Boronated Polyethylene Shielding
Boron-Loaded HDPE for Thermal Neutron Absorption
Boronated polyethylene shielding consists of high-density polyethylene panels loaded with 5 to 10 percent boron carbide, installed as an interior barrier to absorb thermalized neutrons. Without an atmospheric or magnetospheric shield, lunar infrastructure must mitigate secondary neutron flux generated by cosmic radiation and surface nuclear reactors. Utilizing the 3,837-barn thermal absorption cross-section of boron-10, the material captures neutrons slowed by the polyethylene base without generating secondary gamma radiation. A 5-centimeter-thick panel with 7 percent boron loading achieves 99 percent thermal neutron capture, providing a zero-power, chemically inert shield designed for a 50-year operational lifetime around reactors and crewless cryo vaults.
Boronated polyethylene (5-10% boron carbide loading) at inner shielding layer — absorbs thermalised neutrons via 10B(n,α)7Li reaction without secondary gamma.
Purpose
Boronated polyethylene (5-10% boron carbide loading) at inner shielding layer — absorbs thermalised neutrons via 10B(n,α)7Li reaction without secondary gamma.
Context
Child of L2-RAD-POLY within the Lunar Ark system
Principles
- ▸Boron-10 absorbs thermal neutrons with high cross-section (3837 barns)
- ▸BPE captures neutrons that HDPE only slowed
- ▸5-10% B4C loading typical
- ▸Reduces secondary gamma vs (n,γ) capture in steel/H
- ▸Used as innermost lining behind HDPE
Typical implementations
- ▸NASA HZETRN-validated BPE shielding studies
- ▸Industrial neutron-shielding products (Shieldwerx)
- ▸Reactor shielding heritage
Lunar considerations
- ▸Particularly valuable near reactor and crewless cryo vault
- ▸Long-life polymer; B4C inert in lunar environment
Specifications
Functional
| primary function | Boronated polyethylene (5-10% boron carbide loading) at inner shielding layer — absorbs thermalised neutrons via 10B(n,α)7Li reaction without secondary gamma. |
| thickness cm | 5 |
| b mass percent | 7 |
| thermal neutron capture percent | 99 |
Physical
| mass kg | 500 |
| materials | B4C-loaded HDPE panels, Stainless attachment hardware |
| vacuum compatibility | True |
Operational
| power consumption w | 0 |
| thermal range c | -40, 70 |
| lifetime years | 50 |
| mtbf hours | 1000000 |
Interfaces
Provides
- Inner cryo vault neutron capture
- Reactor shielding inner layer
Requires
- Mounting
- Periodic replacement
Cite this entry
Lunar Ark Codex. "Boronated Polyethylene Shielding" (L3-RAD-POLY-BOR). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-RAD-POLY-BOR
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.