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Westinghouse and Amentum partner to expand delivery capacity for APX fleet deployment. August 4, 2026 - CHANTILLY, VA., August 4, 2026 - Westinghouse Electric Company and Amentum (NYSE: AMTM), a global leader in advanced engineering and technology solutions, have entered into a series of agreements supporting the Westinghouse APX technology platform. These agreements augment Westinghouse capabilities to support fleet-scale deployment of its AP1000(R) reactor while also advancing the development of the AP300(TM) small modular reactor (SMR). "Westinghouse is pursuing a disciplined APX technology strategy built on the proven AP1000 reactor and extended through the AP300 SMR," said Dan Sumner, President and Chief Executive Officer of Westinghouse. "We continue to make investments to strengthen our proven APX platform, and our ongoing collaboration with Amentum is expected to accelerate the licensing of the AP300 SMR with the NRC. Separately, our two companies will work together to enhance our engineering and execution capabilities for delivering 1-gigawatt reactors at scale." "Amentum's expertise spans the full spectrum of the nuclear project lifecycle, accelerating the development and deployment of advanced nuclear solutions, strengthening energy security and powering the growth of AI and other energy critical industries," said John Heller, Amentum Chief Executive Officer. "There is an expanding global market for firm baseload power, and our collaboration with Westinghouse will enable us to help meet that demand." The Westinghouse APX strategy offers a single technology platform enabling the fleet delivery of the AP1000 reactor and the AP300 SMR. The APX platform is based on the proven innovations and technology of the AP1000 plant, including validated engineering, components, licensing strategies, fuel design and supply chain. The APX strategy offers the grid-scale, commercially available AP1000 reactor for near-term global fleet deployments, while developing the AP300 SMR to address additional market segments with smaller energy requirements. Amentum's engineering capacity and nuclear experience will strengthen the industrial base and delivery model, enabling the repeatable deployment of the APX technology suite. Under the most recent agreement, Westinghouse and Amentum will collaborate to obtain regulatory approval for the AP300 SMR by the U.S. Nuclear Regulatory Commission, a major milestone in bringing the technology to market. Westinghouse and Amentum have an established history of partnership on nuclear projects worldwide, including nuclear power and decommissioning projects in the United States, United Kingdom, Poland, Slovakia, Lithuania and South Africa. About Westinghouse Westinghouse Electric Company is the future of energy, providing reliable, innovative nuclear technologies and services globally. Westinghouse pioneered commercial nuclear power, delivering the world's first commercial pressurized water reactor in 1957. The company has industrialized more nuclear reactors than any other company, with its technology forming the basis of half of the world's operating nuclear plants. More than 140 years of innovation makes Westinghouse the preferred partner for advanced technologies covering the complete nuclear energy life cycle. For more information, visit www.westinghousenuclear.com and follow Amentum Holdings, Inc. on Facebook, LinkedIn and X. Media Contact: Brian McCrone +1 445-289-0409 About Amentum Amentum is a global leader in advanced engineering and innovative technology solutions, trusted by the United States and its allies to address their most significant and complex challenges in science, security and sustainability. Its people apply undaunted curiosity, relentless ambition and boundless imagination to challenge convention and drive progress. Its commitments are underpinned by the belief that safety, collaboration and well-being are integral to success. Headquartered in Chantilly, Virginia, Amentum Holdings, Inc. has more than 50,000 employees in approximately 70 countries across all seven continents. Visit Amentum Holdings, Inc. at www.amentum.com to learn how Amentum Holdings, Inc. advance the future together. Follow Amentum on LinkedIn Media Contact: Donna Savarese Forward-Looking Statements This press release contains or incorporates by reference statements by Amentum Holdings, Inc. (the "Company") that relate to future events and expectations and, as such, constitute "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995 and other federal securities laws. These forward-looking statements may be characterized by terminology such as "believe," "project," "expect," "anticipate," "estimate," "forecast," "outlook," "target," "endeavor," "seek," "predict," "intend," "strategy," "plan," "may," "could," "should," "will," "would," "will be," "will continue," "will likely result," or the negative thereof or variations thereon or similar terminology generally intended to identify forward-looking statements. All statements, other than historical facts, including, but not limited to, statements regarding the anticipated work and revenue under the awarded contract, and the Company's objectives, expectations and intentions, applicable legal, economic and regulatory conditions, and any assumptions underlying any of the foregoing, are forward-looking statements. A number of important factors could cause actual results to differ materially from those contained in or implied by these forward-looking statements, including those factors discussed in its filings with the Securities and Exchange Commission (SEC), including, among others: the occurrence of an accident or safety incident; the ability of the Company to control costs, meet performance requirements or contractual schedules; and other factors set forth under Item 1A, Risk Factors in its Annual Report on Form 10-K for the fiscal year ended November 25, 2025, which can be found at the SEC's website at www.sec.gov or the Investor Relations portion of its website at www.amentum.com. Any forward-looking statement speaks only as of the date on which it is made, and the Company assumes no obligation to update or revise such statement, whether as a result of new information, future events or otherwise, except as required by applicable law.

Maverick Capital Ltd. purchased a new position in shares of Amentum Holdings, Inc. (NYSE:AMTM – Free Report) in the 1st quarter, according to the company in its most recent filing with the SEC. The institutional investor purchased 46,335 shares of the company’s stock, valued at approximately $1,208,000. Other hedge funds have also made changes to […]

Plan to build Port of Workington site to treat Japanese nuclear reactor coolant. Cavendish Nuclear and Amentum, in a joint venture (JV), have been selected to build a new facility at the Port of Workington to treat sodium coolant from a nuclear reactor in Japan. The work is subject to planning and regulatory permissions, and would treat material from the Monju Prototype Fast Breeder Reactor (FBR), in Fukui Prefecture, Japan. It is part of a wider project to support the Japan Atomic Energy Agency (JAEA) with the decommissioning of the Monju reactor, which was closed in December 1995, but was restarted in 2010. The new facility will be built and operated by a JV formed of the two firms and will "support skilled jobs both directly and more widely across the supply chain, contributing significantly to the local economy", said a statement from Cumberland Council, which Council owns and operates the port. It added that the plans for the sodium treatment facility follows on from works carried out at the port and nearby Oldside to clear land in preparation for other development in future. Thomas Armstrong Construction is carrying out the land clearance work for Cumberland Council and the work is being funded by approximately £4.5M in government funding as part of the Workington Town Deal. The land clearance works are part of "a wider regeneration project which includes the Workington Gateway and the opening up of better transport links in the town centre", the council said. Related questions you can explore with Ask NCE, our new AI search engine. They are also part of a long-term initiative to turn the area into a hub for "clean energy, manufacturing and intermodal logistics which will support wider regional growth," it said. A Cavendish Nuclear and Amentum spokesperson said: "Cavendish Nuclear and Amentum are grateful to Cumberland Council and the Port's management team for their support in enabling our design and construction programme to move to the next phase. "We are fully committed to adding real social value toWest Cumbria and this new venture will contribute to the regeneration [of] the Port of Workington and support the local economy."