Timing is everything – not only in comedy but also in life. I leave it to you to decide whether they are one and the same thing.
It’s unfortunate for AECL that the AP1000 and EPR are so far ahead of the ACR-1000 in their development. As noted in previous posts, EPR reactors are being built in Finland and France and construction of the first AP1000 design has just started in China with orders on the books from two US utilities. It appears that the ACR–1000 design is not yet complete and the final design will not be ready for construction until 2012.
This timing means that there will be real construction and operating experience for both its competitors before construction even starts on the first ACR-1000.
This reactor will be heavy-water moderated and light-water cooled with a design power of 1,050 MW (electrical). Precise details of the design are either not publicly available or haven’t been fixed yet. For example, there is an optimisation process between the burnup (energy produced from a given quantity of fuel), CVR (void reactivity) and fuel enrichment (percentage of uranium in the fuel that is uranium-235). In the past AECL has been reluctant about specifying an exact enrichment for ACR fuel. I’ve heard 2.1% but I have also been told other numbers.
There are several design options that could be used to reduce costs and enhance performance compared to previous CANDU reactors. For example, it is likely that new fuel will be used. The CANFLEX fuel bundle has 43 fuel elements, instead of 37, and has been undergoing tests for several years. The elements have two different diameters and projections to improve the heat transfer into the reactor coolant. Using slightly-enriched uranium fuel will yield more power from each fuel channel giving a smaller reactor core and other reactor systems could also be scaled down. A smaller and simpler reactor should reduce maintenance and capital costs.
As noted in an earlier post, a CANDU 6 reactor requires 265 Mg (metric tons) of heavy water for its moderator and 192 Mg for its coolant, a total of 460 Mg per reactor. The ACR-1000 as currently envisaged will require 250 Mg, all for its moderator but none for its coolant which will be light water. This even though the ACR-1000 has significantly higher output power, 1050 MW (e), versus an average of 640 MW (e) for the CANDU 6. This again represents a substantial capital cost reduction.
However, like its CANDU predecessors, the ACR-1000 will require replacement of its pressure tubes after thirty years. This would extend its life by another 30 years but still would require a major expenditure even if the projected one year time frame for refurbishment could be maintained.
The ACR-1000 has the possibility to be an excellent next step in the evolution of the CANDU design. We will only know when the first ACR-1000 is built and operated.
Privately many familiar with the Canadian nuclear industry dismiss the ACR-1000 as a viable contender for Ontario’s new reactors simply because it is so far behind its competitors. I think that’s a shame on patriotic grounds even though Canadians generally don’t like flag waving. On the other hand, as a citizen of Ontario who fully expects a reliable and sufficient electricity supply I would be very nervous about staking the future on the success of the ACR-1000.