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Holtec InternationalSMR-300
In Development
Holtec's Gen III+ pressurized water small modular reactor platform, intended for first deployment as the dual-unit Pioneer 1 & 2 project at Palisades and for follow-on projects such as Cottam in the UK.
Latest update Sep 20, 2026
01
Current status
Design is now centered on the SMR-300 architecture; Pioneer 1 & 2 at Palisades has DOE support, the NRC docketed Part 1 of the construction permit application in February 2026 and opened its environmental impact statement review in June 2026. On August 28, 2026 the NRC granted an exemption letting Holtec install permanent support-of-excavation and cutoff-wall systems before a Limited Work Authorization, announced by Holtec on September 15. Engineering News-Record reported on September 18 that the NRC is targeting completion of its final safety evaluation and environmental impact statement by March 31, 2027. The design completed UK GDA Step 2 in March 2026.
02
Specifications7
- Electrical Output
- ~320-340 MWe
(net) per unit (Holtec's FAQ cites >320 MWe; its August 2026 press releases cite ~340 MWe net; NRC materials describe a 300 MWe(e) rated design)
- International Pipeline
Palisades, Green River & Oyster Creek plus a non-binding Gulf South (Entergy/Hyundai) evaluation (U.S.), Cottam (UK/EDF), Rwanda (up to ~5 GW, Development Agreement), and India (up to 200 units)
- Licensing Status
- U.S
CPA Part 1 (LWA + environmental report) docketed; NRC environmental review underway with public scoping closed July 15, 2026; an Aug 28, 2026 exemption authorizes permanent SOE and cutoff-wall work before an LWA (Holtec announced Sept 15); NRC targeting final SE and EIS by March 31, 2027 (ENR, Sept 18); Part 2 filing expected mid-2027; UK GDA Step 2 complete
03
Upcoming milestones5
Announced next steps from Holtec International that mention SMR-300.
Mar 31, 2027
Pioneer 1 & 2 construction permit review
TargetMarch 31, 2027 (NRC final SE and EIS, per ENR); mid-2027 (Part 2 filing)
Advance the SMR-300 through U.S. licensing: SMR, LLC filed Part 1 of a phased construction permit application (a limited work authorization request plus a comprehensive environmental report) for the dual-unit Pioneer 1 & 2 plant on December 31, 2025; the NRC accepted it for docketing on February 27, 2026 and, on June 15-16, 2026, opened the formal environmental-review phase. On August 28, 2026 the NRC granted an exemption authorizing permanent support-of-excavation and cutoff-wall systems, excavation, dewatering, and ground improvement before a Limited Work Authorization, which Holtec announced on September 15; the exemption does not commit the NRC to issue an LWA or construction permit. Engineering News-Record reported on September 18, 2026 that the NRC is targeting completion of its final safety evaluation and environmental impact statement by March 31, 2027. Holtec has asked the NRC to complete its Part 1 review by December 31, 2026, and the NRC expects SMR, LLC to file Part 2 of the construction permit application by mid-2027.
2027
Complete the HI-TEST SMR-300 validation facility at Idaho National Laboratory
Target2027 (system dedication / start of testing)
Holtec said August 25-27, 2026 that fabrication of key components is under way for HI-TEST, a one-third scale test rig at Idaho National Laboratory (backed by the DOE's Advanced Reactor Demonstration Program) with two test loops designed to replicate accident scenarios and steam-generator behavior. An ANS Nuclear Newswire report dated September 1, 2026, citing INL scientist Piyush Sabharwall, said the project is on track to start testing in 2027. The facility will physically corroborate the SMR-300's generation capacity, resilience, and design margin under steady-state and transient conditions, with data intended to support future power uprates; Holtec is targeting system dedication in 2027 ahead of testing.
2029
Build four SMR-300s at the decommissioned Oyster Creek site
Target2029 (decommissioning complete); 2036 (SMR-300 commercial operation)
Following the NRC's July 30, 2026 approval of the License Termination Plan for the retired Oyster Creek Generating Station in Lacey Township, New Jersey (decommissioning more than 50% complete at approval, targeted for full completion by 2029), Holtec plans to build four SMR-300 units there (about 1.36 GW combined), targeting commercial operation in 2036. The project would be Holtec's third U.S. SMR-300 site after Palisades and Green River, Utah, and is projected to support roughly 4,000 construction jobs and 400+ permanent positions.
Early 2030s
UK and international SMR-300 deployment pipeline
Convert UK GDA Step 2 progress and the EDF Cottam partnership (Heads of Terms signed June 2026 for up to four SMR-300s, ~1.3 GW at the former Cottam coal site in Nottinghamshire) into site-specific licensing and follow-on international deployments that can reuse the UK and U.S. regulatory work, alongside the Green River, Utah SMR-300 project, the planned Gujarat, India manufacturing hub, and a May 2026 Comprehensive Development Agreement with Rwanda's Atomic Energy Board (targeting up to ~5 GW, Holtec's first sub-Saharan African market). As of September 16, 2026, no new UK GDA Step 3 request or Cottam licensing filing has been announced since the June 2026 Heads of Terms.
Date not announced
Gulf South SMR-300 evaluation with Entergy and Hyundai E&C
TargetNo target date announced (non-binding evaluation)
On August 4, 2026 Holtec, Entergy, and Hyundai Engineering & Construction signed a non-binding memorandum of agreement to jointly evaluate potential dual-unit SMR-300 projects across Entergy's Gulf South service territory (Alabama, Florida, Louisiana, Mississippi, and Texas), driven by rising industrial, manufacturing, and AI-data-center load growth. The framework covers assessing customer demand, candidate sites, and commercial structures; no site selection, binding commitment, or timeline has been announced as of September 16, 2026.
04
In the news9
Holtec postpones HNUC IPO, keeps SEC filing
Holtec Nuclear Corporation said on September 17 that it is postponing its Nasdaq IPO after talks with its banking syndicate, citing a two-week retreat in equity and nuclear-sector markets driven primarily by uncertainty over data-center development plus higher rates, trade tensions, and inflation fears. The roadshow launched September 8 at $15 to $18 per share for 50 million Class A shares, targeting proceeds of up to $900 million and a valuation of up to $10.2 billion under ticker HNUC. Holtec said it will keep its SEC registration statement on file, keep advancing the Palisades restart and Pioneer SMR-300 plan, and revisit public markets when conditions improve; CEO Kris Singh told the Financial Times the data-center link created a perfect storm for nuclear sentiment.
Holtec International World Nuclear News The Philadelphia Inquirer
NRC lets Holtec start Pioneer excavation work early
Holtec announced September 15 that the NRC granted an August 28 exemption authorizing permanent support-of-excavation and cutoff-wall systems for Pioneer Units 1 and 2 at Palisades before a Limited Work Authorization. The work covers diaphragm walls, soldier-pile soil-mix walls, perimeter cutoff walls, excavation, dewatering, and ground improvement for the nuclear island, turbine island, and balance of plant, a combined 680 MW SMR-300 project. An August 25 environmental assessment found no significant impact; the exemption is not a construction permit.
Holtec's SMR-300 test facility takes shape at Idaho lab
Holtec International said August 27 that fabrication of key components is under way for HI-TEST, a one-third scale test rig at Idaho National Laboratory backed by the DOE's Advanced Reactor Demonstration Program. The facility's two test loops will replicate accident scenarios and steam-generator behavior to validate the SMR-300 design's generation capacity and margin, with Holtec targeting system dedication in 2027 ahead of testing that could support future power uprates.
Holtec, Entergy and Hyundai E&C to evaluate Gulf South SMRs
Holtec International, Entergy and Hyundai Engineering & Construction signed a non-binding memorandum of agreement on August 4 to jointly evaluate potential dual-unit SMR-300 projects across Entergy's Gulf South service territory in Alabama, Florida, Louisiana, Mississippi and Texas. The framework will assess customer demand, candidate sites and commercial structures for the roughly 340 MWe-per-unit reactor, extending the Holtec-Hyundai SMR-300 partnership already underway at Palisades in Michigan to serve data-center and industrial load growth in the region.
NRC clears Oyster Creek closeout, Holtec plans four SMR-300s
The NRC approved Holtec's License Termination Plan for the retired Oyster Creek Generating Station in New Jersey on July 30, the final regulatory milestone in decommissioning the site. Holtec plans to build four SMR-300 small modular reactors there with about 1.36 GW of combined capacity, targeting commercial operation in 2036 and projecting roughly 4,000 construction jobs, making Oyster Creek Holtec's third U.S. SMR-300 site after Palisades and Green River, Utah.
Holtec's Palisades restart clears final major refurbishment phase
Holtec International said on July 2 that its Palisades nuclear plant in Michigan has closed out the last of its major refurbishment projects, transitioning from large-scale construction to routine testing, inspection and operational-readiness work ahead of restart. A key final accomplishment was placing the plant's turbine-generator on turning gear following extensive inspection and maintenance, though more than 5,000 individual work activities remain. Palisades would be the first U.S. reactor to return to service after entering decommissioning, and the progress prompted the Holtec/Hyundai team to begin site-construction planning for the planned Pioneer 1 and 2 SMR-300 units.
Holtec and EDF pitch four SMR-300 reactors for UK's Cottam site
Holtec International and EDF submitted a joint proposal to the UK Government on June 23 to deploy up to four SMR-300 small modular reactors at the former Cottam coal power station in Nottinghamshire, totaling roughly 1.3 GW of clean generating capacity. The companies also signed Heads of Terms to form a joint venture to advance the project. The plan builds on Holtec's UK Generic Design Assessment for the SMR-300 and would make Cottam a second deployment site after the twin Pioneer units Holtec is pursuing at Palisades in Michigan.
NRC opens environmental review of Holtec's Palisades SMRs
The U.S. Nuclear Regulatory Commission launched its environmental review of Holtec's plan to build two SMR-300 small modular reactors at the Palisades site in Covert, Michigan, opening a public comment period that runs through July 15 under docket NRC-2026-0265. The twin 340-MWe pressurized-water units, dubbed Pioneer-1 and -2, would sit alongside the 777-MWe Palisades reactor Holtec is restarting, following the company's December submission of the first part of a two-part construction permit application. Holtec expects to file Part 2 by roughly mid-2027.
Holtec SMR-300 picked for revived Utah Green River nuclear project
A newly formed joint venture between Blue Castle Holdings and Fulcrum Point Holdings will deploy Holtec International's SMR-300 pressurized-water reactors at the long-dormant Blue Castle site in Green River, Utah, the partners said in early June, reviving a project that had spent 19 years collecting environmental, seismic, and groundwater data. The plan calls for two to four SMR-300 units producing a combined 600 to 1,200 MW, and Holtec's air-cooling design is well suited to the arid Emery County site where water is scarce. The revival falls under Utah's 'Operation Gigawatt' clean-energy initiative.
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