Upgrade of the Liquid Helium Storage for the Large Hadron Collider

The cryogenic system of the Large Hadron Collider (LHC) under operation at CERN has a total helium inventory of 140 t. Up to 50 t can be stored in gas storage tanks. The remaining inventory is stored in a liquid helium storage system consisting of six 15-t liquid helium tanks sited in 4 locations. The first phase with the commissioning of the two first liquid helium tanks including their infrastructure was already presented. In a second phase, four new tanks were commissioned at the end of 2010. The paper describes the modifications relating to these four tanks and presents the measurement of their thermal performance.