Discussion of Nuclear Power and Safety

[Annapurna]

Radioactive iodine is one of the ways radiation gets into people's bodies. By taking iodine or kelp tablets ( high in iodine ) their body fills up on iodine, blocking new iodine from getting in.

Lol, Jhana, that's a misunderstanding.

I'm not asking out of ignorance, I live in Southern Germany which was polluted by the Chernobyl fall out.

I am rhethorically asking why it is being handed out NOW.

Answer:

Because the radiation is so high and several people are already polluted.

If the thyroid is saturated with normal iodine, it can't incorporate much of the radioactive one, which-

causes thyroid cancer.

Instant deaths through earthquakes are of course impressive, but I'm just as much impressed by the long drawn-out dying of the contaminated that lasts years.

[Annapurna]

During the atomic bombing of Hiroshima, thousands of Japanese were subjected to unprecedented amounts of radiation, resulting in a horrific situation. It is said that more people died from radiation sickness than the actual atomic blast, since the radiation spread throughout the region. Not surprisingly, the people who survived the radiation ended up having badly mutated children since they were being constructed with mutated DNA.

Studies conducted on mice during the 1960s have showed that young children and babies are the most susceptible to severe radiation sickness complications since they are still growing and need pure DNA to ensure that their bodies grow in a normal manner. Once their DNA is mutated, their body grows in strange ways, often resulting in death or disability.

With acute radiation sickness, the amount of radiation is what decides how severe the radiation sickness will be. A dosage of 100 roentgens is sufficient to cause sickness. A dosage of 400 Roentgens will cause death 50% of the time and a dosage of 100,000 rads will cause death within an hour.

Symptoms of radiation sickness do not usually develop immediately, rather over a period of time since it takes time for the mutated DNA to produce enough proteins to make an obvious change in body chemistry and structure. Among the symptoms are nausea, diarrhea, burns, swelling, weakness, dehydration, hemorrhaging, hair loss, ulcers, vomiting blood, bloody feces, and bruising.

Doctors can't do much about radiation sickness since they have no way of repairing the DNA. They can, however, treat the symptoms using medication and basic comfort care.

Even if you survive radiation sickness, you will likely die early and experience complications in the future.

[Mawkish1983]

There hasn't been a nuclear explosion. There isn't even a chain reaction in the core.

[GIDGE]

The reactor itself at Fukushima is a GE BWR Mark III reactor I believe. In the case of a complete meltdown, they will open the valves designed to vent steam and allow all the water to safely boil off. Then the fuel rods themselves will melt and turn into a shallow pool in the bottom of the containment vessel. Spreading it out will help it cool. Then coolant will be pumped in to further cool it. This will prevent the core from ever exploding and no significant radiation will be released. After a while, the remnants of the core will be collected and shipped to a reprocessing facility. Of course, this worst-case is not going to happen as long as they are able to keep pumping water into the reactors which they have been able to do.

Thanks for the explanation!
It's my understanding that the fuel used to power the pumps injecting cool seawater into the reactor has been exhausted.
Could this potentially (probably) present a whole new set of (incredibly dangerous) challenges - from a structural/engineering standpoint?

[Kim OHara]

For Anna:

Germany rethinks nuclear program

Germany has suspended plans to extend the life of its ageing nuclear power stations in the wake of the Japanese crisis.

Last year chancellor Angela Merkel approved plans to put back the date when Germany abandons nuclear power by a decade to 2030.

But she has now announced a three-month moratorium on these plans.

A little more at http://www.abc.net.au/news/stories/2011/03/15/3163961.htm

For others:

Japan on meltdown alert

Japan has officially asked the UN atomic watchdog to send a team of experts to help stave off a nuclear emergency following Friday's massive earthquake and tsunami.
Two explosions have already rocked the Fukushima plant and now fuel rods at the plant's No. 2 reactor are exposed and at risk of meltdown.
But as Japan struggles to deal with the aftermath of the earthquake and tsunami which are feared to have killed more than 10,000 people, government officials are playing down the nuclear concerns, insisting the situation is under control.
Authorities say the fuel rods in the reactor became fully exposed after the system that pumps cooling water through the reactor failed late last night.
Radiation and pressure levels jumped and engineers are trying to stabilise the situation.
Air pressure inside the reactor rose suddenly when the air flow gauge was accidentally turned off, blocking the flow of water and leading to full exposure of the rods, operator TEPCO said.
"We are not optimistic but I think we can inject water once we can reopen the valve and lower air pressure," a TEPCO official told reporters.
Japan's top government spokesman Yukio Edano said a major explosion was unlikely and insisted the government was not facing a Chernobyl-style disaster. He said engineers were pumping seawater in to stabilise the reactor and radiation around the plant was at tolerable levels.

More at http://www.abc.net.au/news/stories/2011/03/15/3163913.htm


Kim

[poto]

The reactor itself at Fukushima is a GE BWR Mark III reactor I believe. In the case of a complete meltdown, they will open the valves designed to vent steam and allow all the water to safely boil off. Then the fuel rods themselves will melt and turn into a shallow pool in the bottom of the containment vessel. Spreading it out will help it cool. Then coolant will be pumped in to further cool it. This will prevent the core from ever exploding and no significant radiation will be released. After a while, the remnants of the core will be collected and shipped to a reprocessing facility. Of course, this worst-case is not going to happen as long as they are able to keep pumping water into the reactors which they have been able to do.

Thanks for the explanation!
It's my understanding that the fuel used to power the pumps injecting cool seawater into the reactor has been exhausted.
Could this potentially (probably) present a whole new set of (incredibly dangerous) challenges - from a structural/engineering standpoint?

I was under the impression that they are using diesel fuel to power the new backup generators that were flown or trucked in after the plant's backup generators failed. I haven't heard of any shortage of diesel at the plant, and I imagine that it would be simple enough to transport more fuel to the site fairly quickly.

Even if they run out of fuel to power the pumps, what happens is the water in the reactor eventually boils off and is released via the vents. If there is no water in the reactor to cool the core, eventually the fuel rods will melt completely, but that still does not mean they will lose containment. As I said before, these reactors are designed to contain a complete core meltdown. There is a big catch basin underneath the reactor that is designed to contain a complete meltdown. The containment vessels are still completely intact. Had the earthquake damaged the containment vessels, we might have had some big problems, but this is not the case.

Of course, their engineers are working diligently to keep the reactor cores cool, as preventing a complete meltdown is their top priority right now. They will probably have to keep pumping water for a few months, and periodically releasing steam to control any pressure that is building up. After a few months the reactors will be cool enough to be passively cooled and that will be the end of it as far as most people are concerned.

[Jhana4]

I've been reading about the Japanese nuclear power plant both here and on slashdot.org. On both sites there have been two predominant views. One has been

"Aw heck, this is just a paper cut, I'm having a picnic on the grounds next week and I'm not canceling"

and

"Officials have announced a catastrophic meltdown, but are waiting to see if the eruption of the volcano and the release of Godzilla from the glacier will slow it down"

[christopher:::]

The reactor itself at Fukushima is a GE BWR Mark III reactor I believe. In the case of a complete meltdown, they will open the valves designed to vent steam and allow all the water to safely boil off. Then the fuel rods themselves will melt and turn into a shallow pool in the bottom of the containment vessel. Spreading it out will help it cool. Then coolant will be pumped in to further cool it. This will prevent the core from ever exploding and no significant radiation will be released. After a while, the remnants of the core will be collected and shipped to a reprocessing facility. Of course, this worst-case is not going to happen as long as they are able to keep pumping water into the reactors which they have been able to do.

Thanks for the explanation!
It's my understanding that the fuel used to power the pumps injecting cool seawater into the reactor has been exhausted.
Could this potentially (probably) present a whole new set of (incredibly dangerous) challenges - from a structural/engineering standpoint?

I was under the impression that they are using diesel fuel to power the new backup generators that were flown or trucked in after the plant's backup generators failed. I haven't heard of any shortage of diesel at the plant, and I imagine that it would be simple enough to transport more fuel to the site fairly quickly.

Even if they run out of fuel to power the pumps, what happens is the water in the reactor eventually boils off and is released via the vents. If there is no water in the reactor to cool the core, eventually the fuel rods will melt completely, but that still does not mean they will lose containment. As I said before, these reactors are designed to contain a complete core meltdown. There is a big catch basin underneath the reactor that is designed to contain a complete meltdown. The containment vessels are still completely intact. Had the earthquake damaged the containment vessels, we might have had some big problems, but this is not the case.

Of course, their engineers are working diligently to keep the reactor cores cool, as preventing a complete meltdown is their top priority right now. They will probably have to keep pumping water for a few months, and periodically releasing steam to control any pressure that is building up. After a few months the reactors will be cool enough to be passively cooled and that will be the end of it as far as most people are concerned.

My understanding is that all the difficulties so far have to do with this pumping of water to continually cool off the reactor. The fuel rods were inserted immediately, which is good, and which did not happen with Chernobyl. But they've had multiple problems with the pumps. Some parts of the pumping machinary may have been cracked or damaged, there have been problems getting fuel in to the site, for the pumps.

I just listened to Cham Dallas talking on CBS (he's a supporter of the nuclear industry, not anti-nuclear, and spent years studying Chernobyl to see what went wrong there) and he emphasized the potential for human error here, and also that the Japanese crisis is happening in a disaster zone, following earthquake and tsunami. Little things are going wrong, and right now the biggest problem is with keeping water pumping to cool things down.

The system is designed to be safe, when not damaged. They are not sure at all yet about the extent of damage or what specifically may or may not have been damaged, thus making things less "safe." The recent explosions did not damage the reactor containment vessel (we are told) but all these explosions and quakes (there could be another) can damage the pumping systems.

Pumping then stops, and the reactor heat builds up, melting stuff, making it harder to control.

[Justsit]

...The system is designed to be safe, when not damaged....

Engineers and other "Experts" offer scientific rationales for why certain disasters cannot happen.

The problem is, systems DO become damaged, they do not operate as designed, and then they are not safe.

For some unknown (to me, anyway) reason, scientists seem to eliminate the extremes of catastrophic event prediction as if the fact that that certain probabilities are so small, they can be ignored. Therein lies the peril. Those highly unlikely scenarios do in fact develop. Cf, Deepwater Horizon. Dunno, maybe it's just plain arrogance?

The current situation with the reactors in Japan is another example. Yes, there were three redundant cooling systems in the reactors, and still disaster strikes. The TEPCO representative said, problems developed that we couldn't foresee. No kidding.

So, IMO, when you hear a scientist say Oh, it's safe, nothing to worry about....yup, it may be safe, right up until it isn't...time to get the hell outta Dodge.

[Kim OHara]

...The system is designed to be safe, when not damaged....

Engineers and other "Experts" offer scientific rationales for why certain disasters cannot happen.

The problem is, systems DO become damaged, they do not operate as designed, and then they are not safe.

For some unknown (to me, anyway) reason, scientists seem to eliminate the extremes of catastrophic event prediction as if the fact that that certain probabilities are so small, they can be ignored. Therein lies the peril. Those highly unlikely scenarios do in fact develop. Cf, Deepwater Horizon. Dunno, maybe it's just plain arrogance?

The current situation with the reactors in Japan is another example. Yes, there were three redundant cooling systems in the reactors, and still disaster strikes. The TEPCO representative said, problems developed that we couldn't foresee. No kidding.

So, IMO, when you hear a scientist say Oh, it's safe, nothing to worry about....yup, it may be safe, right up until it isn't...time to get the hell outta Dodge.

Yep, that's roughly right.
Someone (in New Scientist, IIRC) was trying to come up with a more formal way of thinking about how to deal with risks that have very low probability but very high costs ($ or human) and concluded that however low the probability, it was worth spending lots of money to avoid or minimise them. It's sort of counter-intuitive, which I guess is why engineers and their managers tend not to act that way. "One chance in a million? We can forget it!" is the attitude. It's wrong.

Kim

[christopher:::]

There are areas of science that deal with this, chaos theory, complexity theory. If you watch the movie Jurassic Park Jeff Goldblum's charactor is a chaos theorist, he talks of this. Along with ignoring very minor probabilities with super high risks scientists also sometimes ignore cumulative and synergistic effects, such as exposure to multiple drugs or toxins that then have a powerful damaging effect. Actually, that seems to also be the case here, it wasn't one thing going wrong but several things going wrong at the same time, which then trigger additional problems. In something like the Challenger space craft explosion it was one very minor thing, a small sealing ring, which then set everything else in motion.

[octathlon]

Unfortunately, a third explosion, at reactor#2 this time, appears to have damaged the reactor itself and they have evacuated all but a minimal number of workers.

[christopher:::]

Unfortunately, a third explosion, at reactor#2 this time, appears to have damaged the reactor itself and they have evacuated all but a minimal number of workers.

Right. Let's hope this isn't as bad as it sounds, or that a solution is found, quickly.

Japan suspects nuclear reactor container damaged

– 1 min ago
TOKYO – Japan's nuclear safety agency said an explosion Tuesday at an earthquake-damaged nuclear power plant may have damaged a reactor's containment vessel and that a radiation leak is feared. The nuclear core of Unit 2 of the Fukushima Dai-ichi nuclear plant in northeast Japan was undamaged, said a spokesman for the Nuclear and Industrial Safety Agency, Shigekazu Omukai.

The agency suspects the explosion early Tuesday may have damaged the reactor's suppression chamber, a water-filled tube at the bottom of the container that surrounds the nuclear core, said another agency spokesman, Shinji Kinjo. He said that chamber is part of the container wall, so damage to it could allow radiation to escape.

"A leak of nuclear material is feared," said another agency spokesman, Shinji Kinjo. He said the agency had no details of possible damage to the chamber.
Radiation levels measured at the front gate of the Dai-ichi plant spiked following Tuesday's explosion, Kinjo said.

Detectors showed 11,900 microsieverts of radiation three hours after the blast, up from just 73 microsieverts beforehand, Kinjo said. He said there was no immediate health risk because the higher measurement was less radiation that a person receives from an X-ray. He said experts would worry about health risks if levels exceed 100,000 microsieverts.

[Kim OHara]

Here's a good clear explanation of the technology and the damage up to the time it was written - i.e. not including the latest events.
http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/


Kim

[Jhana4]

The explanations by nuclear energy fans have been reassuring, but those explanations keep coming before the news gets worse and worse.

[retrofuturist]

Greetings,

Detectors showed 11,900 microsieverts of radiation three hours after the blast, up from just 73 microsieverts beforehand, Kinjo said. He said there was no immediate health risk because the higher measurement was less radiation that a person receives from an X-ray. He said experts would worry about health risks if levels exceed 100,000 microsieverts.

I don't find this logic particularly convincing, because how long are you exposed to X-rays for when you go for an X-ray?

Alternatively if 11,900 microsieverts is the 'ambient environment', it's a continuous exposure over time.

Metta,
Retro.

[christopher:::]

Newest release from the Japanese government...

23 mins ago
SOMA, Japan – Radiation is spewing from damaged reactors at a crippled nuclear power plant in tsunami-ravaged northeastern Japan in a dramatic escalation of the 4-day-old catastrophe. The prime minister has warned residents to stay inside or risk getting radiation sickness.
Chief Cabinet Secretary Yukio Edano said Tuesday that a fourth reactor at the Fukushima Dai-ichi complex was on fire and that more radiation was released. Prime Minister Naoto Kan warned that there are dangers of more leaks and told people living within 19 miles (30 kilometers) of the Fukushima Dai-ichi complex stay indoors.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

vs.

I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.

[christopher:::]

This is a very good explanation (short video and with visuals) from NHK News, translated at CNN, of how the 3 safety systems failed bringing them to the point where salt water was pumped in. It doesn't explain what's happened since...

[GIDGE]

An incredibly brutal reminder that EVERYTHING is impermanent. Even the containment vessel.

[chownah]

Good point Kim, although I'm not sure I'd call 20% 'significant'

Aaaanyway, I've said what I wanted to say, so I'll stop.

Mawkish1983,
If you're not sure if 20% is significant then I guess you are not sure if nuclear power contributes significantly to the US electric supply because it only provides 19.6% of the total electric supply.

So....looks like many countries get a larger (more significant) amount of their energy from renewables than the US gets from nuclear.........if the US invested as much in renewables as it has already on nuclear I dare say that they would in a few years have more than 20% generated by renewables just like all those other many countries which presently do.....

And don't forget that renewable technology is in its infancy and is gaining both in technical efficiencies and economic efficiencies....while nuclear is pretty much topped out for fission...let's hope that fusion is cleaner....we already know that it will be safe...seems like the best bet is to promote development of renewables for the next 30 years and then see if fusion is acceptable.....just skip further fusion[edit "fusion" here to read "fission"] development altogether....too many long term costs and uncertainty with fusion[edit "fusion" here to read "fission"] I think....
chownah

Edit: Corrections are added above in the text. I'm such a dummy....I was trying to say that we should develop renewables for the next 30 years and then re-evaluate the possibility of fusion and SKIP ANY FURTHER DEPLOYMENT OF FISSION ALTOGETHER in that there are too many uncertainties and long term costs with present fission technology....and in my view we can probably just leapfrog over fission into fusion but of course fusion is still not a sure thing. Kim O'Hara will probably be perturbed by this edit in that she responded quite nicely to the post in its original form....sorry about that.
chownah