Irradiation experiments on liquid tritium breeding material Pb17Li in the HFR Petten

Abstract

Lithium-lead alloy samples, Pb-17Li, with natural isotopic abundance of 6Li being irradiated in the High Flux Reactor (HFR) Petten, using specially designed irradiation facilities. The irradiation programme, conenamed LIBRETTO, is at present being performed as a joint programme between JRC Ispra, CEA-Fontenay-aux-Roses and IAM Petten within the European Fusion Technology Programme on Blanket Technology. The LIBRETTO irradiation experiments are designed to investigate tritium release characteristics of static Pb-17Li samples at NET blanket operating conditions. The tritium release rate of purged capsules (plenum swept and bubbled) and the tritium permeation rate through the wall of closed capsules are measured in-situ and on-line. Up to now, two irradiation campaigns were performed during the period 1987–1989. Each campaign lasted ≈ 70 days. The samples were irradiated up to a Li burnup of ≈ 1.1%. Temperature transients between 570 and 760 K were performed to study tritium release kinetics of alloy samples, cladded by AISI 316L capsules with and without a tritium permeation barrier. Post-irradiation examinations were performed to study cladding-alloy interactions, tritium and helium solubility in the alloy and polonium production. Two or more irradiation campaigns are planned for the years 1990–1992 to study tritium recovery methods and the effectiveness of tritium permeation barriers.This paper gives a review on the performed experiments.