Health Physicist

About Fuse

We are building one of the most potentially consequential companies of the century. Our mission is to accelerate the world's transition to fusion energy while safeguarding humankind. This is not a normal company. This is not a normal job. We are committed for the long term to win.

You are the lead Health Physicist on site, responsible for the technical radiation-protection program: source terms, shielding, instrumentation, dosimetry, surveys, and the operational decisions that flow from them. This is a hands‑on lead role.

• Independently verify shielding designs developed by physics and engineering — geometry, source definition, tally choice, variance reduction, and uncertainty. Catch the errors before the concrete is poured.
• Run MCNP, PHITS, or GEANT4 transport calculations for the fusion generators, target chambers, beamlines, diagnostic ports, and shielded penetrations.
• Build and maintain validated source‑term models: D‑T neutron yield and spectrum, capture and inelastic gammas, bremsstrahlung, and characteristic line emission.
• Perform activation analysis on hardware in the neutron field and produce contact dose‑rate vs. cool‑down curves that operations can plan around.

• Specify the radiological instrument fleet from first principles. Match detector physics to field characteristics: pulsed vs. continuous response, neutron energy range, photon discrimination, deadtime behavior, and true dose‑equivalent response across the spectrum we produce.
• Select personal dosimetry technology appropriate for mixed neutron/photon fields and tritium‑intake monitoring.
• Be responsible for the calibration program for high‑end instruments to a standard that survives regulator review.

• Be the technical authority on whether hardware and areas are safe to touch or enter. Survey activated and potentially contaminated hardware, evaluate against release criteria, and document the basis.
• Develop and be responsible for activation‑based clearance procedures: wait times, dominant nuclides over time, allowable contact handling, and packaging for off‑site transfers.
• Conduct radiological surveys before, during, and after non‑routine operations.
• Author radiological work permits with credible dose estimates derived from your own field characterization.

• Sit in design reviews with physicists and engineers from the start, not at the end.
• Partner with the RSO: you produce the technical basis; they translate it into licensed scope, procedures, and regulatory submissions.
• Train operators, engineers, and physicists on what their dosimeters and area monitors are actually telling them, including their limitations.

• Master's degree in Health Physics, Nuclear Engineering, Radiological Sciences, Physics, or a related field.
• Certification by the American Board of Health Physics (CHP). Fuse will support maintenance of certification status.
• 5+ years of operational health physics experience in environments with non‑trivial neutron and photon fields, with at least 2 years in a tritium‑handling environment.
• Demonstrated production‑grade proficiency with at least one major transport code: MCNP, MCNPX, PHITS, GEANT4, or FLUKA.
• Working knowledge of 10 CFR 835 or 10 CFR 20, DOE‑STD‑1098, DOE‑HDBK‑1129, and 20.3 NMAC.
• Hands‑on experience with tritium bioassay programs, internal‑dose assessment, and ICRP biokinetic models for HTO.
• Experience leading activation analysis and authoring defensible "safe to handle" decisions on activated hardware.

• Experience with pulsed radiation sources such as DPF, Z‑pinch, ICF drivers, or pulsed accelerators and the dosimetry challenges they create.
• Prior role…