Terrestrial Energy signed an Other Transaction Authority (OTA) agreement with the US DOE in March 2026 for Project TETRA — work to build a pilot IMSR reactor under DOE support. The OTA agreement provides Terrestrial Energy with DOE authorisation and resources to advance its pilot reactor programme. Project TETRA is separate from the Texas A&M RELLIS campus deployment and represents Terrestrial Energy's DOE-backed demonstration pathway. Following the announcement, IMSR stock surged 50% in three days of trading in March 2026.