The COVID-19 restrictions have impacted the schedules of the LS2 and of the HL-LHC activities. Concerning the LS2 schedule, the hardware commissioning of LHC should be completed by March 2021 for all sectors except the S67, where the installation of the first 11-T dipole cryo-assembly is foreseen during the first quarter of 2021, postponing the end of the hardware commissioning of this sector to August 2021. One week of low intensity beam is scheduled in October 2021. As the recommissioning with beam (Run3 start-up) is now scheduled in February 2022, (the impact of COVID-19 is larger for the Experiments than for the LHC machine). The remaining time in 2021 will be dedicated to the magnet training to 7 TeV and to the installation of the technical infrastructures for a new HL-LHC safety exit which will be delivered in December 2020, i.e. too late to be equipped before the start of the powering tests. The above changes in the LS2 schedule effectively shorten the Run3 period. However, it was decided to keep the current schedule of LS3 and the HL-LHC installation for the moment unchanged, with an end of the Run3 period at the end of 2024.

Concerning the HL-LHC project, the COVID-19 restrictions have slowed down globally the production of components at CERN, in industry and in the collaboration institutes. A first analysis shows that the IT-String test could still be scheduled as previously foreseen in 2023. However, margins have been seriously affected and a second wave of the COVID-19 pandemic could affect the starting date of the IT-String test. The civilengineering worksites have also been affected. The worksites at Point 1 (ATLAS) and at Point 5 (CMS) were strongly disrupted for 6 to 8 weeks following the lockdown imposed by the Authorities in Switzerland and in France. The worksites restarted in May 2020, but with specific additional health and safety measures which are ultimately decreasing work efficiency. Mid-June, the excavation work in both points is about completed (95% of progress), i.e. excavation vibrations are no longer an issue for the LHC Run3. The four safety exits between the HL-LHC galleries and the LHC tunnel are open and the final concrete lining is progressing. On the surface, the construction of the cooling tower buildings and of the cryogenic compressor buildings have started (see Figure 1). As direct COVID-19 impacts, extension-of-times of about 25 days have been claimed by the contractors.