ACR-1000 – the AECL Design

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.      


2 Responses to “ACR-1000 – the AECL Design”

  1. Don Jones Says:

    Re ACR-1000 – the AECL design

    The ACR-1000 Technical Summary is available on the internet. Lots of technical info that cover all the “design options that could be used to reduce cost and enhance performance”.

    AECL’s website is still calling for a 2016 in-service date. The Ontario RFP requires an in-service date of 2018 . For the n th unit the time from first concrete to in-service is 4 years according to AECL so we should allow up to 5 years for the first unit which means first concrete by 2011 to meet AECL’s date and by 2013 to meet the RFP date.

    From Table 1 in the CNSC document INFO- 0756, Licensing Process for New Nuclear Power Plants in Canada, showing the timelines, it could take 7 years from first applying for a license to prepare site to getting a license to construct. The site submission for Darlington was in 2006 Sept. which means first concrete could be in 2013. Allowing up to 5 years from first concrete to in-service for the first unit means an in-service date of 2018.

    The bottleneck appears to be the CNSC not AECL.

    The licensing process for the ACR will be shorter than that for the EPR or AP1000. Maybe someone with more knowledge of the licensing process than I do could add further comments to the timelines.

    To say that, “it is unfortunate for AECL that the AP-1000 and the EPR are so far ahead of the ACR-1000 in their development” and that the ACR-1000 “is too far behind its competitors” is irrelevant for Ontario since there seems no reason why it cannot meet the 2018 in-service date.

    Any construction and operating experience with the LWRs being built in Finland and China will be too late to play a part in the selection of Ontario’s new reactor. In fact experience so far in Finland and France with the EPR doesn’t inspire confidence and Westinghouse construct times are based on computer simulations and not actual experience since, unlike AECL, they have not built a plant since Sizewell B in the UK was ordered in 1979 and this was a very different design to the AP-1000. By the way, the AP1000 had design certification in the U.S. in 2006 but Westinghouse was still making design changes and submitted an application in 2007 May to amend the certified design. The US regulator is currently reviewing this application.

  2. John Walker Says:

    The ACR1000 can also burn reprocessed fuel and therby make better use of the fuel and save money on fuel storage. Canada needs a dozen or more such reactors ASAP to reduce GHGs and help mitigate global warming.
    See article ‘Mitigating Power, Oil and Climate Disasters’ at web site.

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