Q2. Why is the pulse length of plasma operation limited?
due to high thermal stress in the cooling pipes, the pulse length of plasma operation must be limited depending on the number of full load cycles.
Q3. What are the main issues that were considered during the analysis of the PV panels?
Large expansion and deformation during baking and plasma operation due to heat loads, internal pressure, and PV deformation were considered.
Q4. How many TEs are used in the horizontal divertor system?
The TEs are fully fixed to the support rail at the side where they are connected to the cooling pipes, while at the other side they can slide radially relative to the other support rail.
Q5. What is the main issue in the analysis of the PV?
An important issue is the definition of gaps required between WPs in order to avoid collisions and overload of the supports to the PV.
Q6. What is the typical load case for a plasma panel?
The normal plasma operation load case includes 100 kW/m 2 heat load, 5813 W/m 2 K heat transfer coefficient in the cooling channel at constant cooling water temperature of 80 °C, and 2 MPa cooling water pressure.
Q7. What is the design of the stellarator experiment W7-X?
The stellarator experiment W7-X being constructed in Greifswald, Germany, is designed for stationary plasma operation (30 min) with steady state heating of up to 10 MW ECRH and 10 s pulse heating power of up to 20 MW with additional NBI and ICRH [1].
Q8. What are the main issues in the analysis of the TM-H09?
Two significant issues were found in the course of analyses: (1) the large temperature gradient in the pipe results in high stresses and (2) the cooled but still rather hot back surfaces of graphite tiles lead to heat loads on the PV significantly exceeding the design limit.
Q9. How many cycles are needed to predict the operation limit of W7-X?
In order to predict the operation limit of W7-X more precisely, further heat flux tests with an increased number of cycles are necessary.
Q10. Why are the PFCs being installed in the PV?
They are being installed in the PV in order to protect it and other in-vessel components behind them from the convectional/radiative heat coming from the plasma.
Q11. What are the maximum stresses in the cooling pipes, manifold supports, stiff beam and frame?
The maximum stresses in the cooling pipes, manifolds, manifold supports, stiff beam and frame are 209 MPa, 348 MPa, 279 MPa, 138 MPa and 314 MPa, respectively.
Q12. How many cycles can a baffle and heat shield withstand?
FE calculations indicate that the tiles of baffles and heat shields can withstand average steady state heat loads of 250 kW/m 2 .
Q13. What is the maximum stress in the support rails?
In the elastic calculation of load case 1, von-Mises stresses in the support rails are higher than 1000 MPa in a large area, which is far beyond the limit of 525 MPa (secondary stress limit 3Sm) for SS EN 1.4435 at 70 °C.
Q14. What is the main purpose of the FE model?
A 3D global FE model as shown in figure 2 was created for TM-H09 to perform thermo-mechanical analyses with the main purpose to estimate deflections, thermal stresses and requirements for module attachment.
Q15. What are the gap requirements for the panels?
Based on this information, the gap requirements to be checked during assembly were defined in toroidal and poloidal directions separately, depending on the curvature of the WPs, the distances between all relevant support pairs of a series of WPs, and the available sliding space between the panels and their supports.
Q16. How much heat can be withstand in steady state?
The results showed that the tile can withstand the average heat load for steady state operation, but that under local peak heat load it can only be operated in pulses of up to 45 s to limit the thermal stress in the cooling pipe.
Q17. What are the temperatures of the CFC tiles, interlayers and CuCrZr?
The thermal calculation shows that the maximum temperatures of the CFC tiles, interlayers and CuCrZr heat sinks are 911 °C, 481 °C and 321 °C, respectively, which correspond to the experimental results [11].
Q18. How many cycles of a single tile are allowed?
Assuming all of them to be full load cycles, the allowed pulse length of a local peak heat load would be 40 s which is coincidentally consistent with the result of FE elastic analysis of a single tile.
Q19. What are the FE calculations for baffles and heat shields?
Further analyses are ongoing on the baffles, heat shields and wall panels with respect to allowed gaps and steps in between them, relaxation of support restrictions, and non-conformities.
Q20. What is the relation between the edge tiles and the heat sink?
On the other hand, the edge tiles are less critical with respect to thermal deformation of the cooling pipe, which is less restrained in such tiles than in the tiles in the middle of the module.