Environmental impacts of decommissioning a nuclear power plant: A life cycle assessment of a Magnox site

Abstract

With over 400 nuclear power reactors around the world, decommissioning will be an ongoing challenge for some decades. Countries which pioneered nuclear power, such as the UK, USA, Russia and France, are already amassing considerable experience of decommissioning end-of-life reactors. This is a complex undertaking with varied waste streams and has been simplified in previous life cycle assessments of nuclear power, with only one prior study focusing on the detail of decommissioning. The present study applies LCA to the entire decommissioning process of a UK Magnox power plant using Sphera LCA FE (formerly GaBi) with supporting data sourced from ecoinvent v3.9.1. The functional unit is ‘one decommissioned Magnox nuclear site’ and the system boundary is gate to grave, starting once the plant has been defueled and ending with a remediated site. The total climate change impact was found to be 212 kt CO₂ eq., or 3.1 g CO₂ eq./kWh. Across 19 environmental impacts, construction of disposal facilities are key hotspots (35 % ILW disposal facility, 27 % LLW disposal facility), with waste packaging accounting for 30.8 % of the total impact. Sensitivity analysis considered enhanced recycling and waste rerouting, identifying a potential climate change impact reduction of 18.9 % (40 kt CO₂ eq.) if concrete recycling rates were increased to 60 %. Steel recycling saw an overall emission reduction of 10.3 % (21.9 kt CO₂ eq.) when the savings in producing virgin steel were credited to the system via system expansion. Further research is recommended into the environmental impacts (and optimisation) of treatment processes needed to decontaminate and reuse/recycle concrete and steel in order to realise the above gains. Furthermore, greater use of LCA in general within radioactive waste treatment and disposal could lead to substantial improvements in understanding and sustainability.