Terrestrial Energy Appoints Kathryn McCarthy to Board of Directors

New Director Brings Nuclear Research and Strategic Leadership Experience

Kathryn McCarthy's appointment to Terrestrial Energy's Board reflects a strategic addition of deep nuclear energy expertise to the company's leadership structure. The disclosure indicates that McCarthy has held prominent positions across multiple leading nuclear research institutions over a career spanning more than two decades. Her professional background encompasses both fusion and fission energy research, as well as international collaboration on major scientific projects, positioning her to contribute substantively to the company's strategic direction.

McCarthy's current role as Senior Advisor at Oak Ridge National Laboratory, which she has held since 2025, involves supporting strategic decisions in the US ITER Project—a major international collaboration focused on fusion energy research. This ongoing advisory capacity demonstrates her continued active engagement in cutting-edge nuclear energy development and positions her to bring current insights from the broader fusion and fission research community to Terrestrial Energy's boardroom discussions and deliberations.

Leadership Background at Oak Ridge and ITER Project

Prior to her current advisory role, McCarthy served as Director of the US ITER Project Office at Oak Ridge National Laboratory from 2020 to 2025, where she held responsibility for strategic leadership of United States participation in the international ITER fusion energy endeavor. This position required her to manage complex international partnerships and coordinate research initiatives at one of the nation's premier nuclear research facilities. The filing's description of this role underscores the scope of strategic leadership and technical expertise McCarthy has developed in managing large-scale fusion energy programs.

McCarthy's tenure at Oak Ridge coincided with a critical period in global fusion research advancement. Her leadership of the US ITER contribution involved coordinating with international partners and managing technical and strategic priorities for US involvement in one of the world's largest and most ambitious fusion research projects. This background directly aligns with industry developments in advanced nuclear technologies and positions her to contribute informed perspectives on how Terrestrial Energy's work may intersect with broader fusion and fission energy research agendas.

Earlier Career at Canadian Nuclear Laboratories and Idaho National Laboratory

Before joining Oak Ridge, McCarthy served as Vice President of Research and Development at Canadian Nuclear Laboratories from 2017 to 2020, according to the filing. This role expanded her experience across North American nuclear research ecosystems and reflected her progression into senior technical and strategic positions within the nuclear energy sector. Her time at Canadian Nuclear Laboratories occurred during a period when the company was managing transitions in its research portfolio and advancing various nuclear science initiatives.

McCarthy's foundational experience came from Idaho National Laboratory, where she held senior leadership positions from 2003 to 2017. During this tenure, she served as Deputy Associate Laboratory Director for Nuclear Science and Technology and as Director of Nuclear Science and Engineering. These positions placed her at the forefront of national nuclear research initiatives across multiple technical domains, establishing deep expertise in both organizational leadership and technical nuclear science that spans multiple decades. Her progression through increasingly senior roles at Idaho National Laboratory demonstrates sustained leadership in nuclear energy research and development environments.

Director Compensation and Indemnification Arrangements

The filing indicates that McCarthy will receive compensation consistent with Terrestrial Energy's non-employee director compensation policy. The specific parameters of this compensation policy are described in detail in the company's definitive proxy statement filed with the Securities and Exchange Commission on April 29, 2026, in connection with the company's 2026 Annual Meeting of Stockholders. This standard approach to director compensation aligns with established corporate governance practices and transparency requirements.

McCarthy has entered into Terrestrial Energy's standard form of indemnification agreement for directors, which the filing indicates is available as Exhibit 10.11 to the company's Current Report on Form 8-K filed on November 3, 2025. This indemnification agreement provides customary protections and is consistent with governance arrangements established for other board members. The disclosure confirms that no special compensation arrangements or understandings were involved in McCarthy's selection for the board.

Board Selection Process and Related Transactions

According to the filing, no arrangements or understandings between McCarthy and any other person existed pursuant to which she was selected as a director. This disclosure addresses standard corporate governance considerations regarding potential conflicts of interest or undisclosed influencing relationships in the director appointment process. The absence of such arrangements suggests that McCarthy's selection was made through the company's ordinary board development and nomination processes.

The filing also discloses that there are no transactions involving Terrestrial Energy and McCarthy that would be required to be reported under Item 404(a) of Regulation S-K. This regulatory disclosure addresses potential related-party transaction concerns and confirms that McCarthy's appointment does not involve any undisclosed business relationships or financial arrangements with the company that would trigger additional disclosure obligations or raise governance concerns.

Terrestrial Energy's Board Strengthening Through Nuclear Industry Expertise

Terrestrial Energy operates in the advanced reactor technology sector, developing integral molten salt reactor designs intended for power generation and industrial heat applications. The appointment of McCarthy, with her extensive background in both fusion and fission research leadership, signals the company's focus on strengthening board expertise in nuclear energy technology and policy domains. Her experience navigating large international research collaborations and managing complex nuclear science portfolios aligns with the technical and strategic challenges facing advanced reactor developers.

The timing of McCarthy's appointment in July 2026 reflects Terrestrial Energy's ongoing development of its technology platform and commercialization pathways. Board appointments in the advanced reactor sector often respond to strategic milestones, regulatory engagement priorities, or technology development phases. McCarthy's combination of fusion research experience and fission technology leadership positions her to contribute perspectives across both energy domains, potentially informing discussions about technology positioning, regulatory strategy, and stakeholder engagement within the nuclear energy ecosystem.

Public Announcement and Disclosure Timeline

The filing indicates that Terrestrial Energy issued a press release on July 28, 2026, announcing McCarthy's appointment to the Board. This press release was furnished as Exhibit 99.1 to the Form 8-K filing. The announcement became public information on July 28, 2026, providing shareholders and market participants with formal notice of the board composition change. The timing of the announcement followed the board's action on July 22, 2026, by six days.

The information regarding the press release is disclosed under Item 7.01 (Regulation FD Disclosure) in the filing. According to the filing language, this furnished information is not deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, nor is it incorporated by reference in other filings under securities laws except as expressly stated. This distinction reflects standard regulatory practice for current event disclosures that announce material corporate governance changes without constituting audited or formally incorporated financial or legal statements.

Investor Considerations and Board Governance Context

Shareholders and investors monitoring Terrestrial Energy may observe that McCarthy's appointment represents an addition of specialized expertise in nuclear energy policy, research, and international collaboration frameworks. Her background at institutions heavily engaged with US energy policy and international fusion research suggests potential value for a board addressing regulatory engagement, technology positioning, and strategic partnerships in the advanced reactor market. The breadth of her experience across multiple nuclear research institutions may facilitate informed discussion of technology benchmarking, competitive dynamics, and regulatory landscape evolution.

Board composition in the advanced reactor sector carries strategic significance for investors assessing company governance quality and leadership depth. McCarthy's appointment adds nuclear research institution credentials to the board and reflects potential board focus on technical credibility and regulatory interface capabilities. Investors may view such appointments as indicators of the company's prioritization of technical governance oversight and connections to broader nuclear research and policy communities. The filing provides factual disclosure of the appointment without offering forward-looking guidance regarding strategic initiatives or business impacts.