Monitoring & metering I
n the 1980s and 1990s, distributed control systems (DCSs) were typically installed as integrated platforms that incorporated radiological surveillance functionality in the same hardware and software environment. At the time, this made sense. Systems were engineered to the standards of the day, and expected facility lifespans were significantly shorter than those now anticipated.
Today, however, nuclear facilities are routinely expected to operate for at least 80 to 100 years. That fundamental shift has exposed the limitations of tightly coupled control and monitoring architectures, particularly where safety-critical radiation surveillance is concerned.
WHY SEPARATING DCS AND RSS MATTERS
Over time, industry best practice has evolved to recognise that DCSs and radiological surveillance systems (RSSs) serve very different purposes. A DCS is designed to manage and control industrial processes whereas a RSS exists to protect people and the environment.
Separating these systems and ensuring they rely on different hardware and software significantly reduces risk and prevents faults. This separation is now a standard requirement for new nuclear installations and upgrades across all the UK’s nuclear sites and is supported by the Nuclear Decommissioning Authority (NDA). Early detection of radiological anomalies and the ability to trigger alarms and evacuations quickly are critical. Therefore, these functions must remain operational regardless of what is happening elsewhere in the control architecture.
THE NUCLEAR OBSOLESCENCE CHALLENGE
One of the biggest challenges facing nuclear operators is that, while legacy DCS and RSS platforms are becoming obsolete, the facilities remain operational beyond their original
UPGRADING RADIOLOGICAL SURVEILLANCE SYSTEMS IN NUCLEAR FACILITIES
Nuclear plant operators face an uncomfortable reality: many of the control and monitoring systems still in use today were never designed to support the full operational lifespan of the facilities they serve. Here Gary Bradshaw, director of radiation monitoring specialist Omniflex, discusses the impact of this harsh truth and explores how to overcome it.
expected service lives. In fact, many buildings are expected to remain operational for decades still to come, making long-term technological support non-negotiable.
Replacing an obsolete system in a nuclear environment is never straightforward. Wholesale replacement of sensors, cabling and field equipment introduces cost, risk and disruption,
particularly in radiation-controlled areas. For example, installing new network cables involving digging a cable trench is a major hassle as all the materials that have been disturbed must be radiation tested and carefully disposed of as hazardous waste. Risk assessments and method statements must also be written up to determine how the new trench will impact radiation protection across the site, making the process even more complicated. This makes it prohibitively time and cost intensive in most scenarios. Therefore, the challenge is not simply to modernise, but to do so intelligently by reusing existing infrastructure wherever possible while bringing systems in line with modern standards.
DESIGNING FOR FLEXIBILITY AND LONGEVITY
This is precisely the challenge we set out to address when we began working with Sellafield in the mid-1990s. At the time, many of the radiation protection monitors in use were still current models, but operators needed a way to decouple RSS functionality from DCS platforms. The Omniflex solution was to develop a range of modular products, including the Maxiflex and Teleterm series, to provide a
44 April 2026 Instrumentation Monthly
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