MOC for instrumentation and control systems of nuclear power plants

Context and challenges

The project for this client, a major player in the nuclear industry, concerns Maintenance in Operational Condition (MOC) for its systems, in particular the KIT N1.
This system is in fact a processor that ensures acquisition of the majority of digital (On-Off) and analogue (ANA) signals in a nuclear plant unit in order to make them available to the supervision systems for operational support.

For example, the standard KIT N1 configuration for a 900 MW plant unit is 157 acquisition PCB, 32 digital inputs and 24 acquisition units with 60 ANA inputs, for a potential total of 5,024 digital inputs and 1,440 ANA inputs.
Every KIT N1 at all 54 of the 900 and 1300 MW nuclear power plant units requires maintenance operations.

Since 1991, the client has entrusted Assystem with the task of ensuring Maintenance in Operational Condition (MOC) for all the KIT N1 systems.

Project scope

Support for the client's maintenance teams (hotline, on-site work)
Equipment repairs in workshop (total of approximately 20,000 PCB – 700 repairs/year)
MOC for test and requalification rigs
Monitoring of component obsolescence
Technical studies (obsolescence management, malfunctions, technical and commercial aspects of upgrades)
System upgrade management, as part of bolt-on services
Skills maintenance to ensure long-term sustainability
Configuration management for software versions and test tools
Operation of national spare parts warehouse
Periodical re-qualification of spare part batches provisioned at sites for service work.

Client benefits

Extension of system service life well beyond initial estimates (>2030 compared to 2015), through the long-term sustainability strategy that was proposed and implemented
Scalability maintained on systems, enabling upgrades and integration of modifications required by client as part of plant renewal programs for the ten-year inspections and Major Refitting programme
Increased system availability, enabling the customer to improve user comfort for control operators