By: Donald Jones, P.Eng., retired nuclear industry engineer, 2013 August.
This article will appear in the 2013 September edition of the Canadian Nuclear Society’s “BULLETIN”
The Independent Electricity System Operator (IESO) prefers the Enhanced CANDU 6 (EC6) over the Westinghouse AP1000 for new build at Darlington. Well, it is inferred anyway.
On page 6 of the IESO’s written submission to the Ontario Power Authority’s (OPA) 2005 December 9 Supply Mix Advice Report to the Minister of Energy (MOE), Volume 5 – Submissions and Presentations Received, it states,
“To bring supply and demand into balance under Unutilized Baseload Generation (UBG) conditions, baseload generation must be shutdown. For example, if a nuclear unit is unable to perform power reductions it will be shutdown, typically resulting in a 48 hour “poison” outage. Such shutdowns, which assist with low demand concerns, can adversely impact the ability to meet demand during subsequent peak periods until the unit(s) return to service. Any consideration of nuclear generation additions should examine the ability of the different nuclear options to reduce power under UBG conditions, with preference going to those technologies which can better accommodate this requirement”. (author’s emphasis)
Note that the IESO now uses the term “Surplus Baseload Generation” (SBG) instead of “Unutilized Baseload Generation” (UBG). Since the EC6 is much more flexible than the AP1000 (reference 1) it is clear that the IESO preference would be the EC6 for new build at Darlington. Bruce Power’s eight units have already demonstrated what even a limited amount of flexibility can achieve, so much so that they are classified as “flexible nuclear” by the IESO (reference 2). The EC6 will have much more steam bypass capacity than the Bruce units and in addition will be able to do reactor manoeuvring when necessary. Read the rest of this entry »