Pick a number, and that reactor is described as being near a meltdown. The news coverage coming out of Japan is even more confused when American media deciphers it. Hopefully hard facts come in soon…
Meltdown occurred according to Nuclear and Industrial Safety Agency
URGENT: March 12 00:00 PST: Explosion at Nuclear Facility
VIDEO of explosion at nuke plant.
Reuters Live Earthquake News Feed
Several people appear to be injured at Fukushima nuclear plant – NHK
Walls and roof of a building at site destroyed by blast – NHK via Sky News
UPDATE: 22:50 PST: BREAKING NEWS: Pressure successfully released from Fukushima No. 1 reactor: agency
UPDATE: 21:47 PST: Meltdown underway at Reactor #1? http://twitter.com/#!/dicklp
Fukushima fuel cores are melting at 2000C and dropping onto steel floor. Steel melts at 1500C. Could still be brought under control, but Four other Fukushima nuke reactors are struggling with similar problem. If multiple meltdown begins, it will be uncontrollable.
Nuclear reactor coolant systems are running on batteries, and the coolant has reached the boiling point. Extremely critical situation currently at several earthquake affected nuclear reactors. Officials are concerned that a Three Mile Island 1979 meltdown could happen here. Reuters Link
From the LA Times:
Conditions appear to be worsening at a nuclear power plant in Fukushima Prefecture in northeastern Japan, according to local media.
The Kyodo news agency reported that the cooling system has failed at three reactors of Fukushima No. 2 nuclear power plant. The coolant water’s temperature had reached boiling temperature, the agency reported, citing the power plant’s operator, Tokyo Electric Power.
The cooling system failure at the No. 2 power plant came after officials were already troubled by the failure of the emergency cooling system at the Fukushima No. 1 plant, which officials feared could cause a meltdown.
With 10,000 people missing due the tsunami and earthquake , evacuating 200,000 more because of this nuclear “incident” is a huge distraction of man-power and other resources that are needed to help the tsunami victims.
The japanese prime minister has said efforts to control Fukupshimmer has to take prority “over and above” the rescue work.
But let’s carry on pretending that only one person has died as a result of the multiple failures at the two sites and that nuclear power has a remarkable safety record.
Latest statement is that they are pumping in sea water but the levels are not rising, so I guess it is leaking out. Where is this sea water going to I wonder?
With nuclear having a pretty good safety record over the years it does seem that when things bad happen a lack of experience dealing with it causes unforeseen problems.
Unlike an oil refinery if the worse comes to the worst you just can’t let it burn, however here something has to be done, like the BP gulf oil disaster, but unlike that disaster you don’t have the luxury of having multiple stabs at it over a long time period as you “learn” on the job.
The pressure on those guys trying to solve it must be immense 🙁
Andy
I would not be surprised to see the same kneejerk reaction in the USA, that the administration had to the Gulf oil spill a couple years ago. This will make it very difficult – politically speaking – to get any new nuke plants up and running in the US/UK, regardless of the fact that the technology for new plants is far superior to the 50 year old design that is having some problems in Japan. People don’t understand that not all nuke plants are created equal and that technology advances quickly. All they hear is the word “nuke” and they freak out.
Ladies and Gents
(before I start, I’m impressed just how much deep engineering knowledge seems to be represented here)
First, I’ve run some quick numbers based on the standard ANS formula, someone having mentioned that the heat production should be coming well down now. According to that, the numbers (assuming Fukushima 1 was running at full power when it scrammed) , instantaneous heat production 1s after scram should have been about 95MW. At 48 hours it’s about 7-8MW, and about 5-6 at 72 hours.
Applying that to the design parameters for Fukushima 1 (BWR 3 – 400 7×7 fuel assemblies, about a 1cm pin diameter (is that right, anyone?) ,3.6M length.
That gives a heat flux of about 3KW/square metre from the fuel cans. I’ve also approximated a number from the vessel walls, and that’s around 10-15KW/square metre.
On that basis, I’d be amazed if there’s still any further significant boiling going on, and hence, things ought to be getting pretty stable. I’m starting to wonder if there’s a problem with briefings by panicky politicians who aren’t listening to TEPCO.
Re the explosion. It’s obvious that whatever went off did indeed remove the weather cladding from the reactor. That’s not the secondary containment of a BWR, though. The primary containment is the drywell and the suppression pool, the secondary is the surrounding reinforced concrete building.
Given that all the structural steelwork seems to be standing, and is little damaged – it’s basically just blow off cladding – there can’t have been a big overpressure involved. Does anyone know the status of the turbine hall building? I can’t for the life of me see a pathway that would have got hydrogen from faulted fuel into the building, without there being a lot more radioactivity involved. The short spike in radiation readings also suggests that.
Does anyone know where the spent fuel building is on Fukushima 1?
Guardian newspaper now reporting earthquake “upgraded” from 8.8 to 9.0 by the (japanese?) meteorological agency.
That will be a great news for the operators since it was designed to withstand upto 9.0 , looks like it just went from being defective in design to working within its design parameters. Phew! Thanks for the upgrade.
Hydrogen buildup may cause blast at No.3 reactor
http://www3.nhk.or.jp/daily/english/13_27.html
Speaking of hyperbolic statements, the main newspaper in Spain, El Pais, has a headline right now on its front page saying that Japan is fighting to prevent an “uncontrolled NUCLEAR EXPLOSION”
http://www.elpais.com/global/
I imagine they will change that soon when they start to receive complaints, but that’s what it says right now.
kadaka (KD Knoebel)
I hadn’t thought to check if pwl was the person doing the interview. I had assumed it was. I didn’t know where the quotes came from since I haven’t read every comment in this thread. But after checking the link at pwl’s name it looks like pwl is not the one that did the interview.
What do you mean by, “drop a large share of the blame”?
Although I understand the interest, in radiation detection equipment at a time like this, people should be very cautious about buying “budget” radiation detection hardware. As mentioned above, you not only need to have the test equipment you need to have a clue how to use and interpret the readings.
When I worked in emergency management I spent 10 years repairing and calibrating Geiger counter meters and ion chamber Civil defense survey meters. It takes a bit of understanding of radiation to properly interpret the readings and not just scare the crap out of your self. Radiation meters like all other test equipment “should” also be periodically calibrated and tested for function.
High level Ion chamber meters are practically impossible for the average person to test and even verify that they work, but Geiger counters can be at least operations checked by simply measuring normal background radiation, and if you are enterprising enough to search for and pick up a suitably radioactive rock you can use as a check source, you can verify if they are operational.
I have great reservations about some of the new digital monitors, but there is one company I would highly recommend for anyone serious about picking up such hardware. Ludlum instruments, manufactures a full line of equipment (it is one of the companies that the big boys use). The Colorado State Highway patrol Hazmat teams and the Colorado State Health department radiation control division, used their equipment at the time I was working in the field.
The Model 3 with 44-38 GM Detector is the functional equivalent to the Geiger-Müller survey meters I calibrated and repaired for the Civil defense system.
If Anthony were inclined to carry a line of such equipment, I would strongly suggest he look at what they have to offer. They have been in business a long time, they gave us good technical support, and they were not pushing “fad” equipment but real functional hardware that was well designed and it worked.
http://www.ludlums.com/index.php?option=com_multisitescontent&view=article&site_id=:master_db:&id=154&Itemid=95
Larry
Another question for those with BWR experience. According to what I can find via google, it’s typical that the RPV is opened about 4-7 days into the shutdown, and fuel handling/removal starts pretty much immediately?
Is that about right?
Presumably, at that point, the fuel has cooled to a point that the RPV can be opened without boiling, and cooling be achieved with unpressurised water circulation.
@P.Solar I don’t think the reactor suffered much from the earthquake, it SCRAMed normally. The tsunami seemed to have damaged the back up power generators. That then led to the LOCA problems.
Andy D,
I understand you are an ex-UK nuclear industry engineer/physicist like I am. If so then hopefully you’ll understand that its not just as simple as your back of the envelope calculations would seem to indicate (and which I am in general agreement with). Injecting seawater into the reactor cooling system is definitely admission IMO that there have been serious problems in removing the post-trip decay heat from the reactor. If you don’t remove the decay heat at a sufficient rate I’m sure you already know what the consequence are?
I’d agree that they are getting the incident under control but what matters is what lead up to the ‘explosion’ and what caused it. The authorities seem to have admitted that the explosion that blew the cladding off the top level of the reactor building was caused by an ignition of hydrogen that had built up in this part of the building (in the UK we’d call this area the ‘reactor hall’). Given this admission where do you think the hydrogen has come from? Do you think it’s come from the dissociation of the reactor coolant? This looks highly likely to me and if so the coolant (very likely in the form of superheated steam must have been in contact with an appropriate material was also a high temperature. That material could be steel componnets that form part of the internals of the reactor pressure vessel or more likely IMO the zirconium that forms the cladding around the fuel pellets within the the fuel pins of the fuel assemblies of this type of reactor system.
http://www.google.co.uk/imgres?imgurl=http://www.nfi.co.jp/e/product/images/illust_bwr_2.gif&imgrefurl=http://www.nfi.co.jp/e/product/prod02.html&usg=__Gc9C1_PeJXqojgSW5aPhFHCfnBo=&h=435&w=540&sz=89&hl=en&start=0&zoom=1&tbnid=utf1ncTEpFQu2M:&tbnh=137&tbnw=170&ei=Y9t8TaSKDYKEhQfw8YXoBg&prev=/images%3Fq%3Dbwr%2Bfuel%2Bassembly%26um%3D1%26hl%3Den%26sa%3DX%26biw%3D1350%26bih%3D531%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=174&vpy=211&dur=4534&hovh=201&hovw=250&tx=142&ty=85&oei=Y9t8TaSKDYKEhQfw8YXoBg&page=1&ndsp=28&ved=1t:429,r:10,s:0
(sorry for the long URL above)
As you are also probably aware this type of zirconium clad fuel pin assembly is also susceptible to ‘clad ballooning’ (http://www.google.co.uk/url?sa=t&source=web&cd=22&ved=0CBoQFjABOBQ&url=http%3A%2F%2Fsacre.web.psi.ch%2Fcurrent-projects%2Fmain-frames%2Fdocuments%2Foecd-projects%2FSandia%2520Fuel%2520Project%2520SFP%2520Description.pdf&rct=j&q=BWR%20clad%20ballooning&ei=i918Tb7PKMPPhAeYq831Bg&usg=AFQjCNEdks3kZuDQhM-bBsV3WE4p63P3sg&cad=rja) at high temperatures in th event of loss of cooling which is likely to restrict coolant flow between the fuel pins within the fuel assembly and so lead to even higher fuel pellet and clad temperatures.
There have been reports that due to lack of backup cooling the level of coolant within the recator has fallen below the top of the fuel pin assembly level and likely for prolong periods of time (hours as opposed to minutes). I’m not going to attempt to do any heat flux/heat transfer calculations as you have done, but the presence of the hydrogen to me is a pretty clear indication that there have been some significant highly temperatures reached in the reactor at some point over the last 48 hours or so. The detection of significantly higher than normal levels of ceasium and iodine outside of the reactor building would also indicate some degree of fuel pin failure and possible limited fuel pellet melting (resulting the the release of gaseous fission products).
The recent acknowledgement of the need for and subsequent addition of sea water (followed by boronated water) to the reactor vessel coolant is IMO once again a clear admission that all is not well within the reactor core. Would you concur?
I’d agree with you that probably the worst is now over as least as Reactor 1 is concerned. My main concern now is for the other reactors (2 and 3?) rather than for Reactor 1 as they now also seem to be experiencing their own cooling problems.
“Earthquake impact on Fukushima Daiichi
Reactors 1, 2 and 3 were in operation at Tokyo Electric Power Company’s (Tepco’s) east coast Fukushima Daiichi nuclear power plant when the earthquake struck. Three other reactors were already shut for inspection but all three operating units underwent automatic shutdown as expected. Because plant power and grid power were unavailable during the earthquake, diesel generators started automatically to supply power for decay heat removal.
This situation continued for one hour until the plant was hit by the tsunami wave, which stopped the generators and left the plant in black-out conditions. The loss of power meant inevitable rises in temperature within the reactor system as well increases in pressure. Engineers fought for many hours to install mobile power units to replace the diesels and managed to stabilise conditions at units 2 and 3.
However, there was not enough power to provide sufficient coolant to unit 1, which came under greater and greater strain from falling water levels and steady pressure rises. Tepco found it necessary yesterday to vent steam from the reactor containment. Next, the world saw a sharp hydrogen explosion destroy a portion of the reactor building roof. The government ordered the situation brought under control by the injection of seawater to the reactor vessel.”
“Operations to relieve pressure in the containment of Fukushima Daiichi 3 have taken place after the failure of a core coolant system. Seawater is being injected to make certain of core cooling, but two separate malfunctions are hampering efforts.”
http://www.world-nuclear-news.org/RS_Venting_at_Fukushima_Daiichi_3_1303111.html
Preliminary reports are almost always misleading.
The scuttlebutt, from the few people I have been able to communicate with, relay some details.
First, everyone must realize that the outside structure of the reactor, and turbine buildings are merely a facade. They are just a shell of blowout panels designed to blow outward with any rapid pressure excursion.
It was decided to attempt a vent, to and though the turbine hall, to atmosphere, via the turbine hall’s incredible volume. It’s a little vague, as to exactly the reason, for this choice, but I suspect they wanted to introduce some delay and add dilution to the containment vented gases. The turbine hall is equipped with lourves and blowout panels, to vent pressure, in case of a turbine or main steam break.
It is assumed that the hydrogen which exploded came from the hot vented gases, however, in the same hall contains the generator set, containing a large amount of hydrogen gas, used for cooling the generator windings. This gas is kept within the casing via seal oil provided by an emergency powered pump. This, of course, was not available. Hydrogen, would then degas to the hall.
In any event when the explosion ensued, the building shell performed as designed, and completely, and effectively vented the rapid pressure excursion minimizing any real damage. However, from the camera’s perspective the incident appears horrific and devastating, when it actually wasn’t.
If you look at the video carefully, one will notice a clear blast just before the billowing cloud of dust and vapor appears. This is the air inside the building exiting thru the blow out panels. You will also see these blowout panels glittering and fluttering in the air, giving the false impression of massive debris.
The reports coming out are sketchy and contradictory, so no story, can be relied on yet. It is not my intent to minimize this situation, as it remains gravely serious, however, I remain optimistic, that this incident will be resolved, without doom.
Years ago, I made repeated pleas, inside the industry, to environmentally protect vital emergency equipment and field offices, from such accident water and steam conditions. Much of this was implemented. Too bad, they didn’t start with the CTU standby generators.
Please everyone, be patient as reliable data will be soon available. Speculation can only fuel alarm. GK
Japan nuclear crisis indepth
AndyW says:
March 13, 2011 at 12:50 am
“I am puzzled by the comments above this might be nuclear’s finest hour? Up to 170 000 people have had to be evacuated, peiple have been injured and it looks like both reactors are likely write offs.”
-The evacuation is a precaution, right? They do it by the book.
-The reactor that is now cooled with sea-water was supposed to be out of commision within a couple of weeks anyway. Right?
-People have been injured; Are you talking about those 2 or 3 persons with bruises after the explosion? I think that is a bit …..hmmmm…
Dont forget that the reason for all this in the first place is an earth-quake and a tsunami.
The explosion ;
Heaven forbid that the word “Hydrogen” is mentioned. After all, that would be very inconvenient, wouldn’t it? That hydrogen is dangerous? Did you ever mix hydrogen and oxygen in the lab?
Scratch two reactors:
The use of seawater shows that authorities are giving up future use of the Daiichi plant and are focusing solely on protecting people and the environment, experts said.
“If they are (using seawater), it’s because they have no other choice,” said James Walsh, a research associate at the security studies program at MIT. “The last thing you want to do is pump seawater and boron into a reactor.” The salt and boron will corrode the reactor, he said.
“Essentially, they are saving the white flag and saying, ‘This plant is done,’ ” Walsh said. “This is a last-ditch mechanism to try to prevent overheating and to prevent a partial or full meltdown.”
http://www.cnn.com/2011/WORLD/asiapcf/03/13/japan.nuclear.reactors/
Re: Japan tsunami. For gods sake a 20 mt reinforced concrete sea wall should have been built centuries ago. Especially around populated cities. This applies to all countries FACING a major Fault. ie Japan, Indonesia, Chile, West Coast USA. Notice other side of Japan NOT facing fault no problems at all. Thats where ALL the reactors should be duh….Of course they will simply rebuild FACING side AGAIN and of course it will occur again in +- 100 years…Humans can be terribly stubborn/ignorant and do not learn by experience methinks…BTW Expect major earthquake in California this or next year
BTW California are you ready no of course your not!
No large deionized water storage tanks on site. Too bad.
The anti-nuclear crowd are getting worked up. Some interesting tidbits in this video.
mrrabbit says:
March 12, 2011 at 10:59 pm
From the BBC pages for the middle east that’s providing continuing updates:
#
0349: CNN presenter Piers Morgan tweets: “Nuclear expert Bill Nye just said situation at Japan plants sounds ‘way more serious’ than authorities saying. Deeply worrying.
=8-)
[ryanm: oh goodness gracious WTF do we care Bill Nye thinks or says about anything? WTF = Win the Future.]
Jim says:
March 13, 2011 at 4:09 am
How does Bill Nye get away with being called a scientist? Is the dickie bow a testamount to his credentials?
http://edition.cnn.com/2011/WORLD/asiapcf/03/13/japan.nuclear.reactors/
Trust me guys…wasn’t posting that in total seriousness. I too did a double-take when I found that. Never thought I’d see Bill Nye called in during a disaster for an interview on a nuclear reactor emergency.
=8-)
slight correction to my earlier post – 8.08MW at 48 hours post scram, 7.45 at 72 hours.