Engineering design: Five critical steps to drive certainty in the UK Nuclear Industry 

The UK is entering a pivotal phase in its nuclear journey. With the most ambitious expansion in decades now underway, the sector is scaling up—but capability gaps persist. The availability of skilled engineers, project professionals, and specialist suppliers remains constrained, placing intense pressure on productivity, right-first-time execution, and fast, informed decision-making. 

Meanwhile, the Government is under growing pressure to deliver more for public investment. Streamlined delivery models for new-build nuclear and advanced technologies are now central to the national energy strategy. Programmes like Sizewell C and the rise of Small Modular Reactors (SMRs) are set to redefine our energy landscape—but the challenge is no longer just what to build. It’s how to build it—with safety, assurance, and long-term value embedded from the outset. 

In this context, engineering design is no longer a downstream technical activity. It is the strategic engine of delivery—de-risking decisions, compressing schedules, protecting budgets, and securing regulatory confidence. 

At Actemium Design UK, we’ve delivered engineering design across key UK nuclear sites for more than 30 years. From mechanical handling and bespoke machinery to gloveboxes, CE&I and process systems, our proven approach has consistently delivered projects with safety, assurance, and lifecycle value at their core. 

Based on our experience, we believe there are five critical steps programme leaders must embrace to unlock delivery certainty through engineering design: 

Step 1: Engage Engineering Design early to define the problem—without constraining the solution 

In our experience, projects that overrun often do so before engineering even begins. Requirements are vague, interfaces unclear, and constraints get locked in – leaving teams to engineer around assumptions rather than solve the real problem. 

The solution is early, structured engagement. We work closely with clients to co‑create the scope and capture requirements before committing to a concept. 

This isn’t just good practice—it’s essential. Our systems-engineering approach starts with stakeholder mapping and leads to a traceable User Requirements Specification (URS) and Functional Requirements Specification (FRS). These documents anchor every design decision and keep the project aligned with what actually needs to be delivered. 

We apply standards proportionately—avoiding the trap of over-specification that drives up cost without adding safety or operability. And we keep the design flexible long enough to uncover optimal value. 

Our teams also embed directly with client functions—operations, maintenance, safety, procurement—to gather contextualised input early. This collaborative definition phase reduces late-stage changes, cuts down Technical Queries (TQs), and sets the stage for engineering that flows rather than churns. 

The result: A clear, requirement-led baseline that avoids “solutioneering,” minimises rework, and establishes a scope that’s realistic to plan, procure, and deliver—driving both cost and schedule certainty. 

Step 2: Use FEED and optioneering to measure value—not just ideas 

Front-End Engineering Design (FEED) is where over 70% of a nuclear project’s cost and schedule performance is locked in. That makes it one of the most decisive phases in the entire delivery lifecycle—and one that demands more than just good ideas.  

At Actemium, we treat FEED as a strategic exercise in value definition. Our optioneering process provides a structured framework to assess multiple design pathways against weighted criteria: safety case implications, ALARP compliance, constructability, lifecycle cost, and programme risk. It’s transparent, evidence-based, and integrated across disciplines. 

We align this process with the client’s gated model, using formal design reviews to document rationale and justification. That way, the preferred concept isn’t just technically sound—it’s strategically validated and demonstrably fit for purpose. 

The result: A traceable FEED that enables defensible decisions, reduces downstream debate, accelerates stakeholder and regulatory approval, and protects the critical path by avoiding late-stage concept changes.

Step 3: Involve stakeholders to secure buy-in for solutions 

In nuclear, innovation isn’t about chasing novelty—it’s about delivering outcomes that are fit for purpose, meet the safety case, and simplify implementation. But even the best ideas fail without stakeholder buy-in. 

That’s why we involve end users early and often. Through rapid prototyping, 3D modelling, and demonstrators, we test feasibility and gather feedback from operators, maintainers, and safety engineers before designs are locked in. Our teams routinely prototype mechanisms and interfaces to verify assumptions and eliminate technical risk before anything reaches the factory or site. 

We also make the design journey visible. Structured reviews, virtual walkthroughs, and collaborative workshops help stakeholders understand, challenge, and ultimately own the solution. This builds confidence and momentum—especially when we apply standards intelligently and document why certain specifications are included or excluded. 

The result: Testable, transparent innovation that reduces uncertainty, de-risks the safety case, and earns stakeholder support—avoiding late-stage dissent that can derail schedules and inflate costs. 

Step 4: Co-design with manufacturers to ensure buildability 

Great drawings don’t guarantee great outcomes. In nuclear, designs must be manufacturable, testable, installable, and operable—and proven as such before they’re released to the supply chain. 

For this reason, we involve manufacturing partners early. Their practical insights help shape the design itself, not just the execution. For complex programmes—gloveboxes, remote handling, waste retrievals, and process systems—we set clear build-to-print maturity thresholds. Designs are only released after gated reviews and stakeholder due diligence, so suppliers quote against stable, unambiguous information. 

We also apply early Design for Manufacture and Assembly (DfMA) principles to utility assets and modular plant, working with our partners to identify what can be factory-built, tested, and shipped as modules. This boosts productivity, reduces site exposure hours, and supports schedule certainty—an approach now widely adopted across UK asset owners. 

The result: Manufacturing-informed design and mature build packs minimise non-conformances, change orders, and rework—protecting both budget and installation timelines. 

Step 5: Embed quality and assurance to deliver right-first-time 

In nuclear, quality isn’t just a compliance requirement—it’s a delivery strategy. We embed Quality Assurance / Quality Control (QA/QC) directly into our project teams, using defined procedures, SQEP competency assessments, and controlled stage-gates to prevent errors from slipping downstream. 

Where this model is adopted, we’ve seen commissioning handovers with zero rework and measurable improvements in programme adherence. Our experience under NEC contracts and nuclear frameworks gives us the commercial awareness to manage change proactively and maintain delivery flow. 

Our integrated management system aligns with nuclear safety and security standards, including Cyber Essentials Plus and List N compliance for handling Sensitive Nuclear Information (SNI), where applicable. 

The result: Embedded assurance reduces the cost of poor quality and avoids late discovery—keeping budgets intact and programmes on track. 

Engineering success in the Nuclear sector 

Engineering design is no longer a technical silo—it’s the strategic engine of nuclear delivery. In a resource-constrained environment, under intense scrutiny and ambitious timelines, early, rigorous, and executable design is the key to success. Our experience is a clear indicator that good engineering design is the strongest predictor of programme certainty. 

The UK’s nuclear renaissance will be judged on execution—safe, on-time, and on-budget delivery. Achieving that demands design that is not only technically sound, but strategically led. With Actemium, clients gain a partner that combines deep nuclear design heritage with the scale and capability of a global group—turning strategic intent into engineered certainty. 

Want to find out how Actemium can support your nuclear or nuclear defence project? Get in touch with our engineers via reachout@actemium.co.uk.