A permit with national significance
The United States has taken a consequential step towards a new nuclear era. On Tuesday, 29 September, the Nuclear Regulatory Commission approved the Tennessee Valley Authority’s construction permit for a small modular reactor at the Clinch River site in Tennessee.[1][2]
The planned reactor is a 300-megawatt GE Vernova Hitachi BWRX-300 boiling-water design. The approval makes TVA the first US utility permitted to construct this type of commercial small modular reactor.[2][3] The NRC completed its review in 14 months, a notable achievement for an industry that has long struggled with regulatory delays.[2]
Yet the decision is an authorisation to build, not permission to operate. TVA must still complete construction and secure a separate operating licence before the reactor can be fuelled or brought online.[3] No construction date has been announced, and substantial engineering and project-development work remains.
That distinction matters. Nuclear energy’s supporters have often presented small modular reactors as faster, cheaper and easier to deploy than conventional plants. The Clinch River project will test whether those claims can survive contact with construction, supply chains, financing and regulation.
The case for firm power
The renewed interest in nuclear power is being driven by a basic reality: electricity demand is rising while governments are attempting to reduce carbon emissions. Artificial-intelligence systems, data centres, industrial electrification and expanding transport networks are placing new pressure on power grids.
Nuclear generation already provides a large volume of reliable electricity without direct carbon emissions. Global nuclear output reached a record 2,702 terawatt-hours in 2025, an increase of 35 terawatt-hours from the previous year, supplying approximately 9 per cent of global electricity.[4]
That achievement should not be dismissed. Nor should it be treated as a complete answer. Nuclear plants require high upfront capital, long development periods and rigorous oversight. Their contribution to a cleaner grid depends not only on reactor performance but also on whether projects are delivered on schedule and within credible budgets.
Europe reopens a difficult question
The political shift is visible across Europe. Italy’s Senate has passed legislation designed to create a framework for bringing nuclear power back into the country, reversing decades of political resistance.[5] Poland, meanwhile, is progressing towards its first nuclear power plant through a partnership between Polskie Elektrownie Jądrowe and a Bechtel-Westinghouse consortium.[5]
These developments reflect a broader recognition that renewables alone may not always provide the firm, round-the-clock power required by modern economies. Wind and solar are indispensable to decarbonisation, but their output varies with weather and daylight. Nuclear can complement them by supplying stable generation while storage, transmission and demand-management systems expand.
The sensible debate is therefore not nuclear versus renewables. It is how the technologies can work together. A resilient energy system will require low-carbon generation of different kinds, stronger grids, flexible demand and sufficient storage.
Investment follows demand—but so do risks
Private capital is also moving towards nuclear technology. Investment in US nuclear start-ups reportedly reached $4.6 billion in 2026, up from $3.8 billion in 2025, encouraged in part by the expanding electricity needs of artificial intelligence and data centres.[6]
That influx of money is important, but it is not proof of commercial success. Investors may be responding to a compelling strategic narrative before the industry has demonstrated repeatable construction and competitive pricing. Regulatory hurdles, fuel availability, manufacturing capacity and the management of radioactive waste remain central concerns.
The OECD Nuclear Energy Agency and the US Department of Energy addressed these challenges at the fourth “Roadmaps to New Nuclear” conference in Paris on 17–18 September, where officials and industry leaders examined how deployment could be scaled.[7] The emphasis on roadmaps is appropriate: ambition without sequencing, financing and accountability will produce announcements rather than electricity.
Trust must accompany technology
The energy transition requires speed, but nuclear development cannot be rushed at the expense of safety or public confidence. Indiana’s designation as the 41st NRC Agreement State on 24 September illustrates the continuing importance of clear responsibilities for regulating radioactive materials.[5]
Pennsylvania’s Crane Clean Energy Center also demonstrates how difficult the political and environmental process remains. The NRC issued a finding of no significant environmental impact for the proposed restart in June, while related updates included a formal hearing concerning the environmental review.[5]
These procedures may appear cumbersome, but they are essential. Public consent is not a technical footnote; it is part of the infrastructure of nuclear power.
The Clinch River permit is a meaningful milestone, but its true significance will be measured later: when concrete is poured, costs are disclosed, workers are trained and electricity reaches consumers. Nuclear power is back in the policy conversation. Whether it becomes a dependable pillar of the clean-energy system will depend less on bold promises than on disciplined execution.