Ontario’s IESO prefers Enhanced CANDU 6 over AP1000 for new build at Darlington

August 25, 2013

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 »


Candu Energy Inc. says Enhanced CANDU 6 is flexible – so revise the boilerplate

August 9, 2013
By: Donald Jones, P.Eng., retired nuclear industry engineer, 2013 August.

In its media releases on the study of possible use of the Enhanced CANDU 6 (EC6) to burn surplus UK plutonium Candu Energy Inc. has explicitly stated that its EC6 has flexible load capabilities. For example, the media release of 2013 August 1 (reference 1) said,,

“The Enhanced CANDU 6 (EC6) is a 700 MWe class heavy-water moderated and heavy-water cooled pressure tube reactor. It is the only commercialized reactor offering flexible fuelling arrangements from natural uranium to advanced fuels such as recycled uranium, thorium and plutonium mixed oxide (MOX). This fuel flexibility is combined with superior safety and economic performance, high reliability, flexible load capabilities (author’s highlight), very high localization potential and straightforward integration into the existing grid system. CANDU reactor operators currently fabricate or procure their own fuel locally, increasing their energy independence and creating a nuclear fuel infrastructure without the need for enrichment.”

The flexibility attribute was likely mentioned in association with the UK study because new build in Europe has to at least meet the flexibility regulations of the European Utilities Requirements (EUR) that are based on the requirements of the grid operators, subject to licensing approval by the specific nuclear regulator. The EC6 would have to comply with the manoeuvrability specifications of the EUR if Candu Energy wants it to be part of new build in Europe. Read the rest of this entry »