Improving Plant Availability Through Water Treatment Plant Upgrades

The Chemical Ingress Protection System was conceived to provide reliable detection of abnormal water chemistry and prevent contaminated process streams progressing further into critical plant systems. Rather than relying on a single measurement, AMS Nuclear developed a highly resilient architecture incorporating multiple independent conductivity monitoring channels, redundant sampling arrangements and sophisticated relay logic to ensure dependable operation while minimising unnecessary plant interruptions.

From the outset, the engineering challenge extended beyond simply measuring conductivity. The system needed to distinguish genuine chemical ingress events from instrument faults, temporary process disturbances and maintenance activities while providing operators with clear, meaningful information through both local indication and Central Control Room (CCR) alarms. Achieving this required careful integration of analytical instrumentation, sample conditioning equipment, relay logic, alarm management and plant interfaces into a single coherent protection system.

Working closely with EDF engineers throughout the concept and design stages, AMS Nuclear developed a protection philosophy based around four independent conductivity analysers operating in a two-out-of-four (2oo4) voting arrangement. This architecture allowed individual channels to be maintained or taken temporarily out of service while preserving overall system availability, reducing the likelihood of spurious trips without compromising operational confidence. Local Veto functionality, maintenance features, abnormality monitoring, comprehensive self-testing and differentiated alarm strategies were all incorporated into the design to support both operational flexibility and long-term maintainability.

The strength of the Chemical Ingress Protection System lies not only in its original design, but in its ability to evolve alongside changing operational requirements. Rather than delivering a single installation, AMS Nuclear continued to support the system through successive phases of development, applying lessons learned, introducing new technologies and refining the overall engineering solution as station requirements matured.

Early work centred on replacing ageing analytical instrumentation and developing improved conductivity monitoring arrangements, creating the technical foundations upon which the wider Chemical Ingress Protection System would be built. These initial projects provided valuable operational insight into analytical performance, sample handling and equipment integration, informing subsequent developments in protection philosophy and system architecture.

As the programme developed, AMS Nuclear progressed from instrumentation replacement to the design and manufacture of complete Chemical Ingress Protection Systems, incorporating purpose-built stainless steel sample conditioning panels, dedicated logic cabinets, redundant analytical instrumentation and sophisticated relay logic. The modular approach adopted during manufacture enabled safer installation, simplified future maintenance and created a flexible platform capable of supporting ongoing improvements throughout the system’s operational life.

The development of the Additional Chemical Ingress Protection System (ACIPS) represented another significant step forward. Building upon the original design, AMS Nuclear refined the alarm philosophy, introduced timer-controlled logic to minimise nuisance alarms and enhanced fault discrimination, ensuring operators received meaningful information without unnecessary plant interruptions. The engineering solution continued to prioritise reliability, maintainability and operational confidence while preserving the robust protection philosophy established during the original project.

While conductivity measurement formed the basis of the protection system, the true engineering challenge lay in combining multiple disciplines into a single integrated solution.

AMS Nuclear provided complete EC&I design covering analytical instrumentation, sample conditioning, electrical design, relay logic, panel manufacture, software configuration, documentation, testing and commissioning support. Each element was developed as part of a coordinated engineering package rather than as independent equipment selections.

The relay logic philosophy was carefully engineered to balance operational sensitivity with system resilience. Multiple analyser inputs, abnormality detection, equipment health monitoring, maintenance overrides and comprehensive testing facilities were integrated into the overall design to support both plant operations and maintenance activities. Rather than generating unnecessary plant trips, the system progressively escalated indications according to the developing condition, allowing operators to distinguish between approaching limits, confirmed contamination events and instrumentation faults.

Extensive Factory Acceptance Testing, calibration, pressure testing and documentation formed an integral part of every delivery, ensuring equipment was fully verified prior to installation and capable of seamless integration into existing station infrastructure.

One of the defining characteristics of the programme has been its ability to adapt to changing technology.

As original instrumentation approached obsolescence, AMS Nuclear continued supporting EDF through further engineering studies and replacement programmes, identifying suitable modern alternatives while preserving the established protection philosophy.

Most recently, the programme expanded to incorporate replacement of legacy conductivity analysers with Yokogawa FLXA402 instrumentation, ensuring continued availability of critical components while maintaining compatibility with the wider Chemical Ingress Protection architecture. Rather than redesigning the system from first principles, AMS Nuclear applied their extensive understanding of the existing installation to deliver a carefully managed technology transition that retained operational functionality whilst improving long-term maintainability and supportability.

This lifecycle approach demonstrates one of AMS Nuclear’s core strengths: designing systems that remain maintainable and adaptable throughout decades of operation rather than simply delivering a one-off installation.

The Chemical Ingress Protection System demonstrates the value of sustained engineering collaboration. Over more than a decade, AMS Nuclear has continued to support the evolution of multiple systems within the Water Treatment Plant through concept development, detailed design, manufacture, installation support, equipment upgrades and technology modernisation.

Each successive project has built upon the knowledge gained from previous work, allowing improvements to be introduced without compromising the reliability of the overall protection philosophy. This continuity has enabled consistent engineering standards to be maintained while adapting to changing operational requirements, advances in analytical instrumentation and the challenges of equipment obsolescence.

For nuclear operators managing ageing assets, this approach offers significant long-term value. Rather than repeatedly replacing complete systems, AMS Nuclear develops engineering solutions with future adaptability in mind, allowing critical protection systems to evolve alongside operational needs while maintaining the confidence demanded within highly regulated environments.

• Complete EC&I system design
• Analytical instrumentation integration
• Sample conditioning systems
• 2oo4 voting philosophy development
• Relay logic and alarm management
• Control Room integration
• Stainless steel process panel manufacture
• Electrical control panel manufacture
• Factory Acceptance Testing
• Site installation and commissioning support
• Obsolescence management
• Lifecycle engineering and modernisation