Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[tsutsuji]

What kind of specialist(s) would that be? (Sorry, I don't speak Japanese and would be grateful for the additional info.) Thanks.

The members' list is provided on http://www.aesj.or.jp/info/pressrelease/PR20120817.pdf pages 2/3 and 3/3. You can use http://translate.google.com/translate?hl=en&ie=UTF8&langpair=ja%7Cen&u=http://www.aesj.or.jp/info/pressrelease/PR20120817.pdf to find which institutions (universities, etc.) they belong to (in the right column), and which existing AESJ committees are recommending them. The last 5 people are observers.

(*) Contains a few mistakes such as (独) mistakenly rendered by Google as "(Germany)" although it actually means "(independent body)".

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120822/index.html A 57 year old contractor company employee was found unconscious at around 10:00 AM on 22 August in a rest area. He was taken to hospital in Iwaki but declared dead, presumably from myocardial infarct, at around 01:00 PM. He had been working at Fukushima Daiichi since August of last year. On 22 August he was installing tanks for water decontamination, when he felt unwell and left to the rest area. This is the 4th worker dying of presumably myocardial infarct at Fukushima Daiichi since March 2011.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120823/index.html The NISA has issued instructions concerning the so-called "alarm typers", devices which record alarm signals in nuclear power plants, reflecting the fact that one of them failed 12 minutes after the earthquake on 11 March 2011 at Fukushima Daiichi unit 1, because of paper jam, as a consequence of which some records are missing, and the status of some vital equipments cannot be checked, making the analysis of the accident more difficult. Recording devices in 66 nuclear facilities over Japan must be inspected, the NISA instructed. The NISA also required Tepco to check if the failed recorder had had troubles before the accident.

 

[mscharisma]

Thanks a bunch, tsutsuji!

 

[zapperzero]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120822/index.html A 57 year old contractor company employee was found unconscious at around 10:00 AM on 22 August in a rest area. He was taken to hospital in Iwaki but declared dead, presumably from myocardial infarct, at around 01:00 PM. He had been working at Fukushima Daiichi since August of last year. On 22 August he was installing tanks for water decontamination, when he felt unwell and left to the rest area. This is the 4th worker dying of presumably myocardial infarct at Fukushima Daiichi since March 2011.

Umm... does this mean cause of death unknown? I have ugly flashbacks when I see this "presumably" because my country went through a turbulent period a while ago - various people were dying at demonstrations or in police custody and the cause was reported as "cardio-respiratory arrest" - i.e. died of being dead.

Could be just me being paranoid as usual, of course.

 

[Shinjukusam]

Umm... does this mean cause of death unknown? I have ugly flashbacks when I see this "presumably" because my country went through a turbulent period a while ago - various people were dying at demonstrations or in police custody and the cause was reported as "cardio-respiratory arrest" - i.e. died of being dead.

Could be just me being paranoid as usual, of course.

Well, the temperature has been hovering around the mid 30s for the last few weeks. Working in that, wearing protective gear, carrying heavy equipment, 57 years old...it's not that unlikely.

 

[zapperzero]

Well, the temperature has been hovering around the mid 30s for the last few weeks. Working in that, wearing protective gear, carrying heavy equipment, 57 years old...it's not that unlikely.

No it is not. But, the quote seems to imply that autopsies are not performed. I find this troubling.

 

[mscharisma]

Umm... does this mean cause of death unknown? I have ugly flashbacks when I see this "presumably" because my country went through a turbulent period a while ago - various people were dying at demonstrations or in police custody and the cause was reported as "cardio-respiratory arrest" - i.e. died of being dead.

Could be just me being paranoid as usual, of course.

I can't read Japanese, but EX-SKF blog reported/commented on the Mainichi Shinbun article(s) regarding the death, according to which TEPCO announced the cause as myocardial infarction. Personally, I would like to see an autopsy as to what caused the heart attack. The information TEPCO apparently provided that it was not radiation-related without further detail as to the cause of the heart attack does not satisfy me - to say the least. But that discussion probably doesn't belong in this forum. Anyway, you may find further info here:
http://ex-skf.blogspot.it/2012/08/fukushima-i-nuke-plant-57-year-old.html

 

[Shinjukusam]

No it is not. But, the quote seems to imply that autopsies are not performed. I find this troubling.

What would you even expect to see?

 

[zapperzero]

What would you even expect to see?

I'd expect at the very least whole body counts and blood work for all the dead - as opposed to dose tallies based on the readings of personal dosimeters which may or may not have been covered with lead sheets.

 

[Shinjukusam]

No it is not. But, the quote seems to imply that autopsies are not performed. I find this troubling.

I'd expect at the very least whole body counts and blood work for all the dead - as opposed to dose tallies based on the readings of personal dosimeters which may or may not have been covered with lead sheets.

But the symptoms of radiation poisoning don't include dropping dead in the manner of minutes, so, Occam's.

 

[tsutsuji]

Actually the NHK does not say "presumably". Please consider my informations as short summaries or notes taken down after reading the NHK article rather than exact translations. More accurately, the NHK says:

死因は、心筋梗塞とみられるということです。

The cause of death [of the 22 August dead employee] is viewed as being a myocardial infarct, it was said.

福島第一原発では、去年３月の事故のあと、これまでに４０代から６０代の男性作業員４人が心筋梗塞などで亡くなっています。

At Fukushima Daiichi NPP, after the March 2011 accident, until now 4 male workers in their 40s to 60s have died of myocardial infarct etc.

 

[Rive]

But the symptoms of radiation poisoning don't include dropping dead in the manner of minutes, so, Occam's.

Occam is not in the game here. IMHO it's not 'we have better, nicer explanation' time but 'the person did not get more radiation than his record' time.

Occam plays when explanations gets too complex. But here we need knowledge about something what's not there. (I hope it's not there. I even think it's not there. But I can't be sure. )

 

[zapperzero]

But the symptoms of radiation poisoning don't include dropping dead in the manner of minutes, so, Occam's.

I have not claimed that they dropped dead from prompt doses, so you're fighting a strawman here.

Sure, exposure to radiocesium may or may not have direct, immediate effects on the cardiovascular system (iirc there was a study after Chernobyl, never repeated though).

Sure, they were old and frail and doing hard work (which is a health&safety violation in and of its own, but I digress). The issue, as I see it, is that the doses they got may or may not have contributed to their deaths - and we can't tell.

 

[Shinjukusam]

I have not claimed that they dropped dead from prompt doses, so you're fighting a strawman here.

Sure, exposure to radiocesium may or may not have direct, immediate effects on the cardiovascular system (iirc there was a study after Chernobyl, never repeated though).

Sure, they were old and frail and doing hard work (which is a health&safety violation in and of its own, but I digress). The issue, as I see it, is that the doses they got may or may not have contributed to their deaths - and we can't tell.

Okay...now you're just being paranoid.

 

[zapperzero]

...now you're just being paranoid.

 

[zapperzero]

Actually the NHK does not say "presumably". Please consider my informations as short summaries or notes taken down after reading the NHK article rather than exact translations. More accurately, the NHK says:

死因は、心筋梗塞とみられるということです。

The cause of death [of the 22 August dead employee] is viewed as being a myocardial infarct, it was said.

福島第一原発では、去年３月の事故のあと、これまでに４０代から６０代の男性作業員４人が心筋梗塞などで亡くなっています。

Thank you so very much for the clarification.

 

[mscharisma]

...
Sure, exposure to radiocesium may or may not have direct, immediate effects on the cardiovascular system (iirc there was a study after Chernobyl, never repeated though). ...

As far as I'm concerned, that statement hits the nail on the head. If nothing else, Japan has - unfortunately - the opportunity and technology to do extensive studies, and it doesn't seem to be happening. Or at least not publicly, anyway (that I know of). Why on Earth wouldn't deaths be further examined and investigated?
I don't think it has anything to do with being paranoid if one becomes inquisitive or even suspicious about that. Especially in light of the exposed practice to cover dosimeters or simply not wear them as necessary, a thorough examination should be done in this type of case to, at the very least, stop the practice of "cheating" with the dosimeters.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120823/index.html In consequence of the dosimeter lead cover problem that was revealed last month, Tepco made an investigation on radiation exposure management and found 24 cases such as workers losing their dosimeter, or forgetting to carry it. In 19 cases workers lost their dosimeter on the work area or while changing clothes, and in 5 cases they forgot to take a dosimeter in the first place. Tepco made estimates of the radiations received by these workers, and the worst case is estimated to be 0.72 mSv for a 3 hour long work. On 10 August 2012 Tepco initiated a dosimeter checking policy, but on 16 August, one case was found where a worker had lost his dosimeter. Tepco said they want to intensify the recurrence prevention policy.

 

[mscharisma]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120823/index.html In consequence of the dosimeter lead cover problem that was revealed last month, Tepco made an investigation on radiation exposure management ... .

As long as it is Tepco (or any other NPP operator) who makes investigations and provides statements that employee health problems/deaths are not radiation-related, they are, imho, pretty much meaningless. Too much self-interest involved. In fact, the entire accident management and mitigation procedures should have been overseen by an independent, preferably international body from day 1 or at least asap thereafter.

 

[tsutsuji]

http://www.meti.go.jp/committee/notice/2012a/20120823003.html The 9th mid and long term meeting is scheduled on Monday from 10:00 to 12:00 AM at Tepco's main office in Tokyo.

 

[SteveElbows]

Hope something interesting is discussed on Monday, since there isn't very much new information to talk about these days.

In the meantime, this webcam video shows workers on top of the equipment pit crane of reactor 4, and an additional section of the southern platform around reactor 3 building being put into place. The actual movement into place of this piece occurs about half-way through the video.

 

[jim hardy]

i've worked in nuke protective coveralls in 110degF environment before and it is VERY stressful.

There's zero cooling from evaporation because of high humidity so you sweat soaks the coveralls. Tepco workers are likely wearing plastic over the cotton coveralls . Just imagine yourself inside an oven roasting bag, doing heavy phisical work...

it's a game for young men or men who've built up copoius stamina through years of intense physical labor.

that middle aged people are having heart attacks is not at all surprising to me.

i been there

old jim

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120827/index.html Tepco started today (27 August) the visual inspection of the removed fresh fuel assemblies from unit 4 pool. They removed the metal tube and washed the fuel, and seen from the side no conspicuous damage or deformation was found. On the day after tomorrow they will check the handle part and the fuel itself. They will also check the second fuel assembly.

 

[tsutsuji]

The 9th mid & long term meeting was held on 27 August 2012: http://www.meti.go.jp/earthquake/nuclear/20120827_01.html

1) Previous related topics:

The 8th meeting (30 July 2012) https://www.physicsforums.com/showpost.php?p=4020743&postcount=13588

The 7th meeting (25 June 2012) https://www.physicsforums.com/showpost.php?p=3979794&postcount=13512

The 6th meeting (25 May 2012) : https://www.physicsforums.com/showpost.php?p=3933442&postcount=13399

The 5th meeting (23 April 2012) : https://www.physicsforums.com/showpost.php?p=3881074&postcount=12979

The 4th meeting (28 March 2012) : https://www.physicsforums.com/showpost.php?p=3838108&postcount=12764

The 3rd meeting (27 February 2012) was translated into English on Tepco's website : http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/conference-e.html

2) Translation:

27 August 2012 government-Tokyo Electric mid and long term response committee, steering committee (9th meeting)

http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01a.pdf Agenda
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01b.pdf Participants

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01c.pdf Abstract of the proceedings of 8th steering committee meeting

Document 2: Plant status
Document 2-1: Plant status
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01e.pdf Accumulated water storage status

Document 3 Study and execution of each special plan

3-1 Cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01f.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01g.pdf Inspection inside unit 1's PCV
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01h.pdf Installation of unit 2 PCV atmosphere thermometer
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01j.pdf Nitrogen injection into unit 1's suppression chamber
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01k.pdf Status of pipe water removal method study, toward the installation of unit 2 RPV alternative thermometer

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01m.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01n.pdf Status of ground water bypass study
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01p.pdf Simulation of quantities generated by accumulated water treatment, and installation of additional storage tanks
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01q.pdf Additional tank installation plan
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01r.pdf Multinuclide removal facility (ALPS) qualification test status

3-3 Countermeasures to reduce environmental radiations
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01s.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01t.pdf Consequences on water quality of the covering of the sea floor in the harbour
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01u.pdf Results of evaluation of additional releases from reactor buildings
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01v.pdf Unification of methods to evaluate radiation doses at site boundaries

3-4 Improvement of working conditions
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01w.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01x.pdf Countermeasures to fulfill radiation management at Fukushima Daiichi nuclear power plant
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01y.pdf Guidelines in response to the APD dosimeter problem and execution schedule

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01z.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01aa.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01bb.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01cc.pdf Unit 1 operating floor status survey results

3-6 Preparations for fuel debris removal
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01dd.pdf Schedule

3-7 Treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01ee.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01ff.pdf Debris, cut down trees management status
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01gg.pdf Cut down trees (branches, leaves, roots) temperature monitoring status

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01hh.pdf Evaluation in response to the radiation management report dealing with Alarm Pocket Dosimeter (APD) misuse

Document 5
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01jj.pdf roadmap progress (abstract)

27 August 2012 government-Tokyo Electric mid and long term response committee, technical development progress headquarters (8th meeting) ( http://www.meti.go.jp/earthquake/nuclear/20120827_02.html )

http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_02a.pdf Agenda

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_02b.pdf Research and development plans toward the decommissioning of Tokyo Electric Fukushima Daiichi units 1~4 (abstract)

Document 2
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_02c.pdf Progress status of development of machinery and equipments to prepare fuel debris removal

Document 3
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_02d.pdf Fukushima workshop on development of machinery and equipments toward the decommissioning of Tokyo Electric Fukushima Daiichi nuclear power plant (abstract of results)

 

[tsutsuji]

2) translation:[/color]

27 august 2012 government-tokyo electric mid and long term response committee, steering committee (9th meeting)

document 3 study and execution of each special plan

3-1 cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01h.pdf Installation of unit 2 pcv atmosphere thermometer

1/5

2/5

3/5

 

[tsutsuji]

4/5

5/5

 

[zapperzero]

http://www.meti.go.jp/earthquake/nuc...120827_01d.pdf Plant parameters

Shows temps trending up at all three reactors. What gives?

 

[Rive]

Shows temps trending up at all three reactors. What gives?

It's just summer. They had some plan to install some chillers for the main (cooling)water tanks, but I don't know the actual status of that plan.

 

[tsutsuji]

It's just summer. They had some plan to install some chillers for the main (cooling)water tanks, but I don't know the actual status of that plan.

In the following document: http://www.meti.go.jp/earthquake/nuclear/pdf/120528/120528_02g.pdf (28 May 2012, 6th mid and long term meeting) they said they wanted the chiller to be ready by the end of July.

http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01d.pdf says that the chiller was started on July 18.

The July 27th press release ( http://www.tepco.co.jp/en/press/corp-com/release/2012/1207086_1870.html ) says:

"After the full-scale operation of a freezing machine for cooling of treated water buffer tank retained water, the treated water buffer tank temperature declined. The Unit 1-3 RPV bottom temperature and PCV temperature declined accordingly. Since changes in temperature became stabilized, we reduced the amount of water injection into Unit1-3 reactor at 11:28 AM on July 27."

The August 13th press release ( http://www.tepco.co.jp/en/press/corp-com/release/2012/1211835_1870.html ) adds:

"We continued to observe the temporal changes of the plant parameter. Since increase in RPV bottom temperature and PCV temperature became stabilized, we reduced the amount of water injection into Unit 2 and 3 reactor at 11:02 AM on August 13".

The injected water temperature is the thin blue line between 10 and 25° C at the bottom of each plot in http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01d.pdf pages 2, 3 and 4.

 

[zapperzero]

"We continued to observe the temporal changes of the plant parameter. Since increase in RPV bottom temperature and PCV temperature became stabilized, we reduced the amount of water injection into Unit 2 and 3 reactor at 11:02 AM on August 13".

The injected water temperature is the thin blue line between 10 and 25° C at the bottom of each plot in http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01d.pdf pages 2, 3 and 4.

So, you think we should attribute the increase to the lowered volume of cooling water?

 

[tsutsuji]

2) Translation:

27 August 2012 government-Tokyo Electric mid and long term response committee, steering committee (9th meeting)

3-1 Cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01k.pdf Status of pipe water removal method study, toward the installation of unit 2 RPV alternative thermometer

1/7

2/7

3/7

 

[tsutsuji]

4/7

5/7

6/7

 

[tsutsuji]

7/7

 

[tsutsuji]

So, you think we should attribute the increase to the lowered volume of cooling water?

Tepco is saying so in the note at the bottom of http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01d.pdf page 1:

効率的な冷却のため，７／２７，８／１３に注水流量を減少させた結果，原子炉関連温度は上昇傾向を示しており，引き続き傾向監視を継続している。

Because cooling is efficient, water injection rate was reduced on 27 July and 13 August, and as a result, reactor related temperatures are indicating a rising trend. As a follow-up, we are continuously monitoring the trend.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120830/index.html On 30 August afternoon, water injection rates into units 1,2,3 were found temporarily to be lower than the specified values. At 03:00 PM, unit 1 had 4 ton/hour, unit 2 5.5 ton/hour, unit 3 5.6 ton/hour. These are 10% lower than the specified values agreed by the NISA for cooling the reactors. Tepco took countermeasures such as opening valves and one hour later the injection rates had recovered to specified values.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120831/0100_chusui.html The same problem happened again in the night of 30 August at around 08:00 PM. At 10:30 PM the injection rates were recovered, rising above specified values. Tepco suspects there is a problem with the pump, and switched to a back-up pump, while the suspected pump is investigated.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120831/0450_4gouki.html Tepco has completed a new report on unit 4's earthquake resistance, taking into account the most recent findings on wall bulge etc. and the fact that as a consequence of removing the debris on the upper floors, the mass of the building was reduced by 4700 tons. The conclusion is the same as in the May 2011 report: the building can withstand [Japan Meteorological Agency] intensity 6 earthquakes.

http://www.tepco.co.jp/en/press/corp-com/release/2012/1217413_1870.html The new seismic safety report

 

[a.ua.]

tsutsuji

http://www3.nhk.or.jp/news/genpatsu-...50_4gouki.html Tepco has completed a new report on unit 4's earthquake resistance, taking into account the most recent findings on wall bulge etc. and the fact that as a consequence of removing the debris on the upper floors, the mass of the building was reduced by 4700 tons. The conclusion is the same as in the May 2011 report: the building can withstand [Japan Meteorological Agency] intensity 6 earthquakes.

http://www.tepco.co.jp/en/press/corp...7413_1870.html The new seismic safety report

Why not show PVC unit 4 from the inside?
Everything is normal?

 

[Astronuc]

tsutsuji

Why not show PVC unit 4 from the inside?
Everything is normal?

The reactor vessel of unit 4 was fully defueled for maintenance. There is no heat source in the RPV. The core had been removed and stored in the spent fuel pool.

 

[mscharisma]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120830/index.html On 30 August afternoon, water injection rates into units 1,2,3 were found temporarily to be lower than the specified values ...

I'm having a bit of trouble understanding how they measure injection rates given that they can't actually look inside the reactors and see what arrives inside the vessel. And not knowing exactly where the core(s) is (are) and temperature gauges not necessarily working well or at all, I somehow can't seem to wrap my head around how they determine how much water is needed and, hence, whether or not it is getting to where it is needed.

Could someone here maybe offer a "dumbed-down" explanation for a non-technical person like me how this is done?

Many thanks.

 

[a.ua.]

The reactor vessel of unit 4 was fully defueled for maintenance. There is no heat source in the RPV. The core had been removed and stored in the spent fuel pool.

Yes, I know it.
But I'm asking about the primary containment vessel, not the reactor vessel.
TEPСO said that there was no explosion, but
"A picture is worth a thousand words."

 

[clancy688]

On August the 18th, NHK World aired an "investigative" 45 minute documentary about the Fukushima accidents.

It's focusing about what happened in Unit 2 and why it did release so much radiation. They are interviewing workers who were in Unit 2.
Afterwards its focusing shortly upon what happened in Unit 3



Summary Unit 2:
- after the Unit 3 explosion, pressure in Unit 2 rose
- workers used car batteries to provide SR-valve for SR-Valve opening in order to lower the pressure and therefore be able to inject water
- yet the SR-Valve didn't open
- it is concluded that for the SR-valves to work, the pressure difference between the RPV and the PCV must be within certain levels; for Unit 2 the pressure in the PCV was already to high for the SR-valves to open --> the further the melting (and pressure rise in the PCV) progresses, the less likely the SR-valves are to open
- the operators didn't expect this effect and therefore lost time by trying out every single of the eight SR-valves one by one
- their final straw was to vent the "wetwell (primary containment vessel)" by opening the "AO valve"; but this appeared not to work either
- it is concluded that a compressor which opens a necessary valve with compressed air didn't work, therefore the valve didn't open and no vent was performed, furthermore the valve in question doesn't have a manual handle
- so they tried using a portable compressor, it didn't work either
- it's concluded that the air-pipes leading to the valve are overly exposed in the reactor building and therefore may've been damaged by the quake (the pipe's quake resistance was rated at "Class C", the lowest level, since it's no component of the main reactor)
- at 6 am they heard a loud bang and the pressure went down to zero; what happened is unknown (except that afterwards, Japan experienced the largest amount of Fallout during the crisis, which may be connected to Unit 2)Unit 3 Summary:
- suddenly one and and a half days after the tsunami, they couldn't open the SR-valves anymore, which's probably due to emergency batteries losing power
- the JSDF provided 2 Volt batteries to a distribution station near the plant via air lift shortly after the tsunami which's sufficiently for most of the control systems, but for opening the SR-valves 12 volt batteries were needed (120 volts for opening the valves in total), so the operators decided to use their car's batteries
- when they finally succeeded in assembling their jury-rigged power-supply to operate the SR-valves, the water level had already receded far and long enough for core damages and hydrogen generation to occur
- more than 1000 12 volt batteries were stockpiled during the night from the 12th to the 13th at Onahama, which obviously didn't help the operators at the power plant very muchThe documentary is referring to an older documentary (aired in February 2012, "Meltdown: Fukushima Nuclear Crisis Behind the Scenes") about the immediate effects of the tsunami and the Unit 1 meltdown and explosion, does anyone know where to find this program?

 

[SteveElbows]

I'll let you know if I find the older documentary. Hope its better than the one you detailed, I watched it a week or two ago as I was interested in the worker interviews, oh what a dreadful program it turned out to be. It was interesting but not for the right reasons, very bad dramatisation and quite a mess of facts, some misleading details and loads of important detail about problems missing. Not even sure why they bothered mentioning reactor 3 as they failed to tell its story, and the story of reactor 2 seemed rather mangled in some respects.

The one thing they managed to achieve via bad drama and the mess of facts was a sense of the urgency felt on site when struggling to open valves of one sort or another. But those seeking to get clear in their minds the complex set of successful and failed attempts at venting, especially at reactor 2, will not be so well served by that program.

The theory about SR valve problems was interesting but again was not very well served by the format of the program. And by focussing on it for a while and not even mentioning a range of other problems, a rather distorted impression of what might have happened at reactor 2 was given.

 

[tsutsuji]

27 August 2012 government-Tokyo Electric mid and long term response committee, steering committee (9th meeting)

3-1 Cooling by closed loop water injection

http://www.meti.go.jp/earthquake/nuclear/pdf/120827/120827_01g.pdf Inspection inside unit 1's PCV

1) Previous related topics:
https://www.physicsforums.com/showthread.php?p=3934954#post3934954 6th meeting (25 May 2012) Execution of internal survey into unit 1 primary containment vessel (PCV)

2) Translation:

01/17

02/17

03/17

 

[tsutsuji]

2) Translation:

04/17

05/17

06/17

 

[tsutsuji]

2) Translation:

07/17

08/17

09/17

 

[tsutsuji]

2) Translation:

10/17

11/17

12/17

 

[tsutsuji]

2) Translation:

13/17

14/17

15/17

 

[tsutsuji]

2) Translation:

16/17

17/17

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120830/index.html On 30 August afternoon, water injection rates into units 1,2,3 were found temporarily to be lower than the specified values. At 03:00 PM, unit 1 had 4 ton/hour, unit 2 5.5 ton/hour, unit 3 5.6 ton/hour. These are 10% lower than the specified values agreed by the NISA for cooling the reactors. Tepco took countermeasures such as opening valves and one hour later the injection rates had recovered to specified values.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120831/0100_chusui.html The same problem happened again in the night of 30 August at around 08:00 PM. At 10:30 PM the injection rates were recovered, rising above specified values. Tepco suspects there is a problem with the pump, and switched to a back-up pump, while the suspected pump is investigated.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120901/index.html The same problem occurred 5 times again from 00:00 AM to 03:00 PM on 31 August. The cause has still not been found [as of 1 September]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120903_01-e.pdf Decrease in the Reactor Injection Water Amounts at Unit 1-3 of Fukushima Daiichi Nuclear Power Station

 

[zapperzero]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120901/index.html The same problem occurred 5 times again from 00:00 AM to 03:00 PM on 31 August. The cause has still not been found [as of 1 September]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120903_01-e.pdf Decrease in the Reactor Injection Water Amounts at Unit 1-3 of Fukushima Daiichi Nuclear Power Station

Happy thousandth post!

 

[tsutsuji]

Happy thousandth post!

Thanks. I had not noticed it was the thousandth.

 

[Astronuc]

Yes, I know it.
But I'm asking about the primary containment vessel, not the reactor vessel.
TEPСO said that there was no explosion, but
"A picture is worth a thousand words."

It was the secondary containment, the steel and masonary [super]structure above primary containment that had the fire and damage. It is surmised that hydrogen from unit 3 came through the shared duct work that caused the fire. Initially, there was concern that the spent fuel pool went dry and core (reinsert fuel) severely oxidized and produced substantial hydrogen. Later pictures seemed to show that the spent fuel and reinsert fuel was intact, but there might be damage, especially after the introduction of saltwater.

Of course, all primary containments were subject to seismic vibration and possible damage.

I have not followed the details for several months, so I'm not familiar with the current understanding of unit 4's situation.