Update | 4:32 pm It looks like there is some confusion about the source of the fire, which the IAEA reported was “at the spent fuel storage pond.” Keith Bradsher and Hiroko Tabuchi in the New York Times quote an “American official” saying the “fire there may have been caused by machine oil in a nearby facility.” This is good news, but it also means I am trying to doing too much. I am taking the rest of the night off.
FEPC has released another statement that confirms the spent fuel at Reactor 4 burned for about three hours before they were able to put it out.
This is very bad news — yesterday, I noted this was the wildcard scenario. The radiation release was very large — detectors recorded a measurement of 400 millisieverts per hour. Milli, not micro. People can stop with the comparisons to airline flights or X-rays, unless you get your X-rays performed at DARHT.
If you are scoring at home, most folks I know seem to think we are at INES 6 now, heading for 7 (and the Ch-word) unless TEPCO catches a break.
Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:00AM (EST), March 15, 2011
- Radiation Levels
o At 10:22AM (JST) on March 15, a radiation level of 400 milli sievert per hour was recorded outside secondary containment building of the Unit 3 reactor at Fukushima Daiichi Nuclear Power Station.
o At 3:30PM on March 15, a radiation level of 596 micro sievert per hour was recorded at the main gate of Fukushima Daiichi Nuclear Power Station.
o At 4:30PM on March 15, a radiation level of 489 micro sievert per hour was recorded on the site of the Fukushima Daiichi Nuclear Power Station.
o For comparison, a human receives 2400 micro sievert per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6900 micro sievert per scan.
- Fukushima Daiichi Unit 1 reactor
o As of 10:00PM on March 14, the pressure inside the reactor core was measured at 0.05 MPa. The water level inside the reactor was measured at 1.7 meters below the top of the fuel rods.
- Fukushima Daiichi Unit 2 reactor
o At 6:14AM on March 15, an explosion was heard in the secondary containment building. TEPCO assumes that the suppression chamber, which holds water and stream released from the reactor core, was damaged.
o At 1:00PM on March 15, the pressure inside the reactor core was measured at 0.608 MPa. The water level inside the reactor was measured at 1.7 meters below the top of the fuel rods.
- Fukushima Daiichi Unit 3 reactor
o At 6:14AM on March 15, smoke was discovered emanating from the damaged secondary containment building.
- Fukushima Daiichi Unit 4 reactor
o At 9:38AM on March 15, a fire was discovered on the third floor of the secondary containment building.
o At 12:29PM on March 15, TEPCO confirmed extinguishing of the fire.
- Fukushima Daini Unit 1 reactor
o At 7:00PM on March 14, TEPCO confirmed cold shutdown.
o As of 12:00AM on March 16, TEPCO continues to cool the reactor core.
- Fukushima Daini Unit 2 reactor
o At 7:00PM on March 14, TEPCO confirmed cold shutdown.
o As of 12:00AM on March 16, TEPCO continues to cool the reactor core.
- Fukushima Daini Unit 3 reactor
o At 12:15PM on March 14, cold shutdown.
o As of 12:00AM on March 16, TEPCO continues to cool the reactor core.
- Fukushima Daini Unit 4 reactor
o At of 7:15AM on March 15, cold shutdown.
o As of 12:00AM on March 16, TEPCO continues to cool the reactor core.
Thanks for such a precise rundown on the situation. You have to feel sorry for japan after their stock market took a complete tonking this morning. Its like two punches in one for the Japanese government. Good luck to them all.
Tim Hill
Since reactor 4 is apparently empty due to inspections, unspent mixed oxide fuel cells (783) are in the storage pool. Is this correct? Are they stored in fuel storage racks? What is their storage configuration? Do they have borated-aluminium caskets? When were they initially put into the reactor?
Yes, the IAEA reports that spent fuel pond is loaded.
I presume they are racked, but I don’t know the configuration, casking or how long this load was in.
Loaded = UNSPENT (verus spent!). When were they going to reload unspent from the pools into the reactor?
I was wondering how the fuel burning for 3 hours jives with either the Windscale fire (fuel burned for 48 hours, and is considered Level 5) and Kyshtym disaster (non-nuclear explosion of nuclear fuel, which is considered level 6).
I don’t want to say things don’t sound bad…but I’m wondering how you came to the opinion that this is a level 6 instead of level 5.
I’ve been reading about Windscale, which is a treat. My recollection of it wasn’t quite correct. I am sort of surprised it was only a five. This is going to be harder to answer than I thought!
Or, to put it another way, I am not sure it makes sense to place both Windscale and TMI in the same level. Damn it. Now I am going to have to order like five books on Windscale.
Sad news. But it illustrates again the point that the old plants should have been retired from service many years ago. These were built 35+/- years ago and probably are far older design. Unfortunately the opposition to new (safer) plants plays a perverse role in actually making an accident more likely as lifetimes of existing plants are extended to avoid losing generating capacity.
There were 63 operating reactors (54.6 GWe net) with GE BWR Mark I and II Containment Buildings at 31-DEC-2009 by my count. I think you are right, but the world loosing around 50 GWe of generation in one go would be quite a hit.
Fukushima Daiichi 1 to 4 use GE BWR Mark I Containment Buildings, but the Mark II ones are the same design in principle, most of the changes being cost-saving simplifications. Retiring both building types covers GE models BWR/1 to BWR/5. BWR/4 uses both Marks of Building.
BWR/6 changed to the Mark III Building, which is a classic dome with enough space to refuel within the secondary containment, rather than on top of the containment under a thin-ish metal roof. Must especially the at-reactor spent fuel pond is within the secondary containment, rather than outside (under the metal roof) as in Marks I and II. So we would not have had the Unit 4 spent fuel release, and possible spent fuel losses at the others.
In an underreported development, Japan withdrew/retracted (IAEA officials aren’t sure of the transitive verb) their March 11 INES-4 report. If you go to the IEC News website, you’ll now see a “N/A” label. While the significance may be lost the lumpen population, I figure that Wonkers will want to take note. Why wasn’t this fact included in the IAEA’s official update?
I presume the Japanese know this will be more than a 4. Thanks for pointing it out. I will ask.
It’s interesting to note that according to Kyodo (dated some time on Wednesday 16th JST) TEPCO operators have learned from Chernobyl at least this much:
“The firm said its workers were only able to remain in the central control rooms at the Fukushima plant for 10 minutes to avoid exposure to excessive radiation levels. They have retreated to a remote site to monitor data on the reactors, it added.”
Makes one wonder exactly how high the radiation levels are there and whether they are observing standard nuclear worker maximum doses or perhaps dose rates authorized for life saving emergency operations. 10 min per worker doesn’t allow much coordination, so basically they have to send less trained people to make quick observations, then decide on actions at the remote site and send different more trained personnel to make any control inputs.
It would be on the scale of 10-100 mSv h-1. Perhaps some of their staff would most likely not be able to receive much more without deterministic effects. I would have a guess that some of their staff have already exceeded their life-time permissible doses, the universe forbid. I really hope they can plug the problems and stay safe.
TEPCO reports a new fire 5.45 am 16th March (local time). Can not approach due to high radiation doses.
Maybe they’ll now try the plan to drop water from a firefighting helicopter, which was dismissed earlier because they didn’t think the holes on the roof of unit 4 were big ebough or positioned directly over the pond.
Or the fire could be in some other part of the reactor building, like NEI reported about the first fire (0915 EDT):
“Tokyo Electric Power Co. said that an oil leak in a cooling water pump at Unit 4 was the cause of a fire that burned for approximately 140 minutes. The fire was not in the spent fuel pool, as reported by several media outlets.”
However, the 400 mSv/h dose rates are quite difficult to explain, if you at the same time maintain that reactor containment for melted fuel rods is intact and that no fuel rod out side of containment could be melted either.
My understanding is that the top edges of spent fuel pools are at a height of about 35 m (100 ft) above ground level, so something like using a normal ladder fire truck to pump in water, due to the high delivery height, flow rate would not be that impressive.
Also, there is a lot of debris at least around reactor 3 according to the satellite photos, so getting close enough might be a problem in any case. In the Digital Globe shot 3 minutes after the “biggest bang” of reactor 3, the fire trucks were parked at the intersection of service roads approximately 50 m away from the closes wall of the reactor building.
I think they refer to this 1984 experimental study
the conclusion which matches the above (zircaloy tubing will not catch fire at any temperature).
Again, the guestion remains, is 1984 the latest word on this subject?
Maybe this will show the link:
http://www.osti.gov/bridge/servlets/purl/5791423-14Pgn9/5791423.pdf
According to information provided by the german “Gesellschaft für Anlagen- und Reaktorsicherheit” (GRS) which is analysing the events for the german government the spent fuel pool of reactor 4 does infact house the complete core assembly. The pressure vessel itself is empty.
http://www.grs.de/informationen-zur-lage-den-japanischen-kernkraftwerken-fukushima-onagawa-und-tokai
After having read the paper about reducing risks regarding spent fuel pools and after having confirmed reports of repeated burning of the spent fuel building this sounds really bad.
The GRS also provides graphs created by plotting the japanese radiation measurements. The tried to correlete peaks with venting events. The first graph is included in the second graph, it’s just barely visible because of the height of the new event peaks.
http://www.grs.de/sites/default/files/images/Japan_Messungen_Fukushima_Daiichi_7Uhr.png
http://www.grs.de/sites/default/files/images/Messungen_Japan_16.3_6Uhr_klein.png
Interesting to note is that they stopped providing radiation measurements from sites nearer to the reactors.
The german press did also write that isotopes have leaked into ground water…
Not good. 🙁
Their analysis – Block 4 had the largest radiation release – perhaps suggesting a radioactive fire
If you are speaking of levels of contamination nobody has even mentioned the nuclear castrophe in western siberia in the swamplands east of the Urals in the fifties. Gary Powers was shot down in his U-2 because he tried to fly low enough to take detailed pictures for the times and fell pray to a SAM. The original cause for this soviet disaster was actually an accidental chemical explosion placed far too close to concentrated nuclear waste which was spread for many miles by the explosion. It is now still an uninhabitable area in russia.
People in the comments have mentioned Kyshtym, particularly in the context of asking whether this is a 5 or a 6.