CANDU cousins in India – Performance in 2016

April 8, 2017

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 April 5

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 (Author’s note: I know because I was part of design team). 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 17 PHWR units operating in 2016 (excludes RAPP-1 which has been shutdown since 2004) 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 three operating non-PHWR units are mentioned. Read the rest of this entry »


Performance of Ontario’s CANDU nuclear generating stations in 2016

April 3, 2017

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 March 31

At the end of 2016 Darlington had a four unit average lifetime Capacity Factor (CF) of 83.6 percent and an average annual CF of 83.6 percent. Bruce A had a four unit average lifetime CF of 69.4 percent and an average annual CF of 81.9 percent. Bruce B had a four unit average lifetime CF of 83.5 percent and an average annual CF of 82.3 percent. The six unit Pickering station had a six unit average lifetime CF of 72.5 percent and an average annual CF of 73.6 percent. More information, and performance data for 2015 are in reference 1.

The raw performance data for 2016 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 CF. CFs are based on the (net) Reference Unit Power and on the (net) Electricity Supplied, as defined in the PRIS database.

The performance of some of Ontario’s nuclear generating stations is affected by the surplus baseload generation (SBG) in the province. The surplus usually arises because of unreliable intermittent wind generation coming in at times of low demand and wind generation is expected to increase even more over the next several years. 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, from PRIS data, Bruce B unit 5 has a 2016 annual CF of 94 percent and an EAF of 97.4 percent. However based on what was just said above this EAF of 97.4 percent must really be a UCF of 97.4 percent and this anomaly may 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 increase the electrical output of the unit.

All manoeuvred reductions in electrical output from Ontario’s nuclear stations to accommodate the much more expensive wind generation are done by the flexible Bruce A and Bruce B stations using turbine steam bypass to condenser and they get paid for the lost revenue. Of course it makes little environmental, economic or technical sense to reduce the low cost output from nuclear stations, with practically zero greenhouse gas emissions, to accommodate expensive unreliable wind generation on the grid that is not needed anyway. The provincially owned Darlington and Pickering stations do not manoeuvre but would have to come off line to accommodate wind and they would not get paid for the lost revenue. While the Bruce electricity output reductions are easily seen from the hourly Generator Output and Capability Report on the website of Ontario’s Independent Electricity System Operator (IESO) it is more difficult to know if nuclear unit shutdowns are to mitigate SBG or are due to forced outages. Maybe an outage was extended, or a planned outage was rescheduled, to accommodate anticipated SBG. However, according to the Bruce Site Updates website there appeared to be be just one overnight shutdown, on unit 2, caused by SBG.
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CANDU 6 Performance in 2016

March 30, 2017

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2017 March 29

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.

More information on the CANDU 6 projects can be found in, CANDU 6 Performance in 2015 (reference 1).

Capacity Factor

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. Read the rest of this entry »


Enhanced CANDU 6 and NuScale SMR have capability to easily integrate wind and solar

August 17, 2016

by: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 August 17.

Nuclear power plants do not like to operate at anything less than 100 percent full power. The main reason is that capital costs for nuclear are high and fuel costs are low so fuel cost savings are negligible at reduced power while revenue losses are appreciable. Another reason is that when reactor power is reduced relatively quickly there is an increase of Xenon-135 in the fuel, a fission product, that tends to reduce reactivity and sets a limit on the rate and depth of any power reduction that can be achieved before the reactor shuts itself down, the so called “poison out”. On a CANDU this is about a 40 percent reactor power reduction to a reactor power of 60 percent after a fast power reduction. Xenon also slows the return to full reactor power. The xenon transient means that frequent power changes, down and up, in support of load following dispatches, would be difficult. Indeed CANDU was not designed to load follow although it was designed to load cycle, that is, reduce reactor power overnight and return to full power in the morning, without bypassing steam around the turbine to the condenser. Light water reactors use enriched fuel so are better able to respond to the xenon transient, at least with a fresh core.

In the past some domestic units and off-shore units (CANDU 6) did accumulate considerable good experience with load cycling, with some deep reactor power reductions, but not on a continuous daily basis. For example back in the 1980s several of the Bruce B units experienced nine months of load-cycling including deep (down to 60 percent full power, or lower) and shallow power reductions. All done without steam bypass. Analytical studies based on results of in-reactor testing at the Chalk River Laboratories showed that the reactor fuel could withstand daily and weekly load-cycling. However this load cycling capability has been configured out of the Ontario CANDUs and they presently operate continuously at 100 percent reactor power. Note that the eight units at the Bruce Nuclear Power Station load cycle when required to do so by bypassing steam around the turbine to the condenser but the reactor remains at full 100 percent power. With certain restrictions station electrical output can be reduced to around 60 percent of the full electrical output (reference 1).
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CANDU cousins in India – Performance in 2015

March 28, 2016

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 March 28

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 (Author’s note: I know because I was part of design team). 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 17 PHWR units operating in 2015 (excludes RAPP-1 which has been shutdown since 2004) 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 three operating non-PHWR units are mentioned. Read the rest of this entry »


CANDU 6 Performance in 2015

March 28, 2016

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 March 27

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.

More information on the CANDU 6 projects can be found in, CANDU 6 Performance in 2014 (reference 1). Note that the Power Reactor Information System (PRIS) database of the International Atomic Energy Agency (IAEA) identifies the Qinshan units in China as Qinshan 3-1 and Qinshan 3-2, that is, units 1 and 2 of Phase 3 of the Qinshan Nuclear Power Project. These were identified previously (reference 1) as Qinshan 4 and 5.

Capacity Factor

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. The annual Energy Availability Factor (reference 2) will only be given in this article if it is significantly different from the unit Capacity Factor.

CANDU 6 Units

Point Lepreau, New Brunswick, Canada. At the end of 2015, just over three years after refurbishment, the “refurbished lifetime” Capacity Factor was 75 percent and the annual Capacity Factor for 2015 was 74.0 percent. The lifetime Capacity Factor since start of commercial operation in 1983 was 69.7 percent, including the refurbishment outage. Read the rest of this entry »


Performance of Ontario’s CANDU nuclear generating stations in 2015

March 18, 2016

By: Donald Jones, P.Eng., retired nuclear industry engineer, 2016 March 19

At the end of 2015 Darlington had a four unit average lifetime Capacity Factor (CF) of 83.6 percent and an average annual CF of 76.1 percent. Bruce A had a four unit average lifetime CF of 69 percent and an average annual CF of 86.1 percent. Bruce B had a four unit average lifetime CF of 83.5 percent and an average annual CF of 84.4 percent. The six unit Pickering station had a six unit average lifetime CF of 72.4 percent and an average annual CF of 78.6 percent. Performance data for 2014 are discussed in reference 1.

The raw performance data for 2015 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 CF. CFs are based on the (net) Reference Unit Power and on the (net) Electricity Supplied, as defined in the PRIS database.

The performance of some of Ontario’s nuclear generating stations is affected by the surplus of generation in the province. The surplus usually arises because of unreliable intermittent wind generation coming in at times of low demand and wind generation is expected to increase even more over the next several years. 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) or the Energy Availability Factors (EAF) that are shown in the PRIS database. The EAF adjusts the available energy generation for energy losses attributed to plant management 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 attributed to grid related unavailability and other things. This means that on unreliable grids, for example, UCF will be significantly higher than EAF but for Ontario there will be no significant difference. The UCF and the EAF take into account reductions in plant output due to load cycling and load following. For units that load cycle and/or load follow the CF will be significantly lower than the EAF. For example, Bruce B unit 5 has a 2015 annual CF of 86.4 percent and an EAF of 91 percent. 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 is more than the EAF because of lower than design cooling water temperatures that increase the electrical output of the unit. The only reason for using the EAF here (see later for Bruce units) instead of the UCF is that EAFs are now available in PRIS and UCFs are not presently available (well, the author could not find them).
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