Anyone else afraid of nuclear energy?

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Solar panels today are about 10% efficient. If they could be made 20% efficient, then 1/2 as many panels would be needed, and if the price per panel stays the same, then naturally the overall cost for a given installation would go down.

Most homes with a peaked roof only have one part of the roof that is optimally situated for collecting solar power. Otherwise ugly and added cost stands need to be built to orient the panels towards the sun (roughly at perhaps a 30 degree angle from horizontal towards the south). Hipped roofs have an advantage over gable roofs because they have four slanted sides and therefore are better able to present at least one surface to the southern exposure.

Not sure how you get that solar is more efficient than coal. The average natural gas generation station is about 40% efficient, higher is co-generation and other energy recovery tricks are used. I can't think that coal is all that much less efficient than natural gas; after all, it's all BTU's once it's burned. Perhaps more energy is required to mine coal and transport it? Even so, I'd think that coal is at least twice as efficient as current photovoltaic solar panels.

35 years for a lead-acid battery must be some kind of record... My own experience with car batteries is that five years is the average - some last longer, some last shorter. Keeping them charged up all the time helps - I got some floating trickle battery chargers a year or two ago, and my car and bike batteries seem to be lasting much longer as a result. Bike batteries are particularly short lived, with three years more the average. They are generally undersized, and subject to long periods of slow drain (winter/rainy weather), as well as more vibration than the usual car battery. No doubt deep drain (marine type) stationary batteries such as might be used for photovoltaic storage might be longer lasting, with the absence of vibration and the opportunity to protect them from temperature extremes.

Photovoltaic efficiency is also more important in climes where there is more cloud cover than in sunny Australia, I would imagine. Higher efficiency panels can generate electricity even on an overcast day, but I understand that the lower efficiency cheaper panels pretty much go bust when the sun dips behind a cloud.
 
wind power

Hi, all. My uncle in Sieara Vista (spell) has a giant Ge wind turbine to power his entire property. It's about 100 feet tall, but it does the job. You can also get it in custom colors instead of that damn ugly white color....Bill in Az....
 
I think it is mandated here that any subsidized solar system that is connected to the grid must have an automatic cutoff switch that will disconnect it from the grid if there is a grid power failure. The utility is already complaiing about people hooking up emergency generators to their home wiring, without any cutoff from the grid, and when the utility electrical workers try to fix the problem on their end, they risk getting zapped from two directions.

But like I said, earlier, when you connect a solar electric system here to the grid, the meter can spin backwards and the utility acts like the battery, as you put it. The only difference is that the utility keeps any energy over and above what you consume. You don't get that back, not as payment, that is.

I have also seen automatic grid disconnect devices being sold alongside emergency generators. Presumably people use them.

Me, I'd just use the generator to power a the fridge and chest freezer and maybe a few lights/radio/tv/computer etc. And maybe the pond pump so the fish don't all croak. The rest can wait - it would be like camping...
 
The "automatic Disconnect" or transfer switches--in most areas are REQUIRED by the NEC for emergency generators wether for the home or commercial.The only exception is on "load management" generators-at whre I work we have a load management generator.On certain days-(Very hot in summer or cold in winter)The power co. asks us to run the building load and transmitters off the generator.In the Load management mode it is paralled to the power line.If the utility is working on the lines in the area-they ask us NOT to use the gen.Ours can also be operated in the "emergency" mode-isolated from the utility.When it runs in this mode-the "line circuit breaker in the gen system is opened-and the gen breaker closed to feed power.With the line breaker open it cannot feed power back into the line.We follow their requests-even disable the gen so it cannot start if they give us notice they are working on the lines.When they are finished and clear-we restore the gen start.Severasl years ago when Floyd hit this area with its floods-people were using their generators-the utility workers would ask and inspect the householders gen setup-if it was feeding back into the lines-the utility workers had the right to shut the genset off and inform the householder about the incorrect gen connections.Most gen connections complied.Since Floyd-have seen some gensets installed as emergency units-usually "Guardian" brand-they are sold and installed through Home Depot.They have certified electricians install the gensets and transfer switches so they meet codes.the cabinets they are in look like an AC compresser unit.They can generate up to 18Kw of power.Can run most appliances in the house.The gen cannot run electric heat though-but would run a heat pump.
 
Efficiency is not a big issue with solar energy because the energy source is free, unlike a fossil-fuel energy source. Fossil fuel power plants are cheap to build, and can be buit efficiently even at that low cost. 40% efficiency is at the low end. 60% is the high end on most steam based powerplants. Efficiency is a big-time issue with these plants however becasue the fuel must be paid for. The more energy you extract out of the fuel, the more money you can make selling it as electricity.

Internal-combustion fossil fuel power plants, like home backup generators, and portable construction generators are usually only in the 20-25% efficiency range. This is primarly a space issue. If one wanted to make these generators more efficient, they would need to be 4 times bigger and heavier...not to mention out of the price range of the typical homeowner, and out of the skill range required to operate it!

With solar panels however, efficiency is not an issue becaue the energy source if free. The cost to benefit ratio is much higher with a low-efficiency panel. For example, a 50 watt panel that's 10% efficient may cost $200, while a 50 watt panel that's 20% efficient may cost almost $300. If you're doing a whole roof of solar panels in an attempt to make say, 1000 watts, it's going to be much more cost beneficial to buy the lesser efficient panels for the lower price, and just consume more space on the rooftop
 
Actually the Canon solar panels are the least affected by overcast conditions, they are amorphous silicon panels, most other quality full size panels are polycrystalline or monocrystalline. The amorphous Canon panels suffer less output loss from partial shading, overcast, and high temperature - an ironic problem in central Australia is that with most solar panels, the output drops severely in extremely strong sun as the panels heat up too much and the output falls off.

I don't have Canon panels, mine are older Arco and Siemens panels but the high temp factor isn't a problem, I live in the cold, damp, foggy part of Australia, it's not all outback here ya know!
My 35 year old batteries are ex-government, from Telecom Australia. They are Exide 500 amp-hour cells. They were retired from the telephone exchange at twenty years old, I bought them by tender for $22 each (they sold new for $250 at the time) and I have had 15 years solar use from them. They have lost efficiency over time but I treat them well and they are still OK. When we move to the new house I will take all my solar gear except the batteries, they will be recycled and I will buy a new set of Exide Energystore solar batteries.

Safety - the code here demands that the cells must be fully enclosed in a gas-tight enclosure from the room they are in; the enclosure must be vented to outside; the cells must be standing in a containment trays capable of holding all acid in case ALL cells should leak at once; warning signs about explosion risk and chemical burns risk, a supply of clean water to treat any acid spills or injuries, no electrical connections able to be touched/shorted, even low voltage. Plus fuses/breakers, etc. (my current installation complies with almost none of this as it was done before the code came in)

Most crystalline panels on the AU market are 12 to 15% efficient. There are 20% efficient cells available from Sydney University but they are more than twice as expensive as the 15% cells.

The State I live in, Victoria, uses mainly BROWN coal which is horribly dirty and inefficient. It needs to be dried out after having been mined before it can be burnt. One the energy used to mine it and dry it is added in, plus transmission losses, it works out to about 5% efficient. That is, to get 1kwh of heat to your living room, about 20 kwh needs to go into mining, drying, burning the coal and distributing that electricity.

Chris.
 
I can believe that internal combustion generators are only about 25% efficient. However most big fossil fuel power plants here run on natural gas, and these use gas turbines, which are 40% or better efficient (as I understand it). A modern car engine is about 35% efficient, but that is mainly in coverting chemical energy into motion; not chemical energy into electricity.
 
Pennsylvania is a leader in nuclear energy.....

So I just have to chime in. I am interested in nuclear energy and would have gone into it if college went better. My Aunt Edith was a high school science teacher, and one summer she came to our house with a motor home full of material about nuclear power stations. I spent hours reading it when I probably should have played baseball (how boring for me).

Pennsylvania, and Pittsburgh in particular, is a leader in nuclear energy. The first US commercial nuclear power station, The Shippingport Atomic Power Station, started up in 1957 about 30 miles from where I am now typing. This reactor was small and ran well into the 1980's when it was decommissioned and replaced with the two much larger Beaver Valley units, all built by Westinghouse. In Monroeville, Wsstinghouse has its Energy Center and a lot of engineers in our area work there. I read that when Shippingport was decomissioned, workers used Tide to decomtaminate many of the parts.

Pennsylvania now has 9 nuclear reactors, only Illinois has more (11), at one time our state was the leader in the number of nuclear power plants.

Toggle, when you talk about France's nuclear program you might want to go to the web site for Areva, the French reactor maker. They are the company that had the commercials last year with the "Funkytown" song.

This weekend I attended a conference in Harrisburg and could see Three Mile Island in the background, you could see it (the undamaged unit 1) was running all the time. In proportion to the city's size, I believe Harrisburg must be a mostly nuclear-powered city. Pittsburgh is probably nuclear powered when both Beaver Valley units are on.

Gizmo, I think solar energy might work in Austrailia but here in PA it is often, cold, cloudy, miserable, and dark (even thought it was so sunny this weekend I was sunburned!). There is, however, solar panels along the PA Turnpike for electric signs and windmills on the mountaines in Somerset County. Recently a "Combined Cycle Gas Turbine" Generator was built near my sister's house. They don't seem to run that every day though, so I guess it's just when needed.

Now wasn't that interesting about Tide being used to decomtaminate the first nuclear power plant? Nep.

http://www.usareva.com
 
I'm going to resist the temptation to write a long essay here and just say that I'd be glad to have a nuclear reactor next door.

Nuclear is safe and climate-clean, and the new reactor technology is even better. It's also the best foundation for maximizing use of wind and solar on the grid. As oil production peaks out in a few years, we are going to need it even more.

I'm hoping we can get one built in the Central Valley. Out of reach of earthquake faults, and along the main power transmission corridor where an extra gigawatt of power can reach the largest number of users.

BTW, actual construction time is 5 - 7 years for these things. What makes it take longer has nothing to do with safety and everything to do with NIMBYs. So if there is a reactor planned for your area, the thing to do is organize your friends to go to the public hearings and support it strongly, and have good technical arguements to refute all the NIMBY issues. You might be able to make a real difference in helping get it built on-time and on-budget.
 
To make you feel better about nuclear power.

When you look at the track record of nuclear power, in the U.S., how many industries can state that there has never been one death in their operating history. No individual has ever been killed in a commercial nuclear power production plant, due to radiation related death, since their inception in 1956. (one man was killed by a steam pipe break in a turbine building) I know of no industry with such a safety record. Nuclear plants are designed and built from the ground up to mitigate effects, even from catastrohic failure.

As mentioned earlier, Chernobyl, had no containment and used carbon blocks as a moderator. We haven't used such primitive designs in the U.S. since World War II.

Thousands have been killed by dam failures (St. Francis, Teton...)

Coal fired power plants release (much) more radiation to the environment from radon gas, than do nuclear power plants. Cancer and emphysema rates are higher within the vicinity of a fossil fuel plants versus nuclear.

Polyaromatic hydrocarbons, C02, benzopyrenes and flyash particulates foul the environment. Even with scrubbers, emissions are not zero and the waste products from scrubbers, plus hundreds of ton of flyash per year have to be disposed of into the environment.

Nuclear has zero particulate release, zero carbon dioxide and, depending on plant design, approximately 10 times less radiation releases, that coal-fired plants. In many plants it is difficult to measure radiation release as it is below normal background radiation, which interferes with readings.

Alternative energy sources hold promise, but as also mentioned earlier, have their drawbacks.

Windpower is land intensive, ugly, noisy and prone to failure. Solar, on a large scale, is expensive and also land intensive. Production of photovoltaic cells release heavy metals into the environment. Plus you have to live in an area where wind and sun are prevalent enough to make these sources viable.

Geothermal steam is only available in few select areas of the country.

Hydroelectric dams have catastrophic potential for failure and can wreak havoc on aquatiac life and other ecologic ramifications.

There is no one perfect power. Nuclear energy is a source that is environmentally clean, has waste products that can be recycled and used for fuel, is very efficient and can be used in virtually all areas of the country.

GE's new Advanced Boiling Water Reactors (ABWR) rely on natural convection for cooling, should all power be lost to plant. New ceramic uranium fuel rods have higher melting points so they will not be damaged if cooling water is blocked.

As one engineering at GE states, the ABWR is "Walk away safe." He indicated you can have total plant failure with zero cooling water. You can go home and have lunch while you figure out what to do. The ceramic fuel rods will not melt down but quietly wait until cooling is restored.

The single worst nuclear disaster in U.S. history (Three Mile
Island)resulted in no deaths, no injury and no visible damage to the plant (the only damage was to the core inside the reactor vessel). How many industries can state that their single largest disaster in operting history produced no death, no injury and no property damage.

Look in an almanac at deaths in the U.S. in the last forty years and compare nuclear power. Looking at theses figures might leasd one to believe that fertilizer plants, dams and the automobiles are too dangerous for our society to tolerate.

Yet people are afraid of something that has caused zero deaths and injury, and many beieve, has probably saved hundreds of thousands of lives by eliminating pollution to the air and water from radiation, particulates and chemicals that would have been introduced by using fossil fuels to generate the same equivalent amount of electricity.

Barry

Barry Woods
Asst. Chair, Department of Electrical Engineering
Wright State University
Dayton, OH
 
Well yes, but...

Nuclear power plants don't have quite as long a track record as fossil fuel power plants.

Additionally, the potential for a major catastrophe from a nuclear accident is far greater than it would be for any single accident at a conventionally fueled plant. It's all well and good to point to the nuclear power industry's generally good safety record. However, it's a truism that all mechanical things eventually break down, and a nuclear power plant is, among other things, a hugely complex gigantic mechanical thing. There are also issues with safe transport and storage of nuclear fuel and nuclear waste, which to this day are still unresolved.

Finally... last time I looked into this, nuclear power plants have been money losers for utilities. Rate payers have had to pay extra surcharges to help the utilities recover their costs of running and decommissioning these plants. And the plants eventually wear out - the high radiation levels take their toll on components, even highly advanced metal alloys, and you just can't send in a plumber to replace a decomposed cooling line in a highly radioactive core. As a result, these plants can be considered disposable and extremely hazardous waste.
 
I'm also reminded of the fiasco that revolved around the Diablo Canyon Nuclear Power plant in middle California. After years of opposition from a growing environmental movement, the plant went ahead and was installed on a scenic stretch of coastline - sending warm cooling water into a normally icy ocean, raising concerns about temperature effects on the local marine life.

The fiasco was that as construction was well along, it was realized that someone had created a mirror image of the entire cooling system, and that this incorrect version was what was being manufactured and installed. All of it had to be ripped out and restarted from scratch, at a huge cost.

Oh, and I think the plant is waay too close to major fault line. Details, details...

At the same time, I recognize that eventually we'll have little choice but to rely increasingly on nuclear energy to replace fossil fuels and a limited supply of "renewable" energy. I just don't think nuclear is as risk-free as is sometimes painted.
 
But Rich, Diablo Canyon is one of the better looking plants!

You might want to look at the Areva website. They are the French nuclear manufacturer and it is very informative. It is my understanding that some nuclear plants can be "relicensed" to last another 20 years by replacing some of the parts inside. That is what the people in our neighborhood working for Westinghouse tell me.

I would have had a career in nuclear energy myself, inspired by my Aunt Edith the science teacher. But calculus I just didn't know and that drafting made me antsy (just looking at the Hobart hinge drawings was enough to give me a panic attack!).

Areva is building this EPR - The European Pressurized water Reactor in Finland. I believe if they want to build this unit in the United States they better lose the European name. BTW, if it means anything, I live 30 miles from the two Beaver Valley units. (Oh, Oh, maybe I better run).

http://www.areva.com
 
Now, for professor Barry.....

Have you heard about Areva's European Pressurized water Reactor? They are building it in Finland, a cold country that probably needs the energy. Do you have many students in your program? Also, is GE your favoite brand for such plants (I know it is a boiling water reactor, different from Aveva and Westinghouse).

Areva has a film on their website about building the EPR, "50 months in 300 seconds". It has dramatic music, just like a school movie.

BTW, I wonder, is Babcock and Wilcox, the builder of Three Mile Island, still around? If not, won't it be hard to get parts for plants like these?

http://mms//multimedia2.arevagroup.com/framatome/EPR/50mois_300s_eng_2005.wmv
 
Bob,

It's funny. I wound up getting my 4 year college degree in Biochemistry - I had never taken a drafting class, and although I did quite well in the math and physics requirements for my degree, I avoided the engineering fields for somewhat silly reasons.

Fast forward some 30 years, and after getting burned out on a computer career, I went back to school and got three certificates in machining. Part of that requirement was drafting, and I really enjoyed it. It was my first drafting class, ever. I even enjoyed the old-school requirement to spend a couple of weeks just doing lettering. I soon realized what a mistake it had been for me to avoid this part of learning and creating. But, better late than never.

The drawings I posted were jpeg versions of a model I created with a computer program called Solid Works. It's a wonderful application that allows one to build things in 3D first, and then one can create drawings - more or less automatically - from the 3D models. You can do assemblies, check for fits/interferences, etc. A pencil need never touch paper ;-).
 
Like Barry's entry-He has a good point--Nuclear energy has had a good safety record during its history.Like the idea of the Advanced Boiling water reactor boiler--the ceramic fuel rod casings have promise-with newer technology the safety of Nuke power can be improved even more-we just have to do something about the human factor-reactor operation engineers making mistakes.--and some who want to "experiment" with the reactor-remember power reactors ARE NOT research reactors.Its something you don't want to play "Mr Wizard" with like what happened at Cherynobl.I really feel Nuclear power needs another goood look and another chance.We can DO WORSE by not using it.we also have an abundance of nuclear fuel ore in the US.Remember in power generation--try to use the fuels most near and abundant in the area.And yes Bacock & Wilcock is still with us-One of the oldest boiler makers still in use today.I can't remember where-but there was a small B&W boiler built in 1898-A small plant boiler for LP steam heat-was still in use today!!It passed safety tests-was still usable.Its is a book about boilers I have at home somewhere.I thought the 3D drawings of the dishwasher door hinges were beautiful--Machinning is rapidly becoming a lost art in the US-I am glad Sudmaster is trying to preserve it.With the advent of "service Jobs" and industrial arts type jobs on the downslide-I don't like the trend --Machiningis a fascinating feild.Wish I could study it more-the plant where I work has a machine shopand yes has those basic machine tools-lathes and a vertical mill.also have a sheet metal brake and a motorized "kick shear"for cutting sheet metal-have used that a lot.Just need a refrresher on the lathe and mill-last time I used those was in high School metal shop.I also use the "DoAll" metal cutting bandsaw--on high speeds-cuts wood too--and well.It can cut metal to several inches thick.Armor plate fabricators LOVE their DoAlls.Also the "chop type" bandsaws.Very handy.

http://www.babcock.com
 
Dramatic Areva video brings up questions...

Hi all, I just checked the link for the computer animated video but it doesn't seem to work. So go to the main Areva web site and toward the left there is a little search box. Type in "50 months in 300 seconds" and you will be able to play the video, which with it's dramatic music begins a little like "Star Wars". The whole video is animated, and the men they show - and they are all men - look like they all work out, maybe even take a few steroids.

Now for Barry the professor: In the middle of the video, after the reactor is completed but not turned on yet, they show men in a control room with all the controls lit up. But how is that possible if the reactor isn't even on yet? Also they shows a "turbine startup test". But again, how is that possible without steam from the reactor which isn't even fueled yet (that comes next, after "reactor pool filling")?

Toward the end of the video, when the reactor is turned on, the music is heavy drumming like "Stomp". Nep

http://www.areva.com
 
It's true, the US has lost a lot of production machining jobs to Asia and elsewhere. However, the entire field has been chaniging for the past 20 years or so. A lot of old-school machinists couldn't or wouldn't upgrade their skills to include CNC (or computer controlled) machining methods. So they found themselves in dead ends - higher pay but less demand. But ... in the place of large production runs what I've been seeing is more stuff from R&D and "one-offs" for prototypes. These require skill in both traditional machining and CNC. This is stuff that it just wouldn't be economical to send to another country - especially when there may need to be a series of prototypes made with changes between each one as the R&D folks figure out what works best. Then, of course THAT may eventually get sent out to a cheap labor country for mass production.

Also intriguing is the creation of one-off or limited runs of parts to restore old collector machines - whether they be appliances or cars or other nifty devices. With old cars, like some appliances, some parts are simply no longer available, and the ability to create a replacement part as needed can be very handy.
 
Thats the idea of the machine shop at the site where I work-The tools could be used to make transmitter parts that are NLA.Instead we have been contracting machine shops to do some of the parts.We can make the simpler ones.Some of the equipment here was built in the 40'sbut still in use.I am using it right now-all of those pretty tubes inside!!-and pumping out 250Kw of power.
 
Rodney Says:

Can produce as much energy as eight metric tons of coal" - with a Canadian accent. Here's another dramatic nuclear-powered video.

Speaking of machine shops, did you know that up until the 80s the Westinghouse plant in East Pittsburgh was one of the largest machine shops in the world? But forgive me, I didn't even know what a "machine shop" was until I started watching "American Chopper", I just know a lot of our neighbors worked there.

http://www.areva.com/servlet/Conten...orporateFullTemplate&c=Page&cid=1034149659343
 
Fear of the Cloud

I grew up as a "Downwinder" in the shadow of Hanford Nuclear Reactor. I support a generous flow of energy at low cost. We have manipulated so many resources into serving us, it seems odd we pick this one to get freaky about. Does it not bother you that we breathe gas fumes all day, sit under powerlines with leaking ozone, eat convenience food filled with chemicals and substitute man made item for ones provided by nature to nourish our bodies? Where and how could we ever prove which factors are killing us at this point. Me, I have no fear and want to live with out restrictions, warm and with electrical assist. Keep me warm, happy and GLOWING and put some money back in my budget that oil industries are sucking out. We work so hard in the US to be polically correct and save the whales and some cultures around us could care less. I am weary of the burden of always having to be wrong and fix the world for everyone else. I just want easy or Easy, any model.
Kelly
 
Machine shops come in many sizes and shapes. It all depends upon the work they are tasked with doing. A mschine shop devoted to automotive work will look rather different from one designed to produce or repair large electricity generator turbines. However the traditional general purpose machine shop will generally have at least one lathe, one vertical mill, a bandsaw of some kind (I'm partial to having at least one vertical and one horizontal band saw), a drill press, and various bench top tools like arbor presses, bench vices, etc... Modern machine shops often have shoved the manual equipment over to the side, to make way for much larger CNC controlled mills and lathes.

On a recent visit to a local machine tool liquidator, I saw a very unique piece of equipment. It was an older massive Milwaukee tool and die vertical mill with all sorts of extra rotating features - enough to duplicate many of the motions that CNC machines are designed to produce, but all via mechanical controls. It has one glaring problem (besides being rather complex to operate): the largest cutter it can hold is only 5/8" diameter.
 
The shop at where I work is fairly small-almost reminds one of a High School shop.It has a couple of Clausing lathes,and an Index Vertical mill.One of the employees was very good at using the mill.He even has one at his home-he used them to rebuild one of his tractors.Was machining tractor parts.We usually use them to build transmitter parts.And the shop has a Sheet metal shear,a sheet metal brake.And the shop has one "DoAll" vertical bandsaw-love using it-has variable speeds-on high speeds cuts wood very nicely.and two Horizontal band saws-"Chop saws"I have used them to cut many metal parts to size-like when making water level sensor electrodes for the GE transmitters.And oh yes a drill press.We have several drill presses about this plant-one in the electronics shop,another in the machine shop,and another in the garage,and yet a fourth in the building HVAC equipment room.They are vintage Powermatics.Power tool collectors would LOVE this place.Most of the tools are from the early 60's.
 
The Clausing is a good lathe. We have one at our shop where I work, but it's seen a lot of hard use and could use a rebuild. I've heard the Index mills are also quite good. And the Doall verical band saw is a good machine as well.
 
The machine tools here lead a pretty easy life-thats why they have lasted so long-they don't get used every shift like in a factory.At present we don't have enough people to use them all the time!However some of the cutters for the mill are getting dull.-and its belts will need to be replaced at some time.The belts slip when you try to do a heavy cut that it would normally make-that and the dull blades.No one has requesioned any because its used so infrequently.
 
HSS cutters can be resharpened, although it usually alters their diameter. And of course the drive belt can be tightened or replaced - although that would depend on whether or not this is a belt-pulley drive head or a variable speed head.

Tell you what - you pay for shipping and I'll take that troublesome mill off your hands ;-)
 
The mill isn't mine-its the US govts.We don't want to get rid of it-its still useful.Its fine for the occasional jobs it has to do.I would bet the belts could be tensioned-haven't really looked at it to see if they could be adjusted-that me be all it needs.Its the belt drive head.Its much like what you would see on a drill press-the stepped "cone" pulleys and two belts.One from the motor to a center pulley-then another belt from the center pulley to the cutter shaft.The facilities man uses it more than we do-the fellow who does the building maintenance.
 
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
 
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