CANDU 6 shares the load with light water reactors in China and South Korea

By: Donald Jones, P.Eng., retired nuclear industry engineer – 2014 July

There are two CANDU 6 reactors in China and four in South Korea in a growing sea of pressurized light water reactors. It will be interesting to see how they are performing while operating in the same regulatory environment and safety culture as the other units on the power grid. Performance will be related to the lifetime capacity factor/load factor at the end of year 2013. The International Atomic Energy Agency (IAEA) publishes statistics on all the world’s power reactors in its Power Reactor Information System (PRIS) database.

China

As of the end of 2013 China had 17 operating nuclear power plants, two them of the CANDU 6 type. As of 2014 July China had 20 units in operation with 28 under construction, more about to start construction and more planned. China aims to have 58,000 MW of installed nuclear capacity by 2020, 150,000 MW by 2030 and much more by 2050. For perspective the US has about 100,000 MW installed and Ontario about 13,000 MW. All China’s nuclear units, except for the two French units at Daya Bay and the Chinese designed CNP-300 at Qinshan, entered commercial operation after 2002 and have excellent lifetime capacity factors. The average lifetime capacity factor for the 17 operating units was 88.3 percent. China is now largely self sufficient in power plant design and construction. For anyone interested in China’s massive nuclear plant expansion see, Nuclear Power in China (reference 1).

There are two Russian VVER V-428, each 1060 MWe gross, that went into commercial operation between 2007 May and 2007 August. The average lifetime capacity factor at the end of 2013 was 86.3 percent.

There are four French three loop Framatome (now Areva) units each of around 990 MWe gross that went into commercial operation between 1994 February and 2003 January, the first two units are at Daya Bay with most of their output feeding Hong Kong. The average lifetime capacity factor was 86.4 percent.

China’s four CPR-1000 units each of around 1080 MWe gross are significantly upgraded from Framatome’s Daya Bay and subsequent units and went into service between 2010 September and 2013 June. The average lifetime capacity factor was an excellent 92 percent for these relatively new units. More of these units will be built but not as many as envisaged before the Fukushima event. Instead China is working with Westinghouse in the construction of four, Generation III+, AP1000 units (1,250 MWe gross) with many more to follow and plans to develop its own CAP1000 version and eventually a larger CAP1400.

China’s four CNP-600 units (and one CNP-300) each of around 650 MWe gross are based on early Framatome two loop design work and are all located at the Qinshan site. They went into commercial service between 2002 April and 2011 December. The average lifetime capacity factor was 87.6 percent. China’s first indigenously designed nuclear plant, a two loop CNP-300 unit of 310 MWe gross also at the Qinshan site, had a lifetime capacity factor of 81.1 percent.

The two Canadian CANDU 6 units are each 728 MWe gross at the Qinshan site and went into commercial service between 2002 December and 2003 July. The average lifetime capacity factor was 91.6 percent for these relatively old (for China, anyway) units at the end of 2013. The average capacity factor for the 15 pressurized light water reactors in China was 87.9 percent and if the two CANDU 6 units are included it would be 88.3 percent, an excellent performance by the Chinese nuclear fleet.

South Korea

As of the end of 2013 South Korea had 23 operating nuclear power units, four of them of the CANDU 6 type, that provided nearly one third of Korea’s electricity. The aim is to provide about 50 percent of Korea’s electricity by 2022 and 59 percent by 2030. As of 2014 July there were five units under construction, one OPR-1000 and four APR1400 units each of 1455 MWe gross. Korea is also building four APR1400 units in the United Arab Emirates with more to follow. Korea hopes to become the world’s third largest nuclear exporter by 2030. Korea’s nuclear plants have shown consistently high year to year capacity factors, amongst the highest in the world, but lifetime capacity factors likely suffered because of unplanned outages due to steam generator tube failures, replacement of sub-standard uncertified parts, and safety reviews after the Fukushima event. The average lifetime capacity factor for the 23 operating units was still an excellent 85.3 percent. For anyone interested in Korea’s nuclear plants and planned expansion see, Nuclear Power in South Korea (reference 2).

There are six Westinghouse units with capacities varying from 608 MWe gross to 1042 MWe gross. They went into commercial service between 1978 April and 1987 June. The average lifetime capacity factor at end of 2013 was 86.8 percent.

There are two System 80 units from Combustion Engineering (now Westinghouse) each of about 1050 MWe gross. They went into commercial service between 1995 March and 1996 January. The average lifetime capacity factor was an excellent 90.4 percent.

There are two French Framatome (now Areva) units each of around 1005 MWe gross. They went into commercial service between 1988 September and 1989 September. The average lifetime capacity factor was 88 percent.

Korea’s nine OPR-1000 units, the Korean Standard unit, are based on the Westinghouse, Framatome and Combustion Engineering units and each has a capacity of around 1053 MWe gross. They went into commercial service between 1998 August and 2012 July. The average lifetime capacity factor was 79.4 percent. The relatively low capacity factor was due to outages to replace falsely certified electrical cabling on some of the units.

The four Canadian CANDU 6 units are each around 695 MWe gross and went into commercial service between 1983 April and 1999 October. The average lifetime capacity was 90.5 percent using the Wolsong 1 lifetime capacity factor at end of 2013. However Wolsong 1 has had its mid-life refurbishment and after a few months of operation it had to shutdown because its operating licence had expired (reference 3). If we take the lifetime capacity factor for unit 1 at the end of 2008, its last full year of operation before shutdown for refurbishment, the average lifetime capacity factor for the four units would be 92.5 percent, an excellent performance. Even more astounding is the 94.8 percent lifetime capacity factor for Wolsong 2, 3 and 4, the three later units. The average lifetime capacity factor for the 19 pressurized light water reactors in Korea was 83.8 percent and if the four CANDU 6 units are included (assuming the year 2008 lifetime capacity factor for Wolsong 1) it would be 85.3 percent, an excellent performance despite the unplanned outages mentioned earlier.

CANDU 6

As well as being amongst the best performing reactors in China and Korea CANDU 6 has attributes related to its highly flexible fuel cycle. Since CANDU reactors use natural uranium and not the enriched uranium used in light water reactors, like those in China and Korea, there is an opportunity to recycle the used fuel from the light water reactors to become fresh fuel for the CANDU reactors. The used fuel from the light water reactors is blended with depleted uranium to give a “natural uranium equivalent” fuel. This makes full use of the energy in the residual fissile content of the used fuel from the light water reactors and reduces waste. The depleted uranium is a by product of the enrichment process for the fuel of the light water reactors. In fact natural uranium equivalent fuel bundles have already been successfully irradiated in one of the the Qinshan CANDUs. The next step is full core replacement with natural uranium equivalent fuel. Three to four light water reactors could fuel one CANDU. China and Canada are also collaborating on the use of thorium as an alternative CANDU fuel, further demonstration of CANDU’s fuel cycle flexibility. China has substantial thorium resources. More information on the Canada-China agreement to develop recycled uranium and thorium as alternate CANDU fuel can be seen in the news release by Candu Energy Inc., 2012 August 02 (reference 4). With its very high lifetime capacity factors and extremely flexible fuel cycle CANDU has a lot to offer China and South Korea.

 

References

1. Nuclear Power in China, compiled by World Nuclear Association, http://www.world-nuclear.org/info/Country-Profiles/Countries-A-F/China–Nuclear-Power/

2. Nuclear Power in South Korea, compiled by World Nuclear Association, http://www.world-nuclear.org/info/Country-Profiles/Countries-O-S/South-Korea/

3. Pedigree of the Enhanced CANDU 6 (EC6) proposed for Darlington B, Don Jones, 2014 June, https://thedonjonesarticles.wordpress.com/2014/06/09/pedigree-of-the-enhanced-candu-6-ec6-proposed-for-darlington-b/

4. Candu Signs Expanded Agreement with China to Further Develop Recycled Uranium and Thorium Fuelled CANDU Reactors, http://www.candu.com/en/home/news/mediareleases/candusignsexpandedagreementwithchinatofurtherdevel.aspx

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