BWRX-300 by GE Vernova Hitachi: status and timeline

Milestones

Next · First BWRX-300 operational at Darlington

Ontario and OPG approve construction at DarlingtonMay 2025Complete.
Basemat set at Darlington22 Apr 2026Complete.
NRC issues construction permit for Clinch River to TVA30 Sep 2026Complete.
First BWRX-300 operational at DarlingtonTarget 2029Not yet reached.
Four units operational at DarlingtonTarget Q4 2030Not yet reached.

Most important updates

NRC issues first US construction permit for BWRX-300 SMR to TVA at Clinch River11d ago
Basemat is set at Darlington for the first BWRX-300 in the Western Hemisphere22 Apr 2026

Upcoming

Q1 2027Clinch River construction begins (next)
2029First BWRX-300 operational at Darlington
Q4 2030Four units operational at Darlington

Current obstacles

Regulatory pathway establishmentThe Clinch River permit establishes a repeatable licensing pathway, but future applications still face approval timelines and safety evaluations.
Cost per megawatt competitivenessManufacturing and operating economics at the 300 MW scale must compete with both large reactors and renewable energy.

Physics limits

Small reactor efficiencySmaller reactors have higher capital costs per megawatt than large reactors because fixed overhead (containment, control systems, staffing) is spread across fewer megawatts.
Thermal efficiency limitsAll thermal reactors (nuclear, coal, gas) are fundamentally limited by Carnot efficiency; water-cooled reactors operate at roughly 33% thermal efficiency regardless of size.

How it works

3 parts

Design

Proven reactor technology

The BWRX-300 uses the boiling water reactor design that has decades of operating experience, not a new theoretical concept.

Safety

Passive cooling

Natural circulation removes heat without active pumps, and integral isolation valves prevent coolant loss from containment breaches.

Fuel

Standard nuclear fuel

Low-enriched uranium fuel manufactured by Global Nuclear Fuel, the established supply source.

Spec sheet

Spec	BWRX-300
Electrical output	300 MW^R (reported)
Total Darlington capacity (four units)	1.2 GW^R (reported)
Households powered per unit	300,000+^R (reported)
Darlington construction timeline	First unit by end of 2029^R (reported)

^R reported by the company

Update log

2 updates

Wed 30 Sep

Major: NRC issues first US construction permit for BWRX-300 SMR to TVA at Clinch RiverRegulatorRegulatory

Wed 22 Apr

Major: Basemat is set at Darlington for the first BWRX-300 in the Western HemispherePressManufacturing

About GE Vernova Hitachi

The team behind BWRX-300

GE Vernova Hitachi

BWRX-300 small modular reactor, SMR

GE Vernova and Hitachi develop the BWRX-300, a 300 MW small modular reactor with passive safety systems. Projects are under construction in Canada and the United States.

GE Vernova is GE's power and renewable energy business, spun off in April 2024 under CEO Scott Strazik.
Two major BWRX-300 projects: Darlington, Ontario (first SMR in the West, 2029) and Clinch River, Tennessee (first US permit, Sept 2026).

gevernova.com (opens gevernova.com)Company profile →

Founded: 20242 yrs
Headquarters: United StatesJapan
Status: Private
Valuation: private
Works in: EnergyFission
Coverage: 1 program · 2 updateslatest 11d agochecked 10 Oct
Customers: Ontario Power Generation (opens opg.com)Tennessee Valley Authority (opens tva.gov)
Partners: Hitachi (opens hitachi.com)
People: Scott Strazik (opens gevernova.com)CEO of GE Vernova

Spec

BWRX-300

Electrical output

300 MW^R (reported)

Total Darlington capacity (four units)

1.2 GW^R (reported)

Households powered per unit

300,000+^R (reported)

Darlington construction timeline

First unit by end of 2029^R (reported)