Terrestrial Energy asks NRC to confirm thermal facility build is not nuclear construction
The Oct. 8 report asks the NRC to confirm that building the thermal and electric facility is not nuclear construction.
Ines Halvorsen
On Oct. 8, the third of at least three topical reports planned for 2026 reached the U.S. Nuclear Regulatory Commission when Terrestrial Energy Inc. NASDAQIMSR submitted its thermal and electric facility report. The company's Aug. 11 second-quarter results release reported an estimate of US$2.7 billion in lifetime revenue per IMSR plant, chiefly from core-unit and fuel supply; that release gives no construction budget or early-service revenue forecast. The NRC is the authority asked to review the report, and the Oct. 8 release names no customer, contract term or power price for early service.
Nasdaq's next regular session had not opened when this story was checked on Oct. 9, leaving no regular-session share reaction to measure. The last available close predates the company's filing announcement.
The company asks the NRC to confirm that building the thermal and electric facility does not count as nuclear construction under 10 CFR 50.10(a)(1). If the NRC agrees, Terrestrial says it could customize the facility for a site, then build and operate it ahead of the nuclear plant's construction permit and operating licence.
The thermal and electric facility would house generators, turbines and steam supply systems. A separate nuclear facility would contain the standardized reactor systems. Terrestrial says auxiliary heat, including natural gas, could allow the first facility to provide commercial heat and electricity before the reactor is licensed.
Report Seeks Construction Classification Under NRC Rule
In its Oct. 8 release, Terrestrial says the report uses elements of its previously approved postulated initiating events methodology. The company's analysis says its nuclear systems do not rely on the thermal facility for safe operation, and a failure originating there could be isolated from the nuclear systems. Those are assertions supporting its request, not a finding on this report.
"With its NRC approval, only the nuclear portion of the plant would follow the nuclear licensing timeline," Terrestrial Energy chief executive Simon Irish said in the Oct. 8 release.
The company says the NRC approved its principal design criteria report in 2025 and its postulated initiating events methodology in 2026. It submitted a separate report on its graphite qualification methodology in September 2026, making the thermal submission its third topical report of the year. Terrestrial says an approved topical report can establish an element of the licensing basis for use in later applications without repeating that technical review.
In its August results, Terrestrial reported US$283.4 million in cash, cash equivalents and investments at June 30, alongside a US$9.4 million loss in the second quarter. The same release said Texas A&M agreements cover 77 acres at the RELLIS site for characterization and environmental work. Neither the land agreements nor the Oct. 8 topical report is a nuclear construction permit.
The topical report itself and an NRC acceptance notice were not among the documents reviewed for this story. The company's Oct. 8 release provides no NRC review deadline, construction start or first-power date for the thermal facility. Its lifetime revenue figure remains an estimate for a completed plant, with no signed early-service sale identified in that release.
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Terrestrial said in its Aug. 11 results that it is working toward commissioning its first IMSR plants in the early 2030s. An NRC response to the Oct. 8 report is the next regulatory milestone, but its Oct. 8 release gives no decision date for the request.
