Batch Extrusion Molding of Recycled Polythylene and Boron Carbide Composite Material for Sustainable Nuetron Shielding
Faculty Mentor Information
Dr. Brian Jaques, Boise State University; Allyssa Bateman, Boise State University; and Dr. Scott Phillips, Boise State University
Presentation Date
7-16-2026
Abstract
The Neutron Science Laboratory at Boise State University is installing two Thermo-Fisher Scientific P385 neutron generators capable of 14 MeV neutron irradiations. Neutron radiation is an indirectly ionizing form of radiation that readily penetrates many materials due to its lack of charge. Accordingly, this necessitates the use of specialized shielding to meet Nuclear Regulatory Commission guidelines for allowable human exposure. A ceramic-polymer composite consisting of high-density polyethylene (HDPE) and micro-particles of boron carbide (B_₄C) is particularly effective as neutron shielding: The hydrogen in HDPE elastically scatters neutrons to reduce their energy while boron captures thermal neutrons. Monte Carlo N-Particle simulations were used to determine an effective shielding design using this HDPE/B_₄C composite along with pure HDPE moderator. We developed a process to use recycled HDPE to fabricate 2x4 plastic boards that can be assembled to fit the shielding design. This was achieved through a batch extrusion molding process, in which a single-screw extruder was used to melt HDPE material, shear-mix B_₄C micropowder within it, and fill a rectangular mold. We have demonstrated the viability of this batch extrusion molding for production of HDPE boards that can be post-processed and used as neutron moderator material.
Batch Extrusion Molding of Recycled Polythylene and Boron Carbide Composite Material for Sustainable Nuetron Shielding
The Neutron Science Laboratory at Boise State University is installing two Thermo-Fisher Scientific P385 neutron generators capable of 14 MeV neutron irradiations. Neutron radiation is an indirectly ionizing form of radiation that readily penetrates many materials due to its lack of charge. Accordingly, this necessitates the use of specialized shielding to meet Nuclear Regulatory Commission guidelines for allowable human exposure. A ceramic-polymer composite consisting of high-density polyethylene (HDPE) and micro-particles of boron carbide (B_₄C) is particularly effective as neutron shielding: The hydrogen in HDPE elastically scatters neutrons to reduce their energy while boron captures thermal neutrons. Monte Carlo N-Particle simulations were used to determine an effective shielding design using this HDPE/B_₄C composite along with pure HDPE moderator. We developed a process to use recycled HDPE to fabricate 2x4 plastic boards that can be assembled to fit the shielding design. This was achieved through a batch extrusion molding process, in which a single-screw extruder was used to melt HDPE material, shear-mix B_₄C micropowder within it, and fill a rectangular mold. We have demonstrated the viability of this batch extrusion molding for production of HDPE boards that can be post-processed and used as neutron moderator material.