BWRX-300

Overview

300 MWe Gen III+ boiling-water small modular reactor derived from the NRC-certified ESBWR, using natural circulation and passive safety systems, a 60-year design life, and proven GNF fuel. Designed for a power block that fits within two soccer fields and 24–36 month nth-of-a-kind construction. The first grid-scale SMR under construction in the Western world.

Unit 1 under construction at OPG's Darlington site (construction began May 2025; in service by end of 2030, four units planned); TVA Clinch River construction permit awaiting an NRC commissioner decision still targeted for Fall 2026 (mandatory hearing held August 13, 2026; record closed August 27; permit not issued as of September 17); up to 10 further US units planned under the $40B US-Japan program; new US project with Elementl Power for up to 5 units at Meigs County, Ohio (Early Works Agreement, June 2026); Blue Energy filed the first part of an NRC construction permit on September 15, 2026 for the first BWRX-300 at Port of Victoria, Texas; selected or down-selected in Poland (six units agreed at Wloclawek), Estonia, Hungary, Saskatchewan, Lithuania (MOU, February 2026) and Bulgaria (JV letter of intent, December 2025); UK Generic Design Assessment completed December 2025; MOU with Hitachi to explore Southeast Asia; lost the competitive selection for Sweden's Ringhals project to Rolls-Royce SMR in June 2026, then returned to Sweden on September 3, 2026 when Studsvik selected GVH and Samsung C&T for a proposed four-unit, 1.2 GW ReFirm project.

Key Specs

Output
300 MWe
Design life
60 years
Construction time (nth-of-a-kind)
~24–36 months, first concrete to fuel-load ready
First-unit cost (Darlington)
CAD $7.7B (~US $5.6B)