Objective

The project aim is to implement an expertise methodology on a pilot NPP in order to evaluate the status of the electrical cabling and residual lifetime.

Following related activities are to be performed:

Classification of cables according to Russian rules;
For 1E cables, definition of environmental conditions during normal operation, incident/accident operation (both in and outside containment) and post accident operation;
Define the actual status of 1E cables (both by laboratory tests on representative samples or by site on-line tests);
Determine for 1E cables associated degradation mechanisms and impact on electrical characteristics;
Determine actions to be undertaken by analysing the data gathered;
Define, specify and precise necessary monitoring equipment in the frame of the budget.
Result

The cables in the hermetic zone at NV NPP (Novovoronesh) Unit 3 were identified and classified. The cables were inspected in a walk down at the plant and the present condition of the cables was documented. The environmental conditions in normal operation and DBA (Design Basis Accident) condition were evaluated based on Russian documentation as well as on on-site monitoring during 6 months of plant operation. Cable samples were cut out from selected cables for qualification testing.

Also fresh cables delivered from Russian cable manufacturers were tested in order to evaluate the reference condition. The present condition of selected cables was inspected in the laboratories of RISI (Research Institute of Scientific Instruments). Cables were subjected to thermal and irradiation ageing, and the environmental conditions during normal operation and DBA were simulated. Cables were then tested in RISI in order to evaluate the condition of the cables. Based on laboratory testing, acceptance criteria were elaborated in order to determine the lifetime of the cables.

As a result of the project the residual lifetime of the cables in the hermetic zone at NV NPP Unit 3 was determined. The cable condition was checked and documented. Recommendations for future lifetime management of cables at the NV NPP have also been elaborated.