Helen Launches Statutory EIA Process for Helsinki SMR Plant

EIA Programme Marks Regulatory Milestone

Helsinki-based energy company Helen has published its Environmental Impact Assessment (EIA) Programme for a proposed small modular reactor plant, triggering the statutory EIA procedure in Finland. The programme has been released for public consultation, giving authorities, stakeholders, and residents the opportunity to review and submit opinions on the scope and methodology of the assessment.

The EIA process will proceed in two stages. The current programme stage defines which impacts will be assessed and how. A full EIA report compiling the results is scheduled for publication in 2028, at which point further statements and opinions will be collected. Helen has stated its intention to make a final plant location decision that same year.

Three Candidate Sites, Five Implementation Options

The assessment covers three candidate locations: the Salmisaari and Vuosaari power plant areas within Helsinki, and Norrberget in Östersund. Five implementation options are under evaluation, reflecting different combinations of plant technology and site. A zero-build alternative — in which the project is not implemented — is also included in the assessment.

Both a heat-only plant and a combined heat and power (cogeneration) plant configuration are being considered. However, the cogeneration option is being assessed only at Vuosaari and Norrberget; space constraints at Salmisaari preclude it. A cogeneration plant would require additional infrastructure, including cooling water arrangements and electricity transmission connections.

Capacity Parameters

The EIA will examine maximum plant capacities. For the heat-only configuration, thermal capacity is set at 600 MW, corresponding to a reactor capacity of 630 MW. For the cogeneration configurations, thermal capacity reaches 700 MW with an electrical output of 500 MW, requiring a reactor capacity of up to 1,400 MW. Helen noted that the characteristics of the final plant will be refined as design work progresses and may be smaller than the assessed maximums.

AFRY Engaged as EIA Consultant

Engineering, project management and advisory firm AFRY is serving as the EIA consultant for the project. The company is also supporting Helen's broader nuclear energy programme through studies on potential plant locations and technical solutions.

Helen launched the first phase of its nuclear programme in September 2024, with the stated aim of constructing a small nuclear power plant to supply heat to Helsinki. The programme is evaluating SMRs based on proven technologies capable of producing heat alone or heat and electricity in combination. Ongoing activities include negotiations with potential partner shareholders and evaluation of plant suppliers.

Helen's Nuclear Siting Manager, Melina Laine, noted that initiating the EIA at an early stage allows the project's impacts and implementation conditions to be thoroughly investigated before further planning decisions are taken. Helen Ydinvoima Oy CEO Pekka Tolonen indicated that nuclear power is being explored as a means of stabilising energy prices and securing supply for a growing city.

PNNL Advances Reactor-Grade Alloy Development with New Design Methodology

Materials scientists at Pacific Northwest National Laboratory are working to expand the range of metallic alloys capable of surviving the demanding environment inside nuclear reactors. The effort, led by principal investigator Osman El Atwani, centers on a framework the team calls robust alloy design, or RAD, the details of which have been published in the peer-reviewed journal Materials & Design.

Addressing a Persistent Materials Challenge

Reactor internals are exposed to a combination of elevated temperatures, intense radiation fields, and continuous mechanical stress — conditions that degrade conventional structural metals over time. Finding alloys that can reliably tolerate all three stressors simultaneously, rather than being optimized for just one, has long been a challenge for the nuclear materials community.

The RAD methodology is intended to address this by providing a systematic basis for alloy selection and development. Rather than relying on incremental modifications to existing materials, the approach frames alloy design around the full set of performance requirements imposed by reactor service conditions.

Methodology and Publication

The research team's framework has been formally documented in Materials & Design, a peer-reviewed journal covering materials science and engineering. Publication in a reviewed venue indicates the methodology has undergone independent technical scrutiny, which is a prerequisite for broader adoption in safety-critical applications such as nuclear reactor components.

Details of the RAD approach — including how candidate alloy compositions are evaluated against the combined demands of thermal stability, radiation tolerance, and mechanical integrity — are set out in that publication. The work originates from Pacific Northwest National Laboratory, a U.S. Department of Energy facility with an established materials research program.

Supply-Chain and Operational Relevance

For nuclear supply-chain professionals, advances in structural alloy qualification carry direct implications. Materials that can sustain performance over longer in-service intervals reduce the frequency of component replacement, with downstream effects on outage scheduling, procurement cycles, and overall plant operating costs.

New alloy design frameworks also have the potential to inform qualification pathways for next-generation reactor concepts, where operating temperatures and radiation doses may exceed those of the existing light-water reactor fleet. A structured design methodology like RAD could shorten the development timeline for qualifying novel materials by providing a defensible, reproducible basis for performance prediction.

The PNNL team's work represents an early-stage research contribution rather than a commercially qualified material, and further testing and regulatory engagement would be required before any alloy developed under the RAD framework could be deployed in a licensed reactor. Nonetheless, the publication marks a concrete step toward a more systematic approach to nuclear materials development.

Initial fuel loading completed at San'ao unit 2

China General Nuclear (CGN) completed initial fuel loading at San'ao unit 2 on 2 November, advancing the Hualong One reactor toward nuclear-powered commissioning. The operation transferred 177 fuel assemblies from the spent fuel pool's fuel racks into the reactor core using semi-automatic refuelling equipment.

CGN described the process: after operators completed the fuel loading sequence programming, the programme was imported into the refuelling machine's control system, with specialised fuel operators then directing the sequential transfer. The operation also employed a floating light gun independently developed by CGN to provide underwater illumination of the core, which the company said helped ensure the smooth progress of the loading process.

Project timeline

The San'ao plant received State Council approval for its first phase — units 1 and 2 — in September 2020. China's National Nuclear Safety Administration issued a construction permit for both units on 30 December 2020, with first concrete for unit 1 poured the following day. First concrete for unit 2 followed on 30 December 2021.

Unit 1 achieved first criticality in February 2026 and was connected to the grid in March, before being declared commercially operational on 29 April. Unit 2 completed cold functional tests in October 2025 and hot functional tests in April 2026. Commercial electricity supply from unit 2 is scheduled for 2027.

Expanding capacity

San'ao is the first nuclear power project in China's Yangtze River Delta region to adopt the Hualong One reactor design. Units 3 and 4, also Hualong One reactors, were among 11 reactors approved by China's State Council in August 2024; first concrete for the unit 3 nuclear island was poured on 19 December 2025. A further two Hualong One units are planned as units 5 and 6 at the same site.

Upon full completion, the plant is projected to supply more than 54 TWh of electricity annually to Zhejiang Province and the broader Yangtze River Delta region, while reducing standard coal consumption by more than 16 million tonnes and cutting carbon dioxide emissions by more than 51 million tonnes per year, according to CGN.

Ownership structure

San'ao represents the first Chinese nuclear power project to involve private capital. Geely Technology Group holds a 2% stake in the project company, Cangnan Nuclear Power. CGN is the majority shareholder with 46%, and other state-owned enterprises hold the remaining shares.