Costain has secured a £70m contract to carry out the complex next major phase of decommissioning work at the Trawsfynydd nuclear power station in North Wales.

The four-year project will see Costain deconstruct and partially reduce the height of the site’s two 1960s Magnox reactor buildings from 54m to 25m, reducing their visual impact on the Snowdonia National Park landscape.

More than 100 people will be employed at the peak of the programme, with Costain promising to use local supply chains to boost skills and economic opportunity in the region.

The work forms part of the next stage in the long-term decommissioning of the former Magnox site, which has been in various stages of clean-up since 1991.

Sam White, managing director for natural resources at Costain, said: “This work is all part of creating a sustainable future, and we’re looking forward to deepening our relationship with NRS and working collaboratively with our local supply chain to complete this complex decommissioning project to the highest safety and quality standards.”

Rob Fletcher, chief executive officer at Nuclear Restoration Services, said: “This is a pivotal moment for Trawsfynydd. After years of careful planning and preparation, we’re now moving into the delivery phase of one of the most complex and ambitious decommissioning projects in the UK.”

Costain previously completed enabling works at Trawsfynydd, including new capping roofs for the reactor buildings. The firm is also working with NRS on a six-year programme across 11 other UK sites and is part of Sellafield’s Decommissioning Delivery Partnership.