CANDU 6 Performance in 2018

By: Donald Jones, retired nuclear industry engineer, 2019 April 21

History

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.

Capacity Factor

The Capacity Factors are taken from the PRIS (Power Reactor Information System) database of the IAEA (International Atomic Energy Agency). Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor (CF). Capacity Factors are based on the (net) Reference Unit Power and on the (net) Electricity Supplied figures, as defined in the PRIS database. The Energy Availability Factor (EAF) is another performance indicator and is shown in the PRIS database. The EAF adjusts the available energy generation for energy losses attributed to plant management, planned and unplanned, and for external energy losses beyond the control of plant management. The Unit Capability Factor (UCF), another performance metric, only includes energy losses attributed to plant management and excludes the external losses beyond control of plant management like load cycling/load following, grid failures, earthquakes, cooling water temperature higher than reference temperature, floods, lightning strikes, labour disputes outside the plant etc. The UCF seems a much better indicator of how well the unit is being managed than either CF or EAF but it is not specifically identified in the PRIS database (reference 1). Note that Bruce Power and Ontario Power Generation use UCF as a performance indicator.

CANDU 6 Units

Point Lepreau, New Brunswick, Canada. At the end of 2018 the lifetime CF since start of commercial operation in 1983 was 70.9 percent, including the refurbishment outage, and the annual CF for 2018 was 84.6 percent (EAF 84.5 percent).

Performance of Ontario’s CANDU nuclear generating stations in 2018

By: Donald Jones, retired nuclear industry engineer, 2019 April 9

The raw performance data for 2018 are taken from the Power Reactor Information System (PRIS) database of the International Atomic Energy Agency (IAEA). Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor (CF). CFs are based on the (net) Reference Unit Power and on the (net) Electricity Supplied, as defined in the PRIS database. For Ontario, at least, the Energy Availability Factor in the PRIS database can be read as the Unit Capability Factor (reference 1). For some unknown reason PRIS database had no data on Darlington unit 1 for 2018.

The performance of some of Ontario’s nuclear generating stations is affected by the surplus baseload generation (SBG) in the province. Some nuclear units saw electricity output reductions during periods of surplus baseload generation (SBG). This means the CFs are not a true performance indicator for those units (reference 2). A better metric of performance in these cases would be the Unit Capability Factor (UCF – used by Ontario Power Generation and by Bruce Power). The Energy Availability Factor (EAF) is another performance indicator and is shown in the PRIS database. The EAF adjusts the available energy generation for energy losses attributed to plant management, planned and unplanned, and for external energy losses beyond the control of plant management while the UCF only includes energy losses attributed to plant management and excludes the external losses beyond control of plant management like load cycling/load following, grid failures, earthquakes, cooling water temperature higher than reference temperature, floods, lightning strikes, labour disputes outside the plant etc.

For Ontario there should be little significant difference between CF,  UCF and EAF for units that do not load cycle (an external energy loss) since other external energy losses will be close to zero. For units that load cycle the UCF will be higher than the EAF and higher than the CF but the EAF should  not be significantly different from the CF. For example, going back to 2017 PRIS data, Bruce B unit 7 had a 2017 annual CF of 92.8 percent and an EAF of 96.3 percent. However based on what was just said above this EAF of 96.3 percent must really be a UCF of 96.3 percent and this anomaly will apply to all EAFs given in this article.The UCF and the EAF are based on reference ambient conditions so, unlike the CF, they cannot exceed 100 percent. In some cases the CF can be more than the EAF because the cooling water temperature is lower than the reference temperature and that increases the electrical output of the unit.

CANDU cousins in India – Performance in 2018

By: Donald Jones, retired nuclear industry engineer, 2019 April 1 

Most of India’s nuclear reactors are of the pressurized heavy water reactor (PHWR) type with horizontal pressure tubes, just like the Canadian designed CANDU. In fact the first PHWR (not the first nuclear reactor) in India was the Rajasthan Atomic Power Project (RAPP) unit and was a CANDU designed by Atomic Energy of Canada Limited (AECL) that used the Douglas Point unit in Ontario as reference design but modified to aid localization. RAPP-1 entered commercial operation 1973 December. While RAPP-1 was being constructed the design of  RAPP-2 was started. However the detonation of a nuclear device by India in 1974 curtailed completion of the design by AECL and India was on its own as far as nuclear technology was concerned. The design was completed by India and RAPP-2 eventually entered commercial operation in 1981 April. Since those early days India has developed its own indigenous designs of  PHWRs with net electrical outputs of 202 MW, 490 MW, and 630 MW. They bear little to no resemblance to Douglas Point. All 14 PHWR units operating in 2018 (excludes RAPP-1 which has been shutdown since 2004, Kakrapar units 1 and 2 which were shutdown due to coolant channel leaks, and Madras unit 1 which was shutdown during 2018 for some unknown reason) were 202 MW (220 MW gross) except for two 490 MW (540 MW gross) units. There were four 630 MW (700 MW gross) units under construction with none in operation. All PHWR power units, except for RAPP-1, are designed, owned, and operated by Nuclear Power Corporation of India Ltd. Several of the country’s PHWRs have been refurbished for extended life operation. For more detailed information on the Indian nuclear program see, Nuclear Power in India (reference 1).

The performance data are taken from the Power Reactor Information System (PRIS) database of the International Atomic Energy Agency (IAEA). Note that the Load Factor term used in the PRIS database has the same meaning as Capacity Factor (CF). CFs are based on the (net) Reference Unit Power and on the (net) Electricity Supplied, as defined in the PRIS database, so capacities referenced in this article are net electrical MW output. The lifetime, or cumulative, CF is based on the date of commercial operation and will include the outage time if the unit has been refurbished. Only the performance of India’s PHWRs is reviewed in detail but India’s four operating non-PHWR units are mentioned.