By the OGJ Online Staff
HOUSTON, Oct. 9 -- New nuclear plant designs promise to overcome some of the commercial and safety barriers of nuclear power, said the Baker Institute for Public Policy at Rice University in a recent report.
But the institute said designs are still burdened by poor public perception, the risk of rogue states using nuclear power plant construction and refueling as a cover for nuclear weapon proliferation, and nuclear waste problems.
Nuclear technology is moving towards smaller scale design, just as conventional power plant technology is, the report said.
The so-called micro-nuclear technology involves new designs that make reactors smaller, with fewer components, simpler design, and simpler operation and maintenance. The new designs include:
� International Reactor and Secure Nuclear Power System, a pressurized water reactor with steam generators integrated within the reactor pressure vessel.
� Pebble Bed Modular Reactor, a modular graphite-moderated, helium-cooled reactor that employs a direct cycle gas turbine and fuel contained in small graphite-covered balls.
� 4S, a sodium-cooled modular fast reactor designed to operate for 30 years without refueling.
� Encapsulated Nuclear Heat Source Reactor, a modular lead-cooled reactor designed to function as a nuclear battery; it is shipped to the site fueled and then replaced by a new module after 20 years of operation.
An advantage to modular design would be shortened construction time compared to conventional reactors, which take at least 5 years to construct. The smaller modular units should be built in less than a year, said the institute.
The cost advantage still would not materialize unless enough modular plants were ordered to make the manufacturing facilities cost-effective, noted the institute. It would not be economic to build a manufacturing facility to produce one nuclear plant module. "The chicken-egg problem of the manufacturing process will stand as a barrier," the report said.
Several of the designs expected to be ready after 2020 eliminate the possibility of severe accidents by relying on the physical process itself for safety as opposed to the functioning of mechanical and electrical components like valves and pumps. For example, because some of the new designs don't circulate coolant, they will avoid accidents that involve large loss of coolant, the report said.
However, other safety issues that involve the possible failure or leaks from the containment structure have not been overcome, said the report.
It noted that because these units would require refueling less often, they would help ease concerns about clandestine nuclear weapon proliferation under the pretense of refueling.
The institute proposed that modular plants could be constructed in one country in a heavily guarded "nuclear park." Then the modules could be shipped to the host country. However, the institute admitted the concept might be politically difficult to implement.
Finally, no matter what the technology, waste disposal challenges will be "daunting." The Baker Institute said if nuclear power were to become the fuel of choice internationally, the spent fuel generated annually would be about 50,000 tons -- equivalent to one Yucca Mountain dumpsite being constructed every 18 months.
To date there is no long-term repository for spent nuclear fuel available in the US, as Yucca Mountain is still under review.