Frontier Technology Corporation has extensive experience in neutron shielding, offering custom neutron shielding solutions that provide reliable protection from harmful radiation. To discuss how our neutron shielding walls can help protect against neutron radiation damage in your application, please reach out to our team.
The Challenge of Neutron Shielding
Because neutron radiation endangers the people, structures, devices, and equipment exposed to it, reliable neutron shielding protection is critical. Specially designed shielding walls are used in nuclear power facilities, nuclear medicine systems, radioisotope projects, or particle accelerator work.
Why is Neutron Shielding Needed?
Cf-252 freely emits what are known as fast or fission energy neutrons. These fast neutrons have very high kinetic energy levels, close to 1 MeV (1.6×10−13 J) and a speed of ~14000 km/s. As a result, they move quickly and can penetrate most materials easily. Adverse health effects are seen especially in soft tissues and at the cellular level, in which cell function is altered or cellular reproduction is disabled entirely.
Fast neutrons can also penetrate solid objects, contaminating them and causing structural damage to equipment in the surrounding area. The damage occurs because neutrons move so quickly and transfer massive amounts of kinetic energy to the material they encounter at the atomic level.
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How Neutron Shielding Works
The goal of neutron shielding is to prevent neutrons from reaching people or objects in their path and to mitigate bodily harm and damage to equipment or structures. In order to stop a neutron, as much of its kinetic energy as possible must be transferred to another particle of similar mass.
Materials high in hydrogen, such as water, are especially effective at this moderation step because their nuclei have approximately the same mass as neutrons, facilitating efficient energy transfer during collisions. This reduces the speed at which the neutron travels or stops it outright, a process called thermalizing.
Once neutrons are slowed down to thermal energies, they become more susceptible to being captured or absorbed by other elements in the shielding material. When a neutron is captured, it undergoes a nuclear reaction that effectively removes it from the radiation environment, significantly reducing potential exposure.
Effective neutron shielding also relies on the appropriate thickness and density of shielding materials. The thickness required varies according to neutron energies, the intensity of the radiation source, and specific safety requirements. Frontier Technology Corp. carefully evaluates these parameters, designing custom shielding solutions that provide optimal protection tailored precisely to each unique operational scenario.
Neutron Shielding Materials
Many materials may be used to shield against ionizing radiation. However, the three most popular neutron shielding materials are WEP resin, paraffin, and concrete.
Heavy metals, such as lead, are not used in neutron shielding. The high density of lead means its nuclei are very heavy, far heavier than neutrons. As a result, instead of transferring their kinetic energy upon collision with lead nuclei, neutrons do not stop and continue to pass through the material.
At the atomic level, hydrogen is the most effective material for shielding neutrons. This is because neutrons and protons have a similar mass, so when a neutron hits a single proton (e.g., a hydrogen nucleus), kinetic energy is transferred and the neutron slows or stops. Therefore, materials containing high levels of hydrogen tend to be the best to use for fast neutron shielding. Another important element in shielding is boron, which readily absorbs neutrons.
NuWEP – Water-Extended Polyester
Frontier’s NuWEP shielding walls incorporate materials made of low-atomic-number elements because they have a high probability of forming cross-sections that interact with the neutrons. Hydrogen and hydrogen-based materials, such as water and water-extended polyester (WEP), are preferable for neutron shielding. This is because compounds with a high concentration of hydrogen atoms act as reliable barriers and provide inexpensive yet reliable shielding.
Neutron Shielding Products from Frontier
Frontier’s WEP resin is an ideal material for neutron radiation shielding because:
High Water Content: As a result of the emulsification process, WEP resin’s final hydrogen content is almost as high as that of pure water. Unlike water, WEP resin cures into a hard shield, so it can easily be used in almost any shielding application.- Cost-Effective: WEP resin’s high water content makes it a very affordable substance by weight compared to alternative materials.
- Harsh Environmental Resistance: WEP is completely inert. It doesn’t break down and resists damage from water exposure, weathering, and harsh chemicals. WEP is also fire-retardant (although best-suited for normal operating temperatures).
- Void-Free Curing: WEP resin sets cleanly and with minimal imperfections and no odor. It cures as a contiguous solid material with no voids, holes, or bubbles.
High Water Content: As a result of the emulsification process, WEP resin’s final hydrogen content is almost as high as that of pure water. Unlike water, WEP resin cures into a hard shield, so it can easily be used in almost any shielding application.Custom Neutron Shielding Design
Our shielding walls are custom-manufactured to your requirements, constructed with stainless steel outer materials, and contain WEP inner material. Our neutron radiation shielding options include:
- Custom dimensions available
- Isotope pass-through ports
Frontier can also use WEP to fill shielding walls that our customers have designed and supplied to us.
Neutron Sources
Neutron sources emit neutron radiation for various applications, including scientific research, medical treatments, industrial inspections, and nuclear power generation. Common neutron sources include nuclear reactors, neutron generators, and radioactive isotopes like Californium-252.
Understanding the characteristics of different neutron sources, including neutron energy spectra, intensity, and emission pattern, is critical for selecting appropriate shielding solutions. Effective shielding must account for these factors to ensure maximum protection and regulatory compliance. Frontier Technology Corp. specializes in providing shielding solutions customized to various neutron sources, ensuring optimal protection regardless of the neutron emission profile.
Frontier shielding walls meet industry standards, including 10CFR50 Appendix B, IAEA Special Form Certification, U.S. Department of Transportation (USDOT) regulations, U.S. Nuclear Regulatory Commission (USNRC) regulations, NIST-traceable requirements, ISO 2919, and ANSI 97E6644, 97E6X644, 97E66543, and 97E66344
About Frontier Technology Corporation
Frontier Technology Corporation (FTC) is the world leader in californium-252 neutron source manufacturing and design, and is the foremost expert in logistics and shipping of radioactive material. Founded in 1984 by Treva Janzow and the late Edward Janzow, Frontier Technology is located in Xenia, Ohio. Frontier Technology has over 40 years industry experience in providing the highest-quality neutron sources, PINS sources, nuclear start-up rods, TYPE-A shipping containers, WEP shielding, and antimony-beryllium pellets.
Type-A Neutron Shipping Containers
Frontier designs and fabricates “Type-A” shipping packages of various sizes, shielding, capacities, and configurations for use, rental, or purchase by our customers. All packages are designed and constructed in-house to ensure that the highest quality standards are met.
Type-A Shipping ContainersWEP: The Best Neutron Shielding Material
WEP resin is a newer shielding choice valued for water’s high hydrogen availability. Due to its high content of large, neutron blocking hydrogen molecules, WEP is a highly effective shielding material. It also contains boron, an element that absorbs neutrons and adds additional shielding capability. WEP resin is strong, versatile, durable, and offers better neutron shielding performance than some high-density options.
WEP: The Best Neutron Shielding MaterialNuclear Shielding Applications
Neutron radiation poses significant danger to people, structures, devices, and equipment exposed to it; therefore, effective neutron shielding is critical. In plants, labs, and other buildings where neutron sources and equipment are used, shielding walls are an excellent way to protect against neutron radiation.
Nuclear Shielding Applications