3.2 INSPECTION AND ASSESSMENT ACTIVITIES AT NUCLEAR INSTALLATION:
JE EBO, V-2 NUCLEAR POWER PLANT
EBO V-2 NPP consists of two units with WWER 440 improved type of V-213, which were commissioned in 1984 and 1985. The status of NPP in 1998 is characterized by stable operation, while in the first half of the year the units operated mainly in a automatic "primary control mode" according to the needs of the electric system within the range of nominal capacity (96+/-4%). Based on the request of the Slovak Energy Dispatch Center, both units of EBO V-2 NPP in the second half of the year operated in basic load mode, without regulation according to the needs of the electric system. On both units during, planned outages overhaulings were performed based on a long-term maintenance plan.
In 1998 assessment activities of UJD focused on review of documentation of safety important systems and components of nuclear power units as these were prepared within the elaboration of a safety improvement programme on EBO V-2 NPP and submitted to UJD by the operator.
From those most demanding activities was the
assessment of mechanical strength of the bubble tower water tray system in case of large leakage of coolant from the primary circuit. Assessment of this issue required elaboration of 11 strength analyses. In their assessment UJD co-operated with the Material and Technology Faculty of Slovak Technical University in Trnava, which prepared control analyses for the bubble tower system of EBO V-2 NPP based on numerical methods.
When assessing operational events of EBO V-2 NPP the most important reasons were the following:
Statistical overview on the number of operational events on EBO V-2 NPP and their categorization in INES scale is also shown in Fig 4.
Inspection activity at EBO V-2 NPP focused on planned inspections in compliance with the plan of inspections by UJD. Inspections were directed into areas of verification of adhering to limits and conditions during operation of units, physical protection of the nuclear installation, storage of fresh and spent nuclear fuel, following the program of quality assurance during operation and maintenance, qualification and training of personnel, in-service inspections of the equipment, on control of imposed measures from the previous resolutions and protocols from UJD inspections. Control of fulfillment of tasks, based on follow-up inspections, allows stating a continuous meeting of requirements of the regulatory authority within the set dates.
Based on an overall assessment of results from both assessment and inspection activities, and taking in regard evaluation of operational indicators (see Fig. 4, 5 and 6) UJD evaluated operation of EBO V-2 NPP in 1998 as safe and reliable .