Power plant performance/Load factors
Small, but not forgotten3 December 2012
When NEI began compiling commercial nuclear power station performance in April 1976 (pp22-24), we included only nuclear reactors of 150 MWe gross or above. A decision was made to exclude the small prototype reactors that nations built in the 1950s and 1960s on the path towards development of true commercial nuclear plants.
While that decision remains largely valid, we did exclude one small reactor that was in operation in 1976 and is still generating today: the 137MWe Karachi nuclear power plant in Pakistan.
The reactor, known also as Kanupp, is a CANDU pressurized heavy water design that began commercial operation in 1972. Following considerable investment and life extension work in the early 2000s [‘B’ in chart below], the plant is now expected to continue operating until 2019.
Based on information from the Pakistan Atomic Energy Commission (PAEC), which was presented at a recent IAEA meeting in Vienna, Kanupp has generated 13.7 TWh of electricity over around 40 years of operation (to May 2012). And while its performance has not been one of the best, with a lifetime load factor of 28.5%, Kanupp’s performance is on par (indeed slightly better) than Rajasthan 1, an Indian plant of similar age and design, which has faced similar challenges.
One of the main challenges faced by Kanupp came early on in its life. Embargoes of 1976 caused vendor support to be withdrawn from the plant, leaving PAEC engineers and scientists to develop their own capability to produce fuel, provide technical support and manufacture spare parts. This phase was a difficult time for the plant and hampered performance for over a decade [A]. Generation at Kanupp suffered due to extensive turbogenerator overhaul and maintenance, carried out in 1979-1980 [1-2]; and other major maintenance work . Then, in 1989 a hose rupture incident  meant that the plant only generated 60 GWh that year.
From the 1990s Kanupp entered a record-breaking phase of operation, achieving some of its best performance in the mid-1990s. In 1999, however, a main generator breaker burning incident  curtailed operation for most of the year.
In 2003, Kanupp entered a relicensing and life extension phase [B], comprising two main outages [6-7]. Since its return to normal operation in 2007, the plant has achieved a load factor of 44.2%.
One could easily argue that Kanupp is indeed a commercial facility. I feel, therefore, that we may need to reconsider this >150 MWe limit in future. Inclusion should depend principally on the type of technology used rather than the capacity.
This article first appeared in the November 2012 issue of Nuclear Engineering International magazine.Related ArticlesLoad factors to end June 2012FilesKarachi NPP performance