Objective

When assessing the NPPs operation safety level, one of the major elements is the residual lifetime of equipment and components. Continuous operation of the NPPs for power generation leads mainly to:

1) normal ageing of the operating equipment components;
2) ageing related to the different operation modes of these components which cause systematic and accidental failures due to wear, corrosion, erosion, structural deformation and loss of resistance and/or insulation properties of the materials.
A measurement-based system for defining the residual lifetime of equipment and components in Russian NPPs in compliance with the national regulations has been set up in order to:

collect real-time, valid and thorough data on the evolution of properties of the materials of equipment and components of all the Russian NPPs power units;
allow coherent statistical processing of data on reliability of equipment and components of the same type in different NPP power units.
The main objective of the project is to provide the Russian Beneficiary with a set of tools and normative documents (procedures) containing guidelines for residual life assessment of mechanical components of Russian VVER NPPs and apply them to Novovoronezh NPP Unit 3.

The objective is defined with the following tasks:

Task 1: Project management.
Task 2: Transfer of information.
Task 3: Preparation of normative documents (procedures).
Task 4: Assessment of Residual Lifetime.
Task 5: Assistance in the submission of the normative documents.
Task 6: Assistance in improving the Maintenance Programmes.
Task 7: Reporting.

Planned outputs:

Task 1.1:
Project related time schedule, work plan and QA Programme.

Task 2.1:
Report on the current programme used for determining residual lifetime and standard and preventive maintenance actions in the Contractor’s country.

Task 2.4:
Report on the information gathering visit of selected Beneficiary and Local Subcontractor experts to the Contractor’s country.

Task 3.2:
Report defining the contents of normative documents (procedures) for each class of mechanical components.

Task 3.3:
Report on the specification of mechanical component classes (such as heat exchanges, valves, pumps and mechanical supports) for which the basic normative documents (procedures) are to be developed.

Task 3.4:
Report on the methodology and parameters characterising the limit states used for assessing the residual lifetime of mechanical components in accordance with the VVER NPP safety requirements.

Task 3.5:
Report listing the equipment and devices (including sensors) necessary to make the measurements for assessing the residual life of mechanical components.

Task 3.7:
Report on all actions related to the preparation of the normative documents (procedures).

Task 4.5:
Report on the actions related to the assessment of the residual lifetime of mechanical components at a pilot VVER NPP unit.

Task 5.4:
Report on the actions related to the assistance during the process of submission of the normative documents (procedures) to the Russian Regulator.

Task 6.3:
Report on the assistance provided to the Local Subcontractor for the development of the on-site maintenance programme.

Task 6.4:
Report on the assistance provided to the Local Subcontractor during the process of submission of the maintenance programme to the Russian Regulator.

Task 7.2:
Final project report.

Result

The project resulted in all the outputs agreed in the Inception Report. An essential result for the Beneficiary is the availability of the new sophisticated software, representing new Western trends in the lifetime management of the NPP components, integrating different kinds of data from the operation to the maintenance records.

Although the scope of work was limited due to the budget and time constraints, thus affecting also the results per se, the actual achievements can be considered as really good and useful for the Beneficiary. The project resulted in the successful transfer of the methodology and the preparation of a solid basis for introducing a new normative approach for the assessment of the residual lifetime of the NPP components, acceptable also for the safety authorities. This was confirmed by the practical application of the generated documents/procedures for the pilot case NV-3. Thus the objectives can be considered as achieved.