Holtec submits key nuclear safety report to NRC, advancing construction permit process for two Michigan SMR-300 reactors

Holtec International’s Corporate Engineering unit submitted the Preliminary Safety Analysis Report (PSAR) to the US Nuclear Regulatory Commission on September 30, 2026, completing the second phase of the Construction Permit Application process for two planned SMR-300 small modular reactors. The filing covers detailed technical and safety information for Pioneer Units 1 and 2, slated for the Palisades site in Covert Township, Michigan.

Holtec files PSAR with NRC for Pioneer units 1 and 2

Holtec describes the PSAR submission as the most significant regulatory step yet toward establishing the framework for the Pioneer plant. It follows the first phase of the Construction Permit Application — a Limited Work Authorization application and Environmental Report submitted in December 2025. Together, these two phases map out a structured path toward actually breaking ground on the new reactors.

The submission didn’t come out of nowhere. Holtec says it was preceded by numerous pre-submittal meetings with the NRC and sustained technical exchanges with Commission staff — a sign that both sides have been building toward this milestone for a while.

It also includes provisions for on-site, indefinite-duration subterranean storage of used fuel, which could simplify waste management logistics considerably.

What the PSAR covers and what Pioneer 1 & 2 would deliver

The PSAR gives the NRC the technical and safety detail it needs to evaluate whether Holtec should receive a permit to build Pioneer Units 1 and 2 — two SMR-300 reactors planned for the Palisades site in Covert Township, Michigan. Together, the two units are designed to generate an additional 680 megawatts of electrical capacity.

That’s a substantial addition to the region’s power supply. The twin-unit plant would also anchor the broader Palisades Energy Campus alongside the existing 805 MWe Palisades plant, currently in its final stages before repowering. The campus would combine legacy nuclear infrastructure with next-generation reactor technology on the same footprint — an unusual pairing that reflects how much the site has evolved.

Recent NRC approvals accelerate regulatory momentum

The PSAR is the headline, but it sits inside a broader wave of regulatory progress. Several Licensing Topical Reports — covering innovative aspects of the SMR-300 design — have recently cleared significant NRC hurdles.

A report on a novel shop-fabricated modular civil construction method, validated through testing at Purdue University, was audited and accepted by the NRC in September 2026. Its Safety Evaluation Report is expected by early November 2026. Holtec says the method could significantly reduce labor requirements compared with conventional construction approaches.

Also accepted in September 2026 was a report on an innovative soil-structure interaction methodology — a technique designed to more accurately assess how a reactor structure responds to different seismic and soil conditions, with its Safety Evaluation Report anticipated by the end of October 2026. A third report, covering a new instrumentation and control architecture, was accepted in August 2026, with regulatory approval expected in October 2026. On the first-phase application, the NRC closed its audit in September 2026, and a draft Safety Evaluation Report for the Limited Work Authorization is anticipated in December 2026.

Next steps in the Pioneer development program

The regulatory filings are moving forward, but significant technical work remains. Near-term items include completing a Class 2 construction cost estimate, a 4D simulation showing the step-by-step evolution of the full plant construction sequence, and confirmatory safety analyses supporting the Final Safety Analysis Report.

Two design features of the SMR-300 stand out. It targets the elimination of an exclusion zone — the standard safety buffer required at conventional nuclear facilities. It also includes provisions for on-site, indefinite-duration subterranean storage of used fuel, which could simplify waste management logistics considerably. The US Department of Energy is providing financial support to help accelerate the Pioneer deployment program, something Holtec has acknowledged as a meaningful factor in the project’s pace.

Background: Holtec’s SMR program and the Palisades site

Holtec launched its SMR program in March 2011. Over the following 15 years, the effort moved through research and development, design refinement, testing, and ongoing regulatory engagement — a long runway that’s now producing tangible results.

Development spans a multinational team operating across the United States, United Kingdom, Spain, Ukraine, and India. That geographic spread reflects both the complexity of the engineering effort and the global ambitions behind the SMR-300, which is intended to be deployable across a wide range of sites worldwide. The new soil-structure interaction methodology is specifically designed to support that flexibility. Pioneer Units 1 and 2 are considered likely candidates to become the industry’s first commercial SMR-300 plant, though regulatory and construction milestones still lie ahead before that distinction is confirmed.

Where the Pioneer program stands

As of September 30, 2026, Holtec International has completed two phases of the Construction Permit Application process: the December 2025 submission of the Limited Work Authorization application and Environmental Report, and now the PSAR. Three Licensing Topical Reports have cleared NRC audits in recent months, with Safety Evaluation Reports expected through late 2026. A draft NRC safety evaluation on the first-phase application is anticipated in December 2026.

Work still ahead includes a Class 2 cost estimate, a 4D construction simulation, and confirmatory safety analyses for the Final Safety Analysis Report. If the regulatory path keeps moving at its current pace, Pioneer Units 1 and 2 — and the 680 megawatts they’re designed to deliver — could move meaningfully closer to construction in the months ahead.