ČEZ submits Temelín SMR project for environmental review

ČEZ has submitted environmental-impact assessment documentation for the planned Rolls-Royce small modular reactor at the Temelín nuclear site in Czechia, starting formal environmental review. The Czech Ministry of the Environment will assess the filing and invite public comment, with an outcome expected in 2027; the submission is not a construction licence or a final investment decision.

Key facts

• ČEZ submitted EIA documentation for the Temelín SMR project to the Czech Ministry of the Environment, according to Rolls-Royce SMR.
• The ministry's review includes independent assessment and public consultation, and an outcome is expected in 2027.
• ČEZ and Rolls-Royce SMR signed an early works contract in April 2026; it covers documentation and design work, not equipment delivery.
• Rolls-Royce SMR says its Czech programme could eventually reach up to 3 GW across multiple sites; that is a programme ambition, not approved Temelín capacity.

What happened

The filing moves the proposed Temelín project into an environmental assessment led by the Czech Ministry of the Environment. The ministry is expected to examine the submitted documentation, arrange independent review and provide a public consultation. Rolls-Royce SMR says the outcome is expected in 2027. That timetable is an expectation, not a guaranteed decision date.

The subject of this review is the potential environmental impact of the proposed facility and measures to limit it. That includes the assessment process, not a finding that the project has been cleared. The public record will matter: the ministry's review can examine the documentation, receive comments and require the project team to address issues before it reaches later authorization stages.

This step follows early works contracts between ČEZ and Rolls-Royce SMR. ČEZ's announcement described those works as preparation of design, technical and licensing documents, including materials for environmental review and nuclear and construction permitting. It explicitly said the contract does not include equipment deliveries and is not an investment decision or start of construction.

Why it matters

The filing gives Czechia's first planned Rolls-Royce SMR project a defined regulatory task, but the distinction between assessment and authorization is important. A positive environmental outcome would not, by itself, authorize nuclear operation or construction. The project still needs the relevant nuclear and construction permits, financing and investment decisions, and the engineering and procurement work that follows them.

For ČEZ, the process is also a test of the company's plan to build an SMR programme alongside its established large-reactor fleet. The utility and Rolls-Royce SMR have framed Temelín as the first Czech deployment, while a separate programme points to other potential locations. The proposed up-to-3-GW total covers plans across Czechia, not a single Temelín unit and not a commitment to build that total.

The project is therefore moving through preparation rather than deployment. NNN's 2026 comparison of SMR developers places Rolls-Royce SMR among the programmes with substantial government and utility backing, while noting that announced plans and early works remain distinct from a reactor under construction. That distinction applies here: the EIA is measurable progress, but it does not settle the eventual cost, schedule or construction decision.

Background

The Temelín site already hosts two operating large reactors. ČEZ selected Rolls-Royce SMR as its partner for the Czech small modular reactor programme, and the planned Temelín facility would be the first deployment in the country. The project forms part of a larger UK-Czech partnership that includes work to prepare additional Czech sites, although only Temelín is the subject of this EIA filing.

In April, ČEZ said the early works contract would fund design and documentation needed for permitting at Temelín. The same announcement said Rolls-Royce SMR's first planned UK units are at Wylfa, while the Temelín project would follow as the company's second deployment site. The company has also described possible development at Tušimice and Dětmarovice; those site preparations should not be confused with a permitting approval for a reactor at either location.

The distinction between a project milestone and a licensing outcome is familiar in nuclear new-build. NNN's SMR guide explains the design and deployment terms behind the technology, while the developer ranking tracks where projects sit between selection, licensing and construction. Temelín has advanced from partner selection and early engineering into environmental review, but it remains before construction authorization.

What's next

The next public checkpoint is the Czech ministry's review and consultation. Rolls-Royce SMR expects an outcome in 2027. Readers should watch for the ministry's publication of the assessment materials, questions raised through consultation, and any required updates to the submission. After that, the project would still need to progress through nuclear and construction licensing and secure an investment decision before construction could begin.

The immediate news is a filing, not a groundbreaking. Its value will be clearer when the ministry publishes its review and when ČEZ discloses the next permitting and investment milestones.