Britain needs the latest 21st-century mini nuclear reactors, not just revamped old ones –

Moltex plans to use excess power at periods of low demand to store thermal energy in salts, which conserve heat with a modest loss rate of 1pc a day and can generate top-up power when needed at low cost. “People keep saying that we need baseload power, but that is not true anymore. We need dispatchable power,” he said.

Whether molten salt reactors are safer is disputed. Advocates say they cannot blow up because they operate at atmospheric pressure. “Our reactor is inherently safe because we use an extremely stable coolant. All nuclear accidents – Three Mile Island, Chernobyl, Fukushima – were associated with a failure of the cooling system,” said Terrestrial’s Mr Irish.

However, a study this year by the UK’s Nuclear Innovation and Research Office (NIRO) concluded that such reactors will still need to meet “a very high standard of containment, which may require a second vessel”.

The National Nuclear Laboratory’s Dr Rayment says molten salt reactors are an alluring idea, but the technology is “very corrosive” and needs years of further research: “The jury is out over whether it will be available in the time-frame we need.”

Fine minds are on the case. The US Argonne and Idaho National Laboratories three years ago called for the “systematic development” of nickel-based alloys able to withstand the stress. It said the challenge could be cracked within “four to five years”. This hunt for the right alloy is well-advanced.

Dr Rayment says the UK is looking at four types of advanced generation reactors for the future, including a high-temperature gas reactor that operates at 800 degrees and promises the same benefits for industry and clean hydrogen as molten salt prototypes.

The risk for the UK is that it is spread too thin. Is the Government dabbling without full conviction in multiple options, with relatively small sums of money and mostly for show, while being serious only about the Rolls Royce consortium? If so it could be outflanked by Canada, the US, Russia, or China.