Nuclear power plays an important role in meeting the world’s energy needs and the demand for this technology is increasing.
The plants themselves are heavily regulated and very safety conscious as you would expect. As a result, the sophisticated systems they employ must be kept in the very best condition.
Rolls-Royce works in close cooperation with one of the world’s leading nuclear industry service providers – Westinghouse – to make sure that even the most remote regions deep within nuclear plants are kept clean and operationally sound.
When Rolls-Royce acquired US-based R Brooks Associates, Inc. in 2011, it was securing a proven market leader in secondary side steam generator inspections, along with a range of innovative technologies deployed for niche inspection and retrieval duties in the nuclear steam supply system. (In a pressurised water reactor the system of piping that contains the coolant is called the primary side. The separate system of piping where the steam is produced to spin the turbine generator is called the secondary side).
The acquisition of Brooks also brought with it a mature co-operative relationship with one of the world’s leading nuclear industry suppliers, Westinghouse Electric Company, on whose technology around half of the world’s nuclear power plants (and 60 per cent in the US) is based. Continuing a formal Joint Cooperation Agreement (JCA) that dates back around 20 years, Rolls-Royce now works hand-in-glove with Westinghouse to provide customised solutions to global operators of generating plant based on pressurised water reactors (PWRs).
‘Customers may have quite different needs, so we work very closely with each and every one to understand their operation, and to promote an overall asset management approach through high technology and innovative new techniques,’ says Sonya Forrai, Product Manager for Steam Generator Secondary Side and Decontamination Services at Westinghouse.
Nuclear plants each produce around 1,000 megawatts – enough for the 1-2 million homes and industrial outlets of a very large city. They typically require refuelling every 18 months, and this is when operators undertake services such as steam generator inspections and maintenance services. Such outages may last anywhere between 17 days and a month – a window that easily accommodates the support team’s task list.
‘My key role is to be proactive in showing customers the value of regular inspections and cleaning in order to maintain the long-term health of the generators, both in terms of higher plant efficiency and removing any threat of foreign object damage,’ adds Sonya, ‘and I know I have a top-class team to call upon.’
This is particularly important for nuclear operators looking to extend the lives of their plant. By its very nature, the nuclear industry is diligent in relation to the highest standards of safety it demands. Compliance is largely through operational licences that will only be renewed when all fundamental components of the nuclear plant – including steam generators – are proven to meet strict operational criteria.
The teaming arrangement was established following recognition of both companies’ respective areas of expertise, allowing Westinghouse to focus on its core strengths while having access to Rolls-Royce capabilities and technology.
‘Our success factor is around the value that the collective technologies and skills of the partners bring to the customers,’ stresses Sonya Forrai. ‘We function very much as an integrated team, so the customer has a single point of contact. We can eliminate duplication, streamline our administration and cross-utilise capabilities. Operationally, we can be flexible with the size of crew required for each job, and technically we work together to develop solutions to meet customer needs.’
This can be extremely challenging, because of the diversity of plant and steam generator designs that exist throughout the world. ‘We take proven technology and custom-design it to overcome any specific restrictions or limitations imposed by an individual customer’s installation,’ informs Sonya.
The typical outage period means that the Westinghouse/Rolls-Royce team has an 18-month planning cycle for each job, which includes a readiness review and assessment of the resources required on site. While inspections may be routine in one sense, each inspection is in fact different and can demand a specific, often customised, solution. That solution may involve searching for and retrieving foreign objects that have the potential to threaten plant integrity.
‘We have a good forward view of the overall task, and for each job we have a defined checklist. If we need to develop a custom solution for a new customer, it could take anywhere between six and 12 months,’ claims Sonya.
Bill Harris is the Rolls-Royce Director for Nuclear Services. He explains that the services Rolls-Royce provides draw on the Westinghouse knowledge of steam generators and the quality of the inspection and retrieval solutions Rolls-Royce has been able to develop. ‘The fundamental objective of our inspection service is to provide the customer with data on the condition of the steam generator so he can make informed decisions about maintenance,’ says Bill.
‘We have to get our equipment such as cameras, lighting and retrieval tools into areas of the steam generators that are often very difficult to access. Remotely operating a video probe within a tube gap of 3mm while 6 metres into the generator is common,’ he adds.
Working in close proximity to a steam generator results in radiation exposure for workers. Therefore, many of the tools are specifically designed for remote operation, using sophisticated control systems to deploy the extensive array of inspection and retrieval equipment. As a world leader in its field,
Rolls-Royce has numerous patents for the equipment it has developed and will also licence its use in certain markets.
Once Rolls-Royce has inspected a generator’s secondary side using its remotely-applied tooling, Westinghouse cleaning technology then comes into its own. This is when ‘lances’ are employed, delivering high-pressure water to remove potentially damaging sludge without degrading the base metal. These deposits can build into a hard crust which, if too thick, will affect the efficiency of heat transfer through the tubes – and can even cause cracking that may ultimately lead to leaks from the primary system.
Innovation, technology and teamwork lie at the heart of this productive and focused team which never rests on its laurels in helping to keep nuclear power a safe and plentiful source of power for the future.