Nuclear Radiation Risk low for Alaska. (fence, safe, swimming pool)

[blueflames50]

Originally Posted by Moose Whisperer

The contamination was picked up by rescue crews working on or near shore and tracked back on their clothes, persons, and equipment - not by the ships out at sea. Of course there is no way to tell the exact extent of the contamination because the news media is completely devoid of any useful information such as the nuclides present or actual contamination levels. But given that it was easily cleaned up by a good soapy shower, it couldn't have been that bad. I've had worse myself before.

did you read to the bottom?? the ship according to another report has moved further out to sea due to:
"The wind direction is right for people in Japan. It's blowing out to the Pacific," Lennart Carlsson, director of Nuclear Power Plant Safety in Sweden, told Reuters. "I don't think this will be any problem to other countries."

[Moose Whisperer]

Originally Posted by richelles

I never saw any designs for Japanese nuclear plants but I find it almost unbelievable that emergency generating facilities would be located in a location that could be inundated by even a twenty five foot Tsunami Wave. Here even spent fuel storage is above 18 feet above the highest predicted sea level. Flooding of the diesel powered electrical system could have been prevented at very low cost by simply building a flood wall raising the unit above the possible flood level.

Not sure why the diesels failed, but the reports are that they actually did start an ran for and hour or so before failing. So they obviously withstood the initial shock of the quake, and even the initial surge(s) of the tsunami. But whatever the cause, it apparently took out all the EDGs on the site because both Daiichi 1 & 3 have lost Emergeny Cooling. Whatever it was it obviously exceeded the Defense in Depth Calculations for the design - not surprising given the magnitude of this disaster.

[Moose Whisperer]

Originally Posted by blueflames50

did you read to the bottom?? the ship according to another report has moved further out to sea due to:
"The wind direction is right for people in Japan. It's blowing out to the Pacific," Lennart Carlsson, director of Nuclear Power Plant Safety in Sweden, told Reuters. "I don't think this will be any problem to other countries."

Yes, they are correct. We've got more to worry about here - like all of the stuff China dumps into the air on a daily basis - than a few particulates that will barely be detectable from whatever minor releases are coming from the Daiichi plants right now.

In fact, China probably puts more radioactive contamination in the air on a daily basis from all of the coal they burn than Japan will likely emit during this entire causualty (coal miners have the highest occupational exposure to radiation of any other job - i.e the earth is radioactive).

[RedJacket]

The decorum shown by the people of Japan is pretty amazing to watch, while the media here in America is bound and determined to scare the crap out of everyone...and that's not a real difficult task to pull off.

[roadfamily6now]

Originally Posted by RedJacket

The decorum shown by the people of Japan is pretty amazing to watch, while the media here in America is bound and determined to scare the crap out of everyone...and that's not a real difficult task to pull off.

{Like}

[gobrien]

I'm pretty impressed by the workers who stay at the power plants-heroes all.

[richelles]

Originally Posted by Moose Whisperer

Not sure why the diesels failed, but the reports are that they actually did start an ran for and hour or so before failing. So they obviously withstood the initial shock of the quake, and even the initial surge(s) of the tsunami. But whatever the cause, it apparently took out all the EDGs on the site because both Daiichi 1 & 3 have lost Emergency Cooling. Whatever it was it obviously exceeded the Defense in Depth Calculations for the design - not surprising given the magnitude of this disaster.

I have been involved in building, refitting after TMI, and refueling/maintenance of nuclear plants along the Atlantic, Pacific, and Gulf Coast of the United States. In each of those plants I saw the EDGs and noted how they were protected from storm surge. In each plant I can remember, now some 25 years later, the EDGs were located above what any predictions were for the local conditions. But in recent years I have seen shows on TV which make me wonder if the Atlantic Coast line plants are adequately protected from the Tsunamis that are possible from landslides on the islands in the Atlantic? I recall predictions of Tsunami waves much higher than the defensive barriers that protected the EDGs at those shoreline plants.

All of those plants are located many thousands of miles away from the potential starting points which gives them some hours of safety. But with those Atlantic Coast Line plants could a Tsunami be created of sufficient size to take out those emergency facilities? If the EDGs were able to function for one hour following the dropping of the control rods evidently the steam explosions now occurring prove that isn't enough time to cool down a hot reactor. If this is true where the waves arrived within one hour or less time how long do we have for our coastal facilities to be cooled sufficiently to prevent such heat buildup? Note that the explosions that are being reported are most likely due to excessive steam pressures and aren't nuclear explosions. However GE reactors use water which is radioactive to cool the reactor.

Nuclear plants are supplied with electricity from other generating stations so in this case it is possible the transmission lines were downed by the earthquake cutting that electrical supply forcing the plant to depend on the EDGs from the beginning. The EDGs are sized to handle the base load which includes the cooling pumps and sufficient extra power to bring the plant to a safe shut down. However if there wasn't shore power or power from the EDGs then what? The media is reporting using battery power to run the cooling pups but how long would they last? It seems they to would be sized to safely bring the plant to a cold shut down but that obviously isn't the case. That brings my thoughts back to our coast line plants and how much Tsunami damage could we expect? We might be in a world of trouble if this wasn't thought out correctly when these plants were designed.

[Moose Whisperer]

Well, you are basically asking why the Design Basis Event criteria for Nuke Plants are what they are. I can’t speak for Japanese standards (though these are GE designed and built plants so they are likely to be similar), but I’m pretty sure the USNRC minimum DBE for a seismic event is 8.0 in the Richter scale. Up until a week ago, most people would have probably thought this to be reasonable and adequate. Does it need to be changed? I dunno.

I also believe the NRC only mandates analysis for a single failure mode. In the case we are discussing, a US Plant would analyze for a total loss of offsite power by taking credit for 2 or more redundant sources of alternate A/C power such as EDGs and Battery UPS. Also, the UPS is not meant as a source of power for extended Shutdown/Emergency Core cooling, but is usually sized only to provide enough capacity for the expected time to restore A/C power from a more permanent source (offsite, EDGs, portable generator sets, etc). Again, in the case we are discussing, you are looking not just at single or even double failures, but multiple, cascading events. I’m no expert in failure analysis, but I’m pretty sure even the experts will say that you just can’t engineer for such scenarios. The possible permutations are simply too great.

But getting back to your question, how high do we want to set the standards? Do we design Aircraft to withstand direct, midair collisions? In which case they would probably be too heavy to get off the ground. Do we design passenger cars to be able to withstand a 100 mph collision with a brick wall? In which case your average sedan would probably cost $200,000. Or do we just accept that modern life always involves some finite amount of risk, and just get on with living life?

[AADAD]

the issue in the Japanese plants rests on the fact that the generators which should have been available to cool the rods were built to low and the tsunami overwhelmed them relegating the next step being sea water. the situation at plant #2 is dire now and a full meltdown is possible according to MSNBC this afternoon. Finally, most nuc power plants are designed to withstand ground movement in g's not a richter scale and that is hard to predict. I mean it's the earth...it is going to do what it wants....just like an angry woman.

The videos of the power of the tsunami is simply stunning. We are vulnerable to nature. The Japanese poured 1.5B into the sea walls which we can see being easily and completely overwhelmed by the power of the ocean...The thinking to create a planetary grid which is available and safe has yet to be perceived.....

[RedJacket]

Originally Posted by Moose Whisperer

Or do we just accept that modern life always involves some finite amount of risk, and just get on with living life?

I've lived around nuke plants over half my life. The last thing on my mind was turning a brighter shade of RED due to some accident.

I'd much prefer we have our own nuclear power as opposed to relying on the middle east for their black gobbledegoo.

I'm sure nuclear technology has come a long way since those plants were built in Japan. Even so, they've done a pretty remarkable job of withstanding a 9.0 quake along with a tsunami.

Our reliance on oil has done more than its fair share of ruining lives; financially speaking.