1. Tritium Breeders Li 2 OLi 2 AlO 2 Li 2 ZrO 3 Li 4 SiO 4 Li 2 TiO 3 Li Vaporization ( in additional H 2 ) > 600˚C> 900˚C> 800˚C> 700˚C> 800˚C Long period use (2 years) Instability (Li vaporization) StabilityInstability (crack) Instability (Li vaporization) Instability (Reduction of Ti) Tritium release ( easy release ) > 400˚C > 350˚C> 300˚C Optimum operating temp. 400 - 600˚C 400 - 900˚C 400 - 800˚C 350 - 700˚C 300 - 800˚C Tritium breeding ratio (TBR) HighLowerMiddle Thermal conductivity HighMiddle These tritium breeder are available in DEMO blanket? 300 - 800˚C High Why we need advanced tritium breeder? 400 - 900˚C Stability

2. Development target TBR Stability (high temperature use) Li 2 O Li 2 TiO 3 LiAlO 2 Li 2 ZrO 3 Li 4 SiO 4 DEMO Blanket Development target of advanced tritium breeder is influenced by requirement of DEMO blanket. Where is yellow area? Requirement 1) ?˚C 2) ? 3) ? Selection of important item

3. USAEUChinaKoreaIndiaJA Temperature 300 – 1000˚C Period of use < 2 years Purge gas 0.1%H 2 - He Local TBR> 1.05 Necessity of mixture (Li and Be) Yes ? Crash load - requirements - or - conditions - Candidate materials and new research project Li 2 TiO 3, Advanced breeder, etc. Requirement Condition

4. For Example 1 TBR Stability (high temperature use) Li 2 O Li 2 TiO 3 LiAlO 2 Li 2 ZrO 3 Li 4 SiO 4 DEMO Blanket in ●● Li 4 SiO 4 will be selected the tritium breeder for DEMO blanket in ●●. 7/20 Requirement 1) 300 – 800˚C →Requirement of stability is lower

5. For Example 2 TBR Stability (high temperature use) Li 2 O Li 2 TiO 3 LiAlO 2 Li 2 ZrO 3 Li 4 SiO 4 DEMO Blanket in ●● LiAlO 2 will be selected the tritium breeder for DEMO blanket in ●●. 8/20 Requirement 1) TBR is enough →Requirement of TBR is lower 2) More stability

6. Advanced Tritium Breeder in JA TBR Stability (high temperature use) Li 2 O Li 2 TiO 3 LiAlO 2 Li 2 ZrO 3 Li 4 SiO 4 DEMO Blanket in JA Li 2 TiO 3 with additional Li (Li 2+x TiO 3+y ) has higher stability at high temperatures in a reducing atmosphere. Why we need advanced tritium breeder? 9/20 Requirement 1) 300 – 1000˚C 2) 30% 6 Li burn up 3) Use for 2 years

7. Reference: Application of high temperature mass spectrometry and work function measurement to evaluation of thermochemical performance of ceramic breeders, Fusion Engineering and Design, Volumes 49-50, November 2000, Pages 681-688 Atsushi Suzuki, Kenji Yamaguchi, Takayuki Terai, Michio Yamawaki Li Vaporization Li 2 O > Li 2 ZrO 3 = Li 4 SiO 4 = Li 2 TiO 3 > LiAlO 2 In my confidential experiment, I become dubious about the credibility of this results. So, I proposed that we try to this measurement again.

8. Li burn-up Loss of Li is 0.27mol Chemical formulaLi burn-up （ mol ） Li vaporization （ mol ） Chemical formula after 2 years Li 2 TiO 3 0.200.07 XLi 1.88 TiO 2.93 + Y(aLi 4 Ti 5 O 12 + bLiTiO 2 ) TBR will be decreased. Condition: 30 ％ Li-6, 900 ℃（ in 1%H 2 -He ), 2years This results are show in domestic conference by Hoshino. Li + n -> T + He Complex mixture Tritium release characteristic will be changes.