TEPCO blames high reactor temperature reading on broken thermometer

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  • 1

    some14some

    “It is almost certain that the thermometer is broken,” said TEPCO spokesman

    no surprises if thermometer is broken since this disaster has broken the backbone of Japanese economy. btw, is tepco planning to fix a new and precise recording meter?

  • 3

    zichi

    Yesterday, at a press conference, TEPCO basically stated that thermocouple was busted?

    TEPCO announced on February 13 that the thermocouple on the bottom of the Reactor 2 Pressure Vessel at Fukushima I Nuclear Power Plant, which had been showing the rising temperature, exhibited the abnormal temperatures after the inspection in the afternoon on February 13, at one time going overscale over 400 degrees Celsius which is the limit.

    TEPCO thinks it is "most certainly broken". The thermocouple had been exposed to high temperature from the core meltdown, and has been in the high humid condition [inside the Reactor 2 Containment Vessel].

    http://ex-skf.blogspot.com/2012/02/fukushima-i-nuke-plant-additional-info.html

  • 2

    zichi

    For me, there are a few points wrong with this story. TEPCO tested the thermocouple by measuring the resistance. The indicated temperature reached the maximum of 400degC, and then dropped to zero.

    Thinking back to my instrument days, it's been awhile, thermocouples are tested by measuring the voltage. Usually, they work or don't work.

    Excuse me for constantly having doubts about TEPCO's woes. Yesterday, at the press conference, the TEPCO spokesperson was very uncomfortable about some of the questions from the journalists, like we should just except what they state.

    After a complete nuclear meltdown inside the reactor, causing very high temperatures, I'm surprised anything is still working.

  • -1

    mitoguitarman

    Nice try Tepco!

  • -1

    NetNinja

    OH that smells like......BS. It must be fresh too cause I doubt anybody put much thought into that. Whatever the case, these guys don't know how to run a nuclear reactor.

  • 1

    namabiru4me

    TEPCO is broken, so of course the thermometer is too!

  • 1

    American Devil

    According to the TV news yesterday, only the one sensor was going up, while the two others at the same level of the water containment vessel said the temperature was going down. And all three sensors at the next level down also showed the temperatures going down... so ... that would be a pretty strong indication that its just a busted sensor.

    Now, yes, that requires us to believe that Tepco is telling the truth about the other sensors as well, but I think its very plausible that one thermometer is broken after all the crap that's gone on. Still, its good for the media to keep an eye on the situation.

  • 2

    DoLittleBeLate

    So... one out of three meters show different readings from the other two, and this is news? I know it is kind of far-fetched, but just for the sake of brainstorming and wild hypothesis, may I suggest that Tepco might actually be telling the truth this time? I know I know, an unlikely scenario. One can't go against one's nature and all that...

  • 2

    peanut666

    Three thermometers. Two read the same. One reads high. There can only be THREE possibilities. 1.) The one that reads high is broken. 2.) The two that reads low is broken. 3.) All three are broken.

    Using probability, it is most likely that the one that reads high is broken. The chances that two are broken and reading the same are statistically lower than one being broken. The chance that all three are broken would mean that all three would read quite differently, since the probability of two reading the same would be rare if each are broken.

    Thus Tepco will state the most positive possibility, not the worse which would be that all three meters are broken. Any of the three possibilities can be "true"

    Why are people so ignorant and say things like "they are lying" or "they are telling the truth"? It has nothing to do with that.

    What gets reported by Tepco are only speculations based upon statistical analysis of the data that they are able to get a hold of. They will always try to report the most positive probabilities not the typical worse case scenario that America tends to report. If they are wrong, they aren't "lying" they were just wrong.

  • 1

    Elvensilvan

    Again, another fabulously detailed post from zichi. Thanks. But at the same time, it made me think.

    If temperatures inside the reactor reached meltdown temperatures, which are about 1500-2500 degrees celcius, depending if the thermocouple came in contact with the molten fuel, would be over the limit of the thermocouple's effective measuring range.

    Since the thermocouple is located at the bottom of the vessel, it may have been damaged by the extreme heat and the subsequent cooling.

    Zichi, can you tell us where the other thermocouples may be located in the reactor?

  • -1

    tmarie

    Probably?! So they still don't know?! Don't worry folks! All is well! Look the other way and ignore the incompetency...

  • -1

    Star-viking

    zichiFeb. 14, 2012 - 07:14AM JST

    For me, there are a few points wrong with this story. TEPCO tested the thermocouple by measuring the resistance. The indicated temperature reached the maximum of 400degC, and then dropped to zero.

    Thinking back to my instrument days, it's been awhile, thermocouples are tested by measuring the voltage. Usually, they work or don't work.

    But wouldn't you have to physically remove the thermocouple and measure the voltage drop across it in that case?

    Besides, Ohm's law http://en.wikipedia.org/wiki/Ohm%27s_Law states that volatage and resistance are linked. We are talking about the same thing, generally speaking.

  • 0

    YongYang

    It CAN not be second guessed or presumed: it MUST be certain. It is malfunctioning or it is not. TEPCO must determine as to which and NOT 'maybe' a possibility.

  • -1

    Wurthington

    So you're telling me they've been relying on data from just one thermometer.... We're talking about something that could potentially be harmful to millions and these guys are relying on one instrument to measure the heat. Its almost like they really don't want to know the truth themselves.

  • 0

    smithinjapan

    Yup, not the company's fault -- this whole thing is the fault of a malicious little thermometer!

  • 0

    yildiray

    Seems relatively plausible though - if the temperature DID hit 285 degrees, there would be a massive increase in radioactivity and heat escaping into the atmosphere which is something that even tepco cannot cover up!

  • 0

    zichi

    Star-Viking,

    Sorry, I wrote a reply to your comment but damn it, it was lost in the upload and I can't be bothered to rewrite it.

  • 1

    Farmboy

    I've seen broken thermometers that don't move, but I've never seen one that continues to rise.

  • 0

    gaijinTechie

    increase in radioactivity and heat escaping into the atmosphere which is something that even tepco cannot cover up!

    But not for lack of trying, as the Jan. 3rd spike in radioactivity in KEK (Tsukuba) data clearly shows. http://rcwww.kek.jp/norm/

    Maybe that's Tepco style "normality" in the much touted state of "cold shutdown" as explained by Noda-physics.

  • 1

    zichi

    What I've learnt most from this disaster is that the original designers of the reactors never fully planned for the day of a total nuclear meltdown with temperatures above 1500degC, when the maximum temp that could be measured was only 400degC.

    Guess, they believed it could never happen. Thermocouples are not the best way to measure temperatures inside a reactor.

    There needs to be three back-up systems for every essential piece of plant. I hope the nuclear industry are paying attention and gaining much needed info from this disaster, and more importantly, now taking the right actions to improve reactor safety.

    NISA have now approved the stress tests on two KEPCO reactors in Fukui. Now it will go to the Atomic Commission for approval, which is unlikely to reject it. KEPCO will also need to seek the approval of the governor and local people. I think these two reactors will be back on line before early summer. 50% of Kansai power is generated from nuclear reactors.

  • -2

    j4p4nFTW

    Thankfully we have the best engineers in the world working on this and making sure that we all stay safe.

  • 1

    zichi

    Diagram of reactor temperature measuring points. < http://enformable.com/wp-content/uploads/2012/02/tumblrlz98iiCa411rpu7eco11280.png>

  • 0

    Elvensilvan

    Thanks zichi for the link (although it got deleted).

    Anyway, I found this tidbit in TEPCO's website:

    On February 13, 2012, we received the instruction document* titled "Submission request for report on the correspondence for temperature increase in the lower part of the Reactor Pressure Vessel of Unit 2 at TEPCO Fukushima Daiichi Nuclear Power Station" from Nuclear and Industrial Safety Agency (NISA) of Ministry of Economy, Trade and Industry.

    Based on the instruction, we will compile with regard to the thermostat monitoring the temperature at the lower part of the Reactor Pressure Vessel of Unit 2, then submit the report to NISA immediately.

  • 1

    smithinjapan

    zichi: As usual I agree with you, but I guarantee the companies will turn the reactors back on regardless of whether they have the public support or not. The whole 'public opinion/support' thing is a joke -- it only applies when they agree with the government.

  • -1

    Star-viking

    zichiFeb. 14, 2012 - 12:59PM JST

    Star-Viking,

    Sorry, I wrote a reply to your comment but damn it, it was lost in the upload and I can't be bothered to rewrite it.

    No probs. Were you in general agreement, disagreeing, or other?

  • 4

    zichi

    Star-Viking,

    Looking at the available data, I would have to say, it appears to be a busted thermocouple.

  • 2

    zichi

    Smithinjapan,

    I think it was in 2006 when KEPCO decided on its own to extend the life of a Fukui reactor by another 10 years, and restarted it without seeking local approval?

  • -1

    Nathalie Ancelin

    Hi, I follow the Fukushima nuclear plant from Europe because of my interest for this event and because I love Japan. This story of broken thermother is like a bad joke. To check the first tool to assess the temperature sounds so obvious ! Thanks for your reactions.

  • 0

    gonemad

    In a thermocouple the generated voltage increases with the temperature difference. Is there any possible failure mode which leads to an increase in the voltage? I can't think of any, except when it is not a simple thermocouple but some active circuitry is included. But then, the resistance measurement doesn't make sense any more. Something doesn't fit together here...

  • -1

    Cletus

    Its sudden elevation to 94.9 degrees on Monday morning and then 285 degrees by mid-Monday afternoon with no other signs of a nuclear reaction led scientists to conclude the equipment was faulty.

    Ah TEPCO logic at its best, we watched it climb from 95 to 285 degrees and nothing bad happened so all's good again. I wonder if while that temperature gauge was climbing what if any precautions where put in place in case it wasnt just a faultly gauge. Knowing TEPCO probably nothing.

  • -1

    655321

    I'm utterly convinced Frank Drebin, Stanley Spadowski, Presto (D&D), Sloth and Jughead Jones could do a better job than Tepco.

  • 1

    nigelboy

    Ah TEPCO logic at its best, we watched it climb from 95 to 285 degrees and nothing bad happened so all's good again. I wonder if while that temperature gauge was climbing what if any precautions where put in place in case it wasnt just a faultly gauge. Knowing TEPCO probably nothing.

    They tested the Xenon 135 level well below what is required for recricality hence, "nothing bad happened".

  • -1

    Thomas Smith

    Reporting that your equipment is falty and therefore your data is unreliable doesn't exactly engender confidence when you try to convince the public youre on top of things. How many other broken thermometers or other equipment? Was it always too high or too low? How long did it take you ro discover it? How dangerous is that? I'm in IT and we test things before they break on less than mission critical hardware/software. Is TEPCO just waiting for things to break before they replace? Not likely I'd say this is probably more obfuscation to make things seem safer than they are...but not having the desired effect. Yes I'm paranoid about it this point. Noones given me reason not to be unfortunately.

  • 2

    nigelboy

    http://www.tepco.co.jp/cc/press/betu12_j/images/120214c.pdf

    Me thinks people need to start reading the summarized reports that is issued by TEPCO.

    Here it states what they had done when the increase in temperature was discovered on one of the thermocouples. To summarize, during a week that this problem was detected, they increased the injection of water on numerous times, checked for Xenon 135 level three times, injected Boric acid three times, and did I mention "increase the water injection". It's as though TEPCO suspected malfunction in the thermocouple from the beginning but since the media will always look for the hysterical scenario spin, they had no choice to to conduct these actions. Result: Two thermocouples indicate a decreasing temperature (which it should!) and one in question started to increase. Logical conclusion... Never mind.

  • 0

    Cletus

    nigelboy

    Me thinks people need to start reading the summarized reports that is issued by TEPCO.

    Ah yes TEPCO press releases and they have been so factual and timely in the past. Not worth the paper they are written on nigelboy. But you believe them hey!!!!

  • -1

    DoLittleBeLate

    Thankfully we have the best engineers in the world working on this and making sure that we all stay safe.

    No, the best engineers are the ones who don't need to work on things like this. That is what makes them "best".

    @j4p4nWTF, perhaps you could use these "best engineers" before the next level 7 disaster, ok? Let's do that instead.

  • -1

    nigelboy

    Ah yes TEPCO press releases and they have been so factual and timely in the past. Not worth the paper they are written on nigelboy. But you believe them hey!!!!

    Timely? Yes. Factual? Majority of the time, hell yes. I guess "it not worth the paper they are written on" to you since you can't read it but rely on AFP, AP, and other poorly written article to come up with that conclusion. But hey!!!

  • 0

    ivarwind

    Ah yes TEPCO press releases and they have been so factual and timely in the past. Not worth the paper they are written on nigelboy. But you believe them hey!!!!

    No no, why would anyone believe them? If they wanted to cover-up something, they couldn't possibly have come up with the idea of... Not announcing the (erroneous) rising temperature data to begin with! No they must first announce rising temperatures, and then explain that the thermometer is out of order. Clearly a much easier and straightforward way to go about a cover-up than just not saying anything.

  • 3

    zichi

  • 0

    peanut666

    Wow! There are so many "engineers" posting their expertise here. I didn't know there were so many. What did TEPCO do wrong? Nothing. Why would they cover up anything? 99% of you can't even fix your own car and change a flat tire and you guys are complaining about what they should or shouldn't of done. You don't even read the news. The tsunami wiped out the infrastructure so even getting to the reactor was diificult when the roads are destroyed, no electricity, no lights, or fuel, most of the experts who worked or lived in the area were killed from the tsunami, they didn't have any equipment to measure if it was even safe to go in because they couldn't transport it there. That's why early reports were so sketchy and rare. It wasn't because they were trying to hide anything. Now they need to monitor the temperatures. How can they do this? Only remotely because they can't go inside because of the radiation. They can access three thermometers remotely. I see absolutely nothing wrong with the reports. It is a terrible situation and they are dealing with it the best way they can.

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