Helium cooling systems for Indian LLCB TBM testing in ITER

Abstract

One of the key missions of ITER is to test and validate the various design concepts of tritium breeding blankets relevant to a power-producing reactor like DEMO. India is developing lead-lithium cooled ceramic breeder (LLCB) test blanket module (TBM) along with associated systems for testing in ITER. In LLCB TBM, Pb-Li eutectic alloy is used as multiplier, breeder, and coolant for the ceramic breeder (CB) zones, and lithium meta-titanate (Li2TiO3) the ceramic breeder is used as a tritium breeding material. The outer box structure is India-specific reduced activation ferritic martensitic steel (IN-RAFMS) and is cooled by high pressure, high temperature (8MPa, 300–500°C) helium gas named as first wall helium cooling system (FWHCS). The molten Pb-Li eutectic, flows separately around the lithium ceramic breeder pebble bed compartments to extract heat from the CBs. The Pb-Li system is cooled by separate helium system named as lead-lithium helium cooling system (LLHCS). This paper discusses the details of the process design, and process flow diagrams of the both the helium cooling systems, their operational states with reference to the ITER machine operational states, and performance & behavior of the helium systems during normal operation and accidental conditions.