Long-term Radiation Rugged Rotary Vacuum and Water Seals in Heavy-Ion Accelerators

The Department of Energy’s Office of Nuclear Physics Isotope Development and Production for Research and Applications Program has identified a need for materials that will survive high radiation environments to support next generation rare isotope beam facilities. Specifically, long-lifetime, rotary vacuum and water seals are needed to survive 0.5 – 15 MGy/month. Current gaskets and seals do not offer the combined mechanical and radiation survivability needed for years of service, and can evolve HF which is a major safety hazard. How this problem is being addressed: The objective of Phase I and II of this program is to develop and demonstrate advanced rotary vacuum and water seals with extreme radiation durability. The approach involves the synthesis of innovative non-fluorinated polymers that do not evolve HF and offer combined low air and water permeability with extreme radiation durability. What was done in Phase I: In Phase I, advanced polymers were developed and exposed to harsh irradiation alongside candidate commercial seal materials for a durability study to reach a Technology Readiness Level 5. Mechanical, thermal, and thermomechanical testing were conducted prior to and post irradiation. What is planned for Phase II: 2-3 A down-selected set of polymers shall be irradiated under harsh radiation up to 600 kGy, and then under conditions representative of the rare isotope beam facility at Brookhaven's Linac Isotope Producer, up to 20 MGy. Seal prototypes shall be extruded, and seal performance shall be evaluated. Technology Readiness Level 7 shall be reached via experiments in a representative rare isotope high radiation environment. Commercial applications and other benefits: Radiation durable rotary vacuum and water seals shall be manufactured for use with rare isotope beam facilities for the stable production of new and rare isotopes. These isotopes shall benefit advanced imaging needs within the medical community. Many dual-use applications are being explored with partners in space, military, and nuclear energy markets.