Blanket manufacturing technologies: Thermomechanical tests on helium cooled lithium lead (HCLL) blanket mocks up

In the Helium Cooled Lithium Lead (HCLL) blanket concept, the lithium lead plays the double role of breeder and multiplier material, and the helium is used as coolant. The HCCL blanket modules are made of steel boxes reinforced by stiffening plates. These stiffening plates form cells in which the breeder is slowly flowing. The power deposited in the breeder material is recovered by the breeder cooling units constituted by parallel cooling plates. All the structures such as first wall, stiffening and cooling plates are cooled by helium. Due to the complex geometry of these parts and the high level of pressure and temperature loading, thermomechanical phenomena expected in the “HCLL blanket concept” have motivated the present study.The aim of this study, carried out in the frame of EFDA Workprogram, is to validate the manufacturing technologies of HCLL blanket module by testing small scale mock-up under representative operating conditions.The experimental program is carried out on the DIADEMO facility at CEA Cadarache. This experimental device allows the coupling of a PbLi test section and an He cooling loop (pressure of 80 bar, maximum temperature of 500 °C, mass flow rate of 150 g/s) taking advantage of synergies with the gas-cooled fission reactor R&D program. The first step of the test program aims at exposing a simplified HCLL cooling plate mock-up in a fusion blanket environment (i.e. in PbLi and cooled by pressurized Helium) to ITER relevant conditions with thermal transients simulating plasma shut down. Three thousands thermal transient cycles have been performed in about 3 months, without any external visible damages on the mock-up. Post tests analyses are underway in order to investigate the behaviour of the cooling plate mock-up.