Nuclear regulation is founded in International Conventions, nuclear community peer groups and policy. This is overseen by the inter-governmental International Atomic Energy Agency, part of the United Nations family. Our participation in this is unlikely to waiver.
That is probably not the case with the Euratom Treaty, signed in 1957 at the same time as the Treaty of Rome. This was intended both as a tenet of peaceful coexistence and to allow civil use of nuclear for the generation of electricity. The Euratom Treaty administration is integrated with the European Commission.
Pre-referendum indications were that the UK will exit all EU Treaties. Assuming the UK's tie-in through EU membership will come to an end, a new atomic co-operation treaty between the UK and the Euratom community will need to be agreed. An exit from Euratom will also trigger the need to join the queue to agree a Section 123 of the United States Atomic Energy Act of 1954 agreement as a prerequisite for nuclear deals between the US and the UK.
Read full at:
http://www.lexology.com/library/detail.aspx?g=8171e36e-ae22-4a89-9da4-ad1b9a227048