Test blanket module maintenance operations between port plug and ancillary equipment unit in ITER

Abstract

In collaboration between the FZK and KFKI-RMKI, in the frame of the activities of the EU Breeder Blanket Programme a concept for test blanket module (TBM) integration, maintenance schedules and all required special purpose equipments has been developed. During the first 10 years of ITER operation four different plasma scenarios will be used. Hence it will be possible to investigate the characteristics (e.g. tritium breeding performance) of different TBM concepts which will be installed during operation for the different phases of ITER operation in the equatorial ports #2, #16 and #18. In every port two TBMs will be accommodated, in the port #16 will be the European helium-cooled pebble bed blanket. In different phases of ITER operation different TBMs will be used. Therefore a complex maintenance process is necessary for the exchange of TBMs. Two TBMs are mounted onto one common frame, into a port plug (PP), which offers a standardised interface to the vacuum vessel (VV). It is cantilevered with a flange to VV port extension. This attachment system is the same in every equatorial port, so the exchange process of this structure with the TBMs is also the standard operation of ITER. Several components of the helium cooling system of the EU breeder modules, valves, pipes, gas mixers, thermal sleeves, pipes for tritium extraction, measurement system are integrated into the ancillary equipment unit (AEU), which during the operation will connect the port plug to the subsystems. The bigger part of the AEU is accommodated in the port cell and the rest part of it is penetrated into the interspace inside the bioshield and reach the back plane of the installed PP. The remote handling operations for connection/disconnection of an interface between the PP of the EU-TBMs and the AEU are investigated with the goal to reach a quick and simple TBM exchange procedure. The current design of the EU-TBMs foresees up to 18 supply lines for both TBMs. These lines have to be connected here. A new concept was worked out for fitting into each other these 18 pipe-ends and the opposite ones together at the same time in only one step before welding. A special mechanical system is developed, which can transfer the robot from its storing place in the AEU in the port cell to the interface on 6 m distance. This mechanism has a minimized space requirement, and able to send in the robot and all the tools stored in the tool-magazine together. Weld seams can be made by orbital welding tool (OWT). The coolant is helium, so for eliminating the leak of helium it is of high importance to find a safe way for weld seam audit. The installation and removal of thermal insulations around the pipes at the interface is an additional requirement which has to be met by a special tool.