Feature TARMAC B
uilding a new generation of nuclear reactors in the UK will require a specialist approach to concrete and careful consideration of supplying material to manage project risks, says Geoff Fawkes, Business Development Manager at Tarmac.
Developers of the UK’s new generation of nuclear reactors understand that concrete supply is a major element of the construction critical path. Failure to deliver a continuous supply of high-performance, high-quality concrete in the significant volumes required will have implications for the cost and timings of new build programmes.
The importance of managing the risks associated with concrete supply has led one client I know to request that concrete supplied to its nuclear project delivers consistent product quality with ‘relentless predictability’.
The reactor building will clearly need a high-strength and dense concrete that can deliver the structural resilience required to contain and protect the reactor. This concrete will need an appropriate cement content to keep the temperature of the material low. The material will need to be produced without siliceous aggregate to prevent an alkali silica reaction, which can cause cracking and structural damage.
Delivering security of supply in high volumes is a major consideration requiring long-term logistical planning across a provider’s estates, technical and operations teams. With often challenging transport access requirements – some projects will require a lot of material to go in via sea – time is essential to manage quarry development plans in order to provide aggregates as close to the project as possible. This in turn will ensure that the carbon footprint of material will be as low as possible.
the construction of the raft for the nuclear reactor foundation is likely to require a concrete ‘peak pour’ on a nuclear project, which could mean a continuous supply of concrete for over 50 hours
Suppliers will only realise this vision by mitigating the risks of concrete supply. In order to reduce the chances of defects in concrete, providers will potentially need to quarantine parts of a quarry to supply a specific nuclear project with a dedicated source of consistent, high-quality aggregates.
Equally important will be the provision of product and constituent material traceability at every stage of the lifecycle – from reviewing the geological data at the quarry to blasting, crushing, screening and washing of the aggregates through to hauling the material to site and being able to trace each stage of the process. Essentially, this will mean tight auditing and stringent controls over selected raw materials and production.
During construction, concrete will need to possess the fluidity to be pumped over long distances and for long periods of time. For example, the construction of the raft for the nuclear reactor foundation is likely to require a concrete ‘peak pour’ on a nuclear project, which could mean a continuous supply of concrete for over 50 hours.
Equally, careful planning of concrete plant design is also going to be essential. On a nuclear build, there will be a need to commission a concrete plant that can deal with high volumes over long periods of time, working in a nuclear environment. This will require a bespoke plant and the necessary time to integrate the plant into a nuclear site’s infrastructure.
In order to de-risk material supply, concrete suppliers have a major responsibility to understand the nuclear environment and its key drivers – from its high security requirements to its rigorous safety culture. Equally, clients and tier 1 contractors must engage concrete suppliers as early as possible and recognise the time that is required to plan the delivery of high volumes of specialist concrete.
While nuclear developers have not yet confirmed the final timings for the main construction of nuclear sites, the planning for concrete supply must start now.
Words: Geoff Fawkes, Business Development Manager at Tarmac
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