Optimisation of large concrete DfMA structures for the Nuclear Industry

The overall aim of the project proposed is to optimise the design for manufacture and assembly (DfMA) of large
preassembled components for reinforced concrete construction in nuclear and other large construction projects. To bring
these benefits and capability to the UK nuclear construction supply chain, and to establish a world-leading capability, the
project will verify the reliability of preassembled structural components currently available in the UK and develop new ones
that meet the stringent design and assembly requirements of the nuclear environment. The project team includes Laing
O'Rourke (a current nuclear new build constructor), Imperial College London (expertise in optimisation, logistics and
intelligent transport systems), ARUP (expertise in the design of new nuclear power plants) and BRE (capability of testing
prototype designs).
The project will explore the potential of a number of construction approaches, consisting of a range of elemental sizes and
jointing techniques, for both sub- and super-structure applications in nuclear construction. Key considerations for research
are the structural performance of such systems and joints, their reliability, and innovation with regards to associated
manufacturing and assembly techniques. Therefore, the project consists of six main sub-projects as follows:
1) Design of large underground components,
2) Design of large superstructure components,
3) Joint small scale reliability,
4) Reliability assessment of systems,
5) Optimisation and automation of manufacturing techniques and
6) Optimisation and automation of assembly techniques.
The Department of Civil & Environmental Engineering at Imperial College London will lead research in the optimisation and
automation of assembly techniques. The use of preassembled components in nuclear construction presents a significant
opportunity to apply this expertise in the construction sector. The combination of these technologies will allow the industry
to rethink and streamline the entire design and assembly process in nuclear plant construction and beyond.
The aim of the research carried out at Imperial will be to address the difficulties in handling larger-than-usual construction
components as well as taking advantage of their prefabricated nature. The three key quantities to be determined will be the
number, size and location of tower cranes to be used in the construction process, with each combination having direct
consequences on the overall layout of the construction site and the rate at which the assembly process is accomplished.
As the scale of preassembled components that will be considered can vary significantly (with weights between 20 and
1000t) a variety of scenarios will be considered.
The optimisation models and solution approaches to be developed will seek to balance overall transport and handling costs
against the speed of construction, while ensuring that safety and other operational constraints are satisfied. The models
and solutions will be tested through the use of simulation informed with real data and provide feedback to the parties
responsible for the design of the components used, in an iterative approach that will ensure that the overall design and
construction process will be able to extract the maximum benefit from the use of preassembly.

The research to be carried out by Imperial College London is significant as it will focus on the optimisation of assembly
operations, a critical aspect of the entire Design for Manufacture and Assembly (DfMA) approach. The UK Government has
identified eight potential sites for the redevelopment of the UK civil nuclear power sector, with plans for 16 GW of nuclear
generation capacity to be developed by 2025. With estimated construction costs for a nuclear station approaching £2
billion, the overall potential size of the nuclear power plant construction market in the UK is expected to be around £16
billion between 2014 and 2025. A recent report on the New Nuclear Build (NNB) Employment Scenarios by construction
skills shows a potential peak at £3bn per annum. There is currently increased pressure to reduce construction costs by
approximately 10% through higher efficiency levels. The expectation is that this should translate to savings for UK energy
consumers.
1. The use of DfMA aims to enable 70% of manufacturing activities to take place through off-site fabrication and onsite
assembly, with a 60% reduction in on-site labour. As a result, it is estimated that the addressable market opportunity
through the use of DfMA on a single power station is approximately £540-800m, rising to a potential £6bn over all 8
planned power stations. As a result, the return on investment for the entire research project will be significant in terms of
productivity benefits even in the case of a single site. DfMA techniques developed in this project would also be applicable
and adaptable to the wider civil infrastructure market that has in the UK a total estimated value of £15.3 billion.
2. As efficiency levels increase in the construction process, the use of DfMA would have immediate environmental impacts,
as a result of less emissions, water consumption, waste and noise. This would further decrease the disruption to areas
surrounding nuclear construction sites that would already benefit from enhanced construction speeds.
3. The overall project will produce evidence on the performance of prefabricated components both during construction and
in the ultimate permanent state of assembly. These will be obtained through design analysis and physical testing of large
sample pieces. The results will be conveyed to the relevant authorities, to pave the way for regulatory sanctioning of DfMA
practices in the nuclear construction sector and therefore providing the opportunity to realise the economic benefits quoted
above.
4. Beyond the impacts for the research community as discussed in the "Academic Beneficiaries" section, the project would
bring immediate benefits to the other industrial collaborators involved. Laing O' Rourke and ARUP will have the opportunity
to apply the methods developed to other construction and engineering advisory activities services in UK, with further
opportunities in their endeavours abroad. Finally, BRE will expand its capability in the nuclear and heavy engineering
sectors. The expertise developed will be transferable to other companies in the UK, either through IP licensing, training or
consulting services, or in the form of knowledge disseminated through workshops and publicised material.
5. The worldwide market for nuclear power generation technology concerns (as of October 2010) about 441 plants
operating worldwide with generating capacity of 375GW. It has become clear over the last 5 years that many more
countries see nuclear power generation as a vital part of their energy mix. As UK commences an intensive nuclear
construction programme, many of these countries are likely to be assessing the techniques and construction practices used
for implementation in their own projects.