Planning for flexibility critical to reducing nuclear costs

Anticipate change to reduce costs

To lower lifecycle costs in the nuclear sector, facilities must be designed to anticipate future change, says Mott MacDonald technical director John Palmer.

A new nuclear facility is a piece of critical national infrastructure that needs to be sustained for future generations in a way that ensures safety but provides agility. Whether built for national defence or low carbon electricity production, the lengthy lifecycle of these assets make them a 100-year long infrastructure investment. The design process must consider this from the outset by taking a systemic approach that puts the user – and the future – at the heart of the project.

As a pioneer of nuclear technology, the UK has excelled in developing well engineered and code-compliant structures that have safely and reliably provided power and supported defence efforts. But many of the maintenance and end of life requirements were unknown at the time of delivery and so assets were not designed for flexibility. The focus on operational requirements alone created rigidity in the system which has led to major rework when technology has evolved or requirements changed. It was not uncommon for this to lead to a full redesign of a facility in a game of ‘snakes and ladders’ that became more expensive with every change.

Today, we know that rapid technological evolution means that what is essential for a facility now, may not be a good idea in 20 years’ time. In the past, evolving use cases have led to facilities being late, over budget and even abandoned or destroyed rather than adapted to the needs of future generations. Although these needs can’t be fully anticipated, they can be planned for so that what we create today is fit for purpose in the future.

After six decades in the nuclear sector, Mott MacDonald has learned that change is inevitable but how that change is planned for is key.

Pioneering “solutioneering”

This means taking a new approach of “solutioneering” rather than just engineering. By thinking like the users who will inherit these assets and bringing that experience into the design, these facilities can be highly engineered but also reconfigurable. They can continue to be regulatory compliant assets that can withstand a 1:10,000 year earthquake, while also designed with a flexible service strategy. Rather than contracting for a manufacturing facility or an analytical space, clients can have both if the design focuses on delivering large multifunctional, versatile process areas.

By strengthening our teams with operational and decommissioning professionals, Mott MacDonald has upskilled engineers so that the entire lifecycle of an asset is considered from the outset. To design, build, operate, maintain, upgrade, repurpose and, ultimately, decommission a nuclear facility is a multi-generational project and this must shape the initial approach.

A nuclear facility is a multi-generational project and this must shape the initial approach

From the outset, it is critical to think beyond operation to the multiple use cases that will impact its life. These include maintenance, replacement, upgrade, increases or decreases in throughput and, of course, decommissioning. For this, it is important to take a model-based systems engineering (MBSE) approach where these long-term needs can be integrated, any dependencies identified and compromises understood. Infinite flexibility is unaffordable, but not having any flexibility constrains future potential and increases costs.

Designing for maintenance activities could mean incorporating a waste room where items can also be resized. This facilitates access and egress of replacement parts via containers that safely hold and transport contaminated materials. Real world experience means knowing what components are likely to need replacing, when and how this is done, before building this into the original design. Identifying dependencies means that this same space could also be designed to support reconfiguration activities using mid-life refurbishment kits that will prolong the site’s usefulness long into the future.

Taking this lifecycle approach can also increase the operational efficiency of a building dramatically with less time required for unplanned or reactive maintenance, which again reduces lifetime cost. Similarly, extending its life by enabling new future functionality could generate enormous savings if it is considered that this could prevent the need to construct a new facility.

Long-term value

Value engineering must also be undertaken from a lifecycle perspective. Using cheaper ducting or cable trays may shave thousands from the capital cost, but experience shows that these will break easily and more frequently, creating expensive maintenance tasks. Maximising the design life with good quality materials reduces the lifetime cost and increases price certainty.

The industry is facing a massive skills shortage, creating the need to be innovative in how projects are planned and designed.

Moving toward lifecycle design also creates visibility over the future pipeline of work, which is critical in attracting more skilled professionals into the nuclear sector. The industry is facing a massive skills shortage, creating the need to be innovative in how projects are planned and designed. Creating multi-functional, adaptable spaces using systems thinking in our designs is the kind of innovation that will support this. Importantly, combining this with digital technology means that it is replicable and design models could be adapted for other projects.

Mott MacDonald’s decades of experience and analysis of the data from past projects tells us that taking a whole life cost approach is the most realistic and practical way to reduce costs, increase value and protect assets. As an industry, we must anticipate that change is inevitable, design in flexibility and move away from the rigid design approach that dominated earlier development. This is the only way to ensure that much-needed nuclear facilities are seen as successful assets and not liabilities for future generations.