On the Cost of LFTRs: ORNL-TM-7207 and Moir

I looked once again at Ralph Moir's study on MSR costs, and I realized that Moir's data set came from ORNL-TM-7207, a document describing a Denatured MSR using U-238 as a proliferation resistance tool. ORNL-TM-7207 contained a fairly detailed design study that was in turn based on ORNL MSBR research of the late 1960's and early 70's. The information of MSR costs was really derive from cost studies for the MSBR. ORNL cost estimates for the MSBR had been updated as recently as 1975. So

[u]sing a construction materials and labor increase of P2%/year gives a multiplier of 1.4 and a cost for the MSTR in 1978 of about $680 million.

A detailed estimate of the cost of a 1000-MWe DMSR based on a mature technology is given in it fol%owing seetion, From this, we have estimated the cost of a first standardized DMSR by applying a factor of 1.5 to allow for increased first-of-a-kind costs and the cost of a lead commercial prototype by applying another factor of 1.5 to allow for increased prototype costs, Using this proceduree the cost of a POOO-Mk prototype DMSR is estimated to be $1470 million and the first standardized DMSR $980 million

Note that at ORNL in 1980 the MSR was regarded as"a mature technology".

Since MSR research and development has been under way for some 30 years, the basic technology is well understood. However, much of it has not been developed to the stage and scale that would be required for the construction of large reactor systems, Thus, a significant R&D effort would be an important part of any program to commercialize MSRs, In addition, untfl recently, development was concentrated on reactor concepts with a good breeding gain and a low fissile inventory sO that the resulting thermal breeder reactor system would have a reasonably short doubling time and could be considered a viable alternative (or complement) to fast breeder systems. The technology needs of the modified reactor concept that has been developed in response to the recent emphasis on proliferation resistance differ from those of the nominal breeder concept.

In short many of the ORNL concerns under consideration for the 1980 concept might be rethought today. Some might well be discarded, while others might well have already found partial or even complete solutions through other lines of research.

Thus a further R&D program would be needed to bring a commercial MSR online. They projected a business as usual program which included the building and testing of a 200 MWe to 250 MWe Developmental prototype.

The complete base program is projected to cost about $700 million [2.37 billion 2009 US dollars] over about 30 years.

It should be further noted that the pace of development would have been slow, as was the case for MSBR Development at ORNL after the MSRE was shut down in 1969, Thus we have a cost estimates based on business as usual assumptions.

The construction cost of the MSTR way be estimated by updating the cost estimate for the MSTR prepared in 1975 for the MSBR program. Using a construction materials and labor increase of P2%/year gives a multiplier of 1.4 and a cost for the MSTR in 1978 of about $680 million.

A detailed estimate of the cost of a l000-MWe DMSR based on a mature technology is given in it fol%owing seetion, From this, we have estimated the cost of a first standardized DMSR by applying a factor of 1.5 to allow for increased first-of-a-kind costs and the cost of a lead construction prototype by applying another factor of 1.5 to allow for increased prototype costs, Using this proceduree the cost of a 1000-MW prototype DMSR is estimated to be $1470 miliom and the first standardized DMSR $980 million.

The ORNL staff found that:

The DMSR is estimated to cost $653 million, or about .$650/kWe in 1978
dollars.

But the 1975 cost estimates were based on 1970 MSBR cost estimates:

costs were taken (for most accounts) as the basis for the DMSR estimate using the following method.
1. The costs were adjusted to take into account the differences in size or other requirements for the DMSR. For example, the reactor vessel cost was increased to take into account the larger size of the DMSR vessel.

2. The 1978 costs were increased by a multiplier based on the increase in construction materials and labor costs from 1970 to 1978. 'The multiplier was calculated to be in the range 2.3 to 2.5; to be conservative, the multiplier 2.5 was used. This represents an annual rate of increase of about 12X,

In addition, the costs of a pressurized-water reactor (PWR), a bailing-water reactor (BUR), and a coal-fired plant in 1978 were estimated usimg the CONCEPT V code. Were appropriate, some accounts were estimated based the analogous account in one of the CONCEPT estimates. For example, the turbine-generator cost was based on the coal-fired plant estimate because the same type of supercritical steam turbine would be used.

So we have a good idea of the methods which the ORNL staff used to come up with their 1980 DMSR estimate. Further it would appear that the original 1970 cost estimate was to a great extent based on interpolation of coal an LWR power plants ca. 1970. But something is wrong with the model. we are told that in 1978 nuclear capital costs ran

$600/kWe for a PWR plant and $38O/kWe for a coal plant without flue-gas cleaning.

in fact in 1978 PWRs cost a great deal more than the ORNL estimate. A Harvard-M.I.T. study conducted in the mid 1970's found that nuclear capital costs had increased two to three times faster than coal capital costs between the late 1960s and mid-1970s. That trend continued into the 1980's and by the end of the decade nuclear capital costs ran 2.5 times that of coal. In addition to capital cost increases in terms of constant dsollars, inflation increased capital cost for all energy sources. Thus the sort of LWR cost estimates offered by the ORNL staff in ORNL-TM-7207 were extremely inaccurate.

Were the capital costs for the DMSR equally inaccurate? This would not appear to be the case. First while LWR design had undergone substantial and rapid modification between 1970 and 1980,. These design changes, more than any other factor, were responsible for the dramatic increase LWR costs. In contrast, MSR design was basically unchanged form 1970 to 1980. There were of course many design variants, but they had been explored by 1970. This design stability that is characteristic of a mature reactor concept. It is unlikely then that the real cost of MSR would have tracked the price change of LWRs. The cost of LWRs increased by 700% between 1970 and 1980. Once inflationary changes are factored out, LWR capital costs were about 2.8 times higher in 1980 than they were in 1970. Thus while the ORNL staff estimated the cost of a conventional nuclear reactor to be $600 million in 1978, it was probably closer to $1.5 billion. Thus while the ORNL staff would have expected the DMSR to cost $653 million in contrast to the LWR's $597 Million, in fact the LWR probably would have cost closer to $1.5 billion, giving us a DMSR cost of 43% of the LWR. Hay wait a minute, could this be possible? Well if the arguments I have been making regarding LFTR costs is valid, yes it is. In fact, this figure does not take into account many potential LFTR cost savings that were not considered by the ORNL staff in 1980. For example, research has shown that about 27% of worker's time was wasted because of worj flow disorganization at reactor construction sites.

Factory built LFTRs could expect to see workers' time used more efficiently. And of course LFTR factories could install labor saving devices. I have noted siting innovations, including underground siting. The rapid manufacture and set up of small factory built LFTRs would also decrease interest costs. The rapid manufacture of large numbers of small LFTRs would introduce the cost saving avaliable to serial production. The Chinese expect the learning curve for small factory built reactors will yield a 30% cost savings. Rapid manufacture and set up greatly decreases accrued interest. The small LFTR appears to offer a perfect storm of cost savings,

Thus there is probable cause to believe that LFTR capital costs will be 1/4th of that of conventional nuclear or less.