Background

A Nuclear Power Plant (NPP) is equipped with a large number of safety valves of various types, size and operating parameters. Such valves belong to the most heavily strained components of a power plant and thus have, in view of their safety function, to be checked, maintained, repaired and adjusted on a regular basis. Taking into account that the correct and accurate adjustment of the safety valves has a direct impact on the safety of the NPP, a reliable test bench for testing and adjusting these safety valves is necessary in order to ensure the proper execution of safety valves maintenance and testing. The Zaporozhye NPP was not equipped with such kind of state-of-the-art safety valve test bench.
Objectives

The subject of the project was to provide the NPP with a state-of-the-art test bench for adjustment and testing of safety valves to ensure the safety operation of the plant and thus contributing to the safety improvement of the plant.

The safety valve test bench includes

- Valve test bench for valves with a diameter of 10 to 400 mm, including clamping device, control unit and accessories

- High pressure compression unit for increasing the initial compressed air pressure of 7 bar up to 210 bar

- A PC based documentation system for recording, documenting and archiving the valve testing results

The main functions of the purchased equipment are:

- Testing of the valve body with pressurized water and air

- Testing of valve seat tightness with water and air

- Adjusting the set pressure of safety valves with air

The project includes:

- supply of the basic set of equipment

- the supply of spare parts

- the supply of consumables and wear parts

- design, manufacture, acceptance tests, certification, delivery, supervision of installation and commissioning and training of End user personnel
Project Results

The project started with the development of the Technical Specifications which were ready in October1997. The supply contract with the supplier of the test bench EFCO, Germany was signed in January 2001. The equipment including service and spare parts was provided in accordance with the contract requirements. The Final Acceptance Certificate has been signed in December, 2002.

The achievement of this project increased significantly the reliable function of the safety valves which increased the safety and reliability of the plant.