QUALIFICATION OF SAFETY EQUIPMENT

The objective of the project was initially to (re)qualify VVER 230 safety related equipment in Novovoronezh and Kola NPPs under accident conditions (i.e. assuring it maintains the required level of performance). Both design and beyond-design basis accidents were taken into account. Since the operational lifetime of these early reactors needed extension for only a few years, the necessary improvements need to be economically in line with this extension period. The reference plant was Novovoronezh Units 3 and 4. The basis for qualification of components was the Design Basis Accident, the Loss of Coolant Accident (LOCA), corresponding to a break of 32 mm in diameter.

A recognized qualification methodology was developed;
A list of components to be qualified was set up;
Principally Instrumentation & Control (I&C) equipment is considered to be re-qualified;
Equipment qualification has been carried out with computer codes (Russian and Western codes);
For calculation a 32mm diameter LOCA was taken into account and Analyses were made using WAVCO and MARCH-AEP codes for comparison of steam-air-mixture parameters.
Constraints of the project:
Seismic qualification was not in the scope of the project;
Kola NPP was not taken into account;
Originally expected input data from TACIS Project R1.3/91 were not timely available