Energy From Thorium Discussion Forum

Is thorium the energy source we've been waiting for?
It is currently Aug 29, 2014 11:10 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 40 posts ]  Go to page 1, 2, 3  Next
Author Message
PostPosted: Jun 21, 2009 2:08 pm 
Offline

Joined: Jun 17, 2009 9:51 am
Posts: 154
I've read some of the stuff over at Coal2Nuclear.com about converting a coal plant to nuclear by reusing the turbines and generators and using a nuclear reactor to generate steam. I don't know if this is practical, but I like the idea.

I was reading the Progress Energy press releases for the Levy County nuclear plant and it mentioned that when Levy County goes online they plan to close the Crystal River 1 & 2 coal fired plants. I checked and noticed that Crystal River 3 is a nuclear plant, which means the site is already licensed for nuclear power. CR 1&2 were built in the sixties, so I need to see if the plant has had any updates, but it is interesting.

http://en.wikipedia.org/wiki/Crystal_River_Energy_Complex

http://en.wikipedia.org/wiki/Levy_County_Nuclear_Power_Plant


Top
 Profile  
 
PostPosted: Jun 21, 2009 5:25 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 2792
Location: Alabama
LFTRs can reach the same high temperatures that coal plants can reach today--significantly higher, in fact, than light-water reactors can reach. This temperature difference is the reason that you can't simply take a steam turbine for a coal plant and use it in a nuclear plant--it's designed for a temperature range the nuclear (LWR) plant can't reach.

LFTR could, but LFTR can do so much better that you might want to skip the steam turbine altogether and go to a much smaller and more efficient closed-cycle gas turbine. That also opens the doors to economical air-cooling or ocean desalination using waste heat.


Top
 Profile  
 
PostPosted: Jun 21, 2009 5:32 pm 
Offline

Joined: Jan 24, 2007 2:24 pm
Posts: 595
Location: Montreal, Quebec CANADA
Kirk Sorensen wrote:
LFTR could, but LFTR can do so much better that you might want to skip the steam turbine altogether and go to a much smaller and more efficient closed-cycle gas turbine. That also opens the doors to economical air-cooling or ocean desalination using waste heat.


This is true, but the Rankin cycle may be a good first stage to keep switch-over costs under control and to speed the conversion process. This might be particularly important in poorer countries.


Top
 Profile  
 
PostPosted: Jun 22, 2009 1:34 am 
Offline

Joined: Jun 17, 2009 9:51 am
Posts: 154
Would coal plants build in the 60s have used a high temperature cycle?

I found a reference that seems show higher output for these plants than wikipedia listed. Does that imply the plants have been upgraded?

The Interstate Air Quality rule will force Florida utilities to install scrubbers.
Mcilvaine has forecasted individual scrubber start up dates and is revising them continually.
Here is the schedule as of Februrary 2004

2007 Progress Energy Crystal River 4, 739 MW
2008 Progress Energy Crystal River 2, 524 MW
2009 Progress Energy Crystal River 5, 739 MW
2014 Progress Energy Crystal River 1, 44l MW


This schedule is probably wrong, since I found references in the PSC meeting that 4 & 5 could use high sulphur coal, but not 1 & 2.

BTW if you go to http://www.bing.com/maps

and enter
28.95833, -82.6986
Then click on Bird's Eye and then the magnifying glass with the plus sign you can get a pretty good view of the plants.
If you click on E on the compass rose you can also get a Eastern view.


Top
 Profile  
 
PostPosted: Jun 22, 2009 12:43 pm 
Offline

Joined: Aug 29, 2008 4:55 pm
Posts: 656
Location: Idaho Falls, Idaho
I think we are kidding ourselves if we think that coal fired plant owners will willingly shut down a perfectly good plant. We must give them options otherwise they will go on until they wear out perhaps decades longer.


Top
 Profile  
 
PostPosted: Jun 22, 2009 3:09 pm 
Offline

Joined: Jun 17, 2009 9:51 am
Posts: 154
I think what plant owners want is becoming irrelevant. Of course the owners don't want to shut down the plants, they are cash cows. Progress Energy is still dragging their feet on scrubbers on these two plants. You could replace them with a Chernobyl style nuclear plant and improve public safety.You could replace them with an AP1000 with no containment and be orders of magnitude safer.

With the current administration and Congress, the most likely result is that these coal plant will be replaced with a natural gas plant and some token renewables. This will actually be much cleaner, but will still put out megatons of CO2 every year.

In this thread I'm trying to figure out what would make sense in a rational universe. If it actually makes sense to recycle the turbines and generators for a new nuclear plant or if cheaper to build a plant from scratch. In the NRC universe neither option is viable, but in other countries it might work.

In China, coal is becoming a logistical problem. Almost half their rail capacity is being used for hauling coal. If you look at the new nuclear plants they are planning, you notice most of them are going up in the South, which is the furthest from the Northern coal fields. There upgrading a Southern coal plant to nuclear might make sense if it frees up enough rail capacity.


Top
 Profile  
 
PostPosted: Jun 22, 2009 3:29 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 2792
Location: Alabama
I think you need a few things to replace coal with nuclear.

1. A nuclear power plant that doesn't require a 30-mi exclusion zone. If you have this requirement, you won't be able to use existing coal sites.

2. A nuclear power plant that requires very, very little land. This is because most of the land around a coal plant is already taken up with coal piles and ash piles. Even the footprint on an LWR would be far too great for coal plant replacement.

3. A nuclear power plant that can achieve the level of power generation of the coal plant that they replace. No little reactors here--we need 400 to 800 MW at least.

If you can meet these requirements with a nuclear technology, you have a good chance of reusing the transmission infrastructure that is already directed to the coal site, as well as pleasing the local community that you won't be "shutting down the plant and skipping down" and that local jobs will continue.


Top
 Profile  
 
PostPosted: Jun 22, 2009 4:06 pm 
Offline

Joined: Apr 24, 2008 4:54 am
Posts: 625
Location: Columbia, SC
Kirk Sorensen wrote:
I think you need a few things to replace coal with nuclear.

1. A nuclear power plant that doesn't require a 30-mi exclusion zone. If you have this requirement, you won't be able to use existing coal sites.

2. A nuclear power plant that requires very, very little land. This is because most of the land around a coal plant is already taken up with coal piles and ash piles. Even the footprint on an LWR would be far too great for coal plant replacement.

3. A nuclear power plant that can achieve the level of power generation of the coal plant that they replace. No little reactors here--we need 400 to 800 MW at least.

If you can meet these requirements with a nuclear technology, you have a good chance of reusing the transmission infrastructure that is already directed to the coal site, as well as pleasing the local community that you won't be "shutting down the plant and skipping down" and that local jobs will continue.


I know it's a quibble but Exclusion zones are very small(varies by plant), about 1440 yards for late generation designs. Evacuation zones are usually 10 miles. Education zones are 20 miles. These are overlapping zones, not additive.


Top
 Profile  
 
PostPosted: Jun 22, 2009 5:56 pm 
Offline

Joined: Jul 28, 2008 10:44 pm
Posts: 3510
Kirk Sorensen wrote:
I think you need a few things to replace coal with nuclear.

2. A nuclear power plant that requires very, very little land. This is because most of the land around a coal plant is already taken up with coal piles and ash piles. Even the footprint on an LWR would be far too great for coal plant replacement.

This can't be a serious issue. The footprint of the actual buildings isn't very large. Even if you have to move some of the ash pile.
Quote:
3. A nuclear power plant that can achieve the level of power generation of the coal plant that they replace. No little reactors here--we need 400 to 800 MW at least.

Again, I don't see this as a problem at all. Even if the unit size is 100MWe you could gang several together.
Quote:
If you can meet these requirements with a nuclear technology, you have a good chance of reusing the transmission infrastructure that is already directed to the coal site, as well as pleasing the local community that you won't be "shutting down the plant and skipping down" and that local jobs will continue.

One concern Jaro brought out was bringing the 650C CO2 (or He) through the containment walls. If we can't do this then we can't reuse the turbines.

How much residual value do you think there is in the old turbines? Presumably, we are going to replace the oldest coal plants first and these would not be the super-critical ones so I'm thinking we have a significant temperature mismatch. I suppose we could have a poor heat exchanger and simply accept the lower efficiency initially but I wonder if the economics really favor using the old turbine at 35% efficiency over replacing it and getting 45% efficiency. I would have guessed that it would be worth the investment in the turbines to get the higher efficiency (unless we haven't invented the turbine yet).

Clearly we can reuse the transmission lines, physical space, and likely friendly local reaction to replacing an aging coal plant (that might get shutdown on them) with a nuclear plant that will be in place for 60 years. I'm just not sold on reusing the turbines.


Top
 Profile  
 
PostPosted: Jun 22, 2009 6:24 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 2792
Location: Alabama
Lars wrote:
How much residual value do you think there is in the old turbines?


Not much. I don't think we can reuse the turbines. The transmission infrastructure is the real value and that's the part we can easily reuse.


Top
 Profile  
 
PostPosted: Jun 22, 2009 7:53 pm 
Offline
User avatar

Joined: Nov 30, 2006 9:18 pm
Posts: 2209
Location: Montreal
Lars wrote:
How much residual value do you think there is in the old turbines? Presumably, we are going to replace the oldest coal plants first and these would not be the super-critical ones so I'm thinking we have a significant temperature mismatch.

Not if you run a small Brayton turbine as a topping cycle, with heat rejection driving the old steam plant....


Top
 Profile  
 
PostPosted: Jun 22, 2009 9:01 pm 
Offline

Joined: Jan 24, 2007 2:24 pm
Posts: 595
Location: Montreal, Quebec CANADA
Lars wrote:
How much residual value do you think there is in the old turbines?


Probably close to zero. Recertification for the new steam generator along with whatever mods were needed for the conversion would probably drive the cost up where it wouldn't be worth it.

Kirk is right, the real value is in the transmission infrastructure.


Top
 Profile  
 
PostPosted: Jun 22, 2009 9:39 pm 
Offline
User avatar

Joined: Sep 10, 2008 7:40 pm
Posts: 373
Somewhere in this forum someone said that half the cost of a nuclear power plant was in the thermal/electrical energy conversion systems. Is this really true? Maybe for a PWR with a steam generator heat exchanger? For a BWR? And how does this cost compare to a compact supercritical CO2 turbine & generator?


Top
 Profile  
 
PostPosted: Jun 22, 2009 10:11 pm 
Offline

Joined: Jun 17, 2009 9:51 am
Posts: 154
Kirk, sorry if you thought I was being serious about building a reactor without a containment. I was just making the point that a coal plant without scrubbers will kill more people over it's operating life than Chernobyl did. Has anyone else ever read "The Health Hazards of NOT Going Nuclear" by Dr. Petr Beckmann? He spends a lot of time talking about coal.

The point about the transmission infrastructure is pretty good. Progress Energy is spending 3 billion for running the HT lines to Levy County.

From what you guys are saying, it sounds like the only way to make the idea work, even in China, is if the reactor was actually designed for a drop in replacement for a coal plant. Keep in mind that China's coal plants are a lot newer than ours.


Top
 Profile  
 
PostPosted: Jun 22, 2009 11:15 pm 
Offline

Joined: Mar 07, 2007 11:02 am
Posts: 1063
Location: Ottawa
robert.hargraves wrote:
Somewhere in this forum someone said that half the cost of a nuclear power plant was in the thermal/electrical energy conversion systems. Is this really true? Maybe for a PWR with a steam generator heat exchanger? For a BWR? And how does this cost compare to a compact supercritical CO2 turbine & generator?


I know I`ve used that quote as I`ve heard that rough estimate from many in the industry and is for the "steam island" outside containment (i.e. doesn`t include the PWR steam generator cost). Large steam turbines and all that goes with them can be extremely expensive especially for PWR, BWR and CANDUs that need to live with saturated steam with little or no superheat. Gas turbines should be much cheaper but they can have huge development costs to match your particular need (fine once you are selling dozens). I certainly wouldn`t be too quick to rule out some big savings from reusing existing supercritical steam turbines at coal plants (which we`ve discussed in another thread, not sure where though). It all comes down to the price of coal versus reactor costs, if coal prices go way up as some expect, even new coal plants might be eager to switch over.

I think it`s been already mentioned but just a reminder that you can`t do this coal steam turbine recycling at all with a water cooled reactor (not hot enough). Only gas cooled pebble beds are typically suggested and LFTRs would certainly also fit the temperature ranges nicely.

David L.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 40 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: jagdish and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group