MOC for instrumentation and control systems of nuclear power plants

Industrial control systems Nuclear France

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

in figures


processors for nuclear power units


printed circuit boards

> 2,030

service life

Industrial control systems & nuclear: related projects

outil de recherche sémantique
Industrial data science Nuclear

Semantic search engine (GDI) for the decommissioning of a reactor

Etude de sites et permis Assystem
Siting & Permitting Nuclear

Siting and permitting for a Nuclear Power Plant

contrôle-commande site nucléaire assystem
Industrial control systems Nuclear

Renovation of the ventilation instrumentation and control system

Jumeau numérique dans le secteur nucléaire
Digital field services Nuclear

Digital Twin of a nuclear waste treatment plant

a question, a project?

Contact us