Apparently they are working out the bugs in the design… but it’s not a design fault.
He said the second problem is not with the most complex technology but involves the copper sheaths around the superconducting joints in the tunnel.
The copper sheaths are a failsafe mechanism designed to take up the current if one of the magnets in the Large Hadron Collider warms up – an incident known as a "quench".
The 2008 accident caused one tonne of helium to leak into the tunnel and resulted in a series of "quenches" and a 40m Swiss franc (£24m) repair bill.
Engineers believe the machine is now safe to run at 7 trillion electron volts (TeV) but are anxious to avoid another breakdown.
So they have taken the decision to run the machine for 18 to 24 months at half-maximum power before switching it off for a year to carry out improvements to the 27km tunnel.
Dr Myers said the decision was taken jointly with the physicists working on the four giant particle detectors on the LHC.
He said they appreciate the chance to test their own equipment while the machine is running at half its maximum power.