Extending Boiler Lifetime at Dungeness B: Delivering a seismically qualified cubicle solution to support long-term reactor operation

Project Overview

Client: EDF Energy - Dungeness B

Market Sector: Generating

Supporting EDF’s Commitment to Safe, Reliable Generation

EDF’s Dungeness B power station, part of the UK’s Advanced Gas-cooled Reactor (AGR) fleet, required modernised instrumentation cubicles as part of its Boiler Lifetime Improvement Programme. These cubicles support the systems that protect and regulate boiler performance — equipment essential to maintaining the station’s safety case and continued operational reliability.

EDF turned to AMS Nuclear for a solution that would not only meet stringent nuclear design and quality requirements but also deliver long-term value. The project demanded precision engineering, seismically qualified equipment and an assured delivery schedule to align with planned outages.

AMS Nuclear delivered a fully compliant, right-first-time solution ahead of programme, supplying 16 instrument cubicles substantiated to Class 2 seismic and environmental qualification standards. The project was completed on time and within budget, enhancing measurement accuracy, maintainability, and lifecycle performance. Designs were substantiated for continued operation through 2028, supporting safe defueling to 2033.

The Challenge. Designing a Solution Built for Precision and Performance.

EDF’s challenge was to replace the existing instrument cubicles for three key systems: the Automatic Boiler Depressurisation System (ABDS), Boiler Overfeed Protection System (BOPS), and Safety Relief Valve Isolation System (SRVI) with a modern, fully qualified design.

Each system plays a crucial role in the station’s protection strategy, relying on accurate pressure and flow measurement to support automated control logic. The new cubicles had to meet stringent requirements for Class 2 safety-related equipment, incorporating redundant channel segregation, environmental qualification and lifetime substantiation to 2033.

AMS Nuclear’s role was to take full responsibility for the design, build, substantiation and testing of 16 instrument cubicles, while maintaining alignment with EDF’s established engineering and quality assurance framework.

Our Solution. A Collaborative Engineering Approach.

AMS Nuclear developed a bespoke, right-first-time design that balanced technical rigour with practicality. Each cubicle was substantially re-engineered to meet EDF’s performance expectations, seismic withstand requirements and human-factors guidance for ease of operation and maintenance.

The design incorporated:

Segregated compartments to isolate system channels and maintain redundancy.
Welded stainless-steel manifolds and process pipework for long-term integrity.
Nuclear-qualified instrumentation, including GE Unik 5000 pressure transmitters, Delta Controls 201 pressure switches, and Rosemount 3152KD differential transmitters.
Ergonomic layouts that simplified calibration, inspection, and maintenance access.

AMS Nuclear worked closely with EDF’s design authority and quality teams throughout the project lifecycle, ensuring every engineering decision aligned with the site’s operational and safety case requirements.

EDF’s specifications leave no room for interpretation. We built in rigour from the start — every weld, test, and document was traceable to the highest standard.

Engineering Manager, AMS Nuclear

Our Delivery. Delivery with Assurance and Accountability.

From the outset, AMS took responsibility for delivering a complete, quality-assured solution. The project followed a structured lifecycle from concept to completion:

Design and Substantiation: Full engineering analysis and documentation produced to EDF’s CTS-214 Class 2 standard.
Manufacture and FAT: Fabrication under controlled conditions, with witnessed Factory Acceptance Testing (FAT) to verify compliance.
Quality and Documentation: Delivered under QA Grade 2 with complete Lifetime Records Packages (LTRPs).
On-Site Integration Support: Engineering input provided to EDF installation teams during commissioning preparation.

All 16 cubicles were delivered ahead of programme, enabling EDF to align installation with its planned statutory outage and maintain its generation schedule.

SRV Discharge in the AMS Nuclear workshop

Measurable Results. Enabling the Future of Safe Nuclear Operations.

The Dungeness B project demonstrates how AMS Nuclear combines technical expertise with disciplined delivery to solve complex engineering challenges. Through collaboration, precision, and a commitment to right-first-time outcomes, AMS Nuclear provided EDF with a dependable, compliant, and long-term solution – strengthening the integrity of one of the UK’s key nuclear assets.

Our approach is always about ownership. From design and substantiation through to manufacture and delivery, we make sure every detail meets the client’s specification and regulatory expectations.

Project Lead, AMS Nuclear

Delivering a seismically qualified cubicle solution to support long-term reactor operation