Modernising digital I&C

Image: A major I&C modernisation has been completed at the Loviisa nuclear plant in Finland (Photo credit: Fortum)

MOST OF THE NUCLEAR POWER plants in the world have been in service for more than 30 years and are pursuing life extensions to at least 60 years. Their equipment, including old and analogue instrumentation & control (I&C) systems, must be modernised to address obsolescence issues, preserve or enhance their safety and operating licence according to applicable standards, improve their productivity and cut operating costs.

The modernisation or deployment of new I&C systems in commercial nuclear power plants, in particular safety- classified I&C, is complex and risky. Aspects that should be considered while building the scope of the modernisation include qualification and licensing, schedule constraints, overall budget, operating experience of the new system, harmonisation between the new and old systems (especially when the new equipment is based on digital technology while the rest is analogue) and organisational requirements.

Rolls-Royce has developed a complete range of solutions and services to support nuclear utilities for their plant life extension (Plex) and subsequent licence renewal projects as well as efforts to extend the life of individual systems.

Its capabilities include qualification and licensing support in a variety of country settings, extension of qualification, definition of an I&C Plex modernisation strategy (including development and vetting of requirements), system design, I&C Plex turnkey projects (modification, partial and global modernisation), I&C integration, long-term system support and supply chain management.

Rolls-Royce has proprietary analogue and digital technologies (Spinline®, Rodline®, HardlineTM, Boronline®), specifically designed for nuclear applications.

Pre-studies and licensing preparation

For major modernisation projects, utilities and equipment suppliers are required to adapt their plant and critical system design to comply with the latest local regulations and standards. This can result in significant new I&C design and licensing efforts, if standards have significantly evolved since the design and installation of the systems to be replaced or if transitioning from analogue to digital technology.

To minimise these risks, an appropriate methodology must be applied right at the start of the project, including licence application and conceptual or basic design phases.

The availability of the best skillset in I&C experience and project and engineering processes is also key to success. This particularly applies to safety and safety-related I&C, which is closely scrutinised by nuclear regulators.

Capitalising on its experience of various licensing regimes in France, USA, Finland, Czech Republic, China and Slovakia, and the successful completion of safety I&C-lifecycle projects based on IEC standards (IEC 61513, 60880, 62138, 60987, 60780), Rolls-Royce can:

• capture, analyse, organise and trace the huge amount of applicable licensing, design requirements, and input data
• review and propose improvements to the safety I&C architecture specifications, taking into account independence, diversity, interfaces, technology, qualification and performance requirements
• support the preparation of delivery-phase plans, on project quality management, licensing, qualification, cybersecurity, verification and validation etc.
• contribute to safety analyses consolidated by the reactor and plant designers
• support the plant-specific Preliminary Safety Assessment Report for I&C and related chapters.

Such preparation works were provided early in the modernisation of the I&C of two VVERs in Finland’s Loviisa and for the biggest I&C modernisation project in the world: EDF’s 20-unit 900MWe fleet in France.

The customers benefited from:

• a better assessment and more robust safety case related to the safety I&C systems
• documents generated to make up a significant input for the safety authority, so it could issue a preliminary decision on I&C architecture suitability during the licence approval process
• reduced risk of cost overruns and project delays during the main contract execution.

Deployment

Rolls-Royce is currently involved in the digital upgrade of safety-related I&C systems at 60 nuclear units worldwide. This mainly relates to modernisation of class 1E systems such as reactor protection systems and neutron flux monitoring systems, but it includes non safety-related systems such as rod control systems.

In France, under EDF’s Grand Care´nage (major re-fit) industrial programme, which aims to extend the operation of nuclear power plants across France beyond 40 years, Rolls-Royce is currently performing safety I&C modernisation projects for EDF’S 900MW fleet (34 units) and 1300MW fleet (20 units).

For the 1300MW fleet, Rolls-Royce is delivering digital technologies with Spinline for the reactor protection system and neutron instrumentation system, and Rodline for rod control systems. So far 12 units have been modernised, as planned.

For the 900MW fleet, Rolls-Royce is modernising the neutron instrumentation system, replacing the existing analogue system with a Spinline-based digital system. The rod control system is being upgraded by modifying specific parts (cycler, logic and power), as per customer requirements.

In China, Rolls-Royce is modernising the analogue neutron instrumentation system at CGN’s Daya Bay with digital technolgy with Spinline. Rolls-Royce is provding design, manufacturing, supply and installation for replacement of six electronic cabinets per unit, including the conditioning and processing cabinets.

An equivalent project at Lingao was successfully completed on schedule in 2017.

Qualification extension

When nuclear operators want to extend the lifetime of their nuclear reactors, they have to re qualify equipment that has not been modernised since startup and that was qualified for the original reactor life.

Rolls-Royce avoided replacing robust equipment – reducing costs – by carrying out a set of tests (EMC tests, seismic tests, lightning shock, etc) and studies to justify proper functioning for the extended lifetime. This included classified inverters as well as bibloc® pressure transmitters.

It has also developed a comprehensive service package and is committed to maintaining the capability to manufacture, modify, repair and test at board, rack and system level. Long-term support agreements last 20 years and more, and include services such as technical assistance, on-site maintenance, training, spare parts supply and repair, technical intelligence and obsolescence management.

A contract for long-term support of I&C systems and equipment for EDF’s French operating fleet was renewed in 2018 for 10 years. Similar contracts are in place in China, Czech Republic and Finland brings to 80 the total number of reactors supported.

Addressing a heterogeneous fleet

The right skills and experience are even more necessary when addressing a fleet comprising different designs or technologies. Most utilities in the USA that need to modernise their fleet own a mix of PWRs and BWRs, often based on different designs.

One solution would be to address each modernisation independently from the others and choose the best supplier and platform for this particular design, but it does not provide the benefits of a fleet approach, including shared equipment, spare parts, knowledge, support/ maintenance etc. A better solution is to tackle all the modernisations with the same technologies and provider but this is only possible if the technologies can be easily adapted to all the architectures and systems specific and if the supplier can meet efficiency standards across these different designs.

Rolls-Royce I&C technologies can easily be adapted to perform varied functions with no, or very limited, new developments.

Overall, our Rolls-Royce experience offers:

• capability for an in-depth I&C engineering dialogue with the end user and the most stringent safety authorities, to demonstrate that the proposed solution meets safety requirements
• experience in modernising various vintage plant designs using obsolete analogue technology with our digital and modular I&C technologies
• installed operating experience of over 30 years digital with zero failures on demand
• capabilities and readiness to manage complex projects, in close cooperation with local partners and sub- suppliers
• long-term support of the technology with capability to manage component obsolescence.

We can support nuclear operators by helping them to face this challenging step in the lifetime of their nuclear reactors.

Author information: Arnaud Duthou, Marketing segment manager at Rolls-Royce; Romain Desgeorge, Marketing segment manager at Rolls-Royce