Skip to main content

Holtec Delivers Critical Component for Revolutionary US Fusion Reactor

Holtec International has achieved a remarkable feat - the fabrication and delivery of the Centre Stack Casing (CSC) for the Princeton Plasma Physics Laboratory's (PPPL's) National Spherical Torus Experiment-Upgrade (NSTX-U), a revolutionary step towards commercial nuclear power based on nuclear fusion. This magnificent piece of engineering represents the heart of the NSTX-U, which is expected to produce high-performance plasma with low-cost magnetic fields.


The Centre Stack Casing for the NSTX-U (Image: Holtec)

The CSC had to be designed and manufactured with extremely precise tolerances to meet the demanding metrology and magnetic permeability requirements. This challenge demanded Holtec's weld engineers to develop and qualify several unique welding procedures and tools that were then implemented by their highly skilled machinists and welders. The final product, which is made of inconel metal and resembles a hedgehog due to its stud-covered design, will provide the inner vacuum wall of the NSTX-U and structural support for plasma-facing components and coils that must withstand temperatures of up to 10 million degrees Celsius.

PPPL Lab Director Steve Cowley describes the CSC as a "beautiful piece of inconel metal" that is "magnificent" and "well-travelled," having been forged in Italy, machined in New Jersey, and assembled in Pittsburgh. Its arrival marks a significant project milestone and will enable important recovery work to begin.

Holtec's Director of Weld Technology, Brian Farnsworth, expresses immense pride in the team's dedication and diligence to produce this critical component. He notes that fabricating something of this caliber required expertise and weldments of the highest quality. "This is a true testament to what Holtec's manufacturing organization can achieve," he adds.

Holtec's Chief Strategy Officer, Fritz Roegge, believes that this project demonstrates the company's ability to leverage its state-of-the-art human and industrial capability to support emerging energy technologies such as fusion and to support US government customers.

The NSTX-U is the flagship fusion facility at the US Department of Energy's PPPL. Unlike conventional tokamaks, the spherical device is shaped more like a cored apple and can produce high-pressure plasmas with relatively low-cost and cost-effective magnetic fields. Its three main objectives are to explore the facility's capability to produce stable, high-performance plasmas with low-cost magnetic fields, to develop the understanding and tools required to start up and sustain such plasmas non-inductively, and to develop techniques to handle and control the waste heat from fusion reactions.

Holtec's remarkable achievement in the fabrication and delivery of the CSC represents a significant step towards a future of clean, safe, and sustainable nuclear fusion energy.

Comments

Popular Posts

Amsterdam Strikes Geothermal Gold: Hot, Thick, Permeable Reservoir Confirmed

Breakthrough Beneath the Beach: Amsterdam Region Hits Geothermal Paydirt at Strandeiland By: Robert Buluma The Netherlands just took a giant leap toward fossil-free heating. On the artificial island of Strandeiland (part of Amsterdam’s fast-growing IJburg district), the SCAN exploration well has officially confirmed what the geothermal community has been hoping for: a thick, hot, and , most importantly permeable reservoir in the Slochteren Formation. Key numbers that matter:   Reservoir thickness: 152 meters   Bottom-hole temperature: 66 °C   Permeability: confirmed via successful production and injection tests   That’s not screaming-hot by Icelandic standards, but for direct-use district heating in one of Europe’s densest urban areas, 66 °C is more than enough to supply thousands of homes with clean, baseload heat – forever. Why This Well Changes Everything for the Netherlands The Dutch government launched the SCAN program (Seismic Campaign Nethe...

Zanskar’s Big Blind: First Blind Geothermal Discovery in 30 Years

Big Blind: The Geothermal Discovery That Changes Everything By: Robert Buluma Utah startup  Zanskar Geothermal quietly dropped one of the most important announcements in American energy in decades. They discovered and confirmed “Big Blind” ,the first completely blind, commercial-grade geothermal system found in the United States in over thirty years. Let that sink in. No hot springs.   No fumaroles.   No steaming ground.   No prior wells.   Zero surface expression whatsoever. Just desert, sagebrush, and – 7,000 feet below,  a reservoir hot enough and permeable enough to support gigawatt-scale power production. This isn’t incremental progress. This is a paradigm breaker. Why “Blind” Discoveries Matter So Much For the last 40 years, geothermal development in the U.S. has been geographically handcuffed. You could only build plants where nature advertised the resource on the surface – think Yellowstone, The Geysers, or Imperial Valley. Ever...

Exclusive Interview: An In-Depth Look at Exergy’s Game-Changing Gemini Turbine

Exclusive interview with Exergy : discover the new Gemini dual-flow radial outflow turbine, the first single-unit ORC solution for 30–60 MW geothermal projects, offering up to 30 % lower costs and 99 % availability. By:  Robert Buluma .   An interview with  Luca Pozzoni -  Deputy CEO | Group CFO - Exergy International and the Exergy Team 1. Can you walk us through the key design innovations in your new Gemini turbine and how it differs from previous models? The major innovation of the Gemini turbine lies in the dual-flow configuration: unlike conventional radial outflow turbines which are equipped with a single bladed overhung rotor disk, the Gemini features a double-side bladed rotor disk mounted in a between-bearing configuration. This enables the efficient processing of significantly larger volumes of fluid, leading to higher power output having basically two radial outflow turbines in a single machine with enhanced operational stability and simplified mainte...

Eavor’s Geretsried Closed-Loop Geothermal Plant Now Powers the Grid

Eavor Technologies Achieves Historic Milestone: World’s First Commercial-Scale Closed-Loop Geothermal System Now Delivering Power in Geretsried, Germany Published: December 2025 By:  Robert Buluma The Day Geothermal Changed Forever On a crisp Bavarian morning in late 2025, a quiet revolution in clean energy officially went live.   Eavor Technologies Inc ., the Calgary-based pioneer of closed-loop geothermal technology, announced that its flagship commercial project in Geretsried, Germany has begun delivering power to the grid becoming the world’s first utility-scale multilateral closed-loop geothermal system to achieve commercial operation. For anyone who has followed the geothermal sector for the last decade, this is nothing short of seismic (pun intended). What Makes Eavor’s Closed-Loop System Truly Disruptive? Traditional geothermal plants rely on naturally occurring hot water reservoirs or enhanced geothermal systems (EGS) that require hydraulic fracturing and massiv...

Potsdam Goes Deep: How an All-Electric Drilling Rig Is Turning the City’s Heating Completely Fossil-Free

Revolutionizing Urban Heating: UGS GmbH's Pioneering Geothermal Project in Potsdam By: Robert Buluma In the heart of Germany’s energy transition, a quiet but powerful revolution is taking place in Potsdam. UGS GmbH, a German subsidiary of the French energy storage specialist Geostock, has begun a landmark geothermal project that could redefine how entire cities stay warm in winter ,without burning a single drop of oil or cubic meter of gas. The project, awarded by the local utility Energie und Wasser Potsdam GmbH (EWP), focuses on the former site of the HKW Süd combined heat and power plant in southern Potsdam. The goal is ambitious: replace the aging gas-fired plant with deep geothermal energy and other renewables, eventually supplying tens of thousands of households with completely CO₂-free district heating. At the center of this transformation stands a piece of machinery that looks like something from the future: UGS’s fully modernized, all-electric drilling rig “Rig 110”. After...

Chevron’s Big Pivot: Betting Billions on Geothermal and Biofuels

Chevron CEO Sees Growing Potential in Biofuels and Geothermal Energy Posted by  Robert Buluma | December 11, 2025 The energy world is changing fast, and Chevron, one of the oldest and largest oil companies on the planet, is not sitting on the sidelines. In a recent wide-ranging interview with The Wall Street Journal, Chevron CEO Mike Wirth made it clear: the company sees major, long-term growth in two areas that have nothing to do with crude oil,biofuels and geothermal energy. For a company built on drilling for hydrocarbons, this pivot toward heat from the Earth’s core and fuels grown from plants is nothing short of remarkable. From Black Gold to Green Heat: Why Chevron Is Betting Big on Geothermal Geothermal energy has long been the quiet, reliable cousin in the renewable family,always there, rarely flashy, but suddenly very attractive. Unlike solar panels that go dark at night or wind turbines that stop when the air is still, geothermal plants deliver steady, 24/7 baseload p...

Cornell PhD: Earth & Atmospheric Sciences – Fall 2026 Opportunities

Exciting PhD Opportunities in Earth and Atmospheric Sciences at Cornell University (Fall 2026 Admission) By: Robert Buluma If you’re a prospective graduate student interested in cutting-edge research in climate science, glaciology, physical oceanography, geospace physics, volcanology, or cryosphere processes, Cornell University’s Department of Earth and Atmospheric Sciences (EAS) just announced a fantastic set of fully funded PhD positions starting in Fall 2026. The department posted a detailed call on LinkedIn (shared widely on X/Twitter by Prof. Matt Pritchard) listing specific projects and the faculty members actively recruiting students right now. These are not generic openings; each professor has described their project and what kind of student they are looking for. Here are the current opportunities (as of early December 2025): 1. Climate Dynamics   Professor: Flavio Lehner (flavio.lehner@cornell.edu)   Focus: Climate variability with emphasis on how sea-surfa...

🔥 Krafla Magma Testbed: Drilling Into the Earth’s Fiery Heart

Krafla Magma Testbed (KMT) : Humanity’s Bold Leap Into the Heart of the Earth Interview  from Bjorn Gudmundsson the C.E.O-Krafla Magma Testbed and Team By:  Robert Buluma In 2009, deep beneath Iceland’s iconic Krafla volcano, a drilling team made history. During the IDDP-1 project, their drill bit pierced into magma molten rock at just two kilometers below the surface. What began as an accident became a scientific revelation. For the first time, humans had safely accessed magma. This “Eureka” moment gave birth to an idea so daring it almost sounds like science fiction: the creation of a permanent observatory where magma could be directly studied. That idea became the  Krafla Magma Testbed (KMT) a visionary international project that promises to rewrite the future of geothermal science, volcanic monitoring, and sustainable energy. Why Krafla? The Perfect Laboratory Beneath Our Feet Krafla’s  geology is unique. It offers a known shallow magma body, decades of research...

TOPP2 Synchronised: Eastland Generation, Ngāti Tūwharetoa Geothermal Assets & Ormat Success

Milestone Achieved: New Zealand’s Newest Geothermal Power Station TOPP2 Successfully Synchronised to the National Grid By:  Robert Buluma On 3 December 2025, a significant new chapter in Aotearoa New Zealand’s renewable energy story began when the 49 MW Te Onetapu Power Plant 2 (TOPP2) , the country’s newest geothermal station , was successfully synchronised to the national grid for the first time. Located in the Kawerau geothermal field, TOPP2 is the result of a unique and groundbreaking partnership between Eastland Generation (a subsidiary of Eastland Group) and Ngāti Tūwharetoa Geothermal Assets Ltd, the commercial arm of the Ngāti Tūwharetoa Settlement Trust. A True Partnership Success Story This is not just another power station. TOPP2 represents one of the most successful examples of post-Treaty settlement iwi ownership and operation in the energy sector. Ngāti Tūwharetoa Geothermal Assets supplies the geothermal steam and heat under a long-term agreement, while Eastland Gene...

Europe’s Underground Energy Revolution: EGEC Demands 250 GW Geothermal by 2040

Europe’s Geothermal Revolution Is Coming: EGEC Demands a 250 GW Target by 2040 – Here’s Why 2026 Will Be Make-or-Break By: Robert Buluma Published: December 9, 2025   On 5 December 2025, the European Geothermal Energy Council (EGEC) dropped a bombshell policy paper with a crystal-clear message to Brussels: Europe is sleeping on the biggest indigenous, baseload, 24/7 renewable energy source under its feet , and it’s time to wake up. Titled ,The European Geothermal Strategy and Action Plan , Making Europe competitive, secure and affordable, the document is the strongest industry call yet for the European Commission to publish a dedicated European Geothermal Strategy and Action Plan in Q1 2026. And the ambition is massive: 250 GW of installed geothermal capacity by 2040 a six-fold increase from today’s ~44 GW (mostly district heating and a handful of power plants). Why Now? Because Europe Can No Longer Afford to Wait Since Russia’s invasion of Ukraine, Europe has been laser-focu...