Engineering Centre for Diagnostics of NPP Components

B.P. Strelkov Director of the Centre

Main Activities Development, systems integration, commissioning and servicing of diagnostic and monitoring systems for nuclear power plants Development, manufacture and validation of transducers. Development and verification of special-purpose software. Modelling, development and tryout of inspection and diagnostic techniques for NPP components Organisation of in-service inspection and expert testing of plant equipment. Management of centralised databases on supervised equipment

The Centre grew up from a NIKIET division which has to its credit 30 years of expertise in the development, commissioning and testing of various inspection and diagnostic systems in use at nuclear plants and production reactors.

The main emphasis in the Centre's activities is placed on creation of new in-service inspection systems for plant components and pipelines and their application at NPPs.

A step forward was made in the field of ultrasonic examination of pipeline welds when manual inspection tools were replaced by advanced computerised systems which in addition to traditional ultrasonic inspection data provide high-resolution interior images of inspected objects.

Semi-automatic and automatic inspection systems for pipelines and components feature high sensitivity and accuracy.

The Centre's licences for nuclear-related activities

Working together with the scientific and production centre ECHO+, the Service and Diagnostic Centre developed an advanced automatic inspection system Avgur 4.4 which has been successfully tested since and recommended by the Russian regulator Gosatomnadzor for use at NPPs. An important distinction of Avgur 4.4 is its ability to size defects. All the above-mentioned NDE systems have been put in use at NPPs and ensure safe operation of pipelines.

Automatic ultrasonic system for weld inspection in the upper duct of pressure tubes	3-D flaw images

Ultrasonic inspection system with flaw visualisation (Avgur 4.4)	Semi-automatic ultrasonic system for inspection of 300 mm pipes

A very important line in the Centre activities is its R&D on automatic on-line leak detection systems.

An example of such an effort is a bilateral Russian-Japanese project which was aimed at development and installation of a leak detection system at the Leningrad NPP. The system is being installed at other RBMK plants as well.

		High-temperature microphone
	Instrumentation of the microphone leak detection system

The system's capabilities include:

• rapid leak detection (in less than 5 min) by the sound pressure technique against a very noisy background and with considerable signal attenuation;
• early leak detection by a very sensitive correlation technique;
• leak location with the help of the correlation or sound pressure technique;
• leak sizing based on the noises produced and location of the source of sound.

Instrumentation for measurement of airborne activity	Instrumentation for moisture content measurements

Leak location provided by the system's software

The Centre is involved in many projects seeking to develop and put into operation advanced inspection and diagnostic systems designed in Russia and other countries, to enhance operational safety of NPPs and fulfil the latest regulator's requirements, in particular:

• provision of a leak detection system for the main circulation circuit. The system measures moisture content, airborne activity and acoustic noise in the pipelines inspected;
• installation of a hydrogen monitoring system at the Leningrad NPP;
• upgrading of the system monitoring pressure tube integrity in RBMK reactors;
• assessment of effectiveness of passive hydrogen recombiners in RBMK reactors.

To enhance NDE quality, the Centre has been working on validation of inspection tools and techniques to use the most effective of them at the plants, and on development and revision of associated rules and regulations.