UK
Will climate change affect Sizewell C nuclear safety?


Charles Bliss
Fri, 24 February 2023 

Cefas remote pilot aircraft lead Sara Stones (Image: Sizewell)

Sizewell C has received its Development Consent Order (DCO) to build a new nuclear power station on the Suffolk coast, which will generate affordable, low-carbon energy for six million homes over the next 60 years.

Many local organisations and residents took part in the Planning Inspectorate’s (PINS) examination of Sizewell C last year.

PINS concluded that Sizewell C had put in place the necessary measures to monitor, identify and address coastal changes. The project’s coastal defence feature will protect it up to the end of its design life in 2140 and can be adapted to be effective against more extreme climate scenarios.

PINS concluded that Sizewell C had fully addressed the flood risk associated with the project at the main site and the associated developments. It said the project was taking an appropriate approach to managing groundwater and surface water.

But while the Planning Inspectorate concluded that the benefits of the project would “strongly outweigh the potential adverse impacts”, concerns have been raised about how climate change, coastal erosion and flooding might affect the power station.

East Anglian Daily Times: Sizewell C marine environment manager Dr Stephen Roast

Sizewell C marine environment manager Dr Stephen Roast (Image: Sizewell)

Marine environment manager Dr Stephen Roast is responsible for assessing the coastal and marine impacts of the power plant on water quality and local ecology (and vice versa).

“Locals quite rightly ask about sea level rise and erosion due to climate change,” he says. “We know this part of the shore very well and this stretch at Sizewell is comparatively stable.”

The team has put thousands of hours into studying this coastline and designs take into account the effects of erosion to the north of the site.

“Sizewell C coastal defences 'work with nature', so that as material erodes, it will move downdrift to neighbouring beaches, which is what happens naturally,” says Stephen.

The Coastal Processes Monitoring and Mitigation Plan will be enforced throughout construction, operation and decommissioning of the station. Advanced modelling is used to study the possible effects of extreme storms and tides on the shoreline.

“We’ve got a good idea of what could happen over the next 100 years,” says Stephen. Sizewell C uses the Centre for Environment, Fisheries and Aquaculture Science (Cefas).

“We’ve taken into account the possibility that climate change may happen more quickly than predicted. If we end up on a more severe trajectory, we’ve got a plan with layers of resilience that will provide protection.”

If a storm causes erosion, processes are implemented to replenish beaches.

“We will measure the depth of the underlying seabed levels, as well as flying drones with high-resolution photography from Minsmere Sluice to Thorpeness to track coastal processes and address them,” Stephen says. “If erosion reaches a trigger level defined in the monitoring plan, we will recharge that beach with new sediment. Our modelling predicts that no more than four or five recharges will be needed over the whole operational life of the station.”

East Anglian Daily Times: Sizewell C external hazards lead Tom Bulkeley


“We understand how important it is to demonstrate the safety of the nuclear power station,” says Tom Bulkeley, external hazards lead. “We recognise that flooding and coastal erosion could be significant, so we have addressed that via the site’s location, configuration and defences – all of which are justified in line with regulatory requirements.

“We really do consider everything that could possiblyhappen. Even very extreme cases – whether that’s intense rainfall directly on the site, or the ability of the coastal defences to withstand storm surge on high tides, or even tsunamis.

"There is only really one type of tsunami that could threaten the southern part of the North Sea: a Storegga tsunami, which did happen about 8,000 years ago. Even though it’s not particularly realistic that an event like that could happen again soon, the scale of our defences is prepared for it.”

Stephen adds: “One of the main reasons for building Sizewell C in the first place is to try to get a grip on climate change by generating electricity from a low-carbon source. This project will be a big contribution to achieving net-zero.”