R1.06/05 - On-site Assistance to Beloyarsk NPP

The On-Site Assistance (OSA) programmes are a corner stone of the TACIS nuclear safety co-operation with the Russian Federation. Companies or consortia with experience of NPP operation in the EU are contracted by the EC to work on site at nuclear power plants of the Beneficiary country. The aims are to provide the transfer of know-how, in particular through soft assistance, which addresses the human element of safety (i.e. safety culture, quality assurance, maintenance, management and training,…), and to upgrade the safety of the plant through the supply of equipment. At Beloyarsk NPP, the soft assistance also included technical exchanges on topics specific to the operation of sodium-cooled FBRs. Through the TACIS programme, OSA projects were implemented at seven NPPs in Russia (Kola, Balakovo, Kalinin, Leningrad, Smolensk, Beloyarsk and Novovoronezh).

The aim of the On-Site Assistance programme at Beloyarsk NPP was to combine the experience of the OSA Consultant with the experience and needs of the Nuclear Power Plant (NPP) operator in order to:
improve the operational safety of the Beloyarsk NPP through the transfer of know-how and operational best practice;
identify, prepare and implement safety related specific projects which include the tendering and procurement of equipment required to improve the safety of the power plant.
The activities to be implemented were organised under three general areas:
General Operational Assistance
General management and coordination of the contract
Support and advice to the NPP in licensing problems
Exchange of experience on NPP management or modernisation, including short term training
Experience feedback on completed TACIS projects
Soft On-Site Assistance
Maintenance, ISI & Repair of sodium circuit components
Protection against sodium/water reaction.
Maintenance of the new water/steam valves.
Hard On-Site Assistance
Implementation of the Plant Improvement Project (PIP):
• R1.06/05A, Lot 1A: Replacement of safety-related steam/water valves.
• R1.06/05A, Lot 1B: Supply of tools for the valves replacement project.
• R1.06/05A, Lot 2: Supply of emergency circuit breakers.

Assist the EC in the preparation and the implementation of the call for tender, tender evaluation and contracting for Lot 2 of the PIP (Lot 1 was successfully tendered prior to signature of the present contract).
Assist the EC in contract management of all lots of the project, including follow-up of manufacturing and factory tests, documentation approval, licensing support, delivery & customs clearance, assistance during installation, site testing & commissioning, follow-up of the warranty period, etc.

General Operational Assistance
The General On-Site Assistance was performed in accordance with the requirements of the contract.
In support of the PIP equipment supply projects the Consultant prepared explanatory notes on the administrative procedures applying in Russia for imported equipment for use in NPPs and on GOST-R and OIT procedures for replacement of the water/steam valves at BNPP.
Several training courses were organised and implemented by the OSA Consultant specifically addressing sodium-cooled FBR issues and which were aligned with the programme of soft OSA activities.
Soft On-Site Assistance
Soft On-Site Assistance in the present contract comprised the transfer of experience and know-how on a significant number of issues through workshops, presentations, preparation of technical documents, visits to nuclear plant and facilities, training courses and on-the-job training.
Maintenance, ISI & Repair of sodium circuit components
1. Exchange of information on inspection techniques for sensitive primary circuit components
The Consultant shared its considerable experience and provided operational feedback in all the areas of in-service inspection / monitoring described below, which allowed BNPP considerably to improve its in-service inspection and monitoring capabilities:
Ultrasonic inspection at high temperature: It is important to be able to inspect the pipes and equipment of the sodium circuits of FBRs, particularly those classified as important to safety, either because they fulfil a safety function or because their failure could impact a safety function. Ultrasonic inspection techniques allow such kind of inspections, but it is necessary to be able to apply them at high temperature (>100°C).
Inspection of the primary circuit internal structures and components: The internals of a nuclear reactor are elements important for safety. For a pool-type FBR these include the primary pumps, intermediate heat exchangers (IHX), above core structure (ACS), core support structures and the primary vessel. Some of these components can be readily removed whilst for others it is more difficult. The primary vessel and core support structures cannot be removed and require in-situ inspection.
For the upper parts of the reactor block, internal structures and components, remote visual inspection is possible by lowering the sodium level down to the top of the fuel assemblies, but a special safety analysis is required when lowering the sodium level below the IHX inlets.
The structures supporting the reactor core are of particular importance, since their degradation could jeopardize the main safety function "control of reactivity". The Consultant has developed a methodology for ultrasonic inspection of the welds of the core support shell.
Vibration monitoring is a technique that can be used to confirm that there is no evolution of the structural integrity of reactor internal components.

Laser metrology of primary structures: Geometrical stability of the reactor block and primary structures is of utmost importance. The Consultant has experience with the installation of a surveillance system based on laser metrology to monitor the displacements of the important structures and components. Information on displacement monitoring of secondary circuit pipework was also exchanged.
Leaktightness of sodium circuits: Sodium circuits are not pressurised and their pressurisation could cause a sodium spray fire in case of a defect. Therefore, pressure testing cannot be used for performing tightness tests. The Consultant has experience in the application of alternatives to pressure testing at FBRs.
Condition monitoring of rotating machines: Vibratory diagnostics is an important technique which can be used to provide early detection of possible defects in rotating machinery, thereby allowing timely preventive maintenance before any failures are likely to occur.
2. Exchange of information on repair of sodium components
The Consultant shared with BNPP its long experience, knowledge and skills gained in repairing of sodium components carried out on the Phénix NPP. The procedures and techniques covered are applicable to:
Steam generators
Intermediate Heat Exchangers
Primary vessel and internals
Sodium pumps
Sodium pipes, valves and tanks
3. Damage accountancy of components
The Consultant provided information on the methodology, developed by the Consultant, for Events Accounting. This methodology consists of identifying the significant events (in terms of fatigue and creep damage to the critical components of the reactor) that have occurred during the lifetime of the reactor in order to create and maintain a real time, up-to-date damage assessment and residual lifetime evaluation of these critical components.
Protection against sodium/water reaction.
The Consultant shared its experience with BNPP in the area of sodium-water reaction detection and protection measures. Sodium-water reactions are critical events in sodium-cooled fast reactors. A specific monitoring of the steam generators and secondary loops is implemented in order to detect as soon as possible any leak between the steam/water circuit and the sodium circuit. This permanent in service monitoring is complemented by tests carried out during outages to detect incipient leaks in the steam generators (radioactive tracer gas tests are applied). On detection of a leak during operation, protection measures have to be implemented in order to manage the incident and mitigate its consequences. The Consultant shared its design and operational experience of the systems implemented at the Phénix FBR.
Maintenance of the new water/steam valves.
A major part of the current On-Site Assistance at Beloyarsk is the supply of a large number of valves for the water/steam circuit. To complement this equipment supply project, the Consultant shared its experience with BNPP in the maintenance and operation of water/steam valves at the Phénix FBR.
Other soft On-Site Assistance topics
During the course of the project exchange of information was agreed on a number of other topics related to sodium circuits:
a) Design of the secondary circuits trace heating systems and sodium leak detection systems.
b) Design provisions for protection against sodium fires.
c) Sodium cleaning methods for components and fuel.
d) Sodium pipeline lifetime assessment.
e) Decay Heat Removal (DHR):
The Consultant presented its experience related to DHR circuit design and operation at the Phénix and Superphénix FBRs. As a result of the information exchange, BNPP adopted the Consultant's concept and decided to implement an additional, independent DHR system. The Consultant analysed BNPP's preliminary design of the new DHR system and made a number of recommendations that were incorporated into the design. Implementation of this new system will significantly improve the safety provisions of BNPP for decay heat removal.
Hard On-Site Assistance
Concerning the different Lots of the PIP project, the Technical Specifications, evaluation criteria and Tender Dossiers had been prepared in the framework of the previous OSA contract (R1.06/02) and tendering of Lot 1 had been successfully carried out. However, tendering of Lot 2 had to be repeated in the framework of the present contract and some modifications to the tender documents were necessary. These modifications were implemented by the Consultant and the call for tender, tender evaluation and contracting were successfully performed for Lot 2.
The status of the PIP project at the end of the present OSA contract was as follows:
R1.06/05A, Lot 1A: Replacement of safety-related steam/water valves. The project comprises the supply of 231 valves for the water/steam circuit. These are supplied in three identical sets of 77 valves, one set for each of the three water/steam circuits of the NPP. The first set has been delivered and installed, and the warranty period is ongoing. According to the original schedule, the installation of the 3 sets of valves will take place in 3 consecutive plant outages. The installation of the second and third sets will therefore take place in the following two outages, which will be in the framework of the follow-on contract for OSA to Beloyarsk NPP.
R1.06/05A, Lot 1B: Supply of tools for the valves replacement project. This project comprises the supply of four cutting and bevelling machines for preparing the pipes where the valves will be installed, four automatic welding machines for welding the valves in place and two induction heating machine for thermal treatment of the welds. All tools have been delivered and used for the installation of the first set of valves. The warranty period is ongoing at the end of the present OSA contract.
R1.06/05A, Lot 2: Supply of emergency circuit breakers. This project comprises the supply of around 400 circuit breakers for the low voltage power supply system of the NPP. All breakers have been delivered to the NPP. By the end of the present OSA contract a small number had been installed. Installation of those breakers which can be installed during plant operation is continuing. Installation activities are planned to be completed in the next plant outage.
Further Information
The subsequent project for On-Site Assistance to Beloyarsk NPP was project no. R1.06/09.