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Small modular reactors: no advantages in costs and risks

Nuclear Monitor Issue: 

Early March, the US Department of Energy (DoE) has announced three public-private partnerships to develop deployment plans for small modular reactor (SMR) technologies at its Savannah River Site in South Carolina.

The DoE said that it had signed three separate memorandums of agreement with Hyperion Power Generation, NuScale Power and Holtec International's SMR LLC subsidiary. Hyperion has designed a 25 MWe fast reactor, while Holtec and NuScale have designed small pressurized water reactors with capacities of 140 MWe and 45 MWe, respectively. However, the DoE stressed that the new agreements "do not constitute a federal funding commitment." It said that it envisages private sector funding to be used to develop these technologies and support deployment plans. The DoE added that the agreements are unrelated to its funding opportunity announcement for SMR cost-share projects announced in January.

According to their promoters, small modular reactors are the solution to the problems of high cost and risk. But they are not the nuclear nirvana that the industry seeks.

Having built small reactors to start with - Shippingport, the first commercial power reactor in the United States, was just 60 MW - the industry went to 1,000 MW and even larger sizes precisely because of economies of scale. Reactor power output goes up much faster than the materials and fabrication costs as size increases. Economies of scale also apply to electric generators and steam turbines.  So, the costs per kilowatt would tend to rise, not fall if reactor size is decreased greatly.

Proponents claim economies of scale would be offset by mass manufacturing small modular reactors. It is true that on-site fabrication is a cumbersome and expensive process. However, there have to be dozens or hundreds of orders before anyone will invest in a large factory to churn out reactors. Without that level of demand, small reactors will tend to be custom made - and costly.

Second, and even more importantly, building one or two small modular reactors on a site guarantees high costs. An entire security, administrative, control, and monitoring infrastructure must be built at every reactor location - making each kilowatt more expensive.

One approach would be to prepare a site and its infrastructure for a large number of small reactors. But, if they were all built at the same time, we are back to a large, risky project. If they are built one or two at a time, the first units will be very costly - far more than today's reactors - since a disproportionately large infrastructure would be necessary.

The hype about new reactors is hiding many difficult questions. Burning uranium and generating plutonium just to boil water was never a good idea; it was never destined to be cheap. Why would the U.S. government want to throw more tax dollars after a nuclear dream that is likely to dissolve into a harsh reality?

Source: World Nuclear News, 5 March 2012 / Iowa City Press Citizen, 9 March 2012, Arjun Makhijani
Contact: NIRS