New Graduate - Nuclear Engineer

About Radiant

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1‑megawatt, fail‑safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid‑deploy capability can replace similar‑sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases.

Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory‑built microreactors that use existing, well‑qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1‑megawatt, fail‑safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid‑deploy capability can replace similar‑sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases.

Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory‑built microreactors that use existing, well‑qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

• Assist with nuclear design and analysis tasks, including shielding, neutronics, thermal, and fuel‑related studies.
• Support coupled neutronics and thermal calculations to refine system performance models.
• Document methods, results, and findings in clear technical reports and presentations.
• Collaborate with cross‑functional teams and provide technical input as projects evolve.
• Support the development of lower order shielding analysis models to develop rapid shielding design solutions.
• Support the development of uncertainty propagation methodology and its execution on the Kaleidos Demonstration Unit
• Perform criticality safety analysis for the Production Plant of Kaleidos reactors
• Present a final project review at the end of internship to engineers and leadership

• BS or MS in Mechanical Engineering, Nuclear Engineering, or a related discipline.
• Graduating in December 2026 or Spring 2027.
• Strong academic foundation in nuclear engineering principles (e.g., reactor physics, thermal‑hydraulics, radiation shielding).
• Proficiency in at least one programming language (Python, C++, C#, or similar).

• Hands‑on experience through coursework, research, projects, or labs in nuclear system design or analysis.
• Familiarity with nuclear simulation codes (e.g., OpenMC, Serpent, MCNP, MOOSE, BISON, RELAP, CFD, Pronghorn, GRIFFIN).
• Prior software development experience or exposure to version control, testing, or documentation practices.
• Strong communication skills and ability to work in a collaborative team environment.
• Enthusiasm for Radiant’s mission to rapidly deploy nuclear microreactors to provide clean energy in remote locations.

• Stock:
  Substantial incentive stock plan for all full‑time employees.
• Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
• One Medical:
  Sponsored memberships for employees and their dependents.
• Vision: 100% top tier plan coverage + 50% for dependents.
• Dental: 100% top tier plan coverage, orthodontia extra,…