The damages following LHC accident, occurred last month, are more serious than expected. Some design errors have been identified into the valves that should regulate the quantity of helium flowing in such cases. Helium entered inside the ring and the valves were underdimensioned for the aims. Bad news is that repairing damages will require at least eight months. Optimistically one can hope starting of operation on May or June 2009. An article can be read in Nature about (see here). Dynamics of the accident is given by CERN here.
LHC will stop for at least eight months