Pipe stress analysis of first wall helium cooling system for conceptual design development of IN LLCB TBM

Abstract

Indian TBM team is developing Lead-Lithium Cooled Ceramic Breeder (IN-LLCB) Test Blanket Module (TBM) along with its associated systems for testing in ITER. The outer box of LLCB TBM is cooled by first wall helium cooling system (FWHCS) which is designed to remove the heat load of ∼300 kW. FWHCS is a high temperature high pressure closed loop which produces significant movements and propagates high stresses in the piping system. This, in turn, leads to forces and moments on the supports and equipment nozzles. FWHCS may experience a high acceleration (∼59.69 m/s2) during seismic events, the deflection of pipes in this scenario may increase the complexity in the loop operation.This paper describes pipe stress analysis, methodology and results of FWHCS. The pipe stress analysis is performed for sustained and occasional load combinations for various ITER operating states as envisaged for TBMs. FWHCS piping is subjected to category I (likely event) and IV (extremely unlikely event, SL-2) loading conditions. The Pipe stress analysis is performed in accordance with ASME B31.3. The calculated stresses are within the limits for the considered cases. The highest value of stress (about 0.65 times the allowable stress) and the maximum displacement of 23 mm (x direction), 15 mm (y direction) and 11.5 mm (z direction) is observed in recuperator to electrical heater line. The obtained reaction and moment forces are needed as an input for the selection of pipe supports, location of supports and the verification of embedded plates loading criteria. This pipe stress analysis is also used in the optimization of FWHCS layout and further these inputs would be utilized in preliminary design phase.