Anti tsunami walls

*Joe Neubarth*

Quote by tsutsuji

I am not sure if the following statement by the Asahi writer fits very well with the contents of the Japanese Government's report to the IAEA :

....
The Jogan earthquake is presented to the Asahi readership as a problem emerging in February 2011, while the Japanese government tells us that it was raised as early as July 2009.
... :

In the photos of Fukushima, I have never been able to identify the sea walls. I can see them at San Onofre and they are clearly 29 feet high. I figure that I can not identify them at Fukushima because I am getting old. For a nearly blind old man like me, can somebody post a photo of them?

Luca Bevil

Quote by Joe Neubarth

In the photos of Fukushima, I have never been able to identify the sea walls. I can see them at San Onofre and they are clearly 29 feet high. I figure that I can not identify them at Fukushima because I am getting old. For a nearly blind old man like me, can somebody post a photo of them?

Hi Joe, the only sea walls were built with tha plant and are the "harbour" delimiting structures just in front of the plant.

The japanese video about the plant construction that can be found on you tube is quite specific about the height being considered important and able to both protect the plant from sea waves (sic!!) and provide safe and convenient harbour facilities for operating the plant.

Other than that reactor building are elevated at OP+10.

I just watched NHK
http://www3.nhk.or.jp/daily/english/13_04.html

"They also found tsunami reached up to 40.5 meters in Miyako City in Iwate Prefecture, 37.8 meters in Noda village also in Iwate Prefecture, and 34.7 meters in Onagawa town in Miyagi prefecture."

A disaster waiting to happen... and happen it did

regards

tsutsuji

Quote by Joe Neubarth

In the photos of Fukushima, I have never been able to identify the sea walls. I can see them at San Onofre and they are clearly 29 feet high. I figure that I can not identify them at Fukushima because I am getting old. For a nearly blind old man like me, can somebody post a photo of them?

There is no sea wall at Fukushima Daiichi. That's why they plan to build one as "countermeasure #70" "installation of temporary tide barrier (target [end of](1) June)" on page 17 of the road map : http://www.tepco.co.jp/en/press/corp...s/110517e5.pdf : see the white dots on the picture. I wonder what they plan for the North side as I would have expected some white dots on that side too. I suspect the 14 m high see wall protecting the water purifying facility mentioned by the NISA a few days ago (see my post at http://www.physicsforums.com/showthr...35#post3347535 ) is the same one, although I have no clue to confirm this.

The tsunami protection mentioned in my previous post as "the highest water level of each Unit was set as 5.4 to 5.7 m" does not consist of a sea wall, but merely relies on the elevation of the plant. See page III-37 of http://www.kantei.go.jp/jp/topics/20...4-accident.pdf (Japanese version) (2) showing that the pumps are 5.6 m above the "sea level".

By the way, it was decided to build a 17 m high, 800 m long sea wall at the Onagawa Power plant, expected to be completed by April 2012 : http://www.asahi.com/national/update...105180453.html (May 18th)

(1) My own translation of the Japanese version http://www.tepco.co.jp/cc/press/betu...es/110517e.pdf page 17. "middle of June" is a translation mistake on the English version.
(2) Be careful with the English translation page III-39 of http://www.kantei.go.jp/foreign/kan/...pter_iii-2.pdf because there is a discrepancy with the Japanese version showing 5.7 instead of 5.6 m for unit 6.

westfield

Quote by Joe Neubarth

In the photos of Fukushima, I have never been able to identify the sea walls. I can see them at San Onofre and they are clearly 29 feet high. I figure that I can not identify them at Fukushima because I am getting old. For a nearly blind old man like me, can somebody post a photo of them?

Yes, here it was :(

More snapshots of the abovementioned breakwater getting topped and smashed by the tsunami

Source & Copyright TEPCO

clancy688

Quote by Luca Bevil

Hi Joe, the only sea walls were built with tha plant and are the "harbour" delimiting structures just in front of the plant.

Sea walls wouldn't have helped against that monster tsunami. It's sligthly offtopic, but here's a video of the tsunami toppling a 10m sea wall:

http://www.youtube.com/watch?v=X6GzxcXsecg

It's only a matter of seconds until it's over the wall... and that's only the first, small wave. The big one hits a couple of minutes later.
For a monster tsunami to stop, you'd need a monster wall (This one did indeed stop the Tsunami while neighboring villages were wiped out) - or you don't build sensitive equipment at water level...

*Atomfritz*

Quote by Luca Bevil

I just watched NHK
http://www3.nhk.or.jp/daily/english/13_04.html

"They also found tsunami reached up to 40.5 meters in Miyako City in Iwate Prefecture, 37.8 meters in Noda village also in Iwate Prefecture, and 34.7 meters in Onagawa town in Miyagi prefecture."

Thank you for posting this information.

This demonstrates that it is very unwise to build nuclear plants in tsunami zones at ground levels less than 40 meters.

We can just be happy that the 34.7 meter tsunami hit Onagawa city and not the nearby Onagawa nuclear plant.

If the Onagawa NPP had been devastated, the Fukushima No.1 mess we have now would possibly be regarded as a small, negligible accident, at least in comparison.

We see, the interactions between many factors is little understood:

the basically unpredictable location of epicenters
energy, direction and mass of the water wave
the "tsunami-boosting" or tsunami-breaking effects of the particular coastline and submarine layout
the possible side effects of surface deformation, as land sinking for example
and probably several other factors.

So this really calls for research, at least for the protection of nuclear and other installations with devastating long-term contamination potential.

I fear, until this is done and all the nuclear installations with "tsunami potential" have been relocated to higher areas, Japan will be forced to continue this kind of Russian Roulette.
This is scary, as the geological activity that was almost quiet when the reactors were planned and built, is still increasing, making more mega-tsunamis in the near future a real, non-hypothetic danger.

Luca Bevil

Quote by clancy688

Sea walls wouldn't have helped against that monster tsunami. It's sligthly offtopic, but here's a video of the tsunami toppling a 10m sea wall:

http://www.youtube.com/watch?v=X6GzxcXsecg

It's only a matter of seconds until it's over the wall... and that's only the first, small wave. The big one hits a couple of minutes later.
For a monster tsunami to stop, you'd need a monster wall (This one did indeed stop the Tsunami while neighboring villages were wiped out) - or you don't build sensitive equipment at water level...

I agree, completely.
I was just trying to state how undersized and ineffective those protections were, and how even after this exxperience sea walls are being considered with heights that are LESS than the recently experienced maximum heights.
Mankind never seem to learn apparently.

I should have been more effective in my writing obvoiusly.
Thanks for expanding on the topic-

Luca Bevil

Quote by Atomfritz

Thank you for posting this information.

This demonstrates that it is very unwise to build nuclear plants in tsunami zones at ground levels less than 40 meters.

We can just be happy that the 34.7 meter tsunami hit Onagawa city and not the nearby Onagawa nuclear plant.

If the Onagawa NPP had been devastated, the Fukushima No.1 mess we have now would possibly be regarded as a small, negligible accident, at least in comparison.

We see, the interactions between many factors is little understood:

the basically unpredictable location of epicenters
energy, direction and mass of the water wave
the "tsunami-boosting" or tsunami-breaking effects of the particular coastline and submarine layout
the possible side effects of surface deformation, as land sinking for example
and probably several other factors.

So this really calls for research, at least for the protection of nuclear and other installations with devastating long-term contamination potential.

I fear, until this is done and all the nuclear installations with "tsunami potential" have been relocated to higher areas, Japan will be forced to continue this kind of Russian Roulette.
This is scary, as the geological activity that was almost quiet when the reactors were planned and built, is still increasing, making more mega-tsunamis in the near future a real, non-hypothetic danger.

In fact.. I quote you 100% all this is extremely scary, but what scares me most are people attitude towards security.

BTW why do you think Ongawa would have been worse than Fukushima Daiichi ?

*Atomfritz*

Quote by clancy688

Sea walls wouldn't have helped against that monster tsunami. It's sligthly offtopic, but...
It's only a matter of seconds until it's over the wall... and that's only the first, small wave. The big one hits a couple of minutes later.
For a monster tsunami to stop, you'd need a monster wall (This one did indeed stop the Tsunami while neighboring villages were wiped out) - or you don't build sensitive equipment at water level...

Just to give some information and links to this remarkable photo:

This 20 meter high wall was built on the initiative of the former Fudai city mayor.
Many called it "the mayor's folly".
But now, after the tsunami was stopped by the monster wall, only a bit swapping over, doing only minor damage and no casualties, the "fool mayor" now is cherished as the hero of Fudai.

Just one of many article links about this: http://www.eutimes.net/2011/05/japan...m-the-tsunami/

Here an impressive photo gallery of the german magazine "Der Spiegel": http://www.spiegel.de/fotostrecke/fo...cke-67983.html

If the NPP were behind such a wall, the mess would probably way smaller now.

Added:

Quote by Luca Bevil

BTW why do you think Ongawa would have been worse than Fukushima Daiichi ?

In fact it is just a pictorial imagination.
Imagine the plant had been hit with a big tsunami almost submerging the reactor buildings, crushing and flooding away lesser structures like turbine buildings, central waste storage etc.

tsutsuji

Quote by clancy688

Sea walls wouldn't have helped against that monster tsunami. It's sligthly offtopic, but here's a video of the tsunami toppling a 10m sea wall:

http://www.youtube.com/watch?v=X6GzxcXsecg

It's only a matter of seconds until it's over the wall... and that's only the first, small wave. The big one hits a couple of minutes later.
For a monster tsunami to stop, you'd need a monster wall (This one did indeed stop the Tsunami while neighboring villages were wiped out) - or you don't build sensitive equipment at water level...

The youtube video is showing the Ryoishi district of Kamaishi　where the wall is 11.6 m high : http://www.iwate-np.co.jp/311shinsai...sh1103292.html

Here is another picture of the 15.5 m high x 205 m long water gate built in 1984 that was effective in protecting the village of Fudai in Iwate prefecture : http://kenplatz.nikkeibp.co.jp/artic...FD=-1328065538. See on Google maps http://maps.google.com/maps?t=h&q=40.012287,141.895739

The 15.5 high x 155 m long sea wall built in 1967 based on the 15 m tsunami of 1896 was also effective to protect the Otanabe harbour district of that same village : http://www.yomiuri.co.jp/national/ne....htm?from=navr (google maps http://maps.google.com/maps?t=h&q=40...,0.001541&z=20 )

Incidentally, the 15.5 m embankment as shown in Fig. in III-1-16 (right photo) was installed in the [Otanabe](*) area, Fudai village in Iwate Prefecture following a strong desire of the village chief learning from previous experiences with tsunami. This embankment was able to resist the 15m tsunami and prevented the damage within the embankment zone (Yomiuri Shimbun, posted on April 3). These areas are rias type coastlines that have, historically, suffered significantly from giant tsunamis in the 15m range such as the Meiji Sanriku Tsunami (1896) and the Showa Sanriku Tsunami (1933), the lesson of preparation against a 15m-class tsunami has been instructed. (Yomiuri Shimbun, posted on March 30).

Japanese government report to IAEA page III-27 http://www.kantei.go.jp/foreign/kan/...pter_iii-1.pdf
*"Ootabu" is a typing mistake in both the Japanese and English versions.

tsutsuji

Quote by clancy688

I somewhere read that the tsunami at Onagawa NPP reached the footing of the plant, but not more.

I don't think that there would've been troubles as big as in Fukushima if the plant would indeed have been inundated.
First it's newer - from the early nineties. It's highly probable that it has more fancy security systems than Fukushima AND better tsunami protections.
But second you need more than a tsunami to kill a NPP. It's often overseen, but Fukushima Daiichi didn't lose cooling capability because of the tsunami. The station blackout happened because offsite power was lost due to collapsing electricity lines which were damaged by the earthquake.
If those towers would've withstood the earthquake, perhaps emergency cooling could've been sustained.
Did something similar happen in Onagawa? I'm not sure. But they provided shelter for tsunami refuges, so I don't think that they had no electricity.

See my previous post about Onagawa at http://www.physicsforums.com/showthr...wa#post3347322 with a quote from the Japanese government report to the IAEA saying the water leaked through the tide gauge, despite the fact that the water intake should have been protected by the ground elevation.

clancy688

Quote by tsutsuji

See my previous post about Onagawa at http://www.physicsforums.com/showthr...wa#post3347322 with a quote from the Japanese government report to the IAEA saying the water leaked through the tide gauge, despite the fact that the water intake should have been protected by the ground elevation.

Hm... interesting. I discovered a video of the tsunami which showed something similar - water coming out of basins a few hundred metres away from the sea even before the tsunami flooded the land.

It used to be on youtube, but I don't find it anymore... if anyone's interested, I uploaded it on megaupload:

http://www.megaupload.com/?d=LGE4NMWS

tsutsuji

Quote by clancy688

I don't think that there would've been troubles as big as in Fukushima if the plant would indeed have been inundated.
First it's newer - from the early nineties. It's highly probable that it has more fancy security systems than Fukushima AND better tsunami protections.
But second you need more than a tsunami to kill a NPP. It's often overseen, but Fukushima Daiichi didn't lose cooling capability because of the tsunami. The station blackout happened because offsite power was lost due to collapsing electricity lines which were damaged by the earthquake.
If those towers would've withstood the earthquake, perhaps emergency cooling could've been sustained.

Page 78 of http://www.tepco.co.jp/en/nu/fukushi...10525_01-e.pdf shows "installation of a Backup RHRS (Residual Heat Removal System) pump" also mentioned as "underwater pump". Which means it was needed. Even at unit 6 where a Diesel Generator has always been available,

the seawater pump facilities for cooling auxiliary systems in all units were submerged and stopped their functions,

Page 5 http://www.kantei.go.jp/foreign/kan/...-2_outline.pdf

But as Professor Omoto puts it,

Availability of UHS commensurate to decay heat level supports quick recovery but does not seem to be a decisive factor.
‐ 1F5/6 : Use of temporary seawater pump for RHR (units were in refueling outage)
‐ 2F4 : continued Rx water makeup under isolation from UHS until March 14th
page 9 https://www.sfen.fr/content/download...APP_Omoto2.pdf

UHF : ultimate heat sink, the sea
1F : Fukushima Daiichi nuclear plant
2F : Fukushima Daini power plant

In the emergency plans of the Tokai nuclear power plant, you can see a photograph on http://www.japc.co.jp/tokai/teiken/t...10/tenpu-6.pdf and a diagram on http://www.japc.co.jp/tokai/teiken/t...10/tenpu-7.pdf showing that the backup pumps, being carried by trucks looking similar to fire engines, look easy to set up.

tsutsuji

Some details about the impact of the 2004 Indian Ocean tsunami on the Kalpakkam nuclear plant in India are provided by a reader comment:

At the time of tsunami, MAPS-1 unit [Madras Atomic Power Station unit 1] was under maintenance (shutdown) and MAPS-2 unit was under operation. Due to high waves, seawater level in fore bay increased above the operating floor level of pump house, which tripped the Condenser Cooling Water (CCW) pumps and Process Sea Water Pump (PSWP). Within 10 minutes the reactor of MAPS-2 unit brought down to safe shutdown condition with one PSWP operating as a precautionary measure (for details, please refer to a paper by Gupta et al, 2006 “Earthquake and Tsunami Impact on Indian Peninsula: Historical Perspective and Future Directions”, Proceedings of 13th Symposium in Earthquake Engineering, IIT Roorkee, December 18-20, 2006, Vol-I, pp.217-227).

Sushil Gupta, 30 March 2011
http://www.downtoearth.org.in/conten...lants-disaster

In 2005, the IAEA said the following:

The IAEA issued the Kalpakkam reactor a clean bill of health in the tsunami´s wake, rating the event a "zero" or of "no safety significance" on the International Nuclear Events Scale. Around 3.5 cubic metres of seawater, sludge and muck entered a construction pit, where the foundations for a new 500 MWe Fast Breeder Reactor were being built. Water also entered a pump house for cooling water, tripping the nuclear power plant to shut down.
http://www.iaea.org/newscenter/news/2005/tsunami.html

The programme of the "International Workshop on External Flooding Hazards at Nuclear Power Plant Sites", Kalpakkam, August 2005, mentions the participation of Tepco:

“Probabilistic tsunami hazard analysis in Japan”, by Tadashi Annaka,
Tokyo Electric Power Service Co., Japan.

“Tsunami Evaluation Method for NPP Site in Japan”, by Toshiaki Sakai,
Tokyo Electric Power Company (TEPCO), Japan.

http://www.iaea.org/newscenter/news/pdf/tsunamiprog.pdf

A probalistic approach presentation authored by a team led by Toshiaki Sakai in 2006 was mentioned in the other thread: http://www.physicsforums.com/showpos...&postcount=482

http://www-pub.iaea.org/MTCD/publica...NENP-02-04.pdf The short report in Nuclear Power Newsletter Vol. 2 No.4, December 2005, page 3 displays a diagram showing that much emphasis was put on tsunami warning systems. I wonder if the diesel generators at Kalpakkam were sea-water cooled or air-cooled and if the safety of diesel generators was mentioned in the August 2005 workshop.

Kalpakkam's anti-tsunami wall today (March 2011) :

A three-tier system of sandbags, rocks and embankment put in place after the 2004 tsunami that lashed this southern Indian coastal town can nullify the impact of sea waves
(...)
According to the region’s seismic zoning, the station is designed to withstand waves that are 5.2m high. In conjunction with the three-tier system that buffers the plant’s boundaries from the coast by nearly 500m, it is strong enough to withstand even 9m-high onslaughts.

V. Manoharan, an engineer at the plant who survived the 2004 Indian Ocean tsunami by clinging on to rafters at the church he was attending on 26 December, said waves of the height of Japan’s tsunami would send some water into the plant, but it would “gently recede away, like waves at the beach”.

The 2004 tsunami, which sent 6-7m high waves that swept the residential section of the research centre to the Tamil Nadu coast, killed five employees, who were among a total of 30 casualties reported from Kalpakkam.
http://www.livemint.com/2011/03/1800...rds-Kalpa.html

Hurkyl

Quote by Atomfritz

Thank you for posting this information.

[B]This demonstrates that it is very unwise to build nuclear plants in tsunami zones at ground levels less than 40 meters.

We can just be happy that the 34.7 meter tsunami hit Onagawa city and not the nearby Onagawa nuclear plant.

... or knowledge of the local conditions. As I recall, the height of a tsunami depends dramatically on the geography of an area. No point in building a 40 meter wall in an area that has to wait thousands of years just to see a 20 meter wave!

clancy688

Um, I think the following article fits here best:

http://mdn.mainichi.jp/perspectives/...na020000c.html Onagawa nuke plant saved from tsunami by one man's strength, determination:

The breakwater that proved so inadequate to the task of protecting the Fukushima No. 1 nuclear plant from the ocean was 10 meters high. The one defending the Onagawa nuclear plant is 14.8 meters tall, and it turns out Hirai had to fight a one-man war to get it built. The reason he was so determined was his careful study of the past, which revealed that in the year 869 a massive tsunami had hit the spot where the Onagawa plant now stands.

[...]

Hirai was apparently the only person on the entire project to push for the 14.8-meter breakwater, while many of his colleagues said that 12 meters would be sufficient and derided Hirai's proposal as excessive. Hirai's authority and drive, however, eventually prevailed, and Tohoku Electric spent the extra money to build the 14.8-meter-tall shield. Some 40 years later, on March 11, 2011, a 13-meter-high tsunami slammed into the coast at Onagawa.

He died in 1986, so he never witnessed the event that proved him right.

r-j

Quote by Joe Neubarth

For a nearly blind old man like me, can somebody post a photo of them?

There was no wall, just breakwaters. (didn't read the rest of the thread yet)

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