By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 March 29
The two lead CANDU 6 projects were Gentilly 2 in Quebec and Point Lepreau in New Brunswick and these were quickly followed by Embalse in Argentina and Wolsong, now Wolsong 1, in South Korea and all came into service in the early to mid 1980s. These can be regarded as the first tranche of CANDU 6 build.
The second tranche of CANDU 6 units came with Wolsong 2, 3 and 4 in South Korea, Cernavoda 1 and 2 in Romania, and Qinshan 3-1 and 3-2 in China (the other units at Qinshan site are not CANDU), all entering service between 1996 to 2007. Each of the second tranche CANDU 6 units incorporate lessons learned from operation of the earlier units with changes to meet latest regulatory codes and standards.
More information on the CANDU 6 projects can be found in, CANDU 6 Performance in 2015 (reference 1).
The Capacity Factors are taken from the PRIS database. Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor. Capacity Factors are based on the (net) Reference Unit Power and on the (net) Electricity Supplied figures, as defined in the PRIS database.
CANDU 6 Units
Point Lepreau, New Brunswick, Canada. At the end of 2016 the lifetime Capacity Factor since start of commercial operation in 1983 was 70 percent, including the refurbishment outage. For the last four years, post refurbishment, the average Capacity Factor was 76.3 percent and the annual Capacity Factor for 2016 was 78.5 percent.
Gentilly 2, Quebec, Canada. Unit came into commercial operation in 1983 October. The unit was permanently shutdown at the end of 2012 by Hydro-Quebec after election of the short lived Parti Quebecois government earlier in the year. At the end of 2012, when it was shutdown, it had a lifetime Capacity Factor of 76.2 percent with an annual Capacity Factor for 2012 of 70.7 percent.
Wolsong 1, South Korea. The unit re-entered service in 2015 June after receiving its 10 year operating license from the nuclear regulator. The lifetime Capacity Factor since start of commercial operation in 1983 was 73.6 percent, including the refurbishment outage. At the end of 2016 its annual Capacity Factor was 53.6 percent.
Wolsong 2, South Korea. At the end of 2016 it had a lifetime Capacity Factor of 92.5 percent and an annual Capacity Factor for 2016 of 74.2 percent.
Wolsong 3, South Korea. At the end of 2016 it had a lifetime Capacity Factor of 92.8 percent and an annual Capacity Factor for 2016 of 70.8 percent.
Wolsong 4, South Korea. At the end of 2016 it had a lifetime Capacity Factor of 93.8 percent and an annual Capacity Factor for 2016 of 75.6 percent.
The four unit average annual Capacity Factor for Wolsong for 2016 was 68.5 percent. This much lower than usual average annual Capacity Factor was because the units were taken off line as a precautionary measure after two earthquakes on 2016 September 12. One of the earthquakes was a record one for the Korean Peninsula. None of the country’s nuclear plants including those close to the epicentre were affected. The four units at Wolsong were amongst those that were close to the epicentre. The nuclear regulator approved the restart of the four Wolsong units on 2016 December 5. With some assumptions the calculated Capacity Factors for the period the Wolsong units were available during 2016 would be, approximately, 70 percent for unit 1, 98 percent for unit 2, 93 percent for unit 3, and 99 percent for unit 4.
The low Capacity Factor of unit 1 relative to the other units could at least be partially attributed to an unplanned outage, likely a reactor trip, on 2016 July 22. The unit received permission to restart from the nuclear regulating authority on August 12 but it is not known when the unit became fully operational.
Embalse, Argentina. After many postponements the unit finally shutdown at the end of 2015 for refurbishment. Some of the upgrades had already been completed by the plant employees.
Cernavoda 1, Romania. At the end of 2016 it had a lifetime Capacity Factor of 89.8 percent and an annual Capacity Factor for 2016 of 83.5 percent.
Cernavoda 2, Romania. At the end of 2016 it had a lifetime Capacity Factor of 94.5 percent and an annual Capacity Factor for 2016 of 98.5 percent.
Qinshan 3-1, China. At the end of 2016 it had a lifetime Capacity Factor of 90.8 percent and an annual Capacity Factor for 2016 of 92.1 percent.
Qinshan 3-2, China. At the end of 2016 it had a lifetime Capacity Factor of 91.3 percent and an annual Capacity Factor for 2016 of 76.6 percent.
CANDU 6 summary
The average lifetime Capacity Factor for the seven CANDU 6 units in the second tranche of build was 92.2 percent up to end of 2016 and their average annual Capacity Factor for 2016 was 81.6 percent, affected by the precautionary shutdown of the four Wolsong units due to the earthquake in South Korea.
Note for 2017. As of beginning of 2017 January three of the four Wolsong units were on line and unit 2 was restarted early 2017 February after scheduled maintenance, leaving six of South Korea’s 25 nuclear units off line for maintenance.
1. CANDU 6 Performance in 2015, Don Jones, 2016 March 28, https://thedonjonesarticles.wordpress.com/2016/03/28/candu-6-performance-in-2015/