+ 359 2 4748 800 info@gcr.bg

THA Engineer

May 18, 2023


THA Engineer

We’re looking for candidates with different levels of skills in the development of thermal-hydraulic models of the reactor installation, spent fuel pool, containment, etc. using software such as RELAP, TRACE, MELCOR, and/or using the FORTRAN programming language for the purposes of a full-scale simulator of the NPP. Perform analyses for the purposes of probabilistic safety assessments (PSA), safety analysis reports (SAR), or other specific tasks related to the operation and safety of the NPP. Perform analyses for the assessment of nuclear and radiation safety of the NPP under normal operation, deviations from normal operation, and severe accidents. Analysis of results of performed calculations and preparation of documentation. Develop thermohydraulic models and perform analyses for conventional energy systems.


  • Perform thermal-hydraulic analyses, calculations, assessments, and guidance to support a diverse variety of projects supporting the nuclear industry, such as engineering analyses, regulatory/licensing activities, PSA (Level 1 and Level 2), PSA-based licensing applications, EOP/SAMG support, and thermal-hydraulic code development and review
  • Computer models development supporting full-scope simulator using programming code FORTRAN and/or specific tools for FORTRAN code generation
  • Verification and validation of the developed models
  • Develop of reports and other required technical documentation in support of the contract
  • Participate in team meetings to coordinate work, evaluate strategic actions, and innovate improvements
  • Interface with clients to understand thermal-hydraulic and severe accident needs and provide technically excellent and creative solutions
  • Develop and conduct training internally and externally in thermal-hydraulic code and severe accident topics
  • Interface with BNRA to support and defend analyses on behalf of clients



  • Master’s degree in mechanical or Nuclear Engineering or a closely related field from an accredited college or university
  • Basic computer skills – MS Office, Auto CAD, Excel
  • Must meet nuclear requirements for unescorted plant access
  • Fluent English – writing, reading, and speaking
  • Background in nuclear engineering
  • Working knowledge of nuclear reactor core licensing, technical specifications, safety margin bases, code methodology licensing, and related federal regulations

Each one of the following is considered a big plus

  • Experience with thermal-hydraulic computer codes (e.g., RELAP5, RETRAN, SNAP, GOTHIC, etc.)
  • Experience with programming languages such as FORTRAN, C++, and/or others
  • Knowledge of WWER and PWR technology
  • Experience with nuclear thermal hydraulic computer code development, modification, or methods development, V&V, or review
  • Knowledge of Emergency Operating Procedures and Severe Accident Mitigation Guideline use, development, basis, and application (WWER and/or PWR) a plus
  • Experience with thermal hydraulic analysis interface with PSA and SAR
  • Project management skills a plus
  • Russian and/or other additional languages a plus
  • Knowledge of Bulgarian and international legislation in the field of safe use of nuclear energy, nuclear safety, radiation protection, emergency preparedness and regulations related to the use of nuclear energy and ionizing radiation, occupational safety, and fire safety is an advantage
  • Driving license


  • Strong drive for continuous improvement and advancing their proficiency in the filed of TH analyses
  • Ability and desire for a teamwork
  • Honest and straightforward with a high level of personal integrity
  • Detail oriented and accountable for results
  • Strong analytical capabilities, problem-solving skills, and process skills
  • Responsibility to work (client) and team.


  • Attractive salary
  • Bonuses
  • Options for regular work from home
  • Excellent working conditions and opportunity for professional growth
  • Dynamic environment and a variety of paid trainings on specific topics
  • Health insurance
  • MultiSport Card

Submit your application