Why Hermetic Feedthroughs Are a Crucial Part of Nuclear Modernization

Key Points:

• The Trump administration is pushing for increased nuclear power¹ as well as continued work to modernize the United States’ nuclear arsenal.

• The average age of existing nuclear power plants: 43 years²

• Contemporary nuclear gloveboxes are large, custom systems encompassing all process-related equipment. ³

• Nuclear glovebox feedthroughs are critical for proper equipment functioning and operator safety.

• Nuclear reactors, including small modular reactors (SMRs), have pressure/vacuum chamber systems that also rely on feedthroughs.

• Addressing current demands requires flexible solutions, which includes both retrofitting and new application designs.

The Nuclear Imperative

Nuclear power includes both defense applications and power production. The push for nuclear defense modernization in the United States began with Congress tasking Los Alamos National Laboratory (LANL) in 2018 to meet an annual quota of 30 plutonium bomb cores (pits) by 2026. However, the ramp up has been affected by multiple infrastructure projects due to the need to repair and replace several major systems. For example, a single glovebox replacement can take weeks for decontamination and removal.⁴ Amidst these challenges, glovebox feedthroughs play a crucial role in maintaining safe and efficient operations for gloveboxes still in use.

In 2025 the focus on nuclear power expanded beyond the military. The Trump administration is pushing for both the expansion of existing nuclear power plants and the development of SMRs as a method to meet growing energy demands from artificial intelligence (AI) computing, cryptocurrency mining, and electric vehicles.² Data centers require additional forms of power outside the traditional grid to keep up with their demands, which has renewed interest in nuclear power. This places pressure on existing sites like Three Mile Island to increase production while dealing with issues related to worker safety and aging infrastructure. Like nuclear defense sites, gloveboxes are used to conduct multiple activities. However, there are also pressure and/or vacuum chamber systems within nuclear reactors.

Modernizing Nuclear Infrastructure: Glovebox Electrical Pass Throughs

As the United States ramps up efforts to expand nuclear power and modernize its nuclear arsenal, nuclear facilities like Los Alamos National Laboratory (LANL) and Savannah River National Lab (SRNL) are under immense pressure to meet production goals while navigating aging infrastructure and safety concerns. At the heart of this challenge lies a deceptively simple but vital component: the glovebox feedthrough.

Gloveboxes are sealed enclosures used to handle hazardous materials, especially radioactive substances like plutonium, safely. According to the Department of Energy, nuclear gloveboxes have evolved into large custom systems that contain all process-related equipment.³ These enclosures rely on electrical pass throughs, aka feedthroughs, to bring power, data, and signal through the chamber without compromising its hermetic seal. In facilities like LANL’s Plutonium Facility 4 (PF-4), where technicians work with high-hazard nuclear materials, the reliability of these feedthroughs can make or break operational success.

Modernizing Nuclear Infrastructure: Electrical Penetration for Nuclear Power

Nuclear power relies on nuclear reactors, which have gas-tight containment walls. Electrical penetration assemblies are feedthroughs that enable power, signal and data to travel through these walls. At the same time, these feedthroughs need to maintain the boundary created by the chamber wall, which requires a hermetic seal. Therefore, hermetic feedthroughs play a key safety role: they not only provide everyday electrical and data transmission and containment, but also help mitigate the effects of an accident.

Expanding nuclear power involves a two-part strategy: updating existing infrastructure and developing new, next-gen nuclear reactors like SMRs, which can be built more rapidly than a traditional reactor. In 2025, the average age of existing nuclear plants is 43 years, which is why retrofitting is a good option to extend existing reactors’ lifetimes. SMRs may be smaller than existing reactors, but they still have a similar chamber structure that requires electrical penetration feedthroughs to pass through the wall and ensure optimal operation.

Hermetic Feedthroughs: Small Component, Big Impact

Hermetic feedthroughs and connectors are relatively small but crucial to operational effectiveness. Their primary purpose is to serve as electrical pass throughs, providing a leak-proof pathway for external inputs and internal outputs from the system within the chamber, protecting both the operator and the surrounding environment from contamination and radiation. In the case of reactor applications, feedthroughs allow different electronic devices to function inside challenging pressurized areas, while preventing leaks that may jeopardize the functionality of the entire reactor. Ultimately, they serve five key functions:

1.  Electrical Performance. Nuclear gloveboxes contain process-related equipment that depend on the ability to send power, signal, and data in and out of the chamber to function.
2. Support Various Connection Types. Depending on the equipment within and outside of the chamber, feedthroughs may incorporate different types of conductors, connectors, and/or lines. Multiple feedthroughs can be mounted to a single penetration plate or glovebox panel, allowing for different connection types in a single mountable configuration.
3. Maintain Containment. A hermetic seal is crucial to prevent radioactive materials from leaving the glovebox and contaminating the external environment. It also keeps the internal atmosphere free from external contaminants.
4. Facilitate a Controlled Atmosphere. Connecting gas lines through feedthroughs maintains the controlled, inert environment necessary inside the chamber to handle radioactive materials and other sensitive substances.
5. Ensure Safety. Creating a robust hermetic seal contributes to the overall safety of the glovebox system, which protects workers from direct exposure.

What makes these feedthroughs indispensable is their ability to maintain a hermetic seal while allowing for the transmission of power, signal, and data in and out of the glovebox environment. The ideal solutions are epoxy-based seals which are chemically inert and tested for long-term performance, ensuring that operators remain protected from hazardous materials inside the glovebox for decades.

Meeting Legacy Challenges with Modern Solutions

One of the most pressing issues in nuclear facilities is the need to retrofit new components into existing infrastructure. When it comes to nuclear power, many people are aware of incidents like the Three Mile Island accident in 1979 that led nuclear power to take a backseat to the overall mix of energy sources. This is part of the reason why the average age of nuclear power plants is 43 years, requiring maintenance and modernization to ensure high performance under increased demand.

This also holds true with nuclear defense modernization. PF-4, for example, was originally designed for research, not production. Its gloveboxes and feedthroughs are decades old, and replacing them is a slow, meticulous process due to contamination risks and the complexity of decontamination.⁴ 

This challenge is easily addressed by custom-designed feedthroughs made to fit legacy systems. Extend the life of existing equipment with feedthroughs designed to work within current schematics. In addition, there are push-through feedthrough assemblies that allow for the replacement of hermetic inserts without breaking the seal, enabling upgrades without exposing the environment to contamination. This capability is especially valuable in nuclear facilities, where downtime and safety risks must be minimized.

Design Flexibility and Integration

Epoxy feedthrough technology is chemically compatible with a wide range of materials. This enables a level of design flexibility that goes beyond retrofitting to ensure nuclear facilities have the right materials to support their application. Feedthroughs may contain a wide range of electrical and optical connections, including MIL-spec connectors, USB, RJ-45, coaxial, fiber optics, and quick connect solutions, as well as power connections and cables. This flexibility allows labs to integrate modern instrumentation and control systems into older gloveboxes without extensive redesigns.

Moreover, bulkhead housing options are integrated with elements like O-ring face seals, weld-in assemblies, and NPT threads to ensure compatibility with various glovebox wall configurations. This adaptability is crucial for nuclear facilities juggling renovation and production simultaneously, as seen at LANL.

Even in modern nuclear production, design flexibility ensures engineers can make the most out of glovebox feedthroughs. Whether it’s augmenting a design to create a turnkey solution that allows system operators the ability to easily connect and disconnect equipment or combining multiple conductors into one feedthrough to optimize the space, working with a feedthrough specialist provides opportunities to create the best solution for the application.

Safety and Compliance

Safety is paramount in nuclear environments. Feedthroughs must not only perform reliably but also meet stringent regulatory standards. Look for a vendor who engages in 100% quality testing. To ensure a true hermetic seal, you want parts tested for leak rates below 1×10⁻8 cc He/sec and comply with certifications like ITAR, DFARS, and have traceability reports and certified material test reports (CMTRs) available. These standards ensure that electrical feedthroughs can operate safely under extreme conditions, including high radiation and temperature from hot nuclear environments.

In PF-4, where even minor leaks or spills can spread radioactive contamination, the integrity of feedthroughs is critical. Incidents involving water leaks and manual handling of nuclear materials have already led to contamination and productivity losses. Reliable feedthroughs help mitigate these risks by maintaining sealed environments and enabling safe transport of materials

Supporting the Future of Nuclear Energy

The demand for secure, efficient nuclear infrastructure is growing. On one hand, people are looking to nuclear power as a way to meet growing energy demands. On the other hand, nuclear defense systems are not only being modernized, but also are expected to grow. Both benefit from systems that isolate hazardous nuclear materials while enabling their use.

Nuclear feedthroughs may seem like a small part of the puzzle, but they are foundational to the safe handling of nuclear materials. By enabling upgrades within legacy systems, reducing contamination risks, and supporting modern instrumentation, they help nuclear facilities like LANL, SRNL, and Three Mile Island meet production goals and national security mandates.

Ready to Upgrade Your Nuclear Systems?

Whether you’re retrofitting legacy equipment or designing new glovebox systems, Douglas Electrical Components offers custom-engineered feedthroughs that meet the highest standards of safety, reliability, and compatibility. Contact our design team today to discuss your application needs and ensure your systems are ready for the future of nuclear energy.

References

1. Hughes, T. (2025, Aug. 8). Nuclear power roars back, thanks to Trump administration push. USA Today. https://www.usatoday.com/story/news/politics/2025/08/08/nuclear-power-getting-major-push-trump-administration/85516824007/
2. Frequently Asked Questions (FAQs). U.S. Energy Information Administration. Accessed Nov. 3, 2025 at https://www.eia.gov/tools/faqs/faq.php?id=228&t=3
3. Chapter 7: Glovebox Filtration. US Dept. of Energy. Accessed Nov. 3, 2025 at https://www.standards.doe.gov/standards-documents/1100/1169-bhdbk-2003-ch7/@@images/file
4. Inez Guzmán, A. (Oct. 28, 2025, Oct. 8). In a looming nuclear arms race, aging Los Alamos faces a major test. New York Times. Retrieved from https://www.nytimes.com/2025/10/28/us/los-alamos-nuclear-program.html