Upgrading the quality of the in-service inspections of the main primary components (steam generator, main coolant lines, reactor pressure vessel) of the VVERs has been seen as a major contribution for Safety upgrading of these NPPs. This target appeared to be attractive for East European plant operators, who expressed their needs in several occasions in the early 90s.
The main components of the Primary Circuit of the VVER 1000 units were selected for that purpose. The general aim was to ensure the long-term consistency of the in-service inspection policy for these NPPs by defining a framework for the various needs (hardware, software, training, qualification and certification systems, ISI management), based on the available experience and expertise and taking into account the specific requirements. The practical aspects would result in the development of tools (upgraded procedures and instructions, technical specification) for the implementation of the most efficient projects, to be selected among the identified proposals, provisionally considered in the TACIS and PHARE 1993 & 1994 budgets.
It was recognised that both the industrial potential provided by the NDT Services Companies and the ISI programme consistency guaranteed by the Utilities, shall be considered. It also appeared that a separate frame for each branch would work the best. Therefore, the optimum chosen by the European Commission was to set-up two twin projects (R2.05/93 & R2.05/93bis) having the same aim.
The objectives of the projects have been defined as follows:
- Transfer of scientific-technical information on experience, results, reliability and implementation in the field of NDE in West European NPPs;
- Assessment of Russian NDE data available from examination performed during manufacturing, erection and operation;
- Prioritisation of the development actions for the different main primary components;
- Development of a technical specification for the delivery of in-service inspection equipment;
- Elaboration of improved and optimised instructions for in-service inspection;
- Presentation of the results to Gosatomnadzor (GAN).
Four main tasks have been originally identified and worked out:
- Assess and elaborate improved in-service inspection programme.
- Assess and define improved technique, operator qualification and training programme.
- Specify the needs for equipment and services for future projects.
- Provide assistance to the beneficiary for the implementation of future projects into a long-term perspective and its follow-up.
The objectives set forth in the TOR were properly covered by the deliverables. All tasks have been achieved as per TOR, but deeper and more voluminous than originally foreseen, except task 4, which could not be worked out at the expected level.
Valuable information on the status of the current ISI programmes in Western European and Russian NPPs has been exchanged and discussed. The general policy for upgrading the ISI instructions with long-term views was discussed and proposed. Some more practical results were achieved like the identification of immediate improved ISI techniques for ISI of primary component, ISI handbook outlines to be used as examples of good practice, Technical Specifications for procurement of ISI equipment, as well as recommendations for the implementation of advanced training courses.
The co-operative work and the documentation provided has had a positive impact by improving the safety culture and building-up a desirable policy for implementing a consistent ISI system, even if no implementation of significant procurement projects has been implemented in that framework in Russia so far.
(The equipment part has been supplied under Project R2.05/93-supply part “NDE Equipment including Manipulator for Main Circulation Piping Inspection”).