The Keys to Lowering Reactor Cost: Research & Development

I have added a number of revisions to the original 2008 post that better reflect my current understanding.

The "Keys" series has pointed to two Generation IV reactor designs as having potential for lowering reactor costs. They are the Pebble Bed Reactor and the Liquid Fluoride Reactor. Of the two the LFTR has a far superior potential for lowering reactor costs and for demishing or eliminating the problem of nuclear waste. The LFTR also has a potential safety feature would revolutionize nuclear safety because radioactive fission products are bonded to fluoride or are dissolved in the liquid fluoride salt mixture. It is possible to extract the fission products from the liquid fluoride salt mixture either by a continuous processing of the salts, or by a periodic batch processing. From the viewpoint of nuclear safety, continuous salt processing holds a decided advantage. If fission products were to be stripped out of the reactor on an ongoing bases, there would be a number of advantages. This possibility was actually explored at ORNL in the MSBR days. If fission products were to be stripped out of the reactor on an ongoing bases, there would be a number of advantages. This possibility was actually explored at ORNL in the MSBR days. (see ORNL-TM-3579: Design and Cost Study of a Fluorination-Reductive Extraction-Metal Transfer Processing Plant for the MSBR) The ORNL study estimated the cost of of a 3 day turn around processing plant for a 1000 MW LFTR would be $25,000,000. This facility would have similar processing capacity to that required for a 6 hour turn around on a 100 MWe LFTR. In 2008 terms the cost would be something over $100,000,000. However it appears that extracting FPs were only a small part of the 1972 fuel processing system's aim, and the extraction of many FPs was expected to take place within a 2.4 hour time frame. Hence a processing plant designed to remove FPs from a 100 MW reactor might cost farless than $100,000,000.

Uri Gat, an ORNL reactor scientist advocated the continuous extraction of FRs as a major safety measure made possible by the LFTR. Gat noted:

"There are two major possible events that can lead to a dispersal of radioactivity from a nuclear reactor and become a health hazard. The first is an uncontrolled reactivity increase that will yield a power burst which would damage the reactor and disburse the radioactive fission products inventory. The other event could be failure to remove the decay heat of the fission products resulting in overheating and dispersal of inventory. The so-called source term - the likelihood for a quantified release of radioactivity -is the product of the inventory of fission products and the driving force or the energy to disperse this inventory."

The first event was basically preventable by use of fluid fuel, As the chain reaction increased in the reactor core, heat levels would rise, fluid fluoride salts expand as they are heated, the expanded salts are pushed out of the reactor core carrying fissionable materials with them. The decrease in fissionable materials means that the nuclear reactor will slow and its heat will drop. Thus arun away chain reaction is impossible because of the design of the reactor and the physical properties of its fluid salt core.

Gat believed that it was possible to build ultimate safety into fluid fueled reactors, and the key was the continuous extraction of fission products:

"The source term in the U[ltimately] S[afe] Reactor is controlled by continuous removal of fission products at the rate they are produced. Fission products are allowed to accumulate only to a level of 1 to 6 hours of full power operation equivalent. That is an equilibrium level as if the reactor had operated for the equivalent time without any removal of fission products ; then any additional fission products are removed as they are produced. . . . It has been determined 2] that at the 1 to 6 hours equivalent build-up time the fused fuel salt of The U .S . Reactor will not reach boiling due to after-heat even without any heat removal . Thus decay heat cannot provide sufficient energy to disperse the fission products, and there is no source term associated with the decay heat."

Ralph Moir is a retired Lawrence-Livermore National Lab scientist. His professional career was spent developing the concept of a Fusion-fission hybrid reactor, but in his retirement Moir's interest has shifted to the development of the LFTR. Moir's co-authored Edward Teller's last paper, which made concrete proposals on the subject. In a previous"Keys" posting, I briefly described the Teller-Moir views on underground siting of LFTRs.

It should be noted that Teller and Moir (Ralph Moir and Edward Teller, Nuclear Technology 151 334-339 (2005), http://www.geocities.com/rmoir2003/2mlt_slt.htm) also advocated stripping FPs from the fluoride salt mixture. Not withstanding the often stated notion that stripping FPs meant that containment was unnecessary, Teller and Moir advocated a 4 barrier containment system. Their containment system structure was, however, not massive. Indeed gravity provided one of the 4 protective barriers to FP release.

Would continuous stripping FPs from LFTR fuel/coolant salts be justified from the viewpoint of cost? This is topic for research. Stripping FPs would make LFTRs not just safer, but safe, and this would boost public confidence in the safety of nuclear power. In addition, some construction savings would result from this feature. The reactor not require a primary emergency cooling system, nor would it requite a cooling system for core drain tanks. Although a system of multiple barriers to FP escape in still in place, one of the 4 barriers would be gravity which has no cost, and two of the 4 barriers would de the reactor vessel, and the reactor housing, that is their serving as safety barriers is only a secondary function. One further barrier is required by the Teller-Moir system, but that outer barrier would need not be massive or expensive.

Massive protection from suicide aircraft attack would be provided by the under ground setting.

Would there actually be construction savings from continuous stripping of FP from the the LFTR fluoride salts? That is a matter for research! Research would lead to one of three conclusions:
1. The stripping FP's from the LF salts, would low construction costs.
2. The cost of stripping FP's from the LF salts would exceed other construction savings, but the added safety benefit would be worth the added expense.
3. Stripping FP's from the LF salts would not be cost effective.

I have drawn attention to efforts to summerize research efforts required before the launching of a commercial LFTR. In 1974 ORNL prepared a detailed research program for the development of MSR/LFTR type reactors. Some of those tasks have since been accomplished. Ralph Moir has more recently provided a list of proposed LFTR research topics here. Moir's research projects would lead to the creation of a first generation of LFTRs commercial power reactors. In a paper titled "Recommendations for a restart of molten salt reactor development," (Ralph Moir, Energy Conversion & Management) Moir justifies the LFTR research on the grounds that it could lower nuclear generated power prices by as much as 20%. In fact, my own findings point to a potential for much lower nuclear cost. The potential savings entailed in my "Keys" series could lower the price of nuclear power to the point where it would be significantly less expensive than the current levelized cost of fossil fuel generation. The levelized cost of LFTR generated electricity would be far lower than wind and CSP in the Southwestern United States. In an interview which I posted on Nuclear Green, Moir stated that a crash research program to develop LFTR technology could be brought to completion for a billion dollars. This is just a guess, and suggestions I have advanced in the "Keys" series. could well cost more than a billion dollars to research.

Moir's suggested research program in his "Recommendations" is a business as usual program. The time for business as usual has past, and in my interview with Moir, he agreed that a Manhattan Projects style research program for the development of the LFTR was warranted.

It is not as if the LFTR is a newly invented idea. My father started research on in the summer of 1950. One of the research projects to look at solubility enhancement, corrosion, neutron loss of NaF, ZrF4, UF4 salts, is actually a return to a fuel salt formula which my father patented. (I must add that I would in no respect profit from my father's research, patent rights are held by the U.S government.) Two Liquid salt reactors were built in the 1950'san '60's, and both were quite successful. I have demonstrated with a detailed analysis of WASH-1222 and a description of the destructive career of AEC bureaucrat Milton Shaw, who made many serious mistakes including the decision to terminate Liquid salt reactor research (see here, here and here).

ORNL generated a large body of research data on liquid salt reactors from about 1950 into the 1970's. These research reports, many of which can be found in the "Energy from Thorium" document repository, constitute the starting point for any LFTR research and development program. The LFTR has been the focus of ongoing research programs in France, the Netherlands, Russia, Japan and the United States. In addition to the Teller-Moir paper, numerous other papers and reports have recommended expanded programs of LFTR research and development.

It is a reflection of how poorly informed the NRC bureaucracy still is, that it continues to ignore proposals from figures like Moir, that LFTR research be reinitiated. The dead hand of Milton Shaw is still on the tiller of our national reactor research and development policy, and we are sailing head on toward the shore.

The Keys to Lowering Reactor Cost: Investment Costs

Aside from a few minor editorial alterations I have no changes to make to this post.

Reactors are built with borrowed money. Any way you look at it, the cost of money is a major factor in the cost of building reactors. The reactor owner must borrow money to finance the reactor's construction. The borrowing starts even before the first spade of earth is turned, and continues until the current starts flowing to electrical consumers. Since it takes at least 3 years for reactor construction to be completed, and complex reactor projects often take far longer, this means that interest may be accumulating for several years before repayment begins. Thus the cost of interest on borrowed money during the construction phase adds significantly to reactor capital costs.

Let us consider two approaches to reactor manufacture/construction. The first is the traditional approach. The second is the cost lowering approach I advocate.

In the first approach a power company orders a 1 GW Generation 3+ reactor from the manufacturer. Once NRC approval for the project is approved, the manufacturer starts ordering parts and contractors begins site preparations. Money has to be borrowed to pay for these activities and interest charges begins accumulate. Once parts are built they are shipped to the manufacturer for module assembly, and as modules are assembled, they are shipped on to the building site for final assembly. Meanwhile construction activity continues at the site. This goes on for several years. At the end of the construction phase the fuel; is ordered, then loaded into the reactor. Tests are run, and only then does the reactor start generating power. The sale of electricity to the consumers from the reactor produces a stream of money with which to begin repaying interest and principal. We have been borrowing money for 3 years before the first repayment can come in.

The second approach is as follows. The power company orders 10 100 MWe Generation 4 reactors. Their construction is to be spaced over a 3 year period. The factory manufacture approach will allow for rapid assembly of large reactor modules - say a reactor module, a power generating module, and a module for chemical processing units. While the reactor moves down the assembly line site preparation is underway. Once the modules arrive on the prepared site, they are given final assembly. The completed reactor is given its first fuel charge, and after initial testing, electrical production begins. Three months worth of interest has accumulated before the reactor can begin to repay the borrowed money. Then construction of the second unit begins. The small reactor approach, has saved the small reactor owner up too 88% of the accumulated construction phase interest, that would be added to the capital cost of a large reactor project. In addition, during the three year construction project. the owner will see a steadily increasing stream of revenue, which pays not only interest and principle but also contributes to the bottom line of the electrical business.

In addition the decreased risk entailed by the small reactor multiple unit model diminishes investor's risk. Not only is far less money at stake, over a far shorter period of time, but project cancellation due to expense over run or over estimate of consumer demand is fat less likely.

Small, relatively inexpensive, reactors are much more likely to be completed in a timely fashion than big reactors are. Owners are not forced to order more generating capacity than they need as they might with huge one size fits all reactors.

A further observation on reactor construction financing

The current reactor financing system assumes a different set of social goals, than the situation we face demands. The current financial system assumes that the construction of power producing facilities is a speculative investment, whose risk should be born by investors, until the project is complete. Once the production of power begins, the investors are entitled to receive compensation for the risk they task.

This approach leads to the problem we noted earlier, that the accumulation of interest during the project construction phase increases project capitol costs.

Our current social goal is quite different than that assumed by the old regulatory model. Priority needs to be given to the replacement of fossil fuel burning, CO2 producing energy sources, by post-carbon energy sources. This would mean that the sources of the about 75% of American electricity that is currently produced by fossil fuel burning electrical generators must be replaced by post carbon electrical generating sources. No matter what technology is used, the potential cost of greenhouse gas induced global warming far outweighs the cost of changing energy sources, hence the over riding social goal is the change in energy sources, not the question of who should bare the risk. The risk clearly comes from a failure to implement a viable system of financing changes in energy production technology.

Our social goal should be to changing the energy system, to motivate that change by penalizing producers and consumers who do not change, and to see to it that the change can be financed at a reasonable price. Subsidies tend to favor the adoption of energy new technologies, but they may have limited CO2 reduction effect, witness of the peak load inefficiency of California wind generators.

My suggestion would be to link the system of penalties for CO2 generation with a system of rewards for post-carbon energy construction. Hence power companies would have to pay carbon penalties for electricity produced by burning fossil fuels. Rather than going into general revenue accounts however, those penalties would flow into escrow accounts that can be used for for post carbon energy construction. The penalties would be past on to consumers who would be motivated by higher electrical costs use more efficient electrical technology.

Thus the risk of generating new post-carbon electrical generating facilities would be passed on from the investors to the rate payers. It might be complained that this system favors investors over rate payers, but in facto this system lowers rather than raises the costs which rate payers eventually carry. First by insuring that financing for new post-carbon power generating facilities is available, and by lowering the cost of that financing. Thus rate payers are assured that they will have electrical energy when they need it, and that they will not have to carry the cost of construction phase interest once power from the new electrical generating facilities comes on line.

The Keys to Lowering Reactor Cost: Labor Costs

I have continued to work on the potential labor cost savings of from factory manufacture of small LFTR's. In a later post I noted:

. Researchers found that work disorganization was a significant cause of conventional reactor costs. Over 25 percent of workers time in reactor construction projects was wasted by work disorganization. Shifting labor from a construction site to a factory would help to solve the work flow problem.

Labor cost are of course a major source of reactor construction expenses. It was recently reported that the on site construction of AP-1000 reactors require from between from 16 to 20 million man hours to complete. The labor required for parts and module manufacture must be added to the cost. I have already suggested that as much work as possible be transfered to a factory where mass production techniques could be used. These techniques could include labor saving automation in the manufacture of standard reactor parts, and the extensive use of of robots in reactor assembly. These are standard well understood aspects of modern manufacturing and should not require further elaboration.

The work force in the reactor factory should be well trained and compensated accordingly. Assembly line workers should be understood to be part of the quality control, assembly technique and reactor design improvements teams, and both encouraged and motivated to make contributions to efforts of those teams.

In addition to the factory team there should be a site development team, whose task is to analyze site conditions, develop site plans, using as much as possible site design information stored in the sight development data base. Once the site conditions are understood, and a plan developed, the site would be quickly developed. The site development should be completed on the same day that the assembled reactor is shipped. The third stage would be reactor assembly and site completion. Again the highest possible degree of assembly automation should be used. Both of the onsite teams should be be part of the manufacturer's quality control, assembly technique and reactor design improvements teams, and both encouraged and motivated to make contributions to efforts of those teams.

The keys to controlling labor cost in reactor construction include using modern mass manuring techniques, carful organization of working activities, the organization of experience based data bases drawing on workers experience, from which best practices can be identified, and the inclusion of all workers as part of management teams. Labor practices should have an over all goal of creating a well-compensated, high morale workforce that is efficient, loyal, productive, and creative. That is an important part of lowering labor costs.