PRACTICAL CHALLENGES OF THE LHC MAIN BEAM DUMP UPGRADES

The two Large Hadron Collider (LHC) beam dumps have to withstand arduous operating conditions and are essential for the safe and reliable operation of the collider. During the LHC Long Shutdown 2 (2019-2020), extensive work was carried out to upgrade the dumps to cope with the more demanding future operating conditions of the LHC Run 3. The upgrades included modifications to the dump blocks, dump block supports and their lubrication, beam windows, the beam pipes leading to the dumps, and the nitrogen pressurisation system of the dump blocks. A comprehensive instrumentation system was installed to monitor the behaviour of the dumps. In addition, an internal endoscope inspection was performed on the ex-operational dumps to check their condition. Many of these operations had to be carried out in underground radiation areas, therefore the optimization of the dose-to-personnel according to the ALARA principle was an important consideration. The return on experience for these activities will be provided, including the critical tasks, unexpected events and lessons learnt.