Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[NUCENG]

Perhaps only the FHM.

FHM capacity is a few hundred pounds. Caskes weigh several tonnes. FHM has fine control needed to prevent damage to a fuel bundle. That is not something easy to achieve with a heavy lift crane.

 

[triumph61]

FHM capacity is a few hundred pounds. Caskes weigh several tonnes. FHM has fine control needed to prevent damage to a fuel bundle. That is not something easy to achieve with a heavy lift crane.

Thats right, but the FHM can take the Fuel into the Cask.

 

[MadderDoc]

This may be the missing Unit 3 refueling crane fallen into the spent-fuel pool as seen in an April, 14 2011 image here:

The graphic shows similar objects between this piece of wreckage in the Unit 3 pool and the intact Unit 4 refueling crane. It also shows a similar spatial conjunction of similar objects, and this meta-similarity makes me confident we're looking at Unit 3's refueling crane.

There are many pre-tsunami photos of the refueling crane here.

Why isn't the proposed refueling crane also bright green? My guess is that the fire that blasted out the south side over the pool and thus onto the crane scorched off the paint.

I feel this area of the SFP3 is a really good candidate for harbouring the missing FHM and its supporting bridge, however in the collection of wreckage I've found nothing really strikingly looking like it's matching parts of the FHM. The best I'd got is the green platform like object that is located submersed, just about where you have written 'railing?' in your photo montage. I think you are right that we shouldn't necessarily be looking for something standing in the original bright green colour.

From the same video source (taken by the crane camera on 18th of april 2011), I have a possible ID of the ladder that used to lead to the NW corner of the bridge which used to carry the FHM3.

If identified correctly, this ladder did end up not too far from its original position, where it got entangled in a fallen cross beam from the roof construction.

Below is a montage of an original photo of the ladder on the intact FHM bridge, some screen shots from the crane camera video, and a Tepco released photo from April 14th of the same ladder. I note the wrecked ladder has the same number, and same unusual positioning of steps, and it has what would represent the right hand rail still attached. While the left hand rail is missing, the Tepco released photo does display in a correct position what would represent remains of the two bolts that held it.

 

[MadderDoc]

At first Tepco wanted to take one more year, but this was refused by the government :

Fair to say, the environment in the SFP4 does remain unpleasantly corrosive (and the developed murkiness and the apparent caking on top of the assemblies might already have something to do with this.) Over a further 2+ year timeline, the prolonged corrosion could jam the assemblies in the racks, making it more difficult to remove them. I wonder how much aluminium alloy is in the pool, anybody knows?

 

[mscharisma]

I thought maybe some of you might find this article interesting, even though it's - thankfully - not of great consequence as far as what's going on at Daichi these days. It's about a cover-up of a defect in the reactor vessel of reactor 4.

http://www.bloomberg.com/news/2011-03-23/fukushima-engineer-says-he-covered-up-flaw-at-shut-reactor.html

 

[nuckelchen]

hi @ all

my name is ulli and i come from germany.
(germanium 71 )
i'm the one who made the masses of edited and timelapsed videos from and around fukuground.
mostly i worked with lapsed and captured streams from fukushima.

i'm not a physics-crack, i had studied *soziologie* and learned and worked as a bakerman too, special as a *bio-vollkorn-bäcker*.

and there i only does *reporting* visual moments from the boths streams.
i failed many times with my first optic impressions and that's okay.
because nobody will hurts by my wrong optical impressions and they based just on a single view and not on a nuclear-techno-study from 6 or 7 years.

but as japan/tepco is covering so much of all, included the optics,
i will find day per day more.
since january i didn't abled to work all the recorded stream time out...
there is to much stuff in it.
special @ the last two months.

so please take my posted videos as that what they are:
just an optic reported impression from a subject view or of a meaning of it.

i think that it will be importent for readers who searches some facts from fukuground, that the discussions in the public will be done correctly and fair.


and i didn't tricked on the videos, only sometimes a bit too much effected and too dramatic soundings...

i will give you all a sample from what i talk about.
remember you on the last poolr-video-releases from tepco in the last days.
(they putted them into a wrong frame size, played to fast and also the colors had a touch too much of tepcolors.)
first i fixed the frame-rate on that what it is, 'cause black-framed isn't usefull.
then i slomo them, shapened and color-editings on every video
and voilá,
here we go:
http://youtu.be/JXdPxd14rU8
http://youtu.be/v5-kXSi1ppA

to have a look how the *pool-area* should look normaly:
http://youtu.be/kvfvLEmMlro


i hope my first post cwill explain to you how i working on the streams and that i didn't "press" the stream-records in that sight, in that i wanne have them.

if there will be nothings to be reporten from the streams, perfect.

the endless drama from tepco had learned me
that only no news are good news...


achja,
one more I've got.
there is a new satellite picture from jan 2012, taken by astrium.
http://regard-sur-la-terre.over-blog.com/article-un-an-apres-le-tsunami-retour-a-fukushima-avec-le-satellite-pleiades-101454894.html
but they given it for free only in a 1111 pixel frame...so i made it a bitly bigger with "photo-zoom-pro-3", onto 4444 pixels.
http://www.img-teufel.de/thumbs/PleiadesJaponFukushima18012012copie3215651949cd7djpg.jpg

 

[zapperzero]

one more I've got.
there is a new satellite picture from jan 2012, taken by astrium.
http://regard-sur-la-terre.over-blog.com/article-un-an-apres-le-tsunami-retour-a-fukushima-avec-le-satellite-pleiades-101454894.html
but they given it for free only in a 1111 pixel frame...so i made it a bitly bigger with "photo-zoom-pro-3", onto 4444 pixels.
http://www.img-teufel.de/thumbs/PleiadesJaponFukushima18012012copie3215651949cd7djpg.jpg

http://www.flickr.com/photos/geoeyesatelliteimagery/6985103913/lightbox/

 

[SteveElbows]

hi @ all

my name is ulli and i come from germany.
(germanium 71 )
i'm the one who made the masses of edited and timelapsed videos from and around fukuground.
mostly i worked with lapsed and captured streams from fukushima.

i'm not a physics-crack, i had studied *soziologie* and learned and worked as a bakerman too, special as a *bio-vollkorn-bäcker*.

and there i only does *reporting* visual moments from the boths streams.
i failed many times with my first optic impressions and that's okay.
because nobody will hurts by my wrong optical impressions and they based just on a single view and not on a nuclear-techno-study from 6 or 7 years.

but as japan/tepco is covering so much of all, included the optics,
i will find day per day more.
since january i didn't abled to work all the recorded stream time out...
there is to much stuff in it.
special @ the last two months.

so please take my posted videos as that what they are:
just an optic reported impression from a subject view or of a meaning of it.

Hello and welcome.

Your slowed down & colour altered videos from things like the reactor 4 fuel pool & reactor well may be of interest to people.

But I would avoid posting much about your TEPCO webcam & TBS feed videos as they do not tend to show anything of scientific interest, they are of little use to this forum. Most of what you will see is related to the weather and other atmospheric affects, nothing to do with the reactors. And the TEPCO webcam suffers from lots of compression artefacts, and if you sometimes see flashing lights in strange places on these videos then you should strongly consider the possibility that its actually a light being reflected off the dome that surrounds the camera.

 

[westfield]

hi @ all

my name is ulli and i come from germany.
(germanium 71 )

<snip >

achja,
one more I've got.
there is a new satellite picture from jan 2012, taken by astrium.
http://regard-sur-la-terre.over-blog.com/article-un-an-apres-le-tsunami-retour-a-fukushima-avec-le-satellite-pleiades-101454894.html
but they given it for free only in a 1111 pixel frame...so i made it a bitly bigger with "photo-zoom-pro-3", onto 4444 pixels.
[URL]http://www.img-teufel.de/thumbs/PleiadesJaponFukushima18012012copie3215651949cd7djpg.jpg[/PLAIN]

A Jan 2012 image of most the fukuichi site. Interesting view of the extent of the siteworks, tank farms etc.
(Unretouched, unscaled. 3300 x 3300 pixel geoEye satellite)

http://geoeyemediaportal.s3.amazonaws.com/assets/images/gallery/ge1/hires/fukushima_31JAN2012.jpg

March 2011 satellite images I hadnt seen before at this resolution

http://geoeyemediaportal.s3.amazonaws.com/assets/images/gallery/ge1/hires/japan_fukushima_daiichi_after_03_14_11.jpg


Satellite image within minutes of Unit 3 coming apart ( It's a very familiar image but in a higher resolution than I had seen before)

 

[duccio]

A Jan 2012 image of most the fukuichi site. Interesting view of the extent of the siteworks, tank farms etc.
(Unretouched, unscaled. 3300 x 3300 pixel geoEye satellite)

The sky on Fuku was quite crowded in those days... very interesting pics! Doubt: is the exhaust stack pipe of R3 missing? It is still there on the pic in which reactor 4 is still intact. Do you believe Tepco removed it, or it was blown away during the explosion of R4?

 

[SpunkyMonkey]

I feel this area of the SFP3 is a really good candidate for harbouring the missing FHM and its supporting bridge, however in the collection of wreckage I've found nothing really strikingly looking like it's matching parts of the FHM. The best I'd got is the green platform like object that is located submersed, just about where you have written 'railing?' in your photo montage.

I'm more drawn to the green platform-like object where I'm pointing. So I made this animation especially for you die-hard refueling-trolley deniers

​

The 'platform' object I'm talking about is clearly a coherent lattice of heavy-metal beams that appears to be roughly consistent with the I-beam undergirding of a refueling-trolly platform seen above and in this patent (Figure 3C). Not an exact match (and it's not the exact refueling trolley), but it would be the same structural concept. Additionally I also highlight the objects that look like pulleys to me, including another circular-seeming shape I just noticed deeper in. (Fyi, the http://www.tepco.co.jp/en/news/110311/images/110415_1f_4_2.jpg).

Further supporting my impression of identity is that the olive-green color of the Unit-3 refueling crane as it http://www.houseoffoust.com/fukushima/MOXinstall3.jpg when the MOX fuel was loaded appears to be a close match to the olive-green color of both the proposed refueling-crane objects and the larger well-known overhead crane as it appeared late last year in this Tepco video. Those photos showing the refueling crane being olive-green can be found in press reports about the MOX installation.

So the question for U3-refueling-platform skeptics is: What large olive-green object with a lattice-girder platform and large pulley-like objects was over the fuel pool and was not the olive-green refueling platform?

From the same video source (taken by the crane camera on 18th of april 2011), I have a possible ID of the ladder that used to lead to the NW corner of the bridge which used to carry the FHM3.

Agreed, good ID! Any idea how what seems to be a roof girder became, it seems, co-mingled with a handle railing on the refueling ladder? And what's your source for the April 18 images of the ladder? I've not seen them before and can't find them on Tepco's site.

 

[tsutsuji]

So I made this animation

Animations such as this one are difficult to understand, because they leave hardly more than one second to watch each picture. Unlike videos on youtube, there is no pause button.

 

[MadderDoc]

<..>
Agreed, good ID! Any idea how what seems to be a roof girder became, it seems, co-mingled with a handle railing on the refueling ladder?

Presently I think something heavily hit the roof construction from aloft, pushing and smashing it down close to where the refueling bridge happened to be at the moment. On collision some parts of all parties naturally came loose and got intermingled. For the major part of them, refueling bridge and FHM ended up in the pool. As indicated, that's just my thoughts at the moment:

And what's your source for the April 18 images of the ladder? I've not seen them before and can't find them on Tepco's site.

It is from some time last year when Tepco released a collection of previously unpublished material, among which were two videos with a total of 50 minutes of capture from the concrete pump camera on April 18. The collection was published only temporarily, timing out by the end of 2011. The link to the collection was posted here, but I believe the link is now dead, (otherwise I should think I'd retained it as a bookmark, which I haven't.) However I retained a.o. grabs of those two videos. Check your mailbox..

 

[zapperzero]

Has this been discussed before? (got to it via ex-skf blog)

http://www.asahi.com/national/update/0603/TKY201106030539.html

"8:30 am on March 12, [tellurium?] was measured and Okuma-machi Namie-machi, Minami Soma City prior to the explosion of Unit 1 and hydrogen vent work" (google translation, sorry, I know no Japanese, this may be very wrong).

This is before even the first attempt at venting, no?

 

[tsutsuji]

Has this been discussed before? (got to it via ex-skf blog)

http://www.asahi.com/national/update/0603/TKY201106030539.html

"8:30 am on March 12, [tellurium?] was measured and Okuma-machi Namie-machi, Minami Soma City prior to the explosion of Unit 1 and hydrogen vent work" (google translation, sorry, I know no Japanese, this may be very wrong).

This is before even the first attempt at venting, no?

Be careful that the Asahi article says "from 8:30 AM to 1:30 PM on March 12". Otherwise your translation is correct.

The data released by the NISA on 3 June 2011 are available at http://www.meti.go.jp/press/2011/06/20110603019/20110603019-2.pdf

I translate the first line of the table page 18/24 :

List of monitoring results in the surroundings of Fukushima Daiichi nuclear power station (atmospheric suspended dust)

Radiation concentrations (Bq/m³):

Sampling location              Measurement time             I-131  Cs-134 Cs-137 I-132 Te-132 other substances  done by                   page number       notes
Nishihara, Takase, Namie   2011/03/12 08:39 ~ 08:49      37                 1.8      90       73                          Fukushima prefecture          1

See also the maps on pages 18/24 ("page 1") to 22/24 ("page 4")

The yellow lines are marked with "in part already publicly released" in the "notes" column.

In http://www.meti.go.jp/press/2011/06/20110603019/20110603019-3.pdf they explain that the previously released data are those of the 21st report (13 March 2011 at 20:30 PM) and 22nd report (14 March at 7:30 AM) :

In the report of 13 March 2011 at 20:30 PM : http://www.meti.go.jp/press/20110313007/20110313007-4.pdf I find the data measured in Front of Fukushima prefecture Atomic Energy Center at 16:00 on 13 March with 1.7 Bq/m³ of Iodine 131 and ND for Tellurium. English version here : http://www.nisa.meti.go.jp/english/files/en20110313-6.pdf (page 14/15)

In the report of 14 March 2011 at 07:30 AM : http://www.meti.go.jp/press/20110314001/20110314001-3.pdf I find the data measured in Front of Fukushima prefecture Atomic Energy Center at 08:00 ~ 08:10 AM on 13 March : 5.8 Bq/m³ of Iodine 131 and 1.7 Bq/m³ of Tellurium 132.

 

[MadderDoc]

Has this been discussed before? (got to it via ex-skf blog)

http://www.asahi.com/national/update/0603/TKY201106030539.html

"8:30 am on March 12, [tellurium?] was measured and Okuma-machi Namie-machi, Minami Soma City prior to the explosion of Unit 1 and hydrogen vent work" (google translation, sorry, I know no Japanese, this may be very wrong).

This is before even the first attempt at venting, no?

Yes certainly, but the D/W pressure of unit 1 reached twice design max pressure at 3 am on March 12th, and shortly after that the radiation dose at the site started to increase above normal. Read, shortly after that, abnormal emission started from the plant.

A 10x increase of normal radiation at the main gate was reported to the authorities at about 5 am on the morning of March the 12th, and radiation increased a further 10x during the next hour, where it kept steady until about noon. The wind at the main gate was south-southeasterly during this period.

 

[SteveElbows]

It is from some time last year when Tepco released a collection of previously unpublished material, among which were two videos with a total of 50 minutes of capture from the concrete pump camera on April 18. The collection was published only temporarily, timing out by the end of 2011. The link to the collection was posted here, but I believe the link is now dead, (otherwise I should think I'd retained it as a bookmark, which I haven't.) However I retained a.o. grabs of those two videos. Check your mailbox..

The ladder can also be seen in less detail shortly after the 6 minute mark on this video:



I concede that it is possible that the FHM is in the pool, although there isn't enough evidence to be sure. I dislike the photo analysis which places too much emphasis on the circular objects being the pulleys, since the material seems like a poor match, although the visual evidence isn't high enough quality to be sure.

 

[zapperzero]

Yes certainly, but the D/W pressure of unit 1 reached twice design max pressure at 3 am on March 12th, and shortly after that the radiation dose at the site started to increase above normal. Read, shortly after that, abnormal emission started from the plant.

A 10x increase of normal radiation at the main gate was reported to the authorities at about 5 am on the morning of March the 12th, and radiation increased a further 10x during the next hour, where it kept steady until about noon. The wind at the main gate was south-southeasterly during this period.

The new factor here is tellurium, which suggests containment damage. Doses could have been increasing from steam escaping the primary coolant loop on the turbine side, or something relatively benign like that.

 

[zapperzero]

Be careful that the Asahi article says "from 8:30 AM to 1:30 PM on March 12". Otherwise your translation is correct.

Thank you very much, I will now look at the documents you referenced as well.

 

[MadderDoc]

The new factor here is tellurium, which suggests containment damage. Doses could have been increasing from steam escaping the primary coolant loop on the turbine side, or something relatively benign like that.

I see what you mean, the very short-lived Te-132 would have to come from somewhere having material that had undergone fission quite recently (within at most a few days). Radioactivity as such could in theory have come from other sources.

However, at the time of events it was certainly interpreted as containment failure. While the radioactive dose increased, it was also observed that the overpressurised D/W began to give in and loose pressure, indicating leakage from the D/W to the exterior. Tepco reported this judgement to the authorities, at 5:14 am on March 12th.

 

[MadderDoc]

The ladder can also be seen in less detail shortly after the 6 minute mark on this video:



I concede that it is possible that the FHM is in the pool, although there isn't enough evidence to be sure. I dislike the photo analysis which places too much emphasis on the circular objects being the pulleys, since the material seems like a poor match, although the visual evidence isn't high enough quality to be sure.

I've seen nothing particular in the pool which to me looks like parts of the FHM itself, however, in the video you linkto, close to the pool gate, I think I can spot something that to me looks like a part of the huge bridge which carried the FHM (The give-away, for the bridge, being the spotting of the rather unique cross-beaming of the structure). So, my current thought, that the FHM is likely in the pool, is rather more based on induction than from observation: thinking, if the FHM bridge has tumbled into the pool, it would seem quite likely that the FHM did too.

 

[SteveElbows]

Details of the next study inside the reactor 2 drywell have been published, they are going to try it on March 26th and 27th:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120322_05-e.pdf

 

[Rive]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120322_01-e.pdf

Can somebody please enlighten me about this 'TIP room'?

They are about to get neutron activity readings, or these are new holes (reachable from a relatively low dose area) on the containment for more borescope investigations?

 

[rmattila]

I see what you mean, the very short-lived Te-132 would have to come from somewhere having material that had undergone fission quite recently (within at most a few days). Radioactivity as such could in theory have come from other sources.

However, at the time of events it was certainly interpreted as containment failure. While the radioactive dose increased, it was also observed that the overpressurised D/W began to give in and loose pressure, indicating leakage from the D/W to the exterior. Tepco reported this judgement to the authorities, at 5:14 am on March 12th.

The containment dome seal would as far as I see have started to leak during the night between March 11 and 12. The Mark I dome seal problems due to pressure > 5 bar are as far as I know a well-known issue, and the heat in the containment increases the probability of a seal failure. I still have the view that the hydrogen got to the service floor directly through the dome seal, and this dry route would make it possible for tellurium to escape as well.

 

[rmattila]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120322_01-e.pdf

Can somebody please enlighten me about this 'TIP room'?

They are about to get neutron activity readings, or these are new holes (reachable from a relatively low dose area) on the containment for more borescope investigations?

TIP = traversing in-core probe. A gamma detector driven into the core every month or so in order to calibrate the in-core neutron detectors, which slowly burn out in the neutron flux. The TIP is driven from a room next to the containment, routed to one TIP channel at a time, and driven through the channel (=a small pipe) from the bottom of the RPV into the core and back.

 

[SteveElbows]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120322_01-e.pdf

Can somebody please enlighten me about this 'TIP room'?

They are about to get neutron activity readings, or these are new holes (reachable from a relatively low dose area) on the containment for more borescope investigations?

Im pretty sure the borescope mission is going through the same penetration as last time, so nothing to do with this room.

My guess is that this room is where existing penetrations that are used by normal neutron measuring equipment are located. And perhaps they have surveyed it now because these penetrations are one of the potential failure points that could leak or otherwise enable contaminated substances to travel through some of this equipment. But as with many other parts of the reactor 2 building, there is no sign of high levels of contamination here.

Alternatively perhaps they would like to start using this equipment again to monitor the situation, although I am not familiar with the technology or whether it would actually be any use once the reactor vessel is so badly damaged.

 

[SteveElbows]

TIP = traversing in-core probe. A gamma detector driven into the core every month or so in order to calibrate the in-core neutron detectors, which slowly burn out in the neutron flux. The TIP is driven from a room next to the containment, routed to one TIP channel at a time, and driven through the channel (=a small pipe) from the bottom of the RPV into the core and back.

Thanks for the info, I hadn't seen your post when I wrote my previous one.

 

[jim hardy]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120322_01-e.pdf

Can somebody please enlighten me about this 'TIP room'?

They are about to get neutron activity readings, or these are new holes (reachable from a relatively low dose area) on the containment for more borescope investigations?

I'm not BWR guy

but i do know BWR's have "Travelling Incore Probes" which are miniature, moveable neutron detectors that traverse the core vertically in hollow tubes coming in from the bottom..
This is similar in principle to the PWR "Flux Mapper" and i do have experience with that system.
Our detectors were miniature fission chambers coated inside with oralloy, about two inches long by 3/16 diameter.
The vessel has penetrations on bottom for the hollow tubes in which the detectors travel. My reactor had five detectors that shared fifty tubes via indexing machanisms. We cleaned our tubes with a .22 caliber rifle bore brush soldered to a cable in place of the fission chamber. But i digress.Seems to me the TIP equipment room must be the room housing the mechanical detector drives and indexing machanisms, at the terminus of the tubes.

A natural place to launch an endoscope exploration.

Perhaps a BWR person can confirm.

EDIT Wow I'm fifth in line!

 

[SteveElbows]

Well like I said earlier I am pretty sure its not for this borescope mission, since they published details of what they will do and its very similar to the last mission.

However I suppose its possible they might have some ideas to use the TIP pipes for something else in future. Perhaps the future mission to install new temperature measurement equipment may consider using these penetrations for example.

 

[Rive]

Wow, thanks for everybody

The next borescope mission will be on the penetration used for the previous mission, that's in the linked document.

But such pipes (even if they are supposedly damaged close to the RPV) holds some possibilities for measurements, borescoping and such... And the starting point of the pipes are in a clean, nice room with low radiation.

Nice. Can't wait to see how will they use them.

 

[jim hardy]

Well like I said earlier I am pretty sure its not for this borescope mission, since they published details of what they will do and its very similar to the last mission.

However I suppose its possible they might have some ideas to use the TIP pipes for something else in future. Perhaps the future mission to install new temperature measurement equipment may consider using these penetrations for example.

AND

But such pipes (even if they are supposedly damaged close to the RPV) holds some possibilities for measurements, borescoping and such... And the starting point of the pipes are in a clean, nice room with low radiation.

Here's a description of the TIP system

http://www.google.com/url?sa=t&rct=...n9CCBg&usg=AFQjCNE3hTkaEtLnbVOEqBcNsW_Dh9PnrA

if link doesn't work search on "ML11258A339.pdf"

If no probes were inserted at time of accident, the fail closed isolation valves should have kept the room clean and dry when the far end of tubes melted with the core.

IF there ARE probes inserted, AND the room is clean, it would say something surprising about conditions in core, , ie core end of tubes didnt melt. Unless they actuated the explosive actuated shear valves before station batteries gave out..

Pushing limits of speculation here. Will say no more, but await further reports.

old jim

 

[rmattila]

In the BWRs I know, there's only three pipes going through the containment wall, and the multiplexers routing the TIP to different pipes (30 or so) within the core are located inside the containment (and are probably useless by now). But at least three of the pipes should be accessible after opening the containment isolation valves.

Disclaimer: I am mostly familiar with the ASEA BWRs, but I suppose the TIP system in those is more or less the same as in the American-designed BWRs.

EDIT: Fig 5.6-1 of old Jim's post confirms the designs are the same (and that the "multiplexer" I mentioned appears to be more properly called an "indexing mechanism".)

 

[Rive]

By this picture: http://www.tepco.co.jp/en/news/110311/images/120322_11.jpg
they have four equipment of the same kind and one more which is different.

 

[tsutsuji]

http://www.jiji.com/jc/c?g=soc_30&k=2012032200956 As a result of checking the TIP room located on unit 2's reactor building first floor with a robot, Tepco announced on 22 March that there is no pipe or equipment damage there. This is one of the inspections aimed at installing alternative thermometers to replace the broken thermometers. With 2 mSv/hour the radiation is relatively low. The room contains pipes which are directly connecting with the RPV. As no conspicuous damage was found, Tepco said that installing an alternative thermometer is possible.

The short list of alternative thermometer routes Tepco is considering, after having studied all the routes through all the RPV nozzles, are listed in the 2 March 2012 report http://www.tepco.co.jp/cc/press/betu12_j/images/120302a.pdf table 1-2 page 17/91 and 18/91. Route names are in the second column from left, and priority numbers are in the right most column. The circled numbers are references further used on the floor layout maps on the following pages.

On page 18/91, the Jet Pump instrumentation line is marked as "priority=1" but the TIP is marked as priority "2". The radiation for TIP was then marked as "unknown" in the table.

While there is only one priority 1 item (or you may say that there are as many as jet pump instrumentation lines - that must be 24), there are 2 other "priority 2" routes:

Water level instrumentation line: nozzles N16A and N16B; check valve = no; T-junction= no ; radiation=unknown; reactor building 2nd floor 4.5 m above floor; priority = 2

Boric acid injection system (differencial pressure sensor line) Nozzle N10 (in the case you do not insert further than the T on the reactor outside) check valve = no; T-junction= no ; radiation=unknown; reactor building 1st floor 4.8 or 4.5 m above floor; priority=2

 

[tsutsuji]

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120323_01-j.pdf Results of onsite surveys for the purpose of installing alternative thermometers, Fukushima Daiichi unit 2. English is here: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120323_01-e.pdf

http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120323_03-j.pdf One of unit 1's RPV thermometers was not connected because it was broken (since long ago, before the accident, I guess) and instead of recording the temperatures from that thermocouple, there was a jumper connecting with the nearby thermometer, so that what was recorded was a duplicate of the temperatures of the nearby thermometer.