Initial design and test of the tritium breeder monitoring system for the lead-lithium cooled ceramic breeder (LLCB) module of the ITER

Highlights: • We propose a system for measurement of tritium-breeding dynamics in module of the ITER. • Lithium carbonate sensors and neutron detectors are used for the measurements. • The sensors and detectors are irradiated by neutrons under ITER plasma operations. • A pneumatic concept is suggested for conveying of the samples in the module. • The results of the tritium measurements in the sensors after irradiation are discussed. -- Abstract: The demonstration of a tritium breeder is an important part of an ITER mission. A concept for an experimental estimation of the tritium-breeding ratio (TBR) and the tritium-breeding dynamics in a test breeder module (TBM) of ITER has been developed. A system for the experimental estimation of the values is proposed for the lead–lithium cooled ceramic breeder (LLCB) TBM of ITER. The system is based on tritium breeder and neutron flux measurements under ITER plasma D-T experiments and the use of lithium carbonate sensors and neutron detectors. Three capsules with lithium carbonate (Li2CO3) containing different relative abundances of lithum-6 and lithium-7 (Li-6/Li-7 ratios of that found in nature: 1/1 and 9/1) and three capsules with neutron detectors are placed in a container. The low-level activities of the structural materials of the container and the capsules are used to prevent operation in a hot cell after the reactor irradiation of the container. For the delivery/withdrawal of the containers into/from the TBM, a pneumatic concept is suggested with a monitor channel connecting the TBM and an operating zone for conveying the containers in the TBM before the pulse and extracting them after the pulse. The initial design of the container with the capsules for the samples and the channel part in the TBM are presented in this paper. A laboratory facility for the investigation of the pneumatic parameters and the container moving in the channel is proposed. Neutron calculation is performed to estimate the tritium content in the lithium carbonate under reactor irradiation. The container model with the samples is proposed for testing on the nuclear reactor IVV-2M. The results of the tritium measurements in the lithium carbonate are discussed