Thermo-mechanical Analysis of Steam Generator Bottom Tube Sheet of Steam Generator Test Facility

S. P. Ruhela[1], V. Vinod[1], S. Kishore[1], B. K. Sreedhar[1], I. B. Noushad[1], B. Krishnakumar[1], P. Kalyanasundaram[1], and G. Vaidyanathan[1]
[1] Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
Published in 2009

Steam Generator Test Facility (SGTF) is set up in IGCAR to optimize the design of Steam Generators (SG) for Fast Breeder Reactors. In the SG of SGTF heat exchange takes place from sodium which enters at 525 ºC and leaves at 355 ºC temperature to the water/steam which enters at 235 ºC and leaves at 493 ºC. To reduce the steady state differential temperature and thermal shock during transients, four baffles are provided above the BTS. In this paper the thermo-mechanical analysis of the BTS under steady state conditions of pressure & temperature is brought out. A three dimensional static thermo-mechanical analysis was done for the bottom tube sheet with with and without thermal baffle assembly. The analysis was done with a 30o sector Finite Element model of tube sheet with baffles. From the static thermal analysis it is found that temperature difference of 120 oC in the process fluids gives a temperature difference of 95 oC in the tube sheet. From thermo-mechanical stress analysis the maximum stress region was found to be the ‘top shell to BTS junction'. Comparison of Von Mises stress profiles in the BTS for with & without thermal baffles cases it was found that there is a significant reduction in the maximum stress.

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