The role of nuclear power in a low carbon future

OVERKILL

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Anyone have knowledge of the accident tolerant fuel programs? I had the absolute pleasure of working on the program from inception to test samples. Lead Scientist is (was) the best leader I've ever dealt with..
I've been following it, it is definitely a noble pursuit, though I think there have been some concerns around cost.
 

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Anyone have knowledge of the accident tolerant fuel programs? I had the absolute pleasure of working on the program from inception to test samples. Lead Scientist is (was) the best leader I've ever dealt with..
For example Tristructural Isotropic (TRISO) uranium fuel for the XE-100 helium cooled reactor? They are ceramic fuel balls that can't melt, because in a loss of coolant condition, the balls will heat up and lose reactivity. Even the NRC agrees that they would never melt. Pretty impress nuclear engineering.

 

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For example Tristructural Isotropic (TRISO) uranium fuel for the XE-100 helium cooled reactor? They are ceramic fuel balls that can't melt, because in a loss of coolant condition, the balls will heat up and lose reactivity. Even the NRC agrees that they would never melt. Pretty impress nuclear engineering.

This is the one I was thinking of, which is a modification of PWR/BWR fuel assemblies:
 
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I remember there were / was incident of PBR reactor with the balls getting stuck, and their waste takes up more space than other reactors (despite still a small amount in absolute term). Also coating scraped off during handling / shuffling.
 
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>The [XE-100] reactor core is made of graphite

That is a proven bad idea. How does this design merit any serious consideration after several graphite-moderated reactors have caught fire?
 

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>The [XE-100] reactor core is made of graphite

That is a proven bad idea. How does this design merit any serious consideration after several graphite-moderated reactors have caught fire?
I'm not even as concerned about the fires as I am the longevity.

Yes, the RBMK was a graphite-cored reactor, but the cores were ABSOLUTELY MASSIVE, and they had no secondary containment originally (Soviet cost cutting). However, the UK has/had a pretty significant number of graphite cored reactors (Magnox, later AGR) and the big issue, particularly with the latter, was that the cores end up cracking, and then "she's dead Jim". There's no way to replace the graphite, so the unit is scrap. This seems to be happening at around 40 years, the same amount of time, roughly, that the CANDU alternative that the UK was considering (along with several other designs) gets its mid-life refurbishment, uprates, and all sorts of other goodness. PWR's and BWR's are also getting significant life extension, some even to 80 years, as it has been discovered that the pressure vessels aren't degrading at the rate anticipated.

So, what was originally supposed to be the "superior economic choice" for the UK has left them in a huge bind with respect to replacement capacity, as these units are presenting cracks in their cores and needing to be shutdown sooner than anticipated.
 

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I'm not even as concerned about the fires as I am the longevity.

Yes, the RBMK was a graphite-cored reactor, but the cores were ABSOLUTELY MASSIVE, and they had no secondary containment originally (Soviet cost cutting). However, the UK has/had a pretty significant number of graphite cored reactors (Magnox, later AGR) and the big issue, particularly with the latter, was that the cores end up cracking, and then "she's dead Jim". There's no way to replace the graphite, so the unit is scrap. This seems to be happening at around 40 years, the same amount of time, roughly, that the CANDU alternative that the UK was considering (along with several other designs) gets its mid-life refurbishment, uprates, and all sorts of other goodness. PWR's and BWR's are also getting significant life extension, some even to 80 years, as it has been discovered that the pressure vessels aren't degrading at the rate anticipated.

So, what was originally supposed to be the "superior economic choice" for the UK has left them in a huge bind with respect to replacement capacity, as these units are presenting cracks in their cores and needing to be shutdown sooner than anticipated.
Going to retract that RBMK statement in part, because, despite it being true (compared to its water-cooled peers) it was actually tiny compared to the AGR (which I had no idea about the size of until right now):
1652295946284.jpg


:eek::eek::eek:
 
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People are afraid of what they don't understand and I guess that the word nuclear=bombs in a lot of people's minds. We have decades of safe usage starting with the US Navy. Many years ago I was in a hotel bar next to a guy who worked at the nearby nuclear power plant. He told me that they had recently been taken over by another power company and that they had increased the spending on maintenance. Before the takeover, he had been worried because the company had gone cheap and delayed or neglected maintenance. The new company was very serious about safety and upkeep. Food for thought.
The human factor is always an issue, I knew a couple technicians who work in our local nuclear generator station, and while they've never been too worried about a problem(like calling home worried!), there's seen some stuff happen that shouldn't, and some people that should be a bit more careful. That said, another couple of guys I know in passing that are doing Homer Simpson's job are smart, no BS guys, so I suppose that's reassuring.
Just out of curiosity I had a look at the sea wall around our local plants on Lake Ontario. Looks sufficient for a likely level hurricane type storm surge, but I don't know about the worst case scenario tsunami wave from an underwater sediment slump? I can't find any data for it in a brief online search.
Maybe there's not enough sediment depth and slope anywhere in the lake to make it worth worrying about? There is also meteotsunamis https://www.canr.msu.edu/news/are_there_tsunamis_in_the_great_lakes_msg16_breederland16 but hopefully these were accounted for.
 
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OVERKILL

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The human factor is always an issue, I knew a couple technicians who work in our local nuclear generator station, and while they've never been too worried about a problem(like calling home worried!), there's seen some stuff happen that shouldn't, and some people that should be a bit more careful. That said, another couple of guys I know in passing that are doing Homer Simpson's job are smart, no BS guys, so I suppose that's reassuring.
Just out of curiosity I had a look at the sea wall around our local plants on Lake Ontario. Looks sufficient for a likely level hurricane type storm surge, but I don't know about the worst case scenario tsunami wave from an underwater sediment slump? I can't find any data for it in a brief online search.
Maybe there's not enough sediment depth and slope anywhere in the lake to make it worth worrying about? There is also meteotsunamis https://www.canr.msu.edu/news/are_there_tsunamis_in_the_great_lakes_msg16_breederland16 but hopefully these were accounted for.
Think the only lake big enough for anything notable to happen on (and it would still be small compared to what happens on the ocean, I'm just thinking large wave height) would be Superior, and we don't have any nukes on Superior.

They mention a 10ft wave which isn't very high.

Of course the description of a meteotsunami means that many of us have seen them:
A meteotsunami is defined as a rapidly moving wave that can be generated by quickly changing air pressure or high wind speeds or a combination of both.
I've seen them on Rosseau due to an incoming thunder storm for example and they created some reasonably strong (3-4ft) waves, which can be fun if you are out in your boat or if it hits your dock.

That said, that's not the same, nor anywhere near the same magnitude as what is generated by an earthquake, tsunamis from which Japan has experienced several. Notable tsunamis of this nature are:
- 1667 Emp Boso-oki earthquake (Japan), which was estimated to be an 8.4 and created 23ft waves
- 1896 Meiji Sanriku earthquake (Japan), which was estimated to be a 7.6, created 125ft waves and killed 22,000 people
- 1933 Showa Sanriku earthquake (Japan), which was an 8.5, created 95ft waves and killed 3,000 people
- 1960 Great Chilean earthquake (General, including Japan), which was a 9.4-9.6, created 85ft waves and hit Japan with 20ft waves, killing 138 people
- 1993 Hokkaidō Nansei-oki earthquake (Japan), which was a 7.7, created a 98ft run up in places and 51ft waves that hit Okushiri, topping their sea wall.
- 2004 Boxing Day Tsunami (Indonesia), which killed 220,000 people and was caused by a 9.1-9.3 magnitude quake that created 100ft tall waves

Onagawa NPP had a 48.5ft sea wall, Fukushima Dai-ichi had a 18.7ft sea wall.

It is important to note that run-up, that is, the height the water can go when impacting a surface from a tsunami wave, can be twice as high as the maximum wave height. The biggest wave to hit Fukushima Dai-ichi was ~45ft, well over the height of the sea wall. Ground level of the plant was 33ft. Had the sea wall been higher, it would have only, or mostly been, run-up to go over the wall, which would have had considerably less impact. The fact that the emergency generators were in the basement was mind boggling, given the frequency of tsunamis in the reason, and that was again, part of the grandfathering that the plant had been able to operate under without doing upgrades.
 
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Think the only lake big enough for anything to happen on (and it would still be small compared to what happens on the ocean) would be Superior, and we don't have any nukes on Superior.
Its more bottom depth and steepness, if there can be enough volume of sediment moving fast enough to matter. I'd guess Lake Erie isn't deep or steep enough to have a slump worth thinking about, but Lake Ontario does have much more depth and some steeper bottom slopes.
Anyways, I'm sure above and below water slumps have happened in the past, and probably some big ones in the centuries after the ice sheet retreated. I'm no geomorphologist but I hope one was consulted when they designed the plant, maybe do some rough calcs on what the sediment delta of the Niagara river can do with a good earthquake? Or the bluffs across the lake, how stable they are?
 
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Think the only lake big enough for anything notable to happen on (and it would still be small compared to what happens on the ocean, I'm just thinking large wave height) would be Superior, and we don't have any nukes on Superior.

They mention a 10ft wave which isn't very high.

Of course the description of a meteotsunami means that many of us have seen them:

I've seen them on Rosseau due to an incoming thunder storm for example and they created some reasonably strong (3-4ft) waves, which can be fun if you are out in your boat or if it hits your dock.

That said, that's not the same, nor anywhere near the same magnitude as what is generated by an earthquake, tsunamis from which Japan has experienced several. Notable tsunamis of this nature are:
- 1667 Emp Boso-oki earthquake (Japan), which was estimated to be an 8.4 and created 23ft waves
- 1896 Meiji Sanriku earthquake (Japan), which was estimated to be a 7.6, created 125ft waves and killed 22,000 people
- 1933 Showa Sanriku earthquake (Japan), which was an 8.5, created 95ft waves and killed 3,000 people
- 1960 Great Chilean earthquake (General, including Japan), which was a 9.4-9.6, created 85ft waves and hit Japan with 20ft waves, killing 138 people
- 1993 Hokkaidō Nansei-oki earthquake (Japan), which was a 7.7, created a 98ft run up in places and 51ft waves that hit Okushiri, topping their sea wall.
- 2004 Boxing Day Tsunami (Indonesia), which killed 220,000 people and was caused by a 9.1-9.3 magnitude quake that created 100ft tall waves

Onagawa NPP had a 48.5ft sea wall, Fukushima Dai-ichi had a 18.7ft sea wall.

It is important to note that run-up, that is, the height the water can go when impacting a surface from a tsunami wave, can be twice as high as the maximum wave height. The biggest wave to hit Fukushima Dai-ichi was ~45ft, well over the height of the sea wall. Ground level of the plant was 33ft. Had the sea wall been higher, it would have only, or mostly been, run-up to go over the wall, which would have had considerably less impact. The fact that the emergency generators were in the basement was mind boggling, given the frequency of tsunamis in the reason, and that was again, part of the grandfathering that the plant had been able to operate under without doing upgrades.


As I understand it the height of the tsunami is on top of the other waves. A 10 foot tsunami might not seem tall compared to the bigger ones but if you are on a beach then visualize ten feet in height. The wave is more like a surge.

The Good Friday Earthquake of 1964 produced a tsunami that varied depending on where it hit. One bay in Alaska had a 200 foot swell.
 

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Its more bottom depth and steepness, if there can be enough volume of sediment moving fast enough to matter. I'd guess Lake Erie isn't deep or steep enough to have a slump worth thinking about, but Lake Ontario does have much more depth and some steeper bottom slopes.
Yes, but Ontario is too narrow for anything to really pick up much momentum, that's why I mentioned Superior, as it is insanely deep and wide.
Anyways, I'm sure above and below water slumps have happened in the past, and probably some big ones in the centuries after the ice sheet retreated. I'm no geomorphologist but I hope one was consulted when they designed the plant, maybe do some rough calcs on what the sediment delta of the Niagara river can do with a good earthquake? Or the bluffs across the lake, how stable they are?
Yes, and the post-Fukushima protocols delved into this, and disaster preparedness in general, even further.
 

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As I understand it the height of the tsunami is on top of the other waves. A 10 foot tsunami might not seem tall compared to the bigger ones but if you are on a beach then visualize ten feet in height. The wave is more like a surge.
This is how it was plotted for Fukushima:
1652308421916.jpg

The height of the tsunami that struck the station approximately 50 minutes after the earthquake.
A: Power station buildings
B: Peak height of tsunami
C: Ground level of site
D: Average sea level
E: Seawall to block waves

B was 45ft (over D), which was ~26ft over the height of E above water (5.7m/18.7ft). Onagawa (which was was closest to the epicentre), withstood the incident without issue due to its MUCH higher sea wall.

Excerpt from the Wiki:
Wikipedia said:
The Onagawa Nuclear Power Plant was the closest nuclear power plant to the epicenter of the 2011 Tōhoku earthquake,[14] less than half the distance of the stricken Fukushima I power plant.[15] The town of Onagawa to the northeast of the plant was largely destroyed by the tsunami[16] which followed the earthquake, but the plant's 14 meters (46 ft) high seawall was tall and robust enough to prevent the power plant from experiencing severe flooding. Yanosuke Hirai, who died in 1986, is cited as the only person on the entire power station construction project to push for the 14.8-meter breakwater. Although many of his colleagues regarded 12 meters as sufficient, Hirai's authority eventually prevailed, and Tōhoku Electric spent the extra money to build the 14.8m tsunami wall. Another of Hirai's proposals also helped ensure the safety of the plant during the tsunami: expecting the sea to draw back before a tsunami, he made sure the plant's water intake cooling system pipes were designed so it could still draw water for cooling the reactors.
The Good Friday Earthquake of 1964 produced a tsunami that varied depending on where it hit. One bay in Alaska had a 200 foot swell.
Well yes, they all vary depending on where they hit which is why proper planning is so important. Fukushima was not adequately hardened against tsunamis of the height that Japan could experience.
 
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Yes, but Ontario is too narrow for anything to really pick up much momentum, that's why I mentioned Superior, as it is insanely deep and wide.

Yes, and the post-Fukushima protocols delved into this, and disaster preparedness in general, even further.
I think a relatively narrow width is actually helping a massive displacement of water maintain its energy density, as all the highest tsunami waves are recorded in fjords.

I guess my main point, is that for a nuclear plant site to be reasonably safe for its life span, which is likely to be over 100+ years, very unlikely events have to be looked at and accounted for. Obviously a one in 10000 year event becomes a 1% chance in 100 years... How many 1 in 10000 year events can cause a major release of material, how can the plant be made to negate that risk?

In the Fukushima case, lots of people must've had some numbers that said having a large enough tsunami to matter was very unlikely, for them not to prepare for it better? But there they are, cleaning it up. The 1 in 10000 year chance came pretty early in the draw....

For Darlington they address extreme wave events in the doc below but discount tsunami type waves due to the location. I might dig around a bit more to see what they reference to do that? There are bluffs across the lake with 100's of feet of elevation between their peak and the lake basin bottom with enough potential energy to make huge waves but someone must say they are quite stable? Also the Niagara river has dumped a few cubic miles of sediment into lake over the millennia, and it must be assumed stable as well? I'd be curious to know how much investigation was done? More from an academic stand point than actual fear of an accident, as it must be deemed a very small risk to simply discount it.
 

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I think a relatively narrow width is actually helping a massive displacement of water maintain its energy density, as all the highest tsunami waves are recorded in fjords.
Do you have a source for that? I'd like to read it. All of the large ones I read about were on the ocean, and I listed several of them above (ones with 100ft waves).
I guess my main point, is that for a nuclear plant site to be reasonably safe for its life span, which is likely to be over 100+ years, very unlikely events have to be looked at and accounted for. Obviously a one in 10000 year event becomes a 1% chance in 100 years... How many 1 in 10000 year events can cause a major release of material, how can the plant be made to negate that risk?

In the Fukushima case, lots of people must've had some numbers that said having a large enough tsunami to matter was very unlikely, for them not to prepare for it better? But there they are, cleaning it up. The 1 in 10000 year chance came pretty early in the draw....
Yes, but the story with Fukushima isn't consistent, which I've gotten into. Many studies told Tepco that the seawall wasn't properly sized, that's why Onagawa had a much higher seawall. The problems were compounded by the backup generators being located in the basement in front of the plant. Tepco was aware that a tsunami that was high enough to breach the seawall was a real possibility, they also knew that they should relocate the backup generators. They got away with doing neither due to the nature of the Japanese regulator, the board of which was comprised of the power companies (unlike here in Canada where it is public and run by the Federal government) who allowed the plant to be grandfathered in under historic regulation.
For Darlington they address extreme wave events in the doc below but discount tsunami type waves due to the location. I might dig around a bit more to see what they reference to do that? There are bluffs across the lake with 100's of feet of elevation between their peak and the lake basin bottom with enough potential energy to make huge waves but someone must say they are quite stable? Also the Niagara river has dumped a few cubic miles of sediment into lake over the millennia, and it must be assumed stable as well? I'd be curious to know how much investigation was done? More from an academic stand point than actual fear of an accident, as it must be deemed a very small risk to simply discount it.
I think they mean a seismic tsunami, which isn't deemed a possible event on the great lakes, we don't get 7.0+ earthquakes, let alone ones in the 8's.

My point about the width is you can't get the same massive pile of energy from a body of water that's so narrow, there isn't enough behind it. The great lakes also aren't that deep. All the big seismic tsunamis that I'm aware of have happened in the oceans, which are insanely deep and huge bodies of water. That's why I mentioned Superior, as its the largest of course.

tsunamis are ultimately displacement events, and for them to be that devastating wall of water, they need a lot of it:
NOAA said:
A tsunami is a series of extremely long waves caused by a large and sudden displacement of the ocean, usually the result of an earthquake below or near the ocean floor. This force creates waves that radiate outward in all directions away from their source, sometimes crossing entire ocean basins. Unlike wind-driven waves, which only travel through the topmost layer of the ocean, tsunamis move through the entire water column, from the ocean floor to the ocean surface.


*snip*
NOAA said:
Once a tsunami forms, its speed depends on the depth of the ocean. In the deep ocean, a tsunami can move as fast as a jet plane, over 500 mph, and its wavelength, the distance from crest to crest, may be hundreds of miles. Mariners at sea will not normally notice a tsunami as it passes beneath them; in deep water, the top of the wave rarely reaches more than three feet higher than the ocean swell.

NOAA said:
A tsunami only becomes hazardous when it approaches land. As a tsunami enters shallow water near coastal shorelines, it slows to 20 to 30 mph. The wavelength decreases, the height increases, and currents intensify.

NOAA said:
When they strike land, most tsunamis are less than 10 feet high, but in extreme cases, they can exceed 100 feet near their source. A tsunami may come onshore like a fast-rising flood or a wall of turbulent water, and a large tsunami can flood low-lying coastal areas more than a mile inland.

So you need both the volume, and depth, of water, to produce the huge sliding wall of water that ultimate creates a tsunami, which basically piles-up as it hits shallow water, increasing in height and rolling over itself, pushing huge volumes of water inland.

I don't the great lakes have the area or depth to achieve that at the scale that would be required to cause issues with the plants, that's likely why OPG discounts it.
 
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Do you have a source for that? I'd like to read it. All of the large ones I read about were on the ocean, and I listed several of them above (ones with 100ft waves).

Yes, but the story with Fukushima isn't consistent, which I've gotten into. Many studies told Tepco that the seawall wasn't properly sized, that's why Onagawa had a much higher seawall. The problems were compounded by the backup generators being located in the basement in front of the plant. Tepco was aware that a tsunami that was high enough to breach the seawall was a real possibility, they also knew that they should relocate the backup generators. They got away with doing neither due to the nature of the Japanese regulator, the board of which was comprised of the power companies (unlike here in Canada where it is public and run by the Federal government) who allowed the plant to be grandfathered in under historic regulation.

I think they mean a seismic tsunami, which isn't deemed a possible event on the great lakes, we don't get 7.0+ earthquakes, let alone ones in the 8's.

My point about the width is you can't get the same massive pile of energy from a body of water that's so narrow, there isn't enough behind it. The great lakes also aren't that deep. All the big seismic tsunamis that I'm aware of have happened in the oceans, which are insanely deep and huge bodies of water. That's why I mentioned Superior, as its the largest of course.

tsunamis are ultimately displacement events, and for them to be that devastating wall of water, they need a lot of it:



*snip*






So you need both the volume, and depth, of water, to produce the huge sliding wall of water that ultimate creates a tsunami, which basically piles-up as it hits shallow water, increasing in height and rolling over itself, pushing huge volumes of water inland.

I don't the great lakes have the area or depth to achieve that at the scale that would be required to cause issues with the plants, that's likely why OPG discounts it.
These ones are kind of like throwing a bowling ball into a tub!
Norway has lots of fjords and a tsunami warning system for many of them as the waves have potential to be huge.

Clearly we aren't going to get waves anywhere near this scale without steep shores to contain the wave energy, but it doesn't sound like Darlington is really considering anything above known storm surges which could still cause some water to enter the site, but not expected to cause any harm.
I'm not saying close the plant down tomorrow or anything, but I'd just be interested to see how much geological investigation has been done on the risk of a slump around the lake, and what they predict would happen with a 5m surge? If you look at the depth charts of lake ontario, the bottom of the north shore in the area of the plants has almost a shelf, or a gradual taper so it might increase wave amplitude? The south shore bottom is quite a bit steeper with some areas of bluffs above that. For sure there is plenty of potential energy there to make a large wave, and something like a cubic km of material sliding down from 50' depth to 400' would move some water around! Does this happen, fast enough to matter? Maybe never recently? It would be interesting to see some detailed bathymetry to see if slumping has occurred on a large scale before?

I think nuclear power is a good thing, but the extraordinary costs of a serious failure, should warrant some extra investigation into all sorts of potential causes for problems.
 
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These ones are kind of like throwing a bowling ball into a tub!
Norway has lots of fjords and a tsunami warning system for many of them as the waves have potential to be huge.

Clearly we aren't going to get waves anywhere near this scale without steep shores to contain the wave energy, but it doesn't sound like Darlington is really considering anything above known storm surges which could still cause some water to enter the site, but not expected to cause any harm.
I'm not saying close the plant down tomorrow or anything, but I'd just be interested to see how much geological investigation has been done on the risk of a slump around the lake, and what they predict would happen with a 5m surge? If you look at the depth charts of lake ontario, the bottom of the north shore in the area of the plants has almost a shelf, or a gradual taper so it might increase wave amplitude? The south shore bottom is quite a bit steeper with some areas of bluffs above that. For sure there is plenty of potential energy there to make a large wave, and something like a cubic km of material sliding down from 50' depth to 400' would move some water around! Does this happen, fast enough to matter? Maybe never recently? It would be interesting to see some detailed bathymetry to see if slumping has occurred on a large scale before?

I think nuclear power is a good thing, but the extraordinary costs of a serious failure, should warrant some extra investigation into all sorts of potential causes for problems.
I'm guessing there is no evidence of it ever happening, but I'd also be interested to hear if they looked into it. Also important to note, CANDU's can be passively cooled, so regardless of the fact that our ESG's aren't vulnerable, even if there was a total black, you just flood the SG's and can cool the units via convection.

From that first link you shared:
Just after 3:00 AM on April 7, 1934, the crevice in Langhammaren finally gave, releasing three million cubic meters of rock into the fjord.
o_O
That's a LOT of freakin' rock!!! 13 and 17 meter waves apparently.

Of course we don't have that level of material at a height capable of performing a similar displacement in the great lakes, but an interesting read regardless, thank you for the share!
 

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Something else to ponder, the height of the sea wall has to be high enough to keep the waves from the area you want to protect but how long should this or any sea wall be? If you look at a map this becomes clear.


Good idea to look at Onagawa too, to see if it differs, as it fared just fine:
1652326811675.jpg


Compared to Fukushima:
1652326998947.jpg


And its sister plant, which is being decommissioned, and also didn't fare all that well in the Tsunami (same issue, too low of seawall):
1652327112003.jpg
 
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I'm guessing there is no evidence of it ever happening, but I'd also be interested to hear if they looked into it. Also important to note, CANDU's can be passively cooled, so regardless of the fact that our ESG's aren't vulnerable, even if there was a total black, you just flood the SG's and can cool the units via convection.

From that first link you shared:
o_O
That's a LOT of freakin' rock!!! 13 and 17 meter waves apparently.

Of course we don't have that level of material at a height capable of performing a similar displacement in the great lakes, but an interesting read regardless, thank you for the share!
Well, underwater slumps can have many many times that much material and cause tsumani's as well.
It's good to know that the reactors can be passively cooled when all else fails...
 
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