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Why I am not worried about Japan’s nuclear reactors

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Re: Why I am not worried about Japan’s nuclear reactors

#111

Post by lutorm »

illumen wrote: post #15

The writer is not an expert on earth quakes. Making such a bold claim that nothing can go wrong is plainly false. Just because they are an expert in one area, does not mean they are an expert in all areas. There are already a number of people being treated for radiation poisoning. They have already admitted that there have been radiation releases above safe levels. I feel sorry for the engineers working so hard to fi…

The Boston Globe this morning talked about people with acute radiation sickness, too. I don't know how much faith to put in that statement, but if it's true certainly the amount of radiation release is far, far greater than anything that this post envisions. In that case, he clearly can't be correct.

Re: Why I am not worried about Japan’s nuclear reactors

#112

Post by lispm »

juiceandjuice wrote: post #103
lispm wrote: post #96

Earlier quoted context omitted.

Yeah, it seems to be surprising to you that there are people who did not drink the nuclear Kool-Aid. Why is that? Has your 2-party system, the influence of corporations and your declining media made you unable of critical thinking?

I can't speak for the previous poster, but I started 'sipping the nuclear kool-aid' once I took a nuclear physics class. Of course, the class was taught over cable TV by fox news anchors funded by both GE, the DNC and the RNC. That's pretty much how the US got to be a superpower and stuff.

Did not work out too well, given the history of nuclear power plants in the US. When was the last one built?

The list of cancelled nuclear power plants is impressive:

http://en.wikipedia.org/wiki/List_of_canceled_nuclear_plants...

Re: Why I am not worried about Japan’s nuclear reactors

#113

Post by lispm »

DennisP wrote: post #104
ugh wrote: post #69

Earlier quoted context omitted.

It looks to me as though one or two Chernobyl sized disasters per century can very much upset that balance. Deaths obviously still matter but I don't think looking only at radioactivity is good enough. I would very much like to know the deaths per kWh for energy produced from coal and nuclear energy. It is certainly possible that infrequent nuclear disasters are, well, worth it. (A single airplane crash kills many mo…

Chernobyl killed 50 people immediately, and is estimated to have killed 4000 people worldwide from excess cancers. That's worst case, assuming there's no minimum threshold for radiation causing cancer. Some scientists think there is a threshold, which would drop the number quite a bit. There's too much statistical uncertainty to know for sure either way. TMI is estimated to have caused only one excess cancer. So we'r…

Chernobyl had much higher number of deaths.

WHO:

http://sciencev1.orf.at/science/news/147988

The range mentioned is 14000-17000.

Re: Why I am not worried about Japan’s nuclear reactors

#114

Post by fxj »

VMG wrote: post #110
fxj wrote: post #108

25 years after chernobyl, we still find contaminated material in germany. e.g. mushrooms and wild boar. so i would be VERY carful with such a bold statement as in the linked article. http://www.sueddeutsche.de/wissen/langfristige-folgen-von-ts... "And the willingness to eat contaminated venison has dropped obviously, more and more hunters and forest owners can check the meat of wild boars - and compensation from the…

Thats when different radioactive material than in this case in much higher amounts was lifted to high altitudes, which also didn't happen here. I'd be very careful to compare this incident with Chernobyl

FTA: "Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again."

And my main point is not that i want to set the japanese accident on the same level as chernobyl, but more to make clear that nobody expected such a strong contamination after 25 years thousands of miles away from the center of explosion. World is not behaving linearly, even though some people want us to believe it does.

Re: Why I am not worried about Japan’s nuclear reactors

#115

Post by lutorm »

neutronicus wrote: post #57

The article is mostly correct, but a few corrections from a nuclear engineer: 1. What he refers to as "moderator rods" are actually control rods. The term "moderator" refers to a material that is unlikely to absorb neutrons, but likely to scatter them. This helps lower the average neutron speed inside the reactor, which actually increases the fission rate. Since water serves this purpose just fine, most reactors do n…

Also, correct me if I'm wrong, but Cs-137 has a half life of 30 years or something. It certainly does not disappear quickly. Most of the Chernobyl contamination in Sweden was from Cesium, and that made berries and reindeer (which eat lichens) unsafe to eat for many years, if not decades.

Re: Why I am not worried about Japan’s nuclear reactors

#116

Post by neutronicus »

NY_USA_Hacker wrote: post #107
neutronicus wrote: post #57

The article is mostly correct, but a few corrections from a nuclear engineer: 1. What he refers to as "moderator rods" are actually control rods. The term "moderator" refers to a material that is unlikely to absorb neutrons, but likely to scatter them. This helps lower the average neutron speed inside the reactor, which actually increases the fission rate. Since water serves this purpose just fine, most reactors do n…

Where does the tritium come from? As I recall tritium is one proton and two neutrons. So, you are saying that one hydrogen, that is, one proton, from the water captures a neutron and becomes deuturium and then later the deuturium captures another neutron and becomes tritium? Is that correct? Net, to those two reactions have a signficant reaction rate in the context?

There's a significant amount of conversion from hydrogen to deuterium. The likelihood of neutron absorption by deuterium is much smaller (by a about a factor of ten) than the likelihood of neutron absorption by plain hydrogen, but it still happens since there's a lot of neutron flux.

Canadian reactors (the CANDU design) use heavy water as moderator because it doesn't absorb neutrons as readily, and the improvements in neutron economy allow them to avoid enriching their fuel.

Radiation from tritium is definitely something that we worry about as far as worker safety near piping containing irradiated water, but it's not something that concerns us too much as far as being vented into the environment (we try to minimize that, but there's only so much you can do, especially with a BWR).

Re: Why I am not worried about Japan’s nuclear reactors

#117

Post by neutronicus »

lutorm wrote: post #115
neutronicus wrote: post #57

The article is mostly correct, but a few corrections from a nuclear engineer: 1. What he refers to as "moderator rods" are actually control rods. The term "moderator" refers to a material that is unlikely to absorb neutrons, but likely to scatter them. This helps lower the average neutron speed inside the reactor, which actually increases the fission rate. Since water serves this purpose just fine, most reactors do n…

Also, correct me if I'm wrong, but Cs-137 has a half life of 30 years or something. It certainly does not disappear quickly. Most of the Chernobyl contamination in Sweden was from Cesium, and that made berries and reindeer (which eat lichens) unsafe to eat for many years, if not decades.

Yeah, 30 years.

There was a lot of background radiation from Cs-137 from all the old nuclear testing that's disappearing now.

Re: Why I am not worried about Japan’s nuclear reactors

#118

Post by JoeAltmaier »

Wientje wrote: post #93
JoeAltmaier wrote: post #42

Earlier quoted context omitted.

I hope it remains popular. I know, this is a disaster, but the reactors at risk are old steam-engine types. Comparing this to modern reactors is similar to comparing an old steam-locomotive boiler explosion to a modern formula racecar. e.g. http://www.nuscalepower.com

How, exactly, is this a disaster compared to the greater surroundings? Preliminary results are one death, some injured people and perhaps 10 people who'll die from cancer in 20 years time who otherwise wouldn't. Compare to the thousands deaths, millions homeless and unimaginable damage from the earthquake and the nuclear 'disaster' is but a drop in the ocean.

One way its a disaster is, if it warps public policy for decades to come, armtwists power providers into dirty, ecologically disastrous choices and impoverishes a nation thru expensive energy.

Re: Why I am not worried about Japan’s nuclear reactors

#119

Post by DennisP »

lispm wrote: post #113
DennisP wrote: post #104

Earlier quoted context omitted.

Chernobyl killed 50 people immediately, and is estimated to have killed 4000 people worldwide from excess cancers. That's worst case, assuming there's no minimum threshold for radiation causing cancer. Some scientists think there is a threshold, which would drop the number quite a bit. There's too much statistical uncertainty to know for sure either way. TMI is estimated to have caused only one excess cancer. So we'r…

Chernobyl had much higher number of deaths. WHO: http://sciencev1.orf.at/science/news/147988 The range mentioned is 14000-17000.

Can't read German. My source is Physics for Future Presidents by Richard Muller, a physics professor at Berkeley. He says that's the United Nations estimate.

Wikipedia also says the estimate is 4000, and references a report by the United Nations Scientific Committee of the Effects of Atomic Radiation. It goes on to say that UNSCEAR later decided that was an over-estimate, and that IAEA data corroborates that. It has citations for everything.

http://en.wikipedia.org/wiki/Chernobyl_disaster#cite_note-Ch...

Even if the death toll was 17,000, that's still less than the number of U.S. deaths from coal each year.

Re: Why I am not worried about Japan’s nuclear reactors

#120

Post by CamperBob »

lispm wrote: post #112
juiceandjuice wrote: post #103

Earlier quoted context omitted.

I can't speak for the previous poster, but I started 'sipping the nuclear kool-aid' once I took a nuclear physics class. Of course, the class was taught over cable TV by fox news anchors funded by both GE, the DNC and the RNC. That's pretty much how the US got to be a superpower and stuff.

Did not work out too well, given the history of nuclear power plants in the US. When was the last one built? The list of cancelled nuclear power plants is impressive: http://en.wikipedia.org/wiki/List_of_canceled_nuclear_plants...

Meanwhile, hundreds of coal-fired plants were built in their stead, and those are currently spewing radioactive waste into the air in normal operation.
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