Organic Vacuum Pump Fluids for the Vacuum Pumping of Fusion Power Plants

Abstract

Vacuum pumps are the heart of the fusion fuel cycle, but most currently proposed pumping technologies are not capable of handling the required flow rates and vacuum pressures. Oil-containing vacuum pumps can readily meet the flow requirements, but vacuum fluids will degrade in fusion-relevant environments due to contact with tritium and exposure to high-energy radiation. Here, we describe a methodology to screen vacuum fluid candidates and purify these candidate fluids post oxidation, post exposure to deuterium, and post exposure to gamma radiation (<7.5 MGy) to simulate a process in which vacuum fluids can be recovered and regenerated during the fusion fuel cycle. A series of oils, including a highly purified mineral oil, phenyl silicone oil, and a polyphenyl ether, are shown to be suitable candidates for vacuum pumping. Additionally, we describe a simple purification methodology to remove oxidized functionalities and the associated isotopologues induced by contact with deuterium from the candidate vacuum fluids This purification methodology can also be applied to radiological damage with moderate effect. Finally, we demonstrate that the sorbents can be regenerated through electromagnetic microwave digestion.

Keywords:

• Vacuum fluid
• vacuum oil
• purification
• viscosity, oxidation

Acknowledgments

The authors are grateful for support from the Office of Fusion Energy Sciences and ARPA-E, U.S. Department of Energy (DOE). The publisher acknowledges the U.S. government license to provide public access under the DOE Public Access Plan (http://energy.gov/downloads/doe-public- access-plan).

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was produced by Battelle Savannah River Alliance, LLC under contract number 89303321CEM000080 with DOE.