IEA Implementing Agreement on Nuclear Technology for Fusion Reactors

1. IEA Implementing Agreement on Nuclear Technology for Fusion Reactors Liquid Breeder Blankets Subtask Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders11-12 June 2007, Idaho Falls, ID, USA Permeation coating development J-F. Salavy 1, A. Aiello2, A. Ciampichetti2, F. Gabriel1, O. Gastaldi1, L. Giancarli1, J. Konys3, Y. Poitevin4, I. Ricapito2, M. Zmitko4 (1 CEA, 2 ENEA, 3 FZK, 4 EFDA) J-F. Salavy

2. Outline • Basic features of the HCLL concept • Recall of the EU R&D on anti permeation coatings • Overview from M. Zmitko (EFDA): done this morning • Overview of the permeation results for coatings on PbLi side • Overview from A. Aiello (ENEA) • Overview of the results on oxides coatings on He side • Coatings needs from a HCLL Project point of view • Summary J-F. Salavy

3. The HCLL (He-PbLi) DEMO blanket Module box(container & surface heat extraction) Breeder cooling unit (heat extraction from PbLi) He collector system (back plates) Stiffening grid J-F. Salavy

4. Top cover BUs BUs back plates Stiffening grid BUs He collectors PbLi inlet pipe FW/SW Vertical shear key-way PbLi distribution box He inlet pipe PbLi feeding pipe Horizontal shear key-way Stiffening rod Vertical shear key-way PbLi feeding pipe He outlet pipe BP1 BP2 Back collector PbLi outlet pipe BP3 BP4 The HCLL TBMs to be tested in ITER • TBMs have to be DEMO-relevant TBMs proposal are derived from DEMO programs • First TBMs have to be installed since the first day of the H-H operation(to check interfaces & main operations, compatibility with ITER operations and to support to licensing & safety) • TBM design (mainly Breeder Units) will be specifically optimized for each ITER phase(at least 4 different TBMs could be tested in ITER) • Each party (7) intends to test TBMs in ITER. 3 ports are allocated for TBM testing.Half-port TBM (vertical or horizontal) are considered up to now Breeding zone cell PbLi inlet PbLi flow path Horizontal stiffening plate LiPb outlet LiPb distrib. box Breeding zone column J-F. Salavy

5. Recall of the EU R&D on anti permeation coatings Overview from M. Zmitko (EFDA) See presentation from M. Zmitko at this workshop: « Recent and on-going tritium-related activities in Europe for HCLL blanket » J-F. Salavy

6. Overview of the permeation results for coatings on PbLi side - Overview from A. Aiello, ENEA Brasimone J-F. Salavy

7. Overview of the results for oxides coatings on He side (1/2) from I. Ricapito, A. Aiello, ENEA Brasimone On-line oxidation and test procedure on Eurofer 97 • on-line oxidation: the oxidation part of PERI II can be seen like the device shown abovewhere the oxidation section is represented by the high pressure side of theapparatus. In this case the water content of the Ar gas was measured by means of a hygrometer. During the test humidity was added to high purity gas flowing Argon in a water partially filled bottle. • the performances of the on-line oxidation, and therefore the effectiveness of the self healing, have been tested using one oxidation time, 60 min, at 550 °C with different gas mixtures J-F. Salavy

8. Overview of the results for oxides coatings on He side (2/2) Summary of the main results • Samples of Eurofer 97 were tested in a wide range of gas mixtures, with variable water content, maintaining a constant temperature of 550°C. The variation in the specimen permeability was evaluated using a quadrupole technique while flowing the oxidant mixture in the high pressure side. • The results of the permeation tests gave a PRF in the range 1 – 30 with a Gaussian shape of the PRF curve, centred on the H2/H2O molar ratio of 70/3. • The micrographs confirmed the permeation results, at least in terms of oxide thickness and density. • Results seems to be independent on the water partial pressure or gas mass flow rate. J-F. Salavy

9. Coatings needs from a HCLL Project point of view (1/3) • Do we need anti-permeation coatings for HCLL TBM operation in ITER? • No (low amount of Tritium, no safety concern) • Do we wantto test anti-permeation coatings in HCLL TBM testing campaign in ITER? • Yes (because they will be probably needed for DEMO operation and ITER will be an unique opportunity to investigate their behaviour in representative conditions) • But: • Will we be able to investigate during tests their effects on permeation? • What kind of PIEs can give useful information? • Will we be able to produce in time? J-F. Salavy

10. Coatings needs from a HCLL Project point of view (2/3) • Will we be able to investigate their effects on permeation during ITER testing? • Difficult toanswertoday. Will depend on progresses of R&D on sensors and modelling tools. • Will need to be measured with and without barriers in same precise conditions: probably feasible for oxides on He side but very difficult for coatings on PbLi side • What kind of PIEs can give useful information? • Remaining thickness, presence of cracks, microstructure. • Need of a dedicated PIE programme (to be developed) integrating developments of RH preparation tools to be installed in ITER hot cell. J-F. Salavy

11. Coatings needs from a HCLL Project point of view (3/3) • Will we be able to produce in time? (Note: they are not needed for the first years of operations) • Probablyyes for oxides coatings, depending on He control possibilities in the Coolant Purification System for HCLL TBM He coolant circuit and on future developments onto the characterization under thermal cycle and for more relevant specimens geometries • Probablynot for coatings on PbLi side if a significant increase of the R&D effort in that field is not done very quickly. J-F. Salavy

12. Summary • Coatings needs for HCLL TBM: • Not needed to operate the TBM in ITER. • Unique possibility to test in representative conditions before DEMO. • Al based coatings on PbLi side: • Several techniques investigated at laboratory scale. • Huge difficulties to obtain stable coatings, even with simple geometries. • Discrepancy between anti-permeation coating efficiency data. • Efficiency difficult (impossible?) to be quantified in TBM. • Strong development effort needed to be in time for ITER testing. • need in DEMO HCLL blanket not yet fully established (depends on many parameters such as PbLi/T data, PbLi thermal hydraulic condition, efficiency of the coatings on the He-side, general T-system management, etc..) . • Oxide coatings on He side: • On going promising activities. • PRF ~10 to 30 obtained (ENEA). Optimisation still needed. • Possible testing in TBM for ITER operation (schedule and technical). • Characterization and qualification effort (cycling, relevant geometry) needed. J-F. Salavy