French advanced 3D printing filaments manufacturer Nanovia is introducing the new Flex B4C, a new boron carbide enriched filament that can be used in the nuclear energy industry for neuron shielding. The material is available in the company’s online shop and one 500 gram spool retails for €490 before VAT (€980 per kg). It is available in both 1.75 and 2.85mm.

Nanovia Flex B4C is similar in concept to Nanovia’s PLA XRS, which blocks X-rays with barium sulfate. he company has been using B4C for some time on specification ceramic filament for sintering, the Cr range.

Already used by the French nuclear industry, Nanovia Flex B4C uses bore-10 capability to react with neutrons emitted by the nuclear fission reaction. Combined with an industrial polymer, this filament offers an easy-to-use solution for 3D printing complex custom parts required to keep the reactors running.

Its semi-rigid base allows for structural components but remains able to deform when necessary to absorb shocks. This combination makes Nanovia’s Flex B4C particularly suited for tools, maintenance equipment, and transport vessels for fragile materials.

Nanovia B4C is printable without an enclosure and does not require any build plate adhesives.

When a free neutron hits a person, it can modify or destroy the DNA of a cell. Since the neutrons are not charged particles, they are not easily slowed down by the other atomic elements and can penetrate through very thick layers of material before hitting another atom’s core.

So how does flex B4C capture the free neutron generated by nuclear fission? The boron present in the ceramic elements of B4C is a metalloid of which several isotopes exist. Boron-10 and boron-11 are the only stable versions that exist in nature. This means that these atoms have the same number of protons but a different number of neutrons.

Boron-10 in particular has an extensive core absorption cross-section. When a free neutron, generated by nuclear fission, encounters boron-10, this wide core absorption cross-section effectively functions as a strong net. This makes boron-10 much more likely to get hit than other atoms.

This impact creates a predominantly unstable isotope of boron-11 that fissures into: an alpha particle (Helium atom without electrons), a lithium-7 atom and gamma radiation [10B + nth → 4 He2+ + 7Li 3+ + 2.79 MeV (6%) and 10B + nth  → 4 He2+ + 7Li 3+ + 2.31 MeV + γ (0.48 MeV) (94%), source : Caractérisation de champs neutroniques rapides et épithermiques pour thérapie par capture neutronique basée sur accélérateur / Marine HERVE]

The two elements generated are not actually radioactive as the other elements absorb the gamma radiation as it passes through them. Shielding made from heavier elements such as lead allows for quicker absorption.

These properties make boron-10, in its solid form (boron carbide) and its liquid form (boric acid), an ideal material, used as a regulator (neuron poisons) in nuclear reactors. By inserting boron-10, the liberated neutrons by the fission of uranium-325 are intercepted, neutralizing the chain reaction.