Engineer I–III, Thermal-Hydraulic Safety Analysis & V&V

X-energy LLC conducts a thorough recruiting process and will never issue offers without interview to discuss qualifications and responsibilities. All applications will be submitted via our company career page, . We will never ask you to provide payment information as part of the recruiting process. If anyone claiming to represent X-energy directs you in a manner otherwise, please contact us at . Job Description This role supports the Risk Informed Safety Analysis team that performs nuclear safety analysis for X-energy technology (e.g., Xe-100) licensing and design, with particular emphasis on thermo-hydraulic analysis. Under the direction of senior engineers and team leads, the position contributes to safety evaluations including system and component thermo-hydraulic transient and accident analysis, analysis supporting safety function identification and Structures, Systems, and Components (SSC) safety classification, and deterministic safety assessments that inform PRA. The engineer performs assigned thermo-hydraulic safety analysis work supporting regulatory submittals, applies NRC regulatory guidance (including RG 1.203 and design-specific interim staff guidance) under supervision, and collaborates with engineering disciplines to help establish design requirements derived from safety analysis. The position also supports verification and validation (V&V) activities to ensure thermo-hydraulic analysis codes are appropriately qualified for their safety analysis applications. Depending on level, responsibilities include contributing to Phenomena Identification and Ranking Tables (PIRTs) for thermo-hydraulic phenomena, supporting scaling analyses, performing accident scenario evaluations using system codes, and helping establish thermal-hydraulic safety limits and margins in support of the safety case for TRISO fuel and high-temperature gas-cooled reactor technology. Job Profile Tasks/Responsibilities Perform assigned thermo-hydraulic safety analysis for designated systems and accident scenarios using approved system analysis codes and methodologies, in accordance with NRC regulatory guidance (RG 1.203) and X-energy procedures. Conduct transient and accident analysis evaluating core heat removal, coolant flow behavior, heat transfer mechanisms, and temperature distributions throughout the reactor system and key components for anticipated operational occurrences (AOOs), design basis events (DBEs), design basis accidents (DBAs), and beyond design basis events (BDBEs) to help demonstrate adequate core cooling, heat removal capability, and defense-in-depth. Support the development and maintenance of SSC safety classifications through thermo-hydraulic analysis, providing analytical results that demonstrate component performance and safety function capability during accident scenarios and operational transients. Contribute to the development and maintenance of Phenomena Identification and Ranking Tables (PIRTs) that identify and rank thermo-hydraulic phenomena important to reactor safety for various accident scenarios and operational transients. Support scaling analyses that demonstrate applicability of experimental thermo-hydraulic data and analytical methods to the Xe-100 design, and help document the technical basis for code applicability. Assist in establishing thermo-hydraulic safety limits, safety margins, and acceptance criteria for safety analyses based on regulatory requirements, fuel temperature limits, material temperature limits, and fission product barriers. Support probabilistic risk assessment (PRA) activities by providing deterministic thermo-hydraulic analysis results and supporting the integration of deterministic and risk-informed approaches. Support development of technical documentation for regulatory submittals, including topical reports, safety analysis reports, code applicability reports for thermo-hydraulic codes, and responses to NRC requests for additional information (RAIs). Ensure thermo-hydraulic safety analysis work products comply with NQA-1 quality assurance requirements and X-energy procedures for safety-related calculations, and perform work in accordance with X-energy Quality Assurance procedures, maintaining documentation to NQA-1 standards. Provide technical input to design teams based on thermo-hydraulic safety analysis results, including cooling requirements, flow path design constraints, heat removal capabilities, and operational limitations. Support V&V activities for thermo-hydraulic analysis software used in safety analysis applications, including assisting with software validation exercises to ensure codes are qualified for their intended applications. Collaborate with other engineering disciplines (neutronics, structural, materials, reactor systems) to help ensure thermo-hydraulic safety analysis assumptions are consistent with the design basis and that safety-derived requirements are properly implemented. Assess the quality of information given and ask pertinent questions of stakeholders to ensure thermo-hydraulic safety analysis is based on sound technical foundations. Provide the Xe-100 Team leads with frequent updates on progress and promptly communicate adverse findings or technical concerns related to thermo-hydraulic safety limits and margins. Execute safety analysis and V&V assignments with clear and specified objectives, utilizing conventional specifications, Interface Control Documents, and plans. Maintain professional demeanor and behavior at all times in all forms of communication. Perform other duties as assigned by manager. Job Minimum Qualifications Bachelor’s degree in engineering (nuclear, chemical, mechanical, etc.) or related degree from an accredited institution. A master's degree in engineering or related field (may include a combination of experience obtained through an academic institution, e.g., design projects, research, or design teams, as well as professional experience) may be in lieu of two years of experience. A Ph.D. in engineering or related field (may include a combination of experience obtained through an academic institution, e.g., design projects, research, or design teams, as well as professional experience) may be in lieu of three years of experience. Level I: Typically, zero- two years of experience in an engineering role required. Level II: Typically, three years of experience in an engineering role required. Level III: Typically, five years of experience in an engineering role required. Coursework, academic, or professional exposure to thermo-hydraulics, heat transfer, fluid mechanics, or reactor systems analysis is preferred Familiarity with thermal-hydraulic system codes (RELAP, TRACE, GOTHIC, Flownex, or similar) is preferred but not required. Familiarity with V&V or Commercial Grade Dedication (CGD) activities is a plus. Location: 9801 Washingtonian Boulevard, Gaithersburg, Maryland Work Arrangement: 4 Days Onsite per Week Hours: 8:00am-5:00pm, Mon-Fri Travel Expectation: 10% Compensation As required by Maryland and other applicable state law, X Energy, LLC (X-energy) lists the expected compensation range for a publicly advertised job opportunity based upon the job requirements (e.g. education/training, experience, skill sets, etc.). Individual candidates who meet the job requirements for the posted position will be offered a salary within this range based on their respective levels of education/training, experience, and other qualifications unique to them. Salary ranges may vary based on the specific office location and region referenced in the posting to take into consideration differences in cost of living and may not be reflective of all regions. Please note that compensation ranges listed for US job postings reflect base salary only and do not include benefits or other incentives. Offers within the posted salary range are commensurate with the individual’s qualifications for the position, along with a view on internal equity, market data, and room for growth. The salary range for this position is: $85,000- $135,000 (level 1- III) Position Job Classification Full time - Exempt Benefits X Energy, LLC offers a robust benefits package that includes a 401K plan with an employer match, Medical/Dental /Vision Insurance, Life and Disability Insurance, Paid Time Off, and a Tuition Reimbursement/Professional Development policy that supports the continuing education of our employees. An Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability. X Energy, LLC participates in E-Verify. Please visit the links below for more information about E-Verify and the protection of your Right to Work. Right To Work Link: If you have the right to work, don't let anyone take it away () E-Verify Participation Link: E-Verify Participation Poster English and Spanish