Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
2.9.3 General process for ensuring SSCs required for maintaining the units in safe shutdown
state after earthquake
Under the licensing documents and in accordance with licensing requirements and
conditions, Kozloduy NPP as the operating organization has developed a system of technical and
organizational measures to maintain proper condition of safety related SSCs through diagnostics,
performing preventive measures, maintenance, repair, testing, inspections and operational control,
replacing the structures and components with service life expired. A system for documenting the
results of the activities performed and the operational control has been established.
For qualification of all safety related SSCs of nuclear facilities a continuous process has
been created involving archiving (passports factory instructions), documentating (plans, programs,
instructions) and maintaining data (functional tests, avalability acts, monitoring) to ensure ability of
the equipment to perform its functions during its entire lifetime. This process is started with the
design of the nuclear facilities and will continue until the end of their lifetime taking into account
the aging of SSCs, modifications, repair, service history, failures of components, replacement of
components and distortions in the normal operating conditions.
At Units 5 and 6 "The list of SSCs classified according to safety, seismicity and quality”
[94] has been approved.
Maintenance and repairs in the Kozloduy NPP are performed by highly qualified and trained
personnel. The purpose of maintenance and repair is to ensure that SSCs are able to perform their
design functions and maintain the design features in accordance with the technical specifications of
nuclear facilities.
Activities for maintenance and repair include:
· planning of maintenance and repair;
· carrying out planned maintenance and repair;
· emergency repairs and removal of defects;
· quality control in maintenance and repair.
Scheduled maintenance and repair are performed to maintain and restore the equipment and
its components. These activities are consistent with the requirements of manufacturers, regulators
and normative-technical documents, have a certain periodicity and specified scope and cover the
following types of maintenance and repair: general overhaul, intermediate repair, routine repair, and
planned preventive maintenance.
The frequency and the scope of scheduled maintenance and repair are determined according
to their importance to safety, technical specifications and operating instructions containing the
operating limits of reliability of equipment and systems, results of current monitoring and periodic
functional tests, periodic analyses of the failures occurred and trends of important process
parameters and indicators for safe operation.
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