GE Hitachi Nuclear Energy BWRX-300 (update) Joint venture GE Hitachi Nuclear Energy (Hitachi GE in Japan) is developing the BWRX-300, a small modular reactor (SMR) that is based on the BWR (boiling water reactor) design. Site preparation for its first deployment in Darlington, Canada, has begun. GE Hitachi Nuclear Energy BWRX-300 (update)