Operation Evaluation

The operation of the V1 was reliable, safe, ecological and economically advantageous and it confirmed the soundness of the company’s decision to generate electricity using these means.

This can further be documented by the results of some technical-economic indicators. Since the beginning of operation, the V1 achieved an average gross efficiency of approximately 30.7 %, the specific energy consumption from fuel, to produce electricity, reached an average value of 11.7315 GJ/MWh, while the own consumption remained at a level of about 7.9 %, the average unit load was almost 398 MW, and the number of operating hours of both units, meaning the overall time in which at least one of the TGs was connected to the transmission grid, reached 399,625 hours.

The following diagrams analyze the indicators, which are monitored at an international level, by the WANO (The World Association of Nuclear Operators) or the IAEA (International Atomic Energy Association).

The Load factor indicator shows the usage of the power plant, which is a ratio between the output and possible output in the selected time period. According to the Nuclear Engineering International magazine from May 2006, at the end of 2005 the “world” average lifetime (LF) value for PWR units, the category to which the WWER units belong, was 73.1 %. The lower values in the first years of operation were due to the initial bug fixing after the putting into operation and also due to the inexperience of the operating personnel. The lower values in 1993 and 1997–1999 were caused by unit downtimes in the course of the small and the gradual reconstructions. The values of this indicator were also lowered by the employment of the V1 units in supporting services.
Another of the operational reliability indicators is the number of automatic shutdowns (AS) of a reactor. Aside from the first years of operation, this value remained on an average level, with 1 to 2 interventions a year, and in the last years, after the monitoring and control system modernization the value was zero, up to 2004 when the AS protection was triggered by the malfunction of the TG22 unit transformer and in 2006 when it was triggered during the power-up after the general overhaul. These figures are internationally acknowledged and very positive.
Further indicators are related to the usage and operational reliability of a unit. The unit capability factor (UFC) is defined as the ratio between the possible production minus the planned and the unplanned downtimes and possible production, while the unplanned capability loss factor (UCLF) is defined as the ratio between the unplanned downtimes and possible production. These indicators were being watched since 1990. After the completion of the gradual reconstruction, both factors reached very agreeable levels, with the exception of 2006, when a TG22 generator had to be replaced at Unit 2, due to irreparable damage of the stator. The best values of this indicator were reached in the last year of operation, what is a testament not only to the quality of the facility but also to the high level of operational proficiency.
After the end of commercial operations, the V1 units were in a very good technical condition and the V1 NPP safety level was comparable to other nuclear facilities of a similar generation, which are still in operation in the world, and in many cases their lifetime is being extended.