Anyone else afraid of nuclear energy?

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Forgive my delay in response to your questions Bob, et. al., I hadn't been following up on the thread.

Tolivac answered your questions about Babcock-Wilcox. They are still active as a boiler making company and also produce steam generators for PWR (pressurized Water Reactors).

They still provide some support for the nuclear industry, but no longer actively design or build nuclear power plants. They were the number three company in the U.S. building nuclear power plants (behind Westinghouse and GE.)

As far as the start-up test on the turbines, without the reactor being critical and producing steam...plants generally have small auxillary boilers, that are coal or gas fired. These are used to provide steam for the start up testing for the turbines and generators. (They want to make sure everything is functioning before the reactor goes live, or "critical".

Even though the reactor itself has not gone critical, there are many other systems in the plant that are live. Radiation/safety monitoring systems, turbine systems, generator systems. systems to monitor the power grid the plants feeds into, etc.

Long before the reactor is brought on line, the control room will be lit up like a Christmas tree during the preliminary, start up and test phases.

In answer to your question about GE BWR's. Yes, personally I like the GE BWR over Westinghouse's and Babcock-Wilcox PWR's.

In the BWR systems steam is taken directly from the reactor core and delivered to the turbines.

In the PWR you have an extra loop. Steam from the reactor core goes to a steam generator, which you might compare to a radiator in a car, and heats water in a secondary loop and converts it to steam. The steam from the secondary loop then turns the turbines.

The GE BWR is simpler in concept and MUCH easier to operate, as you have less systems to monitor and control. They are very reliable.

The steam temperture and pressures are less than in a PWR and therefore less likely to cause a pipe rupture or damage.

The disadvantage is that the steam coming our of the reactor core is slightly radioactive, so the turbines need to be in a shielded building.

The Westinghouse/Babcock units have turbines in regular buildings as the steam, (theoretically) has never been in the reactor core and is not radioactive.

However, in reality, the thousands of small thin tubes in the steam generators many times develop leaks and contaminate the turbines anyway. Steam generators are the most trouble-prone part of a nuclear plant. Shutting down a steam generator to repair it is costly. Most PWR reactors have two steam generators. One can be shut down for repairs while the other can continue to operate.

Temperature and pressures are higher in the PWR, so you have a slightly higher operating efficiency.

The GE BWR's, though, have a slightly higher operating capacity factor due to greater reliability and less down time Usually in the high ninety percentiles. The GE Limerick power plant in Pensylvania has been operating in excess of designed capacity and has been given a 100.6% operating capacity rating.

PWR's usually are in the low to mid nineties in capacity factor.

Both BWR and PWR have operating capacity factors greater than fossil fired plants, which average 71% capacity factor or less.

That is why electricity from nuclear power plants (both BWR and PWR) cost so much less than that from oil, gas or coal.

Barry
 
Thank you, Professor Woods...

I have recieved more answers from you than from most of my college professors. Anyway, I have to ask, isn't a nuclear power plant still more expensive than a fossil fuel one, what with the stainless steel, more parts and wires, and sooooooo much concrete?

Someone I knew was a steamfitter (different from a plumber?) who back in 1987/8 worked on the then new Beaver Valley 2 plant. This was also when they were taking Shippingport apart. When his union offered him the Shippingport job he turned it down because "I just got married and we didn't have kids yet". Did he have anything to worry about?

He also told me that nuclear plants have more workers than coal plants, but I can't imagine why? Since it's all machinery, I would think you just need people to take care of it but most of the machinery is automatic? Also, when a reactor is running is anyone in the containment building? I understand that when the accident at TMI took place a lot of steam was released that would have turned the containment building into an autoclave sterilizer. Anyone inside would have been pressure cooked!

Have you heard much about Areva, with the catchy commercials they had last summer? I could imagine "50 months in 300 seconds" being shown in the college auditorium.

If you go to GE's website they don't talk much about their nuclear reactor division at all. Maybe they should look at Areva. Nep.
 
It's too bad they didn't have someone in the containment building, because then they would have noticed that the water level had dropped so far the core was getting exposed.

But I don't think anyone is routinely allowed in there when the reactor is "live", unless it's some sort of emergency.
 
Hi Bob, et.al.,

Once again, I apologize for the delay in response.

Yes, workers can, and occasionally do, enter the containment during reactor operations. As you mentioned, everything is automated, so there is normally no need unless there is a repair to be made. A "biologic shield" surrounding the reactor protects the workers from stray neutrons. The containment building is huge in comparison to the reactor core, any leak would take a long time to pressurize and heat the inside of the containment to a lethal level.

Any slight leak or increase in radiation is designed to set off internal alarms so workers can exit the containment in a timely fashion.

Beyond the reactor itself, a nuclear plant is identical to any other power plant. They use the same turbines, genertors, transformers, etc. So in this part of the plant, you have approximately the equivalent number of employees as in a conventional fossil fueled plant.

The reactor and associated equipment does require more personnel than fossil fueled plants. You have reactor operations, monitoring and evnronmental health personnel present.

The capital cost for a nuclear plant are higher than fossil fueled plants. However, the cost of the fuel is so low and the plant efficiency is so high that your actual cost per kiolowatt hour is lower than coal, oil or gas.

Cost are also saved in refueling. A coal plant has tons of coal going into the boiler, continually, every day. And you also have to continually remove and dispose of the ash and flyash.

A nuclear power plant can run up to two years on one load of fuel. (Most plants will change 50% of the fuel rods yearly, for efficiency. However, the reactor will run quite well up to the full two years with no fuel being brought onsite, as could happen during a war, etc.)

As for your friends concern about radiation, when a plant is decommisioned, such as Shippingport, the biggest risk of radiation exposure is from handling the actual reactor core itself. Because of this, workers wear protective suits, if they will be near core materials, and virtually all work is done with remote control devices.

There is some radiation exposure, but the federal government limits what a worker can be exposed to. If they approach this limit, they are not permitted back on the site. The limit is set at point where there have been no observable biologic reactions.

A greater concern of genetic effects occurs in pregnant woman, as babies developing in the womb, are more susceptible to radiation. A pregnant woman would in reality not be likely to be disassembling a reactor anyway, but in general, they want to stay away from excess radiation. This is why they no longer X-ray babies in the womb, but use ultrasound.

And...Sudsmaster was joking, of course, but you could not see the water level in the reactor core, even if you were standing next to it. The core is four to six inches of solid high carbon steel. All water levels are measured with instrumentation.

Barry
 
Nuclear plant turbines are different than fossil fueled ones-the Nuclear plants don't ahve the same steam pressures that fossil plants have-fossil boilers run at higher temps and pressures-also have reheat-that is the steam that is passed thru the hi pressure turbine is sent back to the boiler for "reheat" and then to the medium pressure turbine-than to the low pressure turbine.After that the water is condesned and sent back to the hi temp part of the boiler again.Nuclear plants don't ahve reheat-their turbines are two stage instead of three stage like fossil turbines would be.also the speeds of a nuclear turbine are diffrent-1800 rpm instead of 3600 for fossil turbines.the power outputs of them are the same.
 
Good article posted by Sudsmaster. I had been exposed to this article previously and found it does a factual job of demonstrating economic advantages of nuclear power over fossil fuelsand doing it without a lot of hype. Other Google searches will yield many additional supporting articles like this.

Note 10 out of 12 countries, per data presented in the article, generate electricity from nuclear power at a cost below that of coal. This data is based on a load capacity of 85% from their slightly dated 2003 data. This had risen to 89.6 in 2005 and is continuing to rise in 2006. This is an average, with some below and some above, with many nuclear now operating in the mid-to high 90 percentiles, with one (Limerick, as mentioned previously) operating beyond design capacity at 100.6%)

In many areas of the U.S., depending on coal costs in that area, nuclear plants are now producing electricity at a cost below that of coal-fired power plants.

Due to reliability records and material degradation falling below expectations, the NRC is now reviewing licenses for current nuclear power plants to operate past the original 40 year limit. Extension of up to twenty years may be given for a total 60 year plant operating life.

This will further reduce operating cost by spreading the initial capital outlay over a longer period of time.

The new advanced reactor designs (ABWR and APWR's) are expected to have operating plant lives of 80 years.

Costs for electricity from nuclear generation are dropping. Cost from fossil-fuel generation are increasing. These cost increase, passed on to the consumer, are not only from the cost of the fuel itself, but increasing standards of air quality mandated by the EPA are requiring plants be retro-fitted with pollution mitigation devices.

This is money well spent; however. Even though fossil plants can never compete with the zero particulate and zero greenhouse gas emissions of nuclear plants, they can be made a lot cleaner than they presently are.

Being an environmentalist, I would rather pay a little more on my electric bill each month to pay for scrubbers on a fossil -fueled plant and have a reduced worry about the witch's brew of chemicals (benzo-pyrene, poly aromatic hydrocarbons), radiation (radon gas inherent in coal) greenhouse gases (CO2) and particulates (flyash)that are released from a coal-fired plant.

The positive economics of nuclear power are well noted among the critics and noncritics and are really no longer an issue. They are still very interesting to study, however.

Not all costs are monetary costs.

The potential cost to society in general, and to the individual, of fossil fuel electrical generation include global warming, smog, increase lung cancer and luekemia (radiation from radon exposure) and well as acidification of lakes (with ensuing killing of aquatic life, and defoliation of trees caused sulfur dioxide combining with moisture in the air and forming acid rain. These are not potential dangers but actual dangers that are occuring right now and are directly traceable to their source of fossil fuel combustion.

Tolivac mentioned the differences in turbines between nuclear plants and fossil fueled (conventional combustion) plants. This may have been in regard to my statement that from the steam pipes on, electricity from a nuclear plant and a fossil fueled plant are generated identically.

Many people think nuclear plants convert atoms directly into electricity (like a giant nuclear fuel cell). They are often surprised to find that steam from the reactor (or in the case of a PWR, the heat exchanger) turns the blades in a turbine which turns a generator just as steam from a boiler, in a conventional fossil fuel plant, turns the blades in a turbine which turns the generator. So the point is that the turbines and the generators are not nuclear devices, and are termed "conventional" for the benefit of the layperson.

It's amazing the misconceptions many have about nuclear power.
We have 103 operating nuclear power plants in the United States and 20% of our electricity comes from nuclear. It's the number two source of power generation in the U.S. behind coal, so you would certainly think we would educate our students about it.

Even college students often have very little idea of how nuclear power operates. I have found, much to my amazement, that they are very open and seem to enjoy learning about it.

When I do find the occasional one who has a fear of nuclear power, I first try to find out why.

Normally, they can't tell me why, exactly, or can't verbalize it. So then I say let's start with you telling me how electricity is generated in a nuclear power plant. Once they fail at this or flounder there way through it, I then ask them to at least point out to me the specific part of the nuclear cycle that they are scares them. By this time they start to smile and get my drift that they are afraid of something they don't know anything about.

When they can tell me something about nuclear power that bothers them, I can ususally trace it back to a science fiction movie, the Simpsons TV cartoon, or something as simple as a mushroom cloud drawn on the placard of a protester.
(In the case of the latter, which actually happened, the student was delighted and relieved to know that a nuclear plant could never explode like a bomb, and could not be made to even if someone wanted, as it only contains uranium enriched to 2-3%, a nuclear bomb requires 100% enriched uranium. 97% of the material needed for a nuclear explosion is absent from a power reactor.)

There has long been speculation that the roots of the anti-nuclear (nuclear power, not nuclear weapons) movement in the late 1960's were begun by the petroleum industry.

In the late 1950's and the 1960's nuclear power plants were the hot item and orders from utilities companies were coming in faster than plants could be built. This was just at the time that the oil industry was trying to convice utilities to switch from coal to oil fired power generation. They lost a lot of business, and correspondingly money, when power companies opted to switch to nuclear over oil.

In response to this, the petroleum companies countered by providing funding to Sierra Club to initiate and promote anti-nuclear activities as well as distribute anti-nuclear materials among the public.

This is somewhat unsubstantiated and, I hope, not true. I would be very dissapointed in the oil industry if it were true.
 
The French ?

If you look to the French as an example, and I don't often like to, but their nuclear program is really a very good model.
When they were first starting their program they selected One Design! and was used all over the nation. This substantially lowered costs for constructing the plants and maintenance and repair cost.
Unlike The U.S. who let everyone and there Aunt design what ever they wanted. Consequently there are no two nuclear power plants in this country exactly the same. Therefore when a part wears out there is no off the shelf replacement. The part has to be fabricated which is very expensive. Also some are very efficient and reliable and others are well….Whoops! A few might get it?

Lokringbob
 
Actually bomb grade uranium need only be enriched about 80%, if I'm not mistaken, but granted it's still far beyond what would normally be used in a uranium powered power plant.

A different matter however are the nuclear plants that take in uranium and convert it to plutonium (breeder reactors). That is much more of a security (and possibly health also) issue.

I recall the days when magazines like Popular Science were printing stories about atomic powered automobiles and airplanes. Thankfully nobody really tried to put those ideas into action.
 
a ton is a tonne, just about.

.......can produce as much energy as eight metric tons of coal.

BTW a metric tonne is 1,000 Kg,
(or 2,204.5 pounds. It is frequently rounded to 2,205 pounds.)

A US /Imperial ton is 2,000 pounds.

When I was with a steel trading co. we used:
*Tonne* for metric ton.
*Ton* for US ton.
 
The French are Areva!

LikringBob, the Rrench company you refer to is Areva, the one I like with the catchy "Funkytown" commercials and the film with the "Star Wars" music. They have one problem: If they want to sell their new EPR, they better change the name, I don't think an American utility will buy a EUROPEAN Pressurized water Reactor!

Toggle, Rodney told me about the "Eight tonnes of coal" He was in Areva's uranium mine in Canada, so I guess that would be a metric tonne.

And Dr. Woods, Areva just announced that they laid the bottom plate of their new EPR in Finland. They must be running a little behind, according to the timeline in their film they should be working on the walls by now. Now, this brings up something about French and college classes.

As you know from Areva's energy quiz, our family does well until they ask how often we bathe and shower. The only way to do better on the quiz is to shower less often. I figure they ask this because people in France are known to not shower - and everyone knows it!

Now, Dr. Woods I have encountered this problem in college: I have to take a difficult class and am trying to listen and pay attention to the professor. Meanwhile, someone in front of me has not bathed or showered and everyone in back knows and it is really hard to learn anything. Has this ever happned in your classes? U suspect it is worse now, with the "Goth" and "Grunge" culture. If it means people will have better hygiene we need nuclear energy!

They say that this bottom liner is 50 meters in diameter so I figure it like a frying pan the size of a our high school football stadium. I guess all the other walls will be supported by this "pan".

Orano | Acteur majeur de l'énergie et du combustible nucléaire

Groupe industriel international de référence, Orano propose des produits et services à forte valeur ajoutée sur tout le cycle du combustible nucléaire.
www.areva.com www.areva.com
 
Hi Bob,

I've had a lot of things happen in my classes, but that's not one of them. Or a least the air from the ventilation system was not moving the aroma in my direction!

People may be dressing sloppily, but at least at my school, they are (fortunately) still bathing. But, yes, that would be very disconcerting if you are trying to take notes and concentrate.

(Strategically placing a can of deodrant on the offending student's seat, before they come into the class, might give them a gentle hint.)

Take care,
Barry
 
Dr. Woods, did you see how they blew up a cooling tower for a power station in Oregon? The article says that the Trojan power plant had a lot of problems and did not run much. I heard that the Rancho Seco plant in California was like that too. Why is it the plants you refer to are so reliable and these plants didn't work well at all? Also, I have read that todays nuclear plants are almost one of a kind. But with only a few manufacturers I can't believe they have no common parts at all? Which brings up, rather than build a whole new building, would it just be possible to change the parts out?

Meanwhile, in Oregon, they say soon the containment building will be demolished but I can't imagine how. If it is made out of 4 foot thick concrete and can withstand a plane or missle how could it ever be blown up? Or will they just plant bushes and try to hide it?

Then I also read that while most power stations have the pool where they keep the bad fuel rods in the ground, like an in-ground swimming pool, some models have it above ground and vulnerable to a leak. Think maybe they should get an in-ground pool?

Oh, duck and run, I ask too many questions! Nep
 
No such thing as too many questions.

Trojan had two major problems. It was built in too close proximity to some earthquake faults that were not known in 1970, when the plant was begun.

The other problem was with the steam generators.

If you recall, Westinghouse only built PWR (pressurized water reactors). These have steam generators to transmit heat from the reactor to a secondary loop, and this second loop provides steam for the turbines.

In theory, the steam going into the turbines is never radioactive as it was never in the reactor vessel itself.

In reality, the thin heat exchanger tubes in the steam generator often leak, and tend to be the single biggest problem in a PWR. You don't want radioactive steam in a unshielded turbine building so you must shut down the steam generator and make repairs. (Nuclear plant operators are very proud of their unequaled power plant capacity (far exceeding all fossil fuel power plants) and they don't like to cut plant output down, or even worse shut a plant down, while repairs are being done.)

In the case of Trojan, the steam generators had developed some big leaks and had a history of continual small ones.

The operators were originally going to replace the generators, but opted not to go that root and just shut the plant down.

This is not to say PWR are inherently bad, because they aren't. Many run flawlessly, but you do have extra complexity, and the more complex a system, the more opportunity for problems to develop. THe U.S. Navy does just fine with both BWR and PWR on their subs, but the commercial power industry has faired a little better with the BWRs.

That's why I have always been a fan of the GE-BWR, simpler to operate, maintain and build. You know from day one that your steam will be slightly radioactive, so you just shield your turbine building when you build the plant.

Plans are to take down the Trojan containment building, in a couple of years (I believe it's slated for 2008). The NRC requires all containments, as you mentioned, to withstand a DIRECT missle strike, so it won't be easy.

However, with the strategic placement of explosives (and great effort) they should be able to make it come down. You can move mountains with explosives, if you do it right.

Spent rod pools generally don't leak, but if one does, it's easier to find and repair the leak for above-ground storage.

Barry
 
The 4 foot thick concrete can be cut with a diamond chain saw-not too much like its wood cutting cousin-diamond impregnated teeth on the chain instead of the wood cutting ones-and water cooling to cool the chain,cutters and bar.Also the cutting chain can be looped over the item being cut and turned by an electric motor,hydraulic motor or gas motor-its also water cooled and the diamond cutting "teeth" are larger.A company in Australia makes these chains and the machines to turn them.They were originally designed for cutting large rock sections in rock quarries.A contractor out here has one for cutting thru thick concrete walls or cutting away unneeded concrete stairs.
On the breeders-these DO NOT make Plutonium that is bomb grade-it is reactor grade nuclear fuel.These reactors should be used here-they can generate steam energy for turbines as well as being used to "recycle" depleted nuclear fission fuel rods.The process operates at higher temps than a standard fission reactor-they can use fossil turbines.Also fossil turnbines turn at 3600RPM instead of 1800 for fission turnbines.The 3600RPM generator is slightly more efficient.less electrical loss in the windings and lower exciter current.
 
Although the capability for cutting through the concrete and the steel liner of this thickness exists, the shear size of the containment will probably lead them to implode it, as they did with the cooling towers. Timewise and costwise, controlled implosions (as used to take down skyscrapers)are often considered more practical for immense structures such as this.

As far as standardization of nuclear plants (as mentioned by Neptune Bob), yes, this is something that has long been desired by the industry. The ABWR (Advanced Boiling Water) and the APWR (Advanced Pressured Water Reactor)are simpler by design and have more interchangeable parts and standardization within design.

This will help to make a very competitive form of power generation into an extremly competitive form by cutting down NRC licensing time, construction time, and repair time.

Whether or not these standardardizations will cross propietary boundaries...probably not.

That is, GE is not going to make their reactors standardized with Westinghouse(BNFL), as they are competitors, and they use quite different systems. Unless the government dictates only one design (BWR or PWR) is to be used in the U.S., we may have standardization within a company's line of reactors, but not entirely from company to company.

GE has always had some standardization within their model lines. That is, a Mark I containment is nearly the same as another Mark I anywhere in the world. A Mark III is basically the same as any other Mark III. The same for the reactor models themself, BWR2, BWR3, etc.

However, a Mark I and Mark III, etc. are quite different from each other (Just as an automobile manufacturer's design of one model line may be quite different from another of their model lines.)

Even within models though, legislation changes, last minute modifications dictated by the NRC, and changes requested by the utility/owner can cause significant differences from plant to plant, even for the same model line.

These plant to plant differences are to be greatly reduced, if not nearly eliminated, with standardization in the Advanced Reactor lines.


Standarization is a win-win situation for everyone, licensing time is cut down, construction time is lessened with greatly reduced costs and operator training does not have to account for plant to plant differences.

Barry
 
Oh, oh, I'm going to brag about Pennsylvana...

Dr. Woods, I notice you are in Dayton. My niece goes to the University of Dayton (is that near your school?). Anyway I looked at the NEI web site and guess what - Pennsylvania has 9 nuclear power stations and Ohio only has 2, none of them near Dayton. Why is that? Besides, how can your school have a nuclear engineering program when there is no plant nearby to tour? I mean, what is the origin for such a major in your area? When I was in high school many years ago our teacher said that Pennsylvania had the most nuclear reactors I don't know if that is still true.

Meanwhile, nuclear plants are near Pittsburgh, Harrisburg, and Philadelphia (Limerick, the one you like). When these units are on, do we live in mostly nuclear-powered cities? Sorry, I don't think Dayton is.

Oh, and I read more bad news, one of Ohio's reactors has been a "bad boy" (that is, if nuclear reactors have genders). The Davis-Besse plant developed a hole in it's lid that could have created a bad leak (its not GE). Davis Besse (where does it get a name like that? Almost as bad a name as Trojan) may need a lot of parts. They are gettng a new reactor head - from Areva.

As for exploding the containment building I thought it might be too hard because the walls are soooooo thick. I remember when the imploded Three Rivers Stadium. It took 6 months of preparation from the last event (an N'Sync concert) to the implosion. But as I remember, the walls in the stands were about 6 inches, not four feet.

I know you like GE but there probably will never be a GE plant in our area. George Westinghouse dnd Thomas Edison were rivals, this is Westinghouse territory, and I never even saw a GE clothes washer until my 20s. Oh, and the first Shippingport plant was owned by Duquesne Light - founded by George.

Thank you and don't mean to be a pest, Nep.
 

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