TY  - JOUR
AU  - Morgan
AU  - Balden, M.
AU  - Schwarz-Selinger
AU  - Li, Y
AU  - Loewenhoff, Thorsten
AU  - Wirtz, M.
AU  - Brezinsek, Sebastijan
AU  - De Temmermann, G.
TI  - ITER monblock performance under lifetime loading conditions in Magnum-PSI
JO  - Physica scripta
VL  - T171
SN  - 1402-4896
CY  - Stockholm
PB  - The Royal Swedish Academy of Sciences
M1  - FZJ-2020-03895
SP  - 014065 -
PY  - 2020
N1  - Kein Post-print verfügbar
AB  - The ITER divertor will be exposed to extremely high plasma fluences over its lifetime, and it is known that plasma exposure can lead to a variety of particle-induced surface-morphology and microstructure changes in tungsten. However, no data exists at fluences comparable to those expected over extended ITER operations (1030−31 m−2) and so it is uncertain how these changes will evolve and affect the divertor performance over such long timescales. Six monoblocks were exposed to high flux plasma comparable to partially-detached plasma conditions in the ITER divertor in Magnum-PSI. Different exposures used different plasma species (H, He, D or D + He) and aimed to replicate conditions similar to those during different phases of the ITER staged approach. The highest fluence achieved was 1030 D m−2, comparable to around one year of ITER Fusion Power Operation. Post-mortem analysis by Nuclear Reaction Analysis revealed very low deuterium retention throughout the blocks, while surface analysis showed no cracking or damage, but did observe helium fuzz growth at low ion energies of 8–18 eV, below typically assumed ion energy requirements for such growth to occur. Metallographic sectioning revealed recrystallization up to 2.2 mm below the surface of monoblocks exposed at peak surface temperatures of up to 1580 °C for different durations up to ~20 h. Finite Element Method analysis coupled to metallographic and Vickers Hardness identification of the boundary of the recrystallized region identified a faster recrystallization process compared to literature expectations, reinforcing that recrystallization dynamics is an important criterion for tungsten grade selection for the ITER divertor. Overall, no major damage or failure was identified, indicating that the design is capable of fulfilling its steady-state performance requirements under high flux, high fluence plasma loading conditions in the ITER divertor.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000520000600065
DO  - DOI:10.1088/1402-4896/ab66df
UR  - https://juser.fz-juelich.de/record/885515
ER  -