

Crap!

Honestly, is this not starting to look like a deadly game of whack-a-mole?

Unbelievable.

[Still a Democrat]

Major setback, discussion ongoing on the Ed Show.

---

This is serious!

---

---

http://www.bbc.co.uk/news/world-middle-east-12307698

1024: Hiroko Tabuchi of the New York Times tweets: "More on plant workers: they took cover for 45mins on site&left water pumps running. There was no suspension of operations. TEPCO official"

[nofurylike]

http://www.bbc.co.uk/news/world-middle-east-12307698

0530: The US State Department tweets: "For concerns about a specific U.S. citizen in #Japan, please call 1-888-407-4747 or email JapanEmergencyUSC@state.gov. Http://go.usa.gov/4Ax."

also has a statement by Secretary of State Clinton:

SECRETARY CLINTON: And I want to, on behalf of the United States, express both our condolence and our solidarity with the government and people of Japan. Japan is always a very generous donor to any disaster anywhere in the world, and today, the world comes together to support Japan in its hour of need. And the minister and I will be discussing a lot of the specifics that we are working on together.

###

[nofurylike]

http://www.bbc.co.uk/news/world-middle-east-12307698

0816: Prices for private jets have leapt up as thousands of people trying to get out of Japan put in orders, Reuters reports. "I got a request yesterday to fly 14 people from Tokyo to Hong Kong, 5 hour 5 minutes trip. They did not care about price," Reuters quotes Jackie Wu of Hong Kong Jet as saying.

11 minutes later:

0827: Following that item on the demand for private jets, Reuters is also running a story on the flight of foreign bankers from Tokyo. This despite a denial from the Tokyo-based International Bankers Association that any exodus was under way.

[nofurylike]

http://www.bbc.co.uk/news/world-middle-east-12307698

there are good videos and streaming live updates at this live BBC site.

[HamdenRice]

Not trying to drive traffic to a different site, but there is a really informative series of posts by a guy on DailyKos who is actually a nuclear engineer and has operated nuclear power plants. His main point is that the hydrogen explosions were extremely energetic. The plants that house the reactors are extremely complicated machines full of electronic equipment, gages, valves, pipes, etc., and although most of the reactor containers are in tact (except possibly for one), there is nothing left to operate them with. They are trying to carry out an operation that would be EXTREMELY difficult in an operable reactor, but they are basically trying to work in a debris field, blind with no gauges or electronics, using little more than fire hoses spewing seawater.

The reactor core is usually surrounded by ultra clean water that does not react to the core and the water itself does not become radioactive for long. The introduction of sea water introduces salt and the rest of the ocean brew which is extremely reactive to the core and container at these temperatures and is full of impurities that will be irradiated and then spewed into the air as the steam is vented.

Lots of other good stuff by people who know a lot about nuclear power.

http://www.dailykos.com/story/2011/03/14...ATED-2X%29

[yowzayowzayowza]

(03-16-2011 06:05 AM)HamdenRice Wrote:  They are trying to carry out an operation that would be EXTREMELY difficult in an operable reactor, but they are basically trying to work in a debris field, blind with no gauges or electronics, using little more than fire hoses spewing seawater.

They are obviously also not communicating the entirety of the situation to the public. Thx for the link.

[jaxx]

Just home from work and trying to piece this together. I am so glad the people on this thread are keeping it up to date, it really helps. From what I have seen the workers were called off, the acceptable radiation rate was raised for them, and they went back to work. Brave souls, I wish them the best.

#
1440: Dr Sally Leivesley, a risk management advisor, says huge amounts are being asked of the "very fatigued" workers battling fires at the Fukushima site. "They've been asked by the emperor to give their all, and they will," she tells BBC News.

[jaxx]

#
1515: US Energy Secretary Steven Chu has just described events at the Fukushima plant as "appearing to be more serious than Three Mile Island". How much worse was not clear, he said, adding that it was very hard to tell how bad things were on the ground.

#
1516: Mr Chu said there were conflicting reports coming from Japan. The US teams who have travelled there are not only assisting the Japanese, but also ensuring that the US can secure its own measurements of what is happening, he said.

Very good Mr. Chu. Get the information. He's a smart man and I hope we hear more from him.

[HamdenRice]

(03-16-2011 07:33 AM)yowzayowzayowza Wrote:  They are obviously also not communicating the entirety of the situation to the public. Thx for the link.

In the DailyKos thread I linked to, take a look at the satellite and other photos of the reactor buildings that experienced explosions. The nuke engineers are saying that the debris field you are looking down on is where the spent fuel pools, which themselves have to be cooled with circulating water are (were?).

I mean you look down and its just a destroyed building and that's the work environment they are trying to stop meltdown in. Another nuke engineer said at first that he didn't think that the explosion did as much damage to the floors under the pools which are part of the containment, but after seeing the pictures of the latest explosion changed his mind.

It's a very grim situation.