# The Man Who Sold His Last Company to Novartis for 3,9 Billion Dollars Is Now Building Nuclear Reactors the Size of a Silo > Stefano Buono's newcleo has raised 780 million dollars at a 2,4 billion dollar valuation to build small lead cooled reactors that run on recycled nuclear waste, and it is heading toward a Nasdaq listing by the end of the year rather than the Italian state funding it turned down. - Source: Italian Insider - Canonical URL: https://italianinsider.net/en/article/newcleo-nuclear-reactor-italy-stefano-buono - Author: Chiara Ricci - Section: Tech - Other edition: https://italianinsider.net/article/newcleo-nuclear-reactor-italy-stefano-buono - Published: 2026-09-18T13:00:00.000Z - Updated: 2026-09-18T13:00:00.000Z - Tags: newcleo, Nuclear energy, Stefano Buono, Small modular reactors --- Stefano Buono has done this before. In 2002 he founded Advanced Accelerator Applications, a medical nuclear company, took it public on Nasdaq in 2015, and sold it to Novartis in 2018 for 3,9 billion dollars. Three years later he started again, this time in energy rather than medicine, founding newcleo with the engineer Luciano Cinotti and the physicist Elisabeth Rizzotti to build a different kind of nuclear reactor from the ones utilities have run for decades. The reactor itself is the pitch. Newcleo's design is lead cooled rather than water cooled, nearly cylindrical, six meters tall with a seven meter diameter, generating 200 megawatts and built to be stacked in multiples depending on how much power a site needs. It runs on a mixed oxide fuel made from recycled plutonium and uranium, a fuel cycle the company says cuts the lifespan of high level waste from hundreds of thousands of years down to roughly 300, and the lead coolant gives the design what Buono calls intrinsic safety, a reactor that shuts itself down or stabilizes during a malfunction without anyone having to intervene. None of that comes cheap or fast. Newcleo has raised 780 million dollars to date at a valuation of 2,4 billion, and is heading toward a Nasdaq listing by the end of 2026 through a SPAC merger that could bring in up to another 429 million dollars. The company has also racked up 324 million euros in cumulative losses since it started, 140 million of those in 2025 alone, and its own auditors at Grant Thornton have attached a going concern warning to its filings, standard for a capital intensive nuclear startup but not a detail Buono can wave away. Backers appear undeterred. Exor Seeds, the steelmaker Danieli, the cement group Cementir, and the Drago and Malacalza families have all put money in, and the roughly 1.000 people newcleo employs are split mostly between Italy, where just over half the workforce sits, and France, where the company is headquartered, in Paris. Notably, newcleo turned down a proposed 200 million euro investment from the Italian state, a deal the League had blocked, choosing instead to lean on the US listing and a partnership struck in October 2025 with Oklo, the reactor company backed by Sam Altman. Washington has since picked newcleo alongside Oklo to negotiate recycling 20 metric tons of plutonium left over from Cold War stockpiles. The timeline runs through the early 2030s rather than this decade's headlines, testing starts this year at Italy's ENEA Brasimone facility, a first production line for the recycled fuel is due in 2031, and the first commercial reactor is targeted for 2032. Buono says newcleo intends to cut the industry's typical nine and a half year construction timeline down to three years by building reactors on a production line rather than one at a time, a claim that would matter enormously if true and means very little until a first unit is actually running. Newcleo says it already has 9,2 gigawatts of mature development opportunities on its books, the equivalent of 46 reactors, in a field that now also includes TerraPower, X-Energy and Oklo, each valued near 7,5 billion dollars, and fusion competitors like Commonwealth Fusion Systems that have raised billions of their own. The one thing none of them can claim yet, and the one thing that will actually decide this, is a lead cooled reactor that has run for decades without the corrosion and material problems only Russia's own program has any real experience managing. --- Originally published by Italian Insider. Free to cite with attribution and a link to https://italianinsider.net/en/article/newcleo-nuclear-reactor-italy-stefano-buono.