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Nuclear Safety and Engineering Consulting

Xron Associates, Inc. provides nuclear safety services and nuclear engineering consulting to Department of Energy (DOE) and commercial nuclear energy clients. Services include nuclear safety management, reactor design and safety analysis, containment analysis, reactor system thermal hydraulic analysis, and probabilistic risk assessment.

Core Competencies

Nuclear Safety Management

  • Safety Analyses preparation for nuclear facility operation such as: DSA, HASP, BIO, SAR.
  • Response Plan development for Defense Nuclear Facility Safety Board issues such as: Waste tank characterization planning for DNFSB 93-5; Plutonium stabilization for DNFSB 94-1; Integrated safety management for DNFSB 95-2.
  • Expert knowledge of the Unreviewed Safety Question (USQ) process.
  • Nuclear Waste and Spent Fuel Management process knowledge to meet environmental regulations, Nuclear Regulatory Commission rules, and Waste Isolation Pilot Plant waste acceptance criteria.
  • 10 CFR 830 Subpart B Nuclear Safety Rule compliant program and process implementation.
  • Nuclear Criticality Safety program assessment for improvement.

Nuclear Power Plant Safety Analysis Reactor System Design and Safety Analysis

  • PWR and BWR Reactor System Design and Safety Analysis preparation to comply with 10 CFR 50, Appendix B quality assurance criteria.
  • PSAR, FSAR and UFSAR preparation for nuclear power plants.
  • Reload Fuel Design to meet NRC licensing requirements and Power Uprate project preparation and implementation

Containment Analysis

  • Blowdown calculations for postulated loss of coolant accident (LOCA) design conditions.
  • Containment design peak pressure and temperature response due to postulated LOCA and steam line breaks.
  • Containment subcompartment analysis for room wall and floor differential pressure loads.
  • Containment and auxiliary building temperature response for equipment qualification in a harsh temperature environment.
  • Containment hydrogen generation and mitigation in a post LOCA environment.
  • Containment analysis training workshops.
  • Containment computer code model development and model technical reviews.

Reactor System Thermal Hydraulic Analysis

  • Reactor system Loss of Coolant Accident analysis (FSAR Chapter 6) and transient analysis (FSAR Chapter 15).
  • Best estimate operational transient analyses under plant benchmarking conditions.
  • Station Blackout Analysis.
  • Anticipated Transient without Scram (ATWS) analysis.
  • Balance of plant and control system transient analysis.
  • Reactor system computer code model development and model technical reviews.
  • Severe accident analysis to support plant specific Probabilistic Risk Assessment.
  • Accident analysis computer code benchmarking in comparison to test facility experimental test results.
  • Operational and plant system engineering support analysis for scram reduction programs, set point optimization, emergency operating procedure development and simulator benchmarking.
  • Independent technical reviews and audit analyses.
Probabilistic Risk Assessment
  • Level I and Level II IPE studies utilizing fault tree and event tree computer codes.
  • Risk and reliability analysis for Nuclear Power Plants in compliance with the PRA requirements of the Nuclear Regulatory Commission.
  • Severe accident transient modeling using the MAAP and STCP computer codes.

Qualifications and Experience

DOE Nuclear Safety


  • Developed the Hanford Tank Farms Safety Management Plan, which implemented portions of Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 95-2. (Tech 5 and Tech 6)
  • Developed the safety management portions of the Plutonium Finishing Plant deactivation program plan that is responsive to DNFSB Recommendation 95-2. (Tech-5 and Tech 6)
  • Developed hazard recognition and hazard baseline development and maintenance approach for PFP deactivation (29 CFR 1910.119).
  • Evaluated the S/RID approaches and developed an integrated site S/RID development approach to facilitate safety requirements management. (DNFSB 95-2)
  • Evaluated compliance with 10CFR830 subpart B, provided program upgrade definition, safety basis acceptance process, and safety basis evaluation.
  • Led Fluor Hanford Team to implement 10 CFR Part 830.
  • Developed and finalized the TRU Retrieval Addendum to the Solid Waste Burial Ground Interim Safety Basis.
  • Updated the Cold Vacuum Drying (CVD) Facility DSA and TSR. Developed and prepared safety basis changes to CVD facility.
  • Developed and prepared Justifications for Continued Operation for the CVD facility.

Waste Isolation Pilot Plant

  • Performed the nuclear safety portion of the Westinghouse Waste Isolation Division’s management assessment conducted in preparation for the operational readiness assessment (DOE Order 425.1).
  • Developed a safety management system implementation plan responsive to Defense Nuclear Facilities Safety Board Recommendation 95-2.
  • Evaluated the SAR, including the hazard and accident analysis. Developed revised safety analysis approaches for key accident scenarios (DOE Order 5480.21 and DOE-STD-3009).
  • Developed the Unreviewed Safety Question process (DOE Order 5480.21).
  • Developed the “event tree” analysis, safety functions and associated safety functions database (DOE-STD-3009).
  • Developed the functional classification process for safety functions and associated implementing procedures (DOE Order 5480.22 and DOE-STD-3009).Evaluated the Price-Anderson Amendment process (10 CFR 820).

Nuclear Power Plant Safety Analysis

Nuclear Safety Analysis

  • Provided on-site QA technical review services to Florida Power & Light in support of Turkey Point plant safety analysis for Station Blackout recovery operating procedures.
  • Member of independent team performing a technical assessment audit of Duke Engineering & Services work safety analysis work packages in support of Vermont Yankee plant.
  • Team member performing an audit of the nuclear safety support function at Ontario Hydro main office and Bruce B power station.
  • Provided on-site consulting transient analysis services using the RETRAN computer code in support of Wolf Creek FSAR Chapter 15 re-analysis for reload fuel, power up rate and scram set point relaxation.
  • Performed and documented PWR FSAR Chapter 15 transient analysis for Siemens Power Corp. using the vendor’s proprietary versions of RELAP5 and COBRA computer codes in support of reload fuel designs for several power plants.
  • Authored PWR Chapter 15 transient safety analysis guidelines for Siemens Power Corp.
  • Performed and documented BWR LOCA analysis for Siemens Power Corp in support of reload fuel designs for several plants. All work performed in accordance with the vendor’s NRC approved Quality Assurance procedures as per 10 CRF 50, Appendix B.
  • Provided on-site consulting support for Florida Power & Light FSAR Chapter 15 topical report submittal for analysis of “decrease in heat removal” class of transients.
  • Participated in independent technical review of the Brown & Root computer codes utilized in the analysis and design of the South Texas Project.

Thermal Hydraulic Analysis

  • Provided on-site consulting support to Framatome ANP Richland (formerly Siemens Power Corp), to benchmark proprietary BWR large break LOCA analysis computer codes in comparison to FIST test facility data.
  • Provided on-site staff support to Hope Creek Fuels Group for RETRAN computer code safety analysis model technical review, and model nodalization study. Also prepared a containment analysis model data notebook.
  • Performed pre-test and post-test analysis and data comparisons for small break LOCA tests of the ROSA-AP600 test facility using the RELAP5 computer code for INEEL.
  • Lecturer for basic and advanced RETRAN computer code training seminars for the nuclear power industry. Seminars included code theory, thermal hydraulic system modeling techniques, input model development and sample problems.
  • Provided on-site safety analysis consulting support, RETRAN safety analysis computer code training seminars and Cofrentes BWR nuclear plant model technical reviews to UITESA.
  • Performed RETRAN safety analysis model development consulting work and FSAR Chapter 15 transient analysis for reactor systems at Big Rock Point, Cofrentes, Hatch-2, Prairie Island, Turkey Point, San Onofre 1, Palisades, St. Lucie, WNP-2, and San Onofre 2&3.
  • Performed RETRAN model technical reviews for reactor systems at Perry, Big Rock Point, WNP-2, Hatch 2, Calvert Cliffs, St. Lucie, Comanche Peak, Sequoia, Palo Verde, Point Beach 1, and Hope Creek.
  • Responsible for review and revision of Perry nuclear power plant preoperational and startup test procedures to obtain and archive all test data applicable to the client’s RETRAN code safety analysis model validation program.
  • Generated piping design loads for the full scale safety relief valve test loop at Combustion Engineering test facility.

Containment Analysis

  • Performed technical reviews under contract to the NRC for several plants and types of containment systems in accordance with NUREG-0800, Standard Review Plan.
  • Modified the CONTEMPT4 computer code for use in analyzing the N-Reactor confinement system response to small break LOCA.
  • Lecturer for containment analysis training workshops for the nuclear utility industry.
  • Generated containment sub-compartment pressure analysis of all major compartments of Combustion Engineering designed PWR containment buildings using NRC approved computer codes DDIF, CONTEMPT, COMPARE and CE-FLASH. Prepared vendor safety analysis licensing reports (PSAR and FSAR) for submittal to NRC.
  • Modeled and correlated the analytically predicted results of the Combustion Engineering sub compartment analysis computer codes versus experimental results from the RS 50 scale model containment blow down test performed in Germany by Battelle-Frankfurt.
  • Performed modification and benchmarking of the Exxon Nuclear proprietary containment analysis code, ICECON.

Severe Accident Analysis

  • Performed Anticipated Transient Without Scram (ATWS) analysis for the WNP-2 BWR reactor system and authored the clients FSAR ATWS section.
  • Participated in severe accident analysis of the Brunswick plant using the NRC’s Source Term Code Package to support the plant PRA.
  • Participated in construction and documentation of the Hope Creek severe accident model using the MAPP computer code.
  • Performed PWR Station Blackout Analysis for the Salem plant in accordance with the station blackout requirements of NUMARC 87-00 and NUREG 1.155.
  • Responsible for analysis of auxiliary building room heat-up transient response to loss of HVA in support of Salem nuclear plant PRA analysis.
  • Analyzed and documented the San Onofre nuclear plant site potential consequences due to off site LPG explosions from adjacent highway and railroad transportation accidents using the ARCHIE computer code.

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