Exiting the European Union could threaten the UK’s nuclear ambitions, a new report has warned.

The nation’s plans to build new reactors and decommission older ones, as well as its nuclear fuel supply could be affected according to the report from the Institution of Mechanical Engineers (IMechE).

In its draft ‘Brexit bill’ released in January, the UK stated its intention to withdraw from the Euratom nuclear treaty when it leaves the EU. However, IMechE said such a move would “have significant implications for the UK nuclear and radioactive waste industries” and would “present the UK nuclear sector with a significant challenge in making alternative mitigating arrangements”.

One issue is the need for nuclear co-operation agreements (NCAs) with non-EU countries, which IMechE said are crucial “to enable any kind of trade in services, products or research” and which have hitherto been managed by Euratom.

“If the UK leaves Euratom without NCAs in place with non-EU countries and Euratom, it will not be able to develop any kind of trade deals for the UK nuclear industry,” IMechE warned.

“It is essential that the UK develops a transitional framework that provides the same provision as Euratom before the deadline to leave both the EU and Euratom.”

The nuclear sector itself is also aware of the potential problem. In a statement earlier this month, the GMB trade union said a potential Euratom exit would “threaten the UK’s entire nuclear industry – including severely delaying the new £18bn ($22.5bn) Hinkley Point C power plant.”

The union called for the UK to stay in Euratom “until nuclear interests can be guaranteed” and “a viable alternative can be found”.