Back in the starting blocks
Close to two years have passed since vacuum vessel assembly was halted when defects were identified in the 澳门六合彩高手 tokamak's vacuum vessel sectors and thermal shield. Following months of analysis, strategy definition and contractor selection, repair operations began in earnest in the first quarter of 2024. Last week, visitors to the Assembly Hall were greeted by a comforting vision: in one of the massive handling tools (SSAT1), vacuum vessel #7 is now free of the dense scaffolding that had kept it hidden for the better part of the year, its bevels restored to their nominal geometry. Attached to one of the tool's rotating wings, one of the sector's thermal shield panels, just back from repair in India, stands at a 90-degree angle. Vacuum vessel assembly is back in the starting blocks.
As assembly operations proceed on vacuum vessel sector #7, which will lead to the completion of a "sector module" ready for installation in the tokamak pit, repairs are also progressing on the two other sectors present on the 澳门六合彩高手 site. In the second handling tool (SSAT2) metal build-up is completed on sector #6 and machining should be finalized by mid-November. In the former Cryostat Workshop, vacuum vessel sector #8—the most affected by non-conformities of the three—is being repaired in horizontal position, with only one side of the component accessible at a time. On the "visible" side, manual metal build-up is now complete and mechanized build-up has started. Once the first side has been repaired, the 440-tonne component will need to be "flipped" and the sequence of operations will be repeated on the other side. The forecast date for completion is July 2025. (See a detailed report here.)
Assembly operations can now proceed on vacuum vessel sector #7 (pictured). In the twin handling tool, repair works on sector #6 should be completed by November 2024. In the former Cryostat Workshop, repairing both sides of vacuum vessel sector #8 will require flipping the 440-tonne component. The forecast date for completion is July 2025.
Of the nine sets of thermal shields that wrap the nine vacuum vessel sectors like a tight-fitting jacket, seven were sent for repairsto INOX-CVA in India. Two have returned, fully repaired, to 澳门六合彩高手. Two extra sets are being completely remanufactured at SamHong Heavy Machinery in Korea. Vacuum vessel thermal shield panels were not the only components susceptible to the same, millimetre-deep cracks in the cooling pipes that had been detected in 2022. As a consequence the cryostat thermal shield and the panels protecting the vertical coil gravity supports—both already installed in the tokamak pit—are concerned by the replacement of the cooling pipe network. In 2023, the 18 gravity support panels were removed and sent for repair to a contractor near Lyon, France.
The lower cryostat thermal shield, which was installed in January 2021, presented a more daunting challenge. Due to space and cleanliness constraints inside the assembly pit, removing and re-welding cooling pipes has been ruled out; instead, a new set of piping will be clamped to the component's surface. As for the other sections of the cryostat thermal shield—support, equatorial and upper, all delivered and stored—the options are still open: either repair or remanufacturing.
