Small Modular Reactors for Data Centres: The Nuclear Security Dimension
As the UK explores Small Modular Reactors (SMRs) to power our fast growing Data Centre sector, the conversation often centres on engineering and carbon savings. But one element is less understood outside the nuclear industry, what makes nuclear security different.
The UK already has some of the most stringent standards in the world, enforced by the Office for Nuclear Regulation (ONR) under the Nuclear Industries Security Regulations (NISR) 2003. Any SMR built to supply a Data Centre would need to comply fully.
So, what is unique about nuclear security compared to “normal” Critical National Infrastructure?
The Design Basis Threat (DBT)
Unlike standard facilities, nuclear sites must be designed to withstand specific threat scenarios defined by government, including highly capable adversaries and the risk of insider threats. These assumptions aren’t generic however they are UK-classified planning requirements, and the site must prove its security measures can delay, detect, and respond to those scenarios.
Graded Protection of Nuclear Areas
In a Data Centre, security often focuses on the layered protection of server halls and network rooms. In an SMR, the highest protection applies to “vital areas” where access could directly impact nuclear safety. The design must layer access and barriers so that even trusted insiders cannot move freely between Data Centre functions and nuclear systems.
Control of Sensitive Nuclear Information (SNI)
Blueprints, layouts, and technical details of nuclear systems are classed as Sensitive Nuclear Information. Unlike some CNI and general commercial information, SNI has strict handling rules around who can access it, how it is stored, and how it is shared with contractors. This applies to all forms of information including digital models (like Building Information Modelling) just as much as paper and hard copy drawings.
Specialist Workforce and Vetting
Not everyone working on a shared campus can enter the SMR. Nuclear staff and contractors require enhanced background checks and ongoing monitoring. This level of scrutiny is unique to nuclear facilities, and far beyond what is currently typical in the Data Centre sector.
Protest and Public Attention
While many critical facilities face protest risk, nuclear sites attract particular focus. Security arrangements must assume well-organised attempts to access or disrupt operations. Designs therefore plan for controlled protest management while still ensuring the nuclear zone remains protected against unlawful entry.
Why it Matters for Data Centres
Closing Thoughts
SMRs could offer the reliable, low-carbon power that UK Data Centres urgently need. But alongside engineering and finance, leaders must understand that nuclear security brings its own non-negotiable standards, from protecting sensitive information to planning against national threat scenarios.
Getting this right will determine not just whether SMRs are approved, but whether communities and customers accept them as part of our digital future.
Gary T.
‘Behind the meter’ applications for SMR does not necessarily require physical co-location, the impact of which may be to drive up the cost of protecting the data asset by potentially requiring it to adhere to higher requirements and more robust security outcomes.
Very insightful; I thought I was the only one really thinking about having SMRs next to a data center to solve the heavy demands on the consumer electricity grid. Especially now with AI data centers being built.
Who has built one and how much did it cost?
What I really like about this framing is that it establishes a natural baseline for cross-collaboration between two forms of critical infrastructure, power and data. If we already treat both as national security assets, then colocating them under unified standards of resilience and protection feels less like a wild idea, and more like the logical future. Aligning them side by side could be the next evolution of critical national infrastructure security.