Reviving the Nuclear Energy Debate

[guitars_are_fly]

One of the cleanest, "greenest," and most cost-effective means of mass energy production every conceived, nuclear energy is often criticized by some who feel it is dangerous.

My question: what's so bad about nuclear energy?

[gallo]

Quote by: guitars_are_fly My question: what's so bad about nuclear energy?

The way our government manages it. Because of the morass of red tape it has become prohibitively expensive in this country. Besides that, events like Chernobyl and Three Mile Island have frightened the American people. And yet, few are even aware of what actually happened at either site. They favor even more obstacles or a complete ban on further development.

After Chernobyl, a girl who became aware that my son was a nuclear engineer asked, "What if something like Chernobyl happened in this country?" My son's answer was, "It violates laws." She objected, "How does passing laws stop something like that?" The answer, "I mean the laws of physics."

If you don't understand that, then you are one of those who isn't aware of what happened at Chernobyl and Three Mile Island.

Remember, you can't put too much water into a nuclear reactor.

[guitars_are_fly]

Quote by: gallo If you don't understand that, then you are one of those who isn't aware of what happened at Chernobyl and Three Mile Island.

I'm not personally a nuclear-energy-buff. My expertise is the law of the land.

I do, however, have a friend who works as site president for the Waterford 3 Nuclear Reactor in Taft, Louisiana. From what he tells me, re-creating Chernobyl or TMI at that particular reactor would necessitate a myriad of errors and near-impossible factors. I've tried to understand what the issues at those two places were, and it seems to me most problems are the result of operator errors. That is, of course, just an observation.

Plus, I saw the Discovery Channel special on Chernobyl a while back. That must make me an expert, right?

[gallo]

Quote by: guitars_are_fly I'm not personally a nuclear-energy-buff. My expertise is the law of the land. I do, however, have a friend who works as site president for the Waterford 3 Nuclear Reactor in Taft, Louisiana. From what he tells me, re-creating Chernobyl or TMI at that particular reactor would necessitate a myriad of errors and near-impossible factors. I've tried to understand what the issues at those two places were, and it seems to me most problems are the result of operator errors. That is, of course, just an observation. Plus, I saw the Discovery Channel special on Chernobyl a while back. That must make me an expert, right?

Of course, as an evolutionary biologist, I must be an expert on nuclear power too. However, I've seen a couple of things on PBS and Discovery about Chernobyl, I read the book, and I have read some of my son's NUEN texts and had him explain it to me. What I was referring to is the fact that all standard power reactors in the U.S. are water moderated/water cooled (some special fast breeder reactors are sodium cooled). Soviet reactors were graphite moderated/water cooled. In a water moderated reactor, if it loses the water coolant, it also loses the moderator and the reaction stops. In graphite reactors, it they lose the cooling water, the reaction continues. If the control rods jam, there is no way to halt the reaction. The underlying cause of Chernobyl was the poor training of the operators. They didn't understand that reactor power doesn't respond to the control rods like a car does to an accelerator peddle.

Anyway, I think I'm leading the thread off topic. France gets somewhere around 90% of its electric power from nuclear plants. They have a different philosophy from ours. Their reactors are smaller and they are all the same. That way, an engineer trained at one site can easily move to another. In this country, reactors are all independently designed and approved. It makes for more difficult training, operation, administration, and regulation. Cookie cutter reactors are less expensive in the long run.

[Milton Bradley]

My bigges complaint is the way they store the spent fuel rods. They're just huge terrorist targets, and I don't plan on giving up liberties in exchange for security.

[gallo]

Quote by: Milton Bradley My bigges complaint is the way they store the spent fuel rods. They're just huge terrorist targets, and I don't plan on giving up liberties in exchange for security.

Please enlighten us. I know how the spent fuel rods are stored at the South Texas Project (STP) nuclear power station. All of it is still on site under 60 feet of water in the spent fuel pool. As I understand it, that is also the case with the other 65 active power reactors in the U.S.

However, I am also aware of the shutdown and razing of at least one old reactor (somewhere in New England, I think). What did they do with the spent fuel? How about government reactors and Navy ships? Where does that spent fuel go? How is it processed?

[Gods_Mercenary]

The best way to prevent something like Chernobyl is not to let Russians run your nuclear reactors. especially if it's probaly only going to be mainly Ukranians affected. My understanding is the Chernobyl came about after the operators came up with the brilliant idea of seeing what would happen if the massive amounts of automatic safety mechanismswere disabled.

I beleive they either are building or have buit a massive underground bunker literally inside a mountain as a repository for spent fuel. It's not the best option, but it sure does provide a lot of energy and France is doing it fine.

[Milton Bradley]

Quote by: gallo Please enlighten us. I know how the spent fuel rods are stored at the South Texas Project (STP) nuclear power station. All of it is still on site under 60 feet of water in the spent fuel pool. As I understand it, that is also the case with the other 65 active power reactors in the U.S. However, I am also aware of the shutdown and razing of at least one old reactor (somewhere in New England, I think). What did they do with the spent fuel? How about government reactors and Navy ships? Where does that spent fuel go? How is it processed?

The Bane of Nuclear Energy: Nuclear Waste - Storage

[gallo]

Quote by: Gods_Mercenary The best way to prevent something like Chernobyl is not to let Russians run your nuclear reactors. especially if it's probaly only going to be mainly Ukranians affected. My understanding is the Chernobyl came about after the operators came up with the brilliant idea of seeing what would happen if the massive amounts of automatic safety mechanismswere disabled.

Nope. That's not what happened. I'll tell you about it below.

I beleive they either are building or have buit a massive underground bunker literally inside a mountain as a repository for spent fuel. It's not the best option, but it sure does provide a lot of energy and France is doing it fine.

So you can't answer any of my questions? I am quite aware of the planned Yucca Mountain disposal site. I thought you had something sort of additional knowledge. So what freedoms were you talking about since you don't seem to know how spent fuel is stored.

As for the first part, here's what happened in brief.

First, it was a change of shift. The oncoming shift had instructions to shut the reactor down for refueling after running some low power tests. They may have been tests of safety equipment, I don't know. Their instructions were to reduce to 5% power. The control rods were lowered into the reactor to a level that they thought would produce 5% power. This was poor training. They didn't know that the process is only possible over a period of hours. The power level reached 5% and kept falling. Reducing the power level so quickly produced what are known as "poisons" that slow the reaction. They don't have a chance to dissipate. To counter act this fall and maintain 5% they began to withdraw the control rods. The reaction continued to fall and they continued to withdraw the control rods. They didn't understand why they could have the control rods at 100% (actually more than that) and a reaction running at less than 5%. I guess it didn't occur to them that it was probably not a good thing. As a result, the reaction went from less than 5% to over 100% in an instant. When the operators reacted and tried to reinsert the control rods (pulled out more than 100%) they jammed and could not be inserted into the reactor. The reactor flashed the coolant to steam, blowing off the top of the containment vessel and exploding the core. Pieces of the graphite moderator were found on the roof of the building. What was left of the fuel melted down. Fire crews arriving to fight the fire were unaware that pieces of the core, both graphite and uranium, were lying around on the ground outside the building. Many of those firement received lethal doses of radiation. Many soldiers who were brought in were ordered to run out onto the roof, to grab two pieces of debris and throw it back into the hole received lethal doses of radiation. Some just got sick.

Poor training and poor equipment design.

By the way, Chernobyl is very close to the boarder with Belarus. Given the way the wind was blowing, they took the greatest dose.

[tivodan1116]

I don't see why there is a "debate" at all about nuclear power...

Take two or three Yucca Mountain-like places in the world, places where no one wants to live anyway, and bury all of the waste there while it cools.

So in exchange for seriously f*cking up three or four already unlivable spots in the world, we all get clean safe power on small footprints (MW of generating power over affected square feet of land - nuclear is much more efficient than say wind or hydro) for the next 150 years or so.

Unless you live on Yucca Mountain, what's the downside?

[Milton Bradley]

Quote by: tivodan1116 I don't see why there is a "debate" at all about nuclear power... Take two or three Yucca Mountain-like places in the world, places where no one wants to live anyway, and bury all of the waste there while it cools. So in exchange for seriously f*cking up three or four already unlivable spots in the world, we all get clean safe power on small footprints (MW of generating power over affected square feet of land - nuclear is much more efficient than say wind or hydro) for the next 150 years or so. Unless you live on Yucca Mountain, what's the downside?

Geolocic activity.


Nobidy can garuntee that the chosen places won't become geologically active in the time required for the rods to lose their radioactive status.

[Gods_Mercenary]

Galo, I wasn't responding to your question directly, you asked Milt, I was throwing sh*t (perhaps literally) out there.

[Gods_Mercenary]

Quote by: Milton Bradley Geolocic activity. Nobidy can garuntee that the chosen places won't become geologically active in the time required for the rods to lose their radioactive status.

Well, unless the mountain literally splits open, it will likely collapse on itself and be automatically capped anyway. Nothing like an entire mountain of solid granite to block radiation.

[tivodan1116]

Quote by: Milton Bradley Geolocic activity. Nobidy can garuntee that the chosen places won't become geologically active in the time required for the rods to lose their radioactive status.

meh... No one can guarantee that a wind turbine won't throw a chunk of ice off in the winter time and come through my window and kill me. No one can guarantee that Hoover dam won't rupture tomorrow and flood half of Nevada. Etc.

If you made an actuarial table using the best scientific data, nuclear power with large repository waste disposal is a good bet.

[Derach]

Nuclear should definitely be part of the equation in a national energy policy. Unfortunately, there is no US energy policy beyond turning your lights off, carpooling, and selling 'energy-star' applainces that use less energy (supposedly).

It is not the only piece of the puzzle, but nuclear certainly can offer more US energy independance and less chance of environmental pollution than fossil fuels, and to eliminate it from the discussion on the basis that it poses too great a risk to the environment is an ignorant and knee-jerk reaction to a more serious crisis than environmental danger (economic stability).

[gallo]

Quote by: Derach It is not the only piece of the puzzle, but nuclear certainly can offer more US energy independance and less chance of environmental pollution than fossil fuels, and to eliminate it from the discussion on the basis that it poses too great a risk to the environment is an ignorant and knee-jerk reaction to a more serious crisis than environmental danger (economic stability).

And it puzzles me as to why the king of knee jerk reactions and scientific illiterate, Dubya, would actually favor the increased development of nuclear power. Maybe because opponents talk so much about environmental pollution and Dubya just automatically takes the opposite side of that debate.

[Domino]

Well, unless the mountain literally splits open, it will likely collapse on itself and be automatically capped anyway. Nothing like an entire mountain of solid granite to block radiation.

If it were granite, that might be swell, but Yucca is a nice, soft, porous rock, and a good crack could take the waste straight to the water table.

That, and it's tricky to design a warning sign that we can be sure will be understood in ten thousand years.

Personally, I have trouble understanding why nuclear waste can't be used for power generation. It sure seems to have a lot of energy to be worthless.

[Gods_Mercenary]

From what I know of nuclear physics, (little to none) the radioactive material has decayed too much for use as fuel, and undergoes changes that make it useless until something is done with it. But don't take my word for it Radioactive waste - Wikipedia, the free encyclopedia

The back end of the nuclear fuel cycle, mostly spent fuel rods, contains fission products that emit beta and gamma radiation, and actinides that emit alpha particles, such as uranium-234, neptunium-237, plutonium-238 and americium-241, and even sometimes some neutron emitters such as californium (Cf). These isotopes are formed in nuclear reactors. It is important to distinguish the processing of uranium to make fuel from the reprocessing of used fuel. Used fuel contains the highly radioactive products of fission (see high level waste below). Many of these are neutron absorbers, called neutron poisons in this context. These eventually build up to a level where they absorb so many neutrons that the chain reaction stops, even with the control rods completely removed. At that point the fuel has to be replaced in the reactor with fresh fuel, even though there is still a substantial quantity of uranium-235 and plutonium present. In the United States, this used fuel is stored, while in countries such as the United Kingdom, France, and Japan, the fuel is reprocessed to remove the fission products, and the fuel can then be re-used. This reprocessing involves handling highly radioactive materials, and the fission products removed from the fuel are a concentrated form of high-level waste as are the chemicals used in the process.

Re-using the waste is an option, but in the end, obviously, you're at the same point, what to do with a bunch of highy deadly stuff.

As to a sign that can be read ten thousand years from now, a good old skull usually scares people. Plus, I'd imagine we'd lock up if we just decided to leave one day, and if we're incapable of locking up, we have bigger problems than worrying about the poor saps 10000 yrs in the future.

[gallo]

Quote by: Domino Personally, I have trouble understanding why nuclear waste can't be used for power generation. It sure seems to have a lot of energy to be worthless.

Sounds good. Have you started working on a way to do that? You see, it is called waste because it can no longer be used to generate power. The level of fission by-products is so high in the fuel that it is no longer possible to achieve a critical mass. Normally, power reactors use enriched uranium as fuel. Natural uranium is about 99.3% U238 and 0.7% U235. For use as a power reactor fuel it is enriched until the U235 is about 3% (I think the average is around 3.3%), the rest still being U238 (about 97%). Spent fuel rods are about 94.3% U238 and about 3.5% fission products (really nasty, highly radioactive, nonfissile stuff). That leaves about 2.2% other stuff. It has 0.81% U235 (the fissile isotope of uranium), 0.51% U236 (also nonfissile), 0.52% Pu239 (fissile), 0.21% Pu240 (fertile), 0.10%Pu241 (fissile), 0.05% Pu242 (nonfissile). If you aren't aware of it, the Pu comes from neutron capture by U238, like this: U238 + n => U239 => (- Beta particle) Np239 => (- Beta particle) Pu239. The other isotopes of Pu are also the result of neutron capture from Pu239. However, Pu239 is also fissile, as is Pu241. In fact, about 1/3 of the total energy output from a nuclear reactor comes from the fission of the Plutonium derived from U238 by neutron capture.

Plutonium for weapons is made in a different type of reactor, known as a fast breeder reactor. Such a reactor may be liquid sodium cooled. In these reactors the fission pile is surrounded by a blanket of uranium oxide (U238). This blanket is outside of the fission reaction but close enough that fast neutrons from the reaction are captured by some of the U238, which then becomes Pu239.

Any way, the "fission product" part of the waste actually would stop the nuclear reaction if it were not taken out of the pile from time to time (about 1/3 of the fuel is replaced at each refueling). There are several products that are produced in pretty standard ratios from fission. They have not been found to be useful, as far as I know.

Depleted uranium comes from the process of enrichment of natural uranium. It has a lower percentage of U235 and therefore a higher percentage of U238. It is less radioactive than natural uranium. It is used for armor piercing tank shells.

[Domino]

Well, I certainly didn't think we could just pour it right back in the reactor.

To say the least, the stuff corrodes the barrels in which it is stored, and most corrosive reactions involve electron exchange, from which we should be able to derive a current, and those are specially made barrels: I'm sure we could come up with something more easily corroded. Of course, for all I know the corrosion is a result of neutron activity, rather than electron exchange. Sadly, I am not a nuclear physicist.

I don't know all relevant details of alpha, beta, or gamma particles, or loose neutrons, but I know that some of those can be converted to light, which could be converted to electricity.

I suppose the electricity obtained in these ways probably sells for less than the cost of developing or producing whatever equipment might be required.

I just hate to see people complain about unharnessed radiation