13 Mar 11
Originally posted by jimslyp69some good points there jim; but nowadays fail-safe design is a major requirement for any OG&C and Nuclear facilities, safety is never compromised or bypassed for these plants even if the cost goes beyond what was originally estimated. At any rate, money is not a problem for the Japanese and they would have used the strictest industrial codes and standards from their location on the edge of a major fault line with the likelyhood of disasters to occur frequently;;; remember that these nuclear plants are perfectly fine and functional under normal conditions, so I guess what happens now is that these codes and standards 'Natural Disaster: Earthquakes and Tsunamis' section would be revised for these 'new' worst cases that have happened recently there in Japan, and it won't be limited to just building and strutural standards but also piping (API, ASME...etc), electrical (NEC, NFPA, IEC...etc), instrument and control systems, mechanical,,, in addition to the international standards there are also the local codes...
I thought they would have tried to make it fail safe. Back ups, double back ups and treble double plans in case any of the emergency cooling gear failed. It's not like they've never had an earthquake over there before and ones of this scale are to be expected every x number of years. I'm guessing that they will start building them to more stringent standards now. It's all down to money I think.
13 Mar 11
Originally posted by Iere manWell I guess they f***ed up then?
some good points there jim; but nowadays fail-safe design is a major requirement for any OG&C and Nuclear facilities, safety is never compromised or bypassed for these plants even if the cost goes beyond what was originally estimated. At any rate, money is not a problem for the Japanese and they would have used the strictest industrial codes and standards f ...[text shortened]... mechanical,,, in addition to the international standards there are also the local codes...
14 Mar 11
Originally posted by jimslyp69what happened was truly f****d up but I won't say it was them...haven't you seen any of the footage yet? I heard the entire island was moved about 8ft and even the earth's axis had shifted a little because of the extreme forces from the earthquake\tsunami...
Well I guess they f***ed up then?
14 Mar 11
1 edit
Originally posted by ChessPraxisIndeed unimaginable, however, the overall initial force of impact (to the island) can nevertheless be approximated to get a general perspective,,,
What amazes me is the speed of a tsunami, I have heard it can reach 500 MPH.
It is hard to imagine a wave travelling at that speed, and the force of such a wall of water to me is unimaginable.
I won’t actually do the calculation but I will outline the procedure below,,,
please be reminded that units must be kept consistent if anyone does make an attempt,,,
To begin, recall Newton's 2nd Law: F = Fx + Fy = (m)(a)Cos ß + (m)(a)Sin ß
From video footage shown, the coastline is pretty much flat so we can assume ß = 0°
Note 1: Only looking at impact because the situation is a bit more dynamic after making landfall and there are cancelling frictional forces primarily from the ground and debris caught up inside and from various obstacles in the path…these all add up and eventually stop the progression of the wave after some distance is travelled.
Continuing with calc, we substitute ß = 0° and simplify to derive: F = (m)(a)
Now, ‘m’ may be a bit more difficult to figure out, but from use of news maps and google earth we can determine the length of affected coastline. We also get an idea of the x and y fault displacement from the news; it was reported the wave reached as high as 10 meters and as far as 10 km inland…
these 3 ‘worst case’ distances can give us a volume of displaced seawater which when multiplied by the density of seawater, we effectively have a maximum estimated mass of the displaced water (i.e. the tsunami itself!)
Note 2: F = (m)(v) is the formula for the momentum of the tsunami for whoever’s curiosity that may fulfill; otherwise for the force calculation, we need a typical value for the acceleration of a tsunami, ‘a’…and that value should be found from the same data source where the measurement of v = 500 mph was referenced…
14 Mar 11
Originally posted by ChessPraxisIt's all about the wavelength. A Tsunami wavelength is massive (50-100km), which means it acts as a shallow water wave propagating through the ocean. For a shallow water wave, wave speed is sqrt(g * water depth), so as it reaches shallower water it slows down greatly.
A 25 ft. wall of water at 500 MPH would be one hell of an impact. Thank God for physics. 😉
14 Mar 11
Originally posted by Iere man...and I heard that the cooling system backup failed because of the power failure. My grip is not that the power of the quake caused such devastation, but rather that they should have had more back up plans in place to cool the reactors down should this thing happen.
what happened was truly f****d up but I won't say it was them...haven't you seen any of the footage yet? I heard the entire island was moved about 8ft and even the earth's axis had shifted a little because of the extreme forces from the earthquake\tsunami...
14 Mar 11
Originally posted by ElleEffSeeeHey Elle,
It's all about the wavelength. A Tsunami wavelength is massive (50-100km), which means it acts as a shallow water wave propagating through the ocean. For a shallow water wave, wave speed is sqrt(g * water depth), so as it reaches shallower water it slows down greatly.
that kinda sparked an idea because all I can remember from that topic was the wave interference aspect and that waves can interfere and cancel out each other, i think it is if they are out of phase with each other by 90 degrees or something like that, someone needs to verify that please. So anyways I was thinking (since the water is shallow as well),,,let's say we can plant steel rods in the sea, not necessarily along the entire coastline but more like say 2 miles out in front of the coastal town...btw these aren't any plain old rods, they have been piled very deeply into the seabed and then there are rods running across to forming grid face pattern to give more strength to the entire structure,,,then there are a few rows of these grid faces forming a extensive, reinforced grid lattice structure...of course the grid spacings must big enough to let the whales wiggle through but I don't see this as a major limitation and closer to the surface ships have to pass through also...anyways, the most special thing is that there are steel plates or fins welded at various angles along all of the lattice edges; i'm calling them "diverters". I think such a structure can break down a tsunami by the interference it will cause as it passes through. Do I sound like a lunatic on this one? Should I lay off Mary Jane a bit? Aren't there tanks where these and similar ideas can be simulated or something? Has that been tried before? What gives here, Anybody knows?
14 Mar 11
Originally posted by jimslyp69The professional term for backup is 'redundancy' but you are correct, the more systems redundancy the more safer your plant becomes, but then at some point the design will become very impractical and\or too expensive...
...and I heard that the cooling system backup failed because of the power failure. My grip is not that the power of the quake caused such devastation, but rather that they should have had more back up plans in place to cool the reactors down should this thing happen.
14 Mar 11
2 edits
Originally posted by Iere manWell I point back to my previous post re costs and possibilities of such like occurring. I don't think you can put a cost on nuclear meltdowns. They are a complete F up and should never happen. If you are going to build these things then they should be built so it is nigh on impossible that this stuff is released into the environment. The effects last more than a life time.
The professional term for backup is 'redundancy' but you are correct, the more systems redundancy the more safer your plant becomes, but then at some point the design will become very impractical and\or too expensive...
Financial cost shouldn't be consideration. Obviously it is though. That was my point.
14 Mar 11
1 edit
Originally posted by jimslyp69No it is NOT obvious, when design becomes too impractical AND\OR expensive, then a different and still feasible alternative is normally considered in which safety does not have to be compromised; nuclear power plants are only ONE type out of many that can be constructed and it was stated that only 30% of Japan's grid is powered by the nuclear plants...
Well I point back to my previous post re costs and possibilities of such like occurring. I don't think you can put a cost on nuclear meltdowns. They are a complete F up and should never happen. If you are going to build these things then they should be built so it is nigh on impossible that this stuff is released into the environment. The effects last more ...[text shortened]... time.
Financial cost shouldn't be consideration. Obviously it is though. That was my point.
14 Mar 11
Originally posted by Iere man"but you are correct, the more systems redundancy the more safer your plant becomes, but then at some point the design will become very impractical and\or too expensive"
No it is NOT obvious, when design becomes too impractical AND\OR expensive, then a different and still feasible alternative is normally considered in which safety does not have to be compromised; nuclear power plants are only ONE type out of many that can be constructed and it was stated that only 30% of Japan's grid is powered by the nuclear plants...
Make your mind up dude...