Practical size limit to nuclear power plant?

[Cliff_J]

Assuming the current anti-nuclear public/political climate remains in place and no new nuclear plant sites would be allowed (nor within a reasonable timeframe) why not just simply increase the existing capacity?

For a hydro plant it makes sense there is only so much water that can be processed and needs to be managed, but nuclear seems like it could be somewhat flexible like the current coal/natural gas combination with the excess above base-load generation from the nuclear plant stored in some other form (aluminum, hydrogren, etc).

Sure the losses may be higher and transmission lines upgraded to 1MV or more, but why not upgrade?

Or is the simple answer the regulations and political climate would never allow it?

 

[Morbius]

Assuming the current anti-nuclear public/political climate remains in place and no new nuclear plant sites would be allowed (nor within a reasonable timeframe) why not just simply increase the existing capacity?

Cliff,
How do you want to increase capacity? Add new plants at the same sites.
That is certainly an option. However, I don't think it buys you much. The only thing
that you could potentially "reuse" from the existing nuclear plant are the site-specific
studies - what's the population around the plant?, ... etc.
However, in the 30 years since the last order for a nuclear plant that was completed,
all the population distributions are out of date. One would have to do new site-specific
studies anyway.
The local residents may have become accustomed to having a nuclear power plant in
their town - but they're not the ones that will be filing lawsuits to block the plant. The
anti-nukes will flock for miles around to protest the plant.
When I was a graduate student at MIT, Boston / Cambridge was the hotbed of activism
against the Seabrook nuclear power plant in New Hampshire. The fact that Seabrook
was many miles away from Cambridge didn't quell any protest.

Dr. Gregory Greenman
Physicist

 

[Cliff_J]

How odd that in a country where the basic premise of majority rule that a loud vocal minority can be so effective.

Yes, I thought maybe it would be a compromise to leverage the specific sites, since they likely have plenty of setback area and (guessing wildly) spare land to build on. As you pointed out, the locals accept it and it likely has some economic benefit to them if there are any metal manufacturing or whatnot still associated with power generation.

Are we (as a country) really that myopic to keep depending on an old infrastructure while other countries progress? Its almost like the high price of oil may indirectly raise the price of goal/natural gas since they are transported with oil fueled machines. And the technology has (at least as reported from Europe) progressed considerably since the last reactor was built here in the US, so the high ROI cost could be much lower than the billions for the old technology, correct?

While on the topic, is this article even 80% correct on its technical information? If so, that sounds like a very promising development too.
http://www.wired.com/wired/archive/12.09/china.html

 

[Astronuc]

Two consortia and some individual utilities are already looking at plans for advanced reactors at current sites.

Nustart Energy (http://www.nustartenergy.com/DisplayArticle.aspx?ID=20050922-1 ) Entergy's Grand Gulf site (Unit 1 operating on a site for at least 2) and TVA's Bellefonte site (two partially complete PWRs ). Entergy has even considered a sister unit at Waterford.

The reactor at Grand Gulf would most likely be an advanced BWR, and the units at Bellefonte and Waterford would likely be advanced PWRs.

I suspect capacity would be on the order of 1000 MWe (1 GWe) each, and possibly 1200-1500 MWe. Single reactor units have not gone beyond 1600 MWe (TVO-3, Areva's EPR), which seems a practical limit.

September 26, 2005

Unistar Nuclear - Constellation Energy, AREVA Inc., and Bechtel Power Corp.

UniStar Nuclear is a venture intended to serve as "a one-stop shop" to design, build, license and operate a fleet of advanced nuclear powerplants. Constellation Energy's role will be to enter joint ventures to develop plants. Bechtel Power Corp.'s role will be to serve as the projects' engineer and constructor. UniStar will promote AREVA's U.S. Evolutionary Power Reactor, an advanced-design 1,600-MW reactor known as the European Pressurized Reactor in Europe. One such reactor is under construction in Finland and the companies are banking on that experience as they eye domestic locations. Constellation is considering its Calvert Cliffs and Nine Mile Point nuclear power stations as viable sites for possible future development.

from http://www.nuclear.com/index-Nuclear_power.html
[Ref: Engineering News-Record, "Bechtel Joins Teams To Develop Next-Generation Nuclear Plants", September 26, 2005, p. 7]

As for the development of nuclear power, after TMI-2's accident, the utilities became weary of new units, and plans for more than 100 other plants were indefinitely deferred or cancelled. Anti-nuclear sentiment was part of that. Although the anti-nuclear movement was very vocal, most of the public was ambivalent or uncertain, and lawmakers (politicians) and regulators imposed more stringent conditions on nuclear power - enough to discourage utilities from new plants.

China may be overly optimistic on their power requirements.

 

[Cliff_J]

Interesting article, and I also found different and much more informative articles on wikipedia that explained the range of existing reactors and the Nuclear Power 2010 and Energy Policy Act of 2005.

http://en.wikipedia.org/wiki/Nuclear_power
http://en.wikipedia.org/wiki/Nuclear_Power_2010_Program

The reason I posted was because of the range of power production from 40MW to 2000MW listed on the following page:
http://en.wikipedia.org/wiki/Nuclear_power_plant

Utopic and over-simplified, if the nuclear plants averaged a small a size (and they don't with 104 plants at 96,000MW for 923MW each according to the article) then increasing their capacity could allow for a direct reduction in coal plants for baseline loads. Which from a pollution standpoint offers the best incentives.

I also didn't realize the economics of the situation were such a complicated matter.

 

[Astronuc]

I am not aware of any single nuclear unit putting out 2000 MWe, which would mean a thermal generation rate of about 6000 MWt. The biggest units in the US generate about 3850 MWt.

The plans for new units are perhaps fluid, but ESBWR seems likely, as Westinghouse's APWR.

Siting is an issue - not only from an evironmental impact, but also with respect to main transmission lines, both geographically and capacity-wise, in relation to the load.

It's not only economics, which includes many factors including reliability, but also safety is a factor.

 

[jdsneeder]

I am not aware of any single nuclear unit putting out 2000 MWe, which would mean a thermal generation rate of about 6000 MWt. The biggest units in the US generate about 3850 MWt.
The plans for new units are perhaps fluid, but ESBWR seems likely, as Westinghouse's APWR.
Siting is an issue - not only from an evironmental impact, but also with respect to main transmission lines, both geographically and capacity-wise, in relation to the load.
It's not only economics, which includes many factors including reliability, but also safety is a factor.

You are correct that no single nuke puts out 2000 MWe, the turbine-generator is currently the limiting component at ~1600 MWe or 1700+ MVA.

There was a plan to place several 1500 MWth nukes on a site and drive one large turbine-generator but it never got very far IIRC.

 

[Astronuc]

Well this confirms it -

Siemens to supply world’s largest steam turbine-generator for the Olkiluoto 3 nuclear power plant

Siemens Power Generation (PG) is to supply the world’s largest steam turbine-generator for the Finnish nuclear power plant Olkiluoto 3. It comprises one high-pressure and three low-pressure turbines, and a generator. "The technology featured in this steam turbine-generator is designed for maximized performance, highest efficiency, highest availability and a long service life," said Dr. Uriel Sharef, member of the Siemens Corporate Executive Committee, during the Corner Stone ceremony in Olkiluoto, Finland, on September 12.

The gigantic piece of equipment, almost 70 meters long and weighing more than 5,000 tons (equivalent to the weight of 3,300 intermediate-class cars), will be built at the Siemens PG manufacturing plant in Muelheim, Germany. The turbine-generator will have a capacity of approximately 1,600 megawatts, which is enough to reliably supply a city with 1.6 million inhabitants and its industry. The shaft of the turbine-generator will rotate at a speed of 1500 revolutions per minute, and the final-stage blades in the low-pressure turbines are almost two-meter-long. These blades have deadweight of 340 kg. The company has already supplied similar turbine-generators to several nuclear power plants around the world.

Almost 2,500 kg of steam at a pressure of 78 bar and a temperature of 293 degrees Celsius flows through the high-pressure turbine cylinder every second. The blades in the four turbine cylinders feature three-dimensional optimization. This ensures that the energy contained in the steam is optimally utilized. The type of blading developed by Siemens PG, with the designation 3DV, already has a proven service record in numerous steam turbines.

The company not only builds steam turbines for nuclear and fossil-fueled power plants. As part of servicing and modernization projects in nuclear power plants, Siemens PG has to date upgraded more than 36 plants with a combined capacity of over 45,000 megawatts in nine countries to the latest state of the art. The company has orders in hand for a further 17 plants with combined capacity of over 19,000 megawatts. In 2004, for example, the existing low-pressure turbines at the Forsmark 3 nuclear power plant in Sweden, which had incurred stress corrosion cracking, were replaced with the Siemens advanced disk design with its proven track record. This measure eliminated the problems in the old machines supplied by a third-party vendor and also uprated the unit by more than 30 megawatts. The investment is thus amortized within a few years not only through the reduced maintenance costs but also through the power uprating.

The contract for turnkey construction of the Olkiluoto 3 nuclear power plant was awarded to the Framatome ANP/Siemens consortium in late 2003 by the Finnish utility Teollisuuden Voima Oy (TVO). Two nuclear power plant units are already in operation at this site. The startup of Olkiluoto 3 is scheduled for 2009.

http://www.powergeneration.siemens.com/en/press/pg200509068e/index.cfm

Siemens was the first to introduced the modern advanced steam turbine design - particularly azimuthally curved blading which increased the steam thermo-fluidmechanical to turbine-mechanical energy conversion.

 

[Astronuc]

There was a plan to place several 1500 MWth nukes on a site and drive one large turbine-generator but it never got very far IIRC.

Yeah, I heard about the modular units - both modular gas and modular fast reactors - which could be combined in pairs and triplets with a common steam header. The benefit there is high station capacity factor because one reactor could be brought down for refueling/maintenance, while the other unit(s) continue to run. This is attractive as long as there is no common mode failure.

On the other hand, one puts all of one's eggs in one basket with respect to the turbogenerator set.


Another thought on the size limitation, at least currently and beyound the T/G set, is the pressure vessel size and power density of the core. The US has essentially lost its capability to produce large PV's or the kind needed for nuclear reactors. Instead these components are made overseas in Japan (Mitsubishi), Italy (Ansaldo), Canada and perhaps a few other places. Possibly Trinity Industries (Texas) might be qualified, but they have not manufactured a PV for a nuclear unit.

Power density in the core is another issue as it relates to the structural integrity of the fuel and structural components. There are still problems with today's core conditions, and some advanced concepts with high temperatures and flows will have additional problems.