A total of 15 potential sites are in the running to host the UK's first prototype fusion power plant.
Fusion is seen as a potential source of almost limitless clean energy but is currently only used in experiments.
An open call for sites was made last year and nominations closed at the end of March this year.
Following checks for compliance with key entry criteria the UK Atomic Energy Agency (UKAEA) has published a long list of possible locations.
The sites, from north to south, with nominating body, are:
- Dounreay - (Caithness and North Sutherland Regeneration Partnership)
- East Airdrie - (Fusion Forward (East Airdrie) Consortium )
- Poneil - (Fusion Forward (Poneil) Consortium)
- Ardeer - (Fusion Forward (Ardeer) Consortium)
- Chapelcross - (South of Scotland Enterprise)
- Moorside - (Cumbria Local Enterprise Partnership, in partnership with Copeland Borough Council)
- Bay Fusion (Heysham) - (Collaboration between industry, Lancaster City Council, Lancashire County Council and Lancaster University)
- Goole - (East Riding of Yorkshire Council)
- West Burton - (Nottinghamshire County Council)
- Ratcliffe on Soar - (Nottinghamshire County Council)
- Pembroke - (Pembrokeshire County Council)
- Severn Edge (Oldbury/Berkeley) - (Western Gateway)
- Aberthaw - (Vale of Glamorgan Council)
- Bridgwater Bay - (Heart of the South West Local Enterprise Partnership)
- Bradwell(Essex) - (Belport Ltd)
The UKAEA said that acceptance of the sites did not indicate that they were "preferred or desired" or that it believed they were "in all cases, possible".
It stressed it was simply that the procedural entry criteria had been met and assessment had now begun.
It said a shortlisting process would take place in the autumn with a final site decision likely by the end of next year.
UKAEA is hoping to have such a plant operating in the early 2040s, with an initial concept design ready by 2024.
The Spherical Tokamak for Energy Production (STEP) programme director Paul Methven said: "The publication of the longlist of sites is the next stage in the process of finding a home for STEP.
"We were pleased to receive a number of high-quality nominations and will now continue with in-depth technical assessment over the summer before we publish a shortlist later in the year.
"We're looking forward to getting out to each of the shortlisted communities at this point to visit the site and engage with both stakeholders and communities."
What is fusion?
Fusion - the process which goes on inside the sun - creates energy by forcing atoms together.
It is the opposite of standard nuclear reactors which rely on fission, breaking atoms apart.
Fusion is viewed as safe and clean but has so far proved difficult to harness.
Critics have said there are still huge hurdles to overcome and some experts believe existing, proven renewable technologies offer a more economical and timely way of tackling climate change.
Read more: Nuclear fusion: 'A question of when, not if'.