PSI - Issue 60

A. Kumar et al. / Procedia Structural Integrity 60 (2024) 541–552 Akshay Kumar/ StructuralIntegrity Procedia 00 (2023) 000 – 000

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Coefficient of variation in stress exponent and activation energy parameter

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Fig. 11: Comparison of pdf of contact time for Case 1 and Case 2

7. Conclusions The material properties of pressure tube have always some statistical distribution. Using constant values in analysis may lead to over-conservatism in many cases and this can be addressed by adding the uncertainty analysis to the deterministic model. Wilk’s is one of the methods which helps in making decisions under such scenarios. In this work, the uncertainties in the time required for the pressure tube in order to come in contact with calandria tube has been estimated. The FE model developed here along with the uncertainty analysis procedure, shall be useful to estimate the safety margins in terms of time for contact of PT-CT in actual reactor postulated accident conditions. References International Atomic Energy Agency. (1997). Thermophysical properties of materials for water cooled reactors, IAEA TECDOC No. 949 . Vienna: IAEA. International Atomic Energy Agency. (2006). Thermophysical properties database of materials for light water reactors and heavy water reactors, IAEA TECDOC 1496. Vienna: IAEA. Kirillov, P. L. (2006). Thermophysical Properties of Materials for Nuclear Engineering. Obninsk: Institute for Heat and Mass Transfer in Nuclear Power Plants. Majumdar, P., Mukhopadhyay, D., Gupta, S., Kushwaha, H., & Venkat Raj, V. (2004). Simulation of pressure tube deformation during high temperature transients. International Journal of Pressure Vessels and Piping, 81, 575581. Mukhopadhyay, D., Majumdar, P., & Gupta, S. K. (2002). Thermal Analysis of Severe Channel Damage Caused by a Stagnation Channel Break in a PHWR. Journal of Pressure Vessel T echnology, 124, 161-167. N., C., Causey, A. R., Holt, R. A., Tome, C. N., Badie, N., Klassen, R. J., . . . Woo, C. H. (1996). Modeling In-Reactor Deformation of Zr-2.5Nb Pressure Tubes in CANDU Power Reactors. Zirconiun in the Nuclear Industry: Eleventh Interational Symposium, ASTM STP 1295. Nandan, G., Majumdar, P., Sahoo, P. K., Kumar, R., Chatterjee, B., Mukhopadhyay, D., & Lele, H. G. (2012). Study of ballooning of a completely voided pressure tube of Indian PHWR under heat up condition. Nuclear Engineering and Design, 243, 301-310. Rastogi, R. (2009). Decision making under uncertainty: The Wilk's method. In H. S. Kushwaha, & H. S. Kushwaha (Ed.), Uncertainty Modeling and Analysis (pp. 177-186). Mumbai: Bhabha Atomic Research Centre. Shewfelt, R. S., Layall, L. W., & Godin, D.P. (1984). High Temperature Creep Model for Zr-2.5 wt. % Nb Pressure T ubes. Journal of Nuclear Materials, 125, 228-235. Singh, R. J., Ravi , K., & Gupta , S. K. (2011). Methodology for developing channel disassembly criteria under severe accident. Annals of Nuclear Energy, 38, 1884 – 1890. Stephan K., Abdelsalam M., (1980). Heat-transfer correlations for natural convection boiling. International Journal of Heat and Mass Transfer, 23(1): 73-87. Wallis, B. G. (2003). Contributions to the paper "Statistical Aspects of best estimate method -1" by Attila Guba, Mihakly Makai, Lenard Pal". Reliability Engineering and System Safety, 80, 309-311. William, T., & Wallis, G. B. (2004). Evaluation of nuclear safety from the outputs of computer codes in the presence of uncertainties. Reliability Engineering and System Safety, 83, 57-77. Yadav, A. K., Kumar, R., Gupta, A., Chatterjee, B., Majumdar, P., & Mukhopadhyay, D. (2013). Thermomechanical Behavior of Pressure Tube Under Small Break Loss of Coolant Accident for PHWR. Journal of Pressure Vessel Technology, 135.