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Post by uwaztec on Mar 16, 2011 13:41:18 GMT -8
I imagine the reason that no one is discussing the Japan situation is because it is just too darn upsetting and sad. I believe that it is the single worst thing I have seen in my 56 years. 9-11 was emotionally difficult, but the magnitude of this disaster exceeds anything I have seen. One point is that for those that hate the stringent environmental review in the US, San Onofre has a 30 foot tsunami wall. The surge in Japan was 23 feet.
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Post by aztecwin on Mar 16, 2011 16:01:16 GMT -8
I imagine the reason that no one is discussing the Japan situation is because it is just too darn upsetting and sad. I believe that it is the single worst thing I have seen in my 56 years. 9-11 was emotionally difficult, but the magnitude of this disaster exceeds anything I have seen. One point is that for those that hate the stringent environmental review in the US, San Onofre has a 30 foot tsunami wall. The surge in Japan was 23 feet. This horrible event is still unfolding. It may be awhile before we know all the facts if we ever do. |
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Post by The Great Aztec Joe on Mar 16, 2011 20:13:39 GMT -8
I imagine the reason that no one is discussing the Japan situation is because it is just too darn upsetting and sad. I believe that it is the single worst thing I have seen in my 56 years. 9-11 was emotionally difficult, but the magnitude of this disaster exceeds anything I have seen. One point is that for those that hate the stringent environmental review in the US, San Onofre has a 30 foot tsunami wall. The surge in Japan was 23 feet. It was that surge that took out the diesel generators so they could not keep cooling the reactors after they scrammed. On another board a bunch of people thought that the reactor's scramming was a fault of design, so I explained to them that it is a safety measure as soon as an earthquake is felt. The Diesel Generators are there to be used for emergencies just like the one on March 11th. Unfortunately they had all been douched because the Japanese did not take into consideration what would happen if a twenty foot wave washed onto the area where the diesels were mounted. All that has happened is related to that inability to drive cooling pumps with the diesel electric power. Of course, we have an additional problem and that is that the Japanese decided to use the attic of the building towering over the reactor to store expended fuel rods for long periods of time. Venting gas from the reactors into the building was quite frankly a very stupid thing to do because it explodes and has a tendency to lead to fires. We believe that the used fuel rods have been burned in two of the reactor buildings. If so, the amount of contamination will be excessive. |
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Post by theMesa on Mar 21, 2011 13:19:49 GMT -8
being an engineer I will say that the original design of the whole facility was extremely short sighted and plain dumb given the fact that an active fault capable of large magnitude earthquakes existed off shore.
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Post by Deleted on Mar 21, 2011 16:56:55 GMT -8
being an engineer I will say that the original design of the whole facility was extremely short sighted and plain dumb given the fact that an active fault capable of large magnitude earthquakes existed off shore. That would preclude any reactors anywhere in Japan. As an engineer, you should understand fundamental constraints. Japan has no oil, coal or natural gas. No nuclear power is not an option for them. The plant was designed in the early 70's, has worked for over a quarter century without incident and only succumbed to a Mag 9 + tsunami. That's like saying the design of your '68 Camaro sucks because it failed the last smog check. |
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Post by uwaztec on Mar 21, 2011 18:40:25 GMT -8
being an engineer I will say that the original design of the whole facility was extremely short sighted and plain dumb given the fact that an active fault capable of large magnitude earthquakes existed off shore. That would preclude any reactors anywhere in Japan. As an engineer, you should understand fundamental constraints. Japan has no oil, coal or natural gas. No nuclear power is not an option for them. The plant was designed in the early 70's, has worked for over a quarter century without incident and only succumbed to a Mag 9 + tsunami. That's like saying the design of your '68 Camaro sucks because it failed the last smog check. So where does "Mesa" say there should be no nuclear reactors in Japan? I think he is talking about a design flaw that does not take into account a Tsunami surge of 23 feet. San Onofre has a 30 foot wall..probably because of the environmental review process you dislike. San Onofre was built in the 70's, just like the Japanese plants were. Japan doesn't have the level of environmental review process we have. Certainly in Japan there are setback locations with adequate elevation that would allow reactor safety. Of course 9.0 is huge and that is an issue of course. Nice to hear a "reasonable" engineer on here though. |
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Post by The Great Aztec Joe on Mar 21, 2011 19:48:56 GMT -8
I had posted on numerous boards that the engineers who put the Emergency Diesels where they could be swept away by a Tsunami were not playing with a full deck. Tsunami, after all, is the Japanese word for that large swell because it happens in Japan with frequency.
You would think that some engineer working for the Electric Company would have questioned the placement of the Diesel Electric generators, and at least arranged for an emergency generator to be flown to any Reactor site if there was an emergency that knocked out the built in Diesel Generators. Apparantly it did not occur to any Japanese working there that they needed an uninterrupted source of Emergency Electricity to drive the pumps.
For want of a diesel generator they have hundreds of Billions of dollars in losses. Unbelievable!
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Post by Deleted on Mar 21, 2011 20:23:27 GMT -8
That would preclude any reactors anywhere in Japan. As an engineer, you should understand fundamental constraints. Japan has no oil, coal or natural gas. No nuclear power is not an option for them. The plant was designed in the early 70's, has worked for over a quarter century without incident and only succumbed to a Mag 9 + tsunami. That's like saying the design of your '68 Camaro sucks because it failed the last smog check. So where does "Mesa" say there should be no nuclear reactors in Japan? I think he is talking about a design flaw that does not take into account a Tsunami surge of 23 feet. San Onofre has a 30 foot wall..probably because of the environmental review process you dislike. San Onofre was built in the 70's, just like the Japanese plants were. Japan doesn't have the level of environmental review process we have. Certainly in Japan there are setback locations with adequate elevation that would allow reactor safety. Of course 9.0 is huge and that is an issue of course. Nice to hear a "reasonable" engineer on here though. The entire country is prone to large magnitude earthquakes. Reactors need to be built in proximity to bodies of water large enough to dissipate the heat from the tertiary reactor cooling system. Therefore, to say that it "was extremely short sighted and plain dumb given the fact that an active fault capable of large magnitude earthquakes existed off shore." is to say that it would be "short sighted and just plain dumb" given the conditions stated to build a reactor anywhere in Japan. |
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Post by The Great Aztec Joe on Mar 22, 2011 8:12:34 GMT -8
So where does "Mesa" say there should be no nuclear reactors in Japan? I think he is talking about a design flaw that does not take into account a Tsunami surge of 23 feet. San Onofre has a 30 foot wall..probably because of the environmental review process you dislike. San Onofre was built in the 70's, just like the Japanese plants were. Japan doesn't have the level of environmental review process we have. Certainly in Japan there are setback locations with adequate elevation that would allow reactor safety. Of course 9.0 is huge and that is an issue of course. Nice to hear a "reasonable" engineer on here though. The entire country is prone to large magnitude earthquakes. Reactors need to be built in proximity to bodies of water large enough to dissipate the heat from the tertiary reactor cooling system. Therefore, to say that it "was extremely short sighted and plain dumb given the fact that an active fault capable of large magnitude earthquakes existed off shore." is to say that it would be "short sighted and just plain dumb" given the conditions stated to build a reactor anywhere in Japan. Afan, those large cooling towers are all that is necessary to dissipate latent heat from the reactors. Of course, there is need for a large reservoir of water to be used in cooling. An Olympic sized swimming pool would probably qualify for three days after a shutdown, but you would need access to more water after that. When a reactor "scrams" (drops the boron (Neutron "poison" control) rods into the reactor to shut it down) the Nuclear Fission (Neutons hitting Uranium 235 and causing it to split) reaction slows down and comes close to stopping, but there is no perfect 100 percent stop in fission, so a few occasional Uranium atom splittings continue to happen and that generates some heat. Each time Uranium 235 splits, it spits out an average of 2.4 neutrons per fission and those neutrons either wander off into uselessness or they split another Uranium atom. Criticality is when each Uranium 235 splitting results in one neutron going on to split another Uranium 235 atom. Shutting down is all about controlling the neutrons and removing as many of them from the equation. The vast majority of heat generated after shutdown is from Delayed Neutron Precursors. The byproducts of fission are things like radioactive Cesium, Strontium, Iodine and elements like that. They are radioactive because they are at a higher energy state than the normal elements (with the same names) and they need to decay to a stable state. They do so by spitting out a neutron or two and lots of gamma radiation (x-ray like radiation). When the neutrons and gamma rays are spit out, they generate heat in the fuel rods AND some of those neutrons go on to split some Uranium atoms and that generates more heat. Thus, reactors have to be cooled for days after shutdown. When the delayed neutron precursors have calmed down, the reactor is about as shut down as it ever will be, but it still generates some heat so it needs a minor flow of cooling water to take that heat away. In Japan they were injecting sea water and bleeding the reactor to remove latent heat. |
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Post by AlwaysAnAztec on Mar 22, 2011 8:23:34 GMT -8
Hey Joe, since you've had the training and worked around naval nuclear power, I've got a few questions.
1) How are reactors cooled on Subs without leaving a heat signature?
2) Couldn't smaller reactors like those on subs be used commercially instead of the massive plants like in Japan?
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Post by The Great Aztec Joe on Mar 22, 2011 8:30:37 GMT -8
For YEARS and YEARS since my Navy days I have recommended that all nuclear generating stations be built on large ships anchored off shore with the power lines running back to shore. A ship can lift up and over a Tsunami swell out at sea. Reactors built along the shore are just targets for a Tsunami. San Onofre has their 30 foot retaining wall from the sea. I have tried to identify it in photos, and I wonder how sturdy it really is, because I have seen a wall that is cinder block thick at the top. A cinderblock wall will not stop a Tsunami wave. Is there anybody who has ever worked out there who can describe the wall structure???
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Post by The Great Aztec Joe on Mar 22, 2011 8:39:44 GMT -8
Hey Joe, since you've had the training and worked around naval nuclear power, I've got a few questions. 1) How are reactors cooled on Subs without leaving a heat signature? 2) Couldn't smaller reactors like those on subs be used commercially instead of the massive plants like in Japan? 1) They always leave a heat signature. We were designing nuc subs to have their condenser effluent to be chopped up by the propellers after it left the sub. 2) As you were typing your question I was typing my post immediately above. We could very easily build multiple nuc plants on ships to generate all of the electricity needed in the US. Why we have not done that, I do not know. We have the engineering knowhow to do so and could have done so way back in 1965 when the S5G prototype I was trained on was built. It had a primary system that did not need pumps to run the heated coolant to the Steam Generators. It did need pumps to return the condensate to the Steam Generator and it did need pumps to run water through the condenser. |
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