HazardEx interview: Nigel Cann, Construction Director at Hinkley Point C
28 November 2012
Nigel Cann, the Construction Director at Hinkley Point C, has worked at the site all his professional life. Starting out as an apprentice 30 years ago, he rose through the ranks to become director of the Hinkley B station before being appointed to his present job.
Nigel Cann, Construction Director at Hinkley Point C
Over the years Cann has seen the nuclear industry wax and wane in popularity, but feels there is now more widespread political and public acceptance.
“In the UK, post-Fukushima we’ve had cross-party support for nuclear projects. A national policy statement was signed after Fukushima supporting new nuclear as the best high-volume, low-carbon electricity generation solution for the country the government thinks we need. Post Fukushima, I think it’s fair to say public support dipped, but since then there has been a rise and the latest figures I have seen show that support is now up slightly on pre-Fukushima levels. Certainly most people I speak to now think we need nuclear as part of the mix. There is no obvious replacement if we’re to progress towards a low-carbon future.”
He says that in his experience around 20% of the population are very anti or very pro, with the remaining 80% balanced between these extremes, and an increasing understanding in this middle sector of the benefits of the nuclear option.
One of the first headaches in his new job was discovering extensive asbestos contamination on the proposed construction site, which had been used as the construction and prefabrication area for the Magnox station during the 1950s and 60s.
“Our borehole results showed low density but far more widespread asbestos contamination than we initially expected, so it’s been a fairly painful operation gauging the full extent by putting in trial trenches, turning the earth over and sorting it, and then taking the contaminated material to a registered landfill site.”
Planning permission for initial site remediation covered a relatively short time period, and the company had to apply for two further remediation periods before receiving the final validation certificate from the local authority certifying the land is clean.
Cann estimates that UK nuclear power stations will have to spend around £200m on post-Fukushima modifications, for example to harden facilities, but says the timing of the Japanese disaster was such that feedback could be incorporated into Hinkley C’s design during the early Generic Design Assessment (GDA) phase.
“There were two main issues with Fukushima: the power supplies – don’t put them all in the basement – and make sure your platform is high enough to avoid flood risk. Other problems concerned battery back-up and the importance of failsafe communications systems, but in the end modifications here in the light of what happened there were not too extensive.
“We have a 13.5m sea wall, much higher than at Fukushima, and our power supplies are high enough not to be at risk. We’ve made some modifications to the diesels where the fuel tanks are, and some of the batteries.
EDF's new EPR plant at Flamanville in France has suffered delays and is reportedly over budget
“One of the main things we learned from Fukushima was the need for hardened facilities, which hasn’t been a priority at UK nuclear stations up until now, and to ensure we have secure control and safeguard buildings if there is an incident.”
The plant’s design already had many active safety systems, as well as multiple redundancy, and post-Fukushima analysis confirmed the importance of passive features such as hydrogen recombiners, which turn hydrogen into an inert gas.
When asked about the relative merits of the second and third generation nuclear power stations at Hinkley, Cann sees benefits in both.
“You can’t really compare AGRs and PWRs – the design is completely different. AGRs have some huge advantages, I grew up with the technology and am very fond of it, but in terms of PWR technology, Areva and Siemens have refined it and taken it to the next level.
“When PWRs started you had two loops, or safety trains, so you need one and have one backup, and in this design you have four, so three backups altogether. With the EPR, levels of redundancy have been enhanced and we have double skin protection, which makes the vessel aircraft-proof. Traditional UK stations only have a single skin.
“Another important element of the EPR is segregation. We have separate diesel units on different sides of the plant and separate muster stations separated by blast walls. Fire will always be a big issue in any kind of power station and segregation is an important way of guarding against this.”
Asked about radiation exposure within the plant, Cann says the new reactor design will ensure doses are even lower than the already low levels achieved in existing nuclear power stations.
“In a PWR, personnel have access to 99% of the plant during a fuel or maintenance shutdown, but in operation would not normally enter the containment building unless there was a leak or urgent maintenance was required.
“Time, distance and shielding are the ways to counter radiation. Using ALARP, if there was a task that had to be performed in an area of radiation we would look first at ways of using special tools and robotics, and to minimise human exposure, practice before entry to reduce the time inside.
China is building four EPR plants at Taishan
“Permissible levels used to be much higher, but because we tended to bump along the bottom, the levels were brought down by the regulator. On top of this, the design of this reactor ensures that doses should be very low indeed.”
At Hinkley, all spent fuel has been removed from the A station, while that from B is sent to Sellafield. C will have a building on site where waste will be stored until the Nuclear Decommissioning Authority finalises its plans for an underground repository. Cann emphasises the small size of the waste storage building, and that from a plant which will produce 6% of the country’s electricity for 60 years.
He expects to close out the remaining issues for the Generic Design Assessment with the Office for Nuclear Regulation by the end of the year.
“We have already received interim certification, an important milestone, so the concept of the design is acceptable to the ONR. What has to be done now is to translate a French design concept, as UK rules and regulations are very different from those in France.”
The new French EPR plant at Flamanville has suffered delays and is reportedly over budget, but Cann thinks there have been many successes as well problems.
“The Flamanville endpoint is clear. It’s always easy to point at things that haven’t gone as well as they should, but some elements have gone very well indeed: for example they will have completed the conventional island in the next few months.
“There have been some issues in the nuclear island, not the nuclear part, but the civils design. That said, there is nothing insurmountable. They said a couple of years ago that it would be finished by 2016 and I think that’s still the target. Longer than originally planned, but still not bad for a new design.
“It’s in our DNA to try and learn the lessons from their experiences,” he says.
Cann visited Taishan a few months’ back to look at the progress there and says the construction of the first two power stations there are progressing well.
“It was really exhilarating visiting the site in China, because we’re still scrabbling around in the mud while they have buildings going up.
“Some of the French engineers from Taishan have come over to join us on this project and we are getting exceptional feedback and picking up on good practices there. Our deputy construction director was in Taishan for 3 years and has very good contacts out there.
“We’ve been in a race with Taishan 3 and 4, but they’ve pulled ahead slightly. It’s all very useful if they hit a problem that we can help with, or vice-versa.”
EDF Energy has said the final decision to go ahead with Hinkley Point C will be taken before the end of March next year. Cann says the approvals process on both sides is by necessity a long-drawn out process. All the right foundations need to be in place before a firm commitment can be made.
“If you’d ever heard our CEO you would know we were totally committed to the programme, but you don’t build nuclear power stations unless you have a long-term commitment and a good return – it’s a massive investment up front. We’re committed, but we can’t swim against the tide with these things. At the end of the day you need support and the right marketplace. We’re building an electricity factory and someone needs to buy the product at a price that makes it worthwhile.”
Hinkley C’s Construction Director says there has been a steep learning curve in the job.
“I’ve spent the last year putting people and processes in place to ensure we build this project well. I don’t underestimate the responsibility. If it goes well, there are likely to be others, but if it goes poorly, there’s likely to be a struggle.
“I’ve had 30 years in the nuclear industry and it’s been very good to me. I started out as an apprentice technician and made it to station director, so part of the desire to do this job is to leave a legacy for other people to follow.
“On a personal level, I’m very excited --- it’s a fantastic thing to be involved with. If anyone can tell me of another more exciting construction project in the UK I’d like to hear about it!”
Contact Details and Archive...