Criticality Safety Engineer

HukariAscendent is seeking Criticality Safety Engineers at associate, engineer, senior, and principal levels to support nuclear and fissile-material operations. The role involves preventing inadvertent criticality events, developing safety controls and evaluations, performing computational analyses, supporting alarm systems and regulatory programs, and providing training and technical leadership.

Responsibilities:

• Design systems, equipment, and facilities to prevent inadvertent criticality events, and evaluate configurations, materials, and processes to keep operations safely subcritical
• Develop safety controls such as geometric barriers, neutron absorbers, volume/mass/concentration limits, moderation control, and administrative controls (spacing, water exclusion, reflector control)
• Conduct criticality risk assessments, analyze upset/abnormal scenarios, and model consequences using computational tools such as MCNP (Monte Carlo N-Particle), SCALE/KENO, ORIGEN, and MicroShield
• Prepare Nuclear Criticality Safety Evaluations (NCSEs), criticality safety limits and postings, and criticality safety assessments
• Design and specify placement for Criticality Accident Alarm Systems (CAAS) and perform detector coverage evaluations
• Support identification and evaluation of Items Relied On For Safety (IROFS) and Criticality Incredibility Evaluations
• Design fuel and fissile material packaging and transportation configurations, and support shielding design and equipment specifications
• Develop and deliver criticality safety training — fissile material handler qualification and general criticality safety awareness — and coursework in neutronics, kinetics, and NCS hand-calculation methods
• Support program and project management activities: program plans, procedures, risk ranking methodologies, schedules, budgets, and risk mitigation plans
• Support development of NCSEs, calculations, and safety basis documentation under the mentorship of a qualified Criticality Safety Engineer
• Perform hand calculations and computer modeling (MCNP, SCALE/KENO) for straightforward fissile material configurations
• Support field walkdowns, postings verification, and criticality safety program implementation
• Work toward formal NCS Engineer qualification per site/contractor qualification standards
• Independently develop and issue Nuclear Criticality Safety Evaluations, limits, and postings for moderate-complexity operations
• Perform and validate criticality safety analyses and computational modeling; interpret and apply double-contingency principles
• Support CAAS design, detector placement, and testing; evaluate IROFS and safety controls
• Interface with Operations, Nuclear Safety, and Engineering to resolve criticality safety issues on active projects
• Fully qualified Nuclear Criticality Safety Engineer per DOE-STD-1135 or site-specific qualification program
• Serve as subject matter expert and Point of Contact for criticality safety on major projects or across a facility/program
• Lead complex criticality safety evaluations, criticality experiment design, and resolution of technical safety issues with regulators (DOE, NRC)
• Review and approve NCSEs and calculations prepared by other engineers; mentor and qualify junior/associate staff
• Develop and teach NCS qualification coursework (neutronics, kinetics, hand-calculation methods) and criticality safety training programs
• Lead criticality safety program development, policy, and continuous improvement initiatives; support licensing and regulatory interface

Requirements:

• Bachelor of Science in Nuclear Engineering, Mechanical Engineering, Chemical Engineering, Physics, or related engineering/physical science field (required for Engineer and Senior levels)
• Advanced degree (MS/PhD) in Nuclear Engineering or Health Physics a plus, particularly for Senior/Principal roles
• Candidates with an equivalent combination of directly relevant DOE/nuclear fissile-material experience and coursework will be considered for Associate-level roles
• 0–30+ years of nuclear/criticality safety engineering experience; specific requirement set by the assignment
• Prior DOE, DOE contractor, national laboratory, or commercial nuclear fuel-cycle experience strongly preferred
• Demonstrated experience applying ANSI/ANS-8 series standards, DOE Order 420.1C (Facility Safety), and 10 CFR 830/835 as applicable
• Formal Nuclear Criticality Safety Engineer qualification (per DOE-STD-1135 or equivalent site qualification program) required or in progress, depending on level
• Active DOE Q clearance strongly preferred; at minimum, ability to obtain and maintain a DOE Q clearance is required for most assignments involving Special Nuclear Material (SNM) facilities
• U.S. citizenship is required for positions supporting DOE facilities and classified/SNM-related work
• Must be able to pass site-specific background investigations, drug screening, and medical/physical qualification requirements as applicable
• Qualified/Certified Nuclear Criticality Safety Engineer (per DOE-STD-1135 or site-specific NCS qualification program)
• Professional Engineer (PE) license a plus, particularly for Senior/Principal-level positions
• Proficiency with criticality/radiation transport codes: MCNP, SCALE (KENO/ORIGEN), MicroShield, or equivalent
• Working knowledge of DOE nuclear facility safety basis documentation (DSA/TSR) and the Documented Safety Analysis process
• Familiarity with ANSI/ANS-8 series, ANSI/ANS-8.1, 8.7, 8.19 and related criticality safety standards
• Experience developing or delivering NCS qualification and fissile material handler training programs
• Strong technical writing skills for NCSEs, evaluations, and regulatory submittals; ability to defend analyses to DOE/client safety review boards