Dr. Yogen Garud
STRUCTURAL MATERIAL DEGRADATION
Dr. Garud has provided engineering and consulting services for over 45 years to electric utilities, research institutes, and Argonne National Laboratory. Key areas of his interest and experience include:
- Development and application of engineering models for assessing corrosion and materials degradation effects on the life and integrity of major metallic components in nuclear power systems:
- systems covering BWRs, PWRs, CANDU, and HTGR,
- environments including high temperature reactor water, steam, and helium gas, and
- effects including corrosion, oxidation, creep, fatigue, embrittlement, SCC/PWSCC, IASCC, & FAC
- Integrity assessment work related to pressure retaining components, stress–strain analysis of complex thermo-mechanical loads, 3D–plasticity effects, finite element analysis, and safety margins
- Mechanical design/analysis including integration of probabilistic, statistical, and exploratory data analysis methods in component integrity and life assessment, and use of risk/reliability methods
- Technical support in nuclear quality assurance, QA (10CFR50, Appendix B), ASME B&PV Code (Sections III and XI parts) rules and their application
- Nuclear power plant license renewal or long-term operation (LTO) and aging management programs, and related technical audits
- Engineering assessment for problem resolution and independent technical/technology reviews
My interest in applied R&D began in earnest with my dissertation on metal fatigue and its relation to ferromagnetism, completed as a requirement for my undergraduate degree (B. Tech. from I.I.T. Bombay, 1972), followed by my dissertation for graduate degree (M. Tech., 1974) on experimental/probabilistic evaluation of Miner’s rule for cumulative fatigue damage.
After a couple of years working in industry, as a mechanical design and development engineer/manager, my keen interest in fatigue of metals, having done two theses and extensive experimental work, brought me to Stanford University where I was offered a research position by late Prof. H. O. Fuchs to work in the field of fatigue. That was the beginning of my engagement with the consulting work on nuclear industry issues and the sponsorship of EPRI which continue to date, including the effect of environment on fatigue. My doctoral work (Stanford University, 1981) led to several pioneering and widely recognized developments such as a new hardening rule for cyclic plasticity and a new energy based parameter for better assessment of fatigue under multiaxial loads.
Interestingly, Dr. T. L. Gerber (ex-GE) who was the external examiner for my doctoral thesis/defense, and who was working on the IGSCC issue of BWRs at the time, offered for me to join the nuclear consulting services group (S. Levy, Inc.) which initiated my greater engagement with the issues of environmentally assisted cracking in BWRs and PWRs, with continued support from EPRI. This early period also gave me the opportunity to work with industry experts like Dr. F. Peter Ford of GE, and late Dr. Roger Staehle on related corrosion/SCC issues. I helped in resolving another major issue concerning the piping snubber-reduction program and related ASME Code rule development based on the ratcheting versus fatigue modes under seismic/dynamic loads. Based on the results from my doctoral work, I was engaged by EPRI in support of this resolution leading to the desired rule development.
Other major projects as a principal consultant at S. Levy, Inc. included:
- Extended state-of-the-art reviews of corrosion in carbon steels and in Alloy 600 in BWRs and PWRs
- Technical review for EPRI of all major EPRI reports on the environmentally-assisted cracking
- Review and modeling of interaction between metals and gases at very high temperatures to assess creep and embrittlement in super alloys for HTGR
- Application of stress–strength interference technique for probabilistic design/analysis of components addressing uncertainty and for likelihood of common-cause multi-failure event in nuclear piping
- Major software developments: Incremental Plasticity Calculations & Ratcheting Evaluation System (IPCRES) and its implementation in early PC-based finite-element analysis code (LIBRA/PC)
After about fourteen years of consulting services at S. Levy, Inc. I worked for APTECH Engineering in similar areas of consulting in resolution of issues for the nuclear industry for fourteen years. I was engaged in the application of risk assessment methods working with other well recognized experts, late Dr. Edwin Zebroski (ex-EPRI) and Dr. Stan Kaplan. During these years I was heavily involved in the assessment of steam generator corrosion and integrity issues for EPRI and nuclear industry. One unique issue of the flow-accelerated corrosion (FAC) in the nuclear steam generators also provided the opportunity to work with well recognized FAC expert from EdF, late Dr. J.-Ph. Berge.
Some of my major projects as a principal consultant at APTECH included:
- Assessment of corrosion-fatigue and environmentally-assisted fatigue (EAF) in nuclear components
- Evaluation of flow-accelerated corrosion in nuclear piping and steam generation
- Tube integrity subject to multiple corrosion mechanisms, tube sleeving, condition monitoring and operational assessment of nuclear steam generator units, based on inspection data
- Assessment of control-rod drive nozzles inspections, longevity and leak probabilities
- Contributions to major software products such as: Flow-accelerated Corrosion Evaluation & Updating Program (FACEUP) for use in inspection planning/optimization/life assessment, and Operational Assessment–Condition Monitoring (OPCON) for nuclear steam generator regulatory assessment
Subsequently, as the founder and President of SIMRAND LLC, I continue to provide consulting services in support of the nuclear industry issues since 2010. Some of the key projects during this period include:
- Effects of cold-work and irradiation on SCC of metals in BWR/PWR components (for EPRI)
- SCC initiation modeling support on xLPR (Extreme Low Probability of Rupture) program
- Technical audits of aging management programs for continued long-term operation of LWRs and related development of guidelines (as STA – Nuclear Reactor Safety Engineer for ANL)
- Development and application of EAF assessment, with support from ANL and EPRI
- Uncertainty quantification, sensitivity analysis, and safety margins for ASME Code-based fatigue, and pipe failure assessments
Throughout my professional career I have participated as a leader/developer of several related technical sessions and authored more than hundred major technical publications and reports, majority of which I presented at the technical forums of ANS, ASME, ASTM, EPRI, NACE, and TMS.