A new blanket tritium recovery experiment with intense DT neutron source at JAEA/FNS

Evaluation of tritium production rate in a blanket mock-up using a compact fusion neutron source

“…As shown in figure 1(b), the diamond (4.5 mm × 4.5 mm, thickness: 140 μm) is in a housing (54 mm × 10 mm × 8 mm). 6 Li-enriched LiF ( 6 LiF) film was pasted on a removable lid. The thickness of the LiF film was 1.9 μm.…”

“…Tritium breeding ratio (TBR), the rate of bred tritium in blankets to consumed tritium in plasma, is required to be greater than unity for a continuous operation of a deuterium-tritium (DT) fusion reactor. In a blanket, tritium is bred mainly by neutron capture reaction in ceramic/liquid breeder via 6 Li(n, t)α, where margins for TBR are required due to tritium loss in a fuel cycle and radioactive decay (required TBR ∼1.05) [1]. Together with material developments for breeding blankets [2,3], an experimental measurement of the tritium production rate (TPR) with spectral neutron flux is needed to guarantee the tritium fuel self-sufficiency.…”

“…However, opportunities for neutron irradiation experiments have been limited by the low availability of fusion neutron irradiation facilities. One symbolic example is the shutdown of the Fusion Neutron Source (FNS) facility at JAEA in the middle of 2010s, which has contributed to the fusion neutronics [4][5][6]. Consequently, an alternative approach for a facile neutronics experiment is desired.…”

“…As its neutron yield is significantly low compared with accelerator-based neutron sources, detectors with ultra-high sensitivity are required [11,12]. One direct method for measuring bred tritium is to count β-rays of irradiated Li 2 CO 3 diagnostic pellets using a liquid scintillation counter (LSC), which evaluates TPR with uncertainties of 4%-10% at the 1σ level [4][5][6][13][14][15]. But, the method is inapplicable for the compact neutron source because the amount of bred tritium would be below the detection limit of LSC with a reasonable operation period.…”

“…We here employ a single-crystal diamond detector (SDD), which has been successfully applied for fusion neutron environments in previous studies [16][17][18][19][20]. By using a thin lithium fluoride (LiF) film convertor, it is possible to separately measure 2.07 MeV alpha and 2.73 MeV triton generated via 6 Li(n, t)α [21][22][23].…”