FP&A Director

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 failsafe microreactor that can be transported anywhere power is needed and run for up to five years without the need to refuel. 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 utilizes modern software engineering to rapidly achieve safe, factory-built microreactors that leverage existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor next year at the Idaho National Laboratory, with initial customer deliveries beginning in 2028.

Radiant is seeking a Director of FP&A to build and lead our financial planning and analysis function. We have strong finance fundamentals across reliable monthly close, clean audits, functioning AP, but we are looking for a leader to drive conversion of financial data into strategic insights and operational decisions. This role will bridge the gap between our accounting foundation and the investor-grade reporting required to support significant capital deployment, production ramp, and aggressive headcount growth.

This is a build role. You won't inherit mature systems or a defined playbook - you'll help create them. You'll need to navigate ambiguity while earning credibility with senior technical and operational leaders.

• Design and deliver monthly reporting packages that answer key operational questions and drive strategic insights
• Build consistent and timely departmental P&L views with variance analysis and trend identification
• Create program-level financial views that track prototype development, production units, and overhead
• Develop M/M and YTD trend analysis across all business units
• Translate complex financial results into clear narratives for leadership and the Board
• Support quarterly board materials and investor updates
• Support regular reporting across treasury yields and cash management strategy

• Deliver monthly budget vs. actual variance reporting with actionable insights for internal and external stakeholders
• Lead monthly rolling forecast process to update outlook based on current business trajectory
• Support annual budget process including bottoms-up planning and scenario modeling
• Create self-service dashboards that enable department heads to monitor their performance
• Conduct sensitivity analysis on key business drivers and help leadership understand trade-offs
• Support strategic decision-making around hiring pace, capital deployment, and investment priorities
• Evaluate make vs. buy decisions and provide financial perspective on build-out plans
• Marry schedule progress with spend on long-lead procurement to assess schedule risks

• Develop unit economics models for our microreactor products, tracking cost evolution from prototype through commercial production
• Define and track key performance indicators across engineering, operations, and G&A functions
• Build KPI dashboards with weekly, monthly, and quarterly reporting cadence
• Partner with operations to track metrics that connect financial performance to operational execution

• Partner with supply chain and operations on procurement planning and spend analysis
• Work with engineering leads to understand program timelines and resource requirements
• Collaborate with accounting to ensure data quality and alignment on reporting
• Support HR on headcount planning and organizational design decisions

• 8+ years finance experience, with 4+ years in FP&A or strategic finance roles
• Demonstrated experience building FP&A infrastructure from scratch (not just inheriting mature systems)
• Experience at a high-growth company navigating significant scale and complexity
• Strong financial modeling skills; comfortable working with ambiguity and imperfect data
• Track record of cross-functional partnership, particularly with operations and…