Newcleo, the Paris-based advanced-reactor developer, has disclosed in a Schedule 425 filed with the U.S. Securities and Exchange Commission that it is shifting the planned site of its first-of-a-kind reactor deployment from France to the United States — a move the filing ties directly to a U.S. Department of Energy program to make surplus plutonium available to advanced-reactor vendors. The disclosure came in a filing made under the company’s pending merger with NewHold Investment Corp III (NHIC), a publicly traded special-purpose acquisition company, and reproduces an interview the company published with chief executive Stefano Buono. Here is what the filing actually says.

According to the document, Newcleo announced in May its intention to list on Nasdaq through the SPAC vehicle, a transaction the company states it hopes will raise up to $429 million in gross proceeds to continue funding development of its lead-cooled fast reactors. The filing reports that Newcleo has raised $780 million to date, a figure it characterizes as ahead of its European competitors but behind U.S. advanced-reactor vendors such as Oklo and X-Energy. It frames the U.S. pivot as a bet, in its words, “that it will be easier to secure the plutonium needed for the mixed-oxide (Mox) plutonium-uranium fuel assemblies that will power its fast reactors and that licensing timelines will be faster.” That bet, the document states, is dependent on the outcome of the DOE surplus plutonium utilization program, which plans to award up to 20 tons of plutonium to selected advanced-reactor vendors.

"The US has been the fastest, because they made a request for application in October to make available 20 tons of plutonium."— Newcleo Schedule 425 (Stefano Buono interview), source

The plutonium allocation is the hinge of the disclosure. In the interview reproduced in the filing, Buono states that Newcleo is “already negotiating with the US government the agreement for the supply of plutonium,” and that the DOE issued a request for application in October to make available 20 tons of material. He describes the quantity as “a huge quantity” that “even a part of” could let the company “manufacture until the end of the next decade.” Asked whether the plutonium would be granted free of charge, Buono answers, “In the RFA, the plutonium was offered for free. We only have to take care of transportation costs.” The document notes that Newcleo is pursuing the DOE material in partnership with Oklo.

What the filing says changed the timeline

The Schedule 425 documents a concrete shift in deployment sequencing. Buono states that Newcleo had long planned a first-of-a-kind reactor in France by 2033, but that a recent presentation now puts a first commercial reactor in the United States in 2032. Asked whether France is off the table for first-of-a-kind deployment, he answers, “No. Maybe second of a kind,” and says the company is keeping “internal competition among the projects,” which also include a site in Slovakia. The filing attributes the reordering to conditions for starting construction: Buono states that in the United States the company needs “an agreement on the initial material to be able to start building,” a condition he says is closer to being met in the U.S. than in France, where the company is going through a public-debate procedure ending in July and where a construction permit, per the filing, “may take two to three years.”

Licensing is the second factor the document records. Buono points to the Nuclear Regulatory Commission’s Part 53 framework for advanced reactors, which he describes as “better adapted to a company like ours” with a licensing timeline of 18 months. He states that Newcleo has had pre-engagement with the NRC and is holding “weekly meetings,” and that the chosen U.S. process “can allow us to start building before obtaining the final license.” The filing also names a candidate site: Buono states the company chose the Savannah River site for its fuel factory, citing the expectation that material would already be on site to reduce transportation costs, and describing the site as “a possible hub for reprocessing.”

The transaction and the fuel-facility question

On the structure of the deal, the filing reproduces Buono’s account of why Newcleo chose a SPAC merger over an IPO. He states the company judged the merger “a faster way to become a public company than an IPO, carrying less transaction risk,” and that Nasdaq “has always been the target” because it is “the most liquid market for innovation.” A companion filing in the same campaign — a translated interview Newcleo published from the Future Investment Initiative summit — records additional figures Buono cited there: a valuation of approximately $2.4 billion in the merger, a raise of €220 million from new investors, and €209 million in existing capital, with the standard SPAC mechanism allowing shareholders to redeem their capital. The proceeds ultimately available depend on redemptions; the filing’s cautionary language explicitly flags “underlying assumptions with respect to shareholder redemptions” as a source of uncertainty.

The Mox fuel-fabrication facility — the plant that would turn plutonium into fuel assemblies for Newcleo’s reactors — is treated in the filing as inseparable from the plutonium question. Buono states that Newcleo had “plans to build three by 2050” and is now putting the country projects “in competition,” with the determining factor being which secures the initial material first: “the factory that has the material first is the factory that we build first.” He states the facility could also produce other advanced fuels such as Haleu oxide fuels, framing the choice as “not a binary decision.” Asked about French plutonium, the filing records that Newcleo is “not in that phase yet” of being able to start building, and that the French material “might also take the form of a loan” against excess plutonium from its European reprocessing strategy.

The technology and the demonstration unit

The filing also documents the state of Newcleo’s hardware. Buono describes a demonstration machine under construction at Brasimone in Italy — a unit with the complexity of a nuclear reactor but heated by 10 megawatts of electrical power rather than a nuclear reaction. He states the installation is roughly halfway complete, is expected to be finished by the end of 2026, and will begin operating the following year, and that it includes power generation via a Fincantieri turbine. The document frames the unit as a validation step for the supply chain and for the eventual reactor’s components rather than as a power-producing nuclear plant. On the design itself, Buono states the basic design of the 200 MW commercial reactor remains in progress across France, Slovakia and the U.S., and that the company aims to complete it by the end of 2027 to begin U.S. licensing.

On competitive positioning, the filing records Buono’s characterization of Newcleo as ranked by the OECD Nuclear Energy Agency database as “the most advanced Generation IV reactor in Europe, and the second in the world after TerraPower,” and notes the stated pipeline figures: 27 gigawatts electric across all opportunities under discussion, of which 9.2 GWe is described as a “true pipeline” of mature projects. The filing also records what Buono declined to disclose: asked to update a previously stated levelized cost of energy of €55 per megawatt-hour and break it down, he states, “as we are approaching the public market, we prefer not to communicate anymore on that.”

The document is a Schedule 425, a filing class used to disseminate communications about a pending business combination, not a registration statement or proxy. Newcleo states it intends to file a registration statement with the SEC that will include the proxy statement and prospectus. The filing repeatedly cautions that its forward-looking statements — including deployment dates, licensing timelines and the plutonium allocation — are subject to risks including the possibility the merger is not completed and the outcome of the DOE program, which the company itself describes as “still under negotiation.”