Candu revamp aimed at boosted sales
Peter Calamai, SCIENCE REPORTER , The Toronto Star
OTTAWA -Atomic Energy of Canada Ltd. wants to replace the unique Candu nuclear reactor with a smaller, cheaper, easy-to-build design that will be more attractive to potential buyers in Europe and the U.S. and adaptable for uses like desalination and tar sands extraction.
But the revamping to boost export sales would mean that Canada would give up its domestic nuclear self-sufficiency.
The new reactor design scraps the home-produced natural uranium fuel that has long been Candu's trademark in favour of low-enriched uranium.
Canadian uranium refined at Port Hope would have to be sent to the U.S. for enrichment and then re-imported for final fuel fabrication here.
AECL, a federal crown corporation, is urging the federal government to finance the major technology overhaul - costing at least $125 million - so it can cash in on a rash of orders worldwide for new nuclear power stations predicted before the end of the decade.
"The technology is not a radical departure. We're taking 50 years of knowledge from building and operating these things and we're enhancing our technology with improvements," says AECL president Robert Van Adel.
The federal government has invested about $6 billion in nuclear research and development since 1952, according to AECL.
Anti-nuclear groups claim the real nuclear energy cost to taxpayers is closer to $17 billion in today's dollars when subsidies for prototype reactors, heavy water plants and foreign sales are included.
In an interview, Van Adel told The Star that the new design would cut construction costs by 40 per cent and make the Next Generation power reactor competitive with cheap electricity produced by gas turbine plants.
The capital cost of the NG reactor works out to $1,000 (U.S.) per kilowatt of electrical generating capacity - compared to $1,850 (U.S.) per kilowatt for existing Candu stations, according to AECL officials.
The standard reactor size would be 600 megawatts, but modular construction means the new stations could range from 400 megawatts to 1,200 megawatts in output.
The AECL president said the Next Generation reactor would be especially attractive to utilities in the United States and Britain because it can also burn reprocessed radioactive wastes from their current reactors. The spent fuel from three of those reactors would provide all the fuel requirements of one NG reactor.
"Not only would you generate power, but (burning it) reduces the amount of radiation in the fuel further and also reduces the quantity," Van Adel said.
The NG reactor also abandons the distinctive Candu feature of pumping costly heavy water to cool the reactor.
Instead, it substitutes ordinary water for cooling, like most reactors in the U.S. and Europe.
Heavy water would still be used in the core of the new reactor to control the rate of nuclear fission, but the more compact design requires a lot less of the stuff, which costs roughly $550 a kilogram.
These two heavy water changes alone cut at least $100 million from the start-up cost of a typical Candu.
The core and surrounding shell of the new design is only two-fifths as large as most Candu reactors sold abroad, according to Van Adel.
But it would produce the same 600 megawatts of power because the two per cent enriched fuel sends out a lot more neutrons, the atomic particles that cause the chain reaction.
"You get much more power in a core that is much smaller so there's a whole lot of cost reductions," says David Jackson, an engineering professor at McMaster University and nuclear power expert.
The switch to enriched uranium and ordinary water for cooling means the NG design will shut off automatically on its own if the cooling water is lost.
Losing the cooling water in the current Candu actually speeds up the nuclear fission so other complex safety systems must shut down the reactor.
[ NOTE : this is only true with a fresh core load, for example when the reactor is brand new.... the equilibrium core, with on-line refueling has a negative reactivity coefficient for coolant voiding -- see http://www.ncf.ca/~cz725/cnf_sectionD.htm#s -- Jaro ]
AECL has been doing preliminary research on the NG design for the past two years and has already tested the new enriched uranium fuel in Quebec's Gentilly-2 reactor.
The crown corporation last year paid a U.S. consulting firm to gauge the potential market worldwide for the new reactor design and submitted that "very positive" report to the federal natural resources department, the AECL president said.
According to AECL officials, a crash research and engineering program to get the NG reactor ready for the market would cost between $25 million and $30 million a year for five or six years but commercial partners might pick up some of the bill.
Construction would take less than five years.
AECL has already signed partner agreements to develop the NG reactor with Hitachi Ltd. and British Energy.