Monday, December 1, 2008

Greening the Black of Coal

Some how great ideas come across as crazy when you first hear them.  I thought that Jim Holm's idea of recycling coal fired power plants by converting them into nuclear power plants was crazy the first time I encountered it.  I now think it is a terrific idea.   I wrote about the idea in May and it recently bubbled up on the "Energy from Thorium" discussion form.  I usually don't openly discuss ideas that come up on the discussion form, because I think what is said in the discussion form is a private conversation.  But in the case of converting coal fired power plants into LFTR plants, this is an idea that has been floated by Holm, and which I seconded in May.  

Jim and I differ on preferred reactor technology.  Jim thinks in terms of Pebble Bed Reactors, I think in terms of Liquid Fluoride Thorium Reactors.   There are several of big reasons why I think my solution is better, but I will put off talking about that right now.  The big advantage of coal plant conversion is cost savings.  What makes nuclear plants so expensive is that you have to build everything from scratch.  

Big power plants occupy lots of land.   You need to build buildings to house the energy producing technology, whether it is coal fired boilers, or nuclear reactors.  You also need a building to house the energy converting technology, the steam or gas turbines and their attached generators.  Finally you need space to handle the waste from your energy production. In the case of coal fired power plans, waste is coal ash.  In the case of conventional nuclear plants and Pebble Bed Reactors, waste is spent fuel.   In the case of LFTRs it turns out that there is little waste, and perhaps even no waste at all.   At any rate, the LFTR has an extremely modest land requirement, and could be easily accommodated in the areas now dedicated to coal fired power plants.  So there is no further need to purchase new land.  The cost of land purchase is thus saved.

Secondly, many of the buildings of a coal fired power plant can be reused.  For example the turbine hall can be recycled.  There would be more than enough office space, for plant management within existing structures.  Workshops already exist.  Facilities for conducting cooling water and cooling towers are already in place.  Out side the structure the reactor housing structure(s), little new building needs to take place.   There are already facilities for hooking up he electricity to be produced to the grid, thus grid related expenses can be kept to a minimum.    

Finally, the existing steam turbines can be recycled.  Reusing the old turbines represents a considerable cost savings.   In totally new facilities, LFTRs would power closed cycle gas turbines for maximum efficiency, but thorium is very cheap, and the savings in building time and cost would more than outweigh the fuel savings that would come from using the more efficient gas turbines.  

The reactor core would, of course be factory produced and could be transported to the power plant site by train. truck or barge.   Coal fired power plants are located close to water sources for cooling purposes and coal is brought to the plant, usually be train, but in some instances by barges.  The reactors can either be transported as whole units, or as smaller modules that can be quickly assembled once they arrive.  Final onsite assembly should not take more than a few months.   

The reactor can either be housed in an underground structure, that would be designed to prevent the release of radioactive materials in the event of a serious reactor accident.  The underground structure would also protect the reactor from terrorists attacks using truck bombs or large commercial aircraft.  

Not every coal plant site is appropriate for underground reactor housing.  A high underground water table would prevent underground reactor housing.  Above surface housing would be safe provided the housing were designed to prevent the accidental release of nuclear materials, and to be robust enough to withstand the largest conceivable bomb blast, or attacks by Boeing 747 class aircraft.  

How much cost savings would we gain from the recycling coal fired plants approach?  In 2002 Dr. Ralph Moir compared the cost of building a large LFTR type power generating reactor to the cost of building more conventional power sources.  The cost of the equipped reactor was about 37% of the total overnight cost of the nuclear power producing facility.  Factory building the reactor even with final onsite assembly would significantly reduce the cost of the reactor component of the power plant.   This points to a cost savings of at least 50% over conventional reactor construction, and it is not at all unlikely that the overnight cost savings of the coal plant approach could be as much as 75% of the cost of conventional nuclear plants.  

This is not all of the savings however.   Because, conventional nuclear plants take years to build, and reactor owners are forced to borrow large sums of money to pay for that construction, a considerable sum of intreat will have been added to the original cost of the reactor.  Interest is of course charged on the unpaid interest, so  by the time the interest become a major expense in the plant construction costs, even if everything goes right during the construction process. The construction time savings that the conversion via factory produced LFTRs approach would gain. would reduce the final capital cost by somewhere close to 25%.   

Not only would our conversion from coal to nuclear be inexpensive, but it would save the electrical utility an enormous amount of money in fuel costs.  The TVA which restored its Browns Ferry Unit 1 reactor to service after a 20 year shut down,  reported that in its first year the Browns Ferry Unit 1 saved the TVA $800 million.  Much of that $800 million can be attributed to the difference between nuclear fuel costs, and fossil fuel costs.  In terms of fuel savings, the LFTR conversion would begin to pay for itself the day it went into operation, and would probably pay for itself in under 3 years.  From the view point of utility investors, the LFTR conversion would be a terrific investment.  

The LFTR conversion of existing coal plants would be far less expensive undertake than building all new reactors, or building part time renewable generating facilities.   Given the excellent safety potential of the LFTR, its capacity to destroy rather than produce nuclear waste,  and the potential to produce large numbers of LFTR's quickly, and at low cost in factories,  we are looking at a potential means of eliminating the use of coal in the production of American electricity by 2030, and  a very large foreign market for the same technology.  

The LFTR is a green reactor because it can be used to inexpensively convert coal fired power plants to carbon free power producers at a fraction of the cost of new but part time renewable power generating facilities.   Buck for buck, the coal to LFTR power plant conversion is the best possible green investment, an investment that will make post carbon power affordable for Americans.  


David Walters said...

Charles, a good one for the Dailykos.


DV8 2XL said...

It's a great idea, I have followed Coal2nuclear since Holm put the site up, glad to see you and others are coming around to the concept.

But boy oh boy is this going to be a steep hill to climb - the licensing issues alone are staggering. What will be needed is a legislative mandate to make this happen, and I don't see that happening soon in any of the countries that could carry this program out. It's going to take a lot of lobbying even to get the idea considered, and even if it is it's going to draw criticism from the coal-funded antinuclear crowd like flies to honey.

Too bad though, it would solve the problem cheaply and elegantly.

Charles Barton said...

David W, It is already posted.

David Walters said...

Saw it, got the last comment in. Very good discussion. I think even a few converts were made.


Jason Ribeiro said...

The only reservation I would have about this idea is the possible residual radioactivity of the coal ash pond being present. Not that I think it would be hazardous, but if the coal ash did have a greater radioactive signature than say a plant built from scratch, then the environmentalist would point to it and say "it came from the nuclear reactor! See how dangerous nuclear is!!" I've heard many nuclear advocates state that if coal plants had to live up to the same radioactive standards as nuclear plants, they'd be shut down. To that point I wonder what potential problems that might pose.

Charles Barton said...

You have an interesting point Jason.

J said...

However, the radioactive material in coal ash is primarily U, Th & their decay chains. Radioactive leakage from a fission plant would include various fission products & so would be distinguishable from the coal waste.

This wouldn't shut up the fanatics, but it can be pointed out to everyone else to show that the antinuke fanatics are off base.

Jason Ribeiro said...

@J, I agree with you that it wouldn't keep the fanatics quiet and I don't think they care where any of the radiation is emitting from either. I've read some pretty bad stuff about those ash ponds and their contaminates for which these coal plants are pretty much exempt from EPA requirements that would otherwise apply for that type of pollution.

Though I don't know about how radiation standards are measured at existing nuclear plants, I would imagine that ash pond could create a problem when held to the NRC standards. As potentially economical as it may be, the complications this could present as DV8 points out might not make it worth the trouble. There would have to be legislation enacted perhaps to make all kinds of exceptions to the existing rules I'm sure.

However, if there was a set national plan to eliminate coal from power generation entirely, maybe some of these sites would be ideal for a coal to liquids plant using small reactors for process heat as they are phased out. Then again, a whole new set of rules would have to be adopted for that too I'm sure.

Maybe in China this idea would be more feasible. They've got lots of coal plants and the manufacturing capability to start cranking out modular reactors when the time is ready.


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