Dr Evans said there was 'a big mess to clean up' at the LHC
The scientist in charge of the Large Hadron Collider (LHC) is confident the experiment to recreate conditions just after the Big Bang will be successful.
The £3.6bn machine in Geneva shut down in September after a malfunction between two of its magnets.
New protection systems will be added as part of £14m repairs to avoid further problems when the LHC is restarted this summer.
Project director Dr Lyn Evans said they had "a lot of work to do".
"But we now have the roadmap, the time and the competence necessary to be ready for physics by summer," he said.
"We are currently in a scheduled annual shutdown until May, so we're hopeful that not too much time will be lost."
An investigation into the LHC's problems concluded the initial malfunction was caused by a faulty electrical connection between two of the accelerator's magnets.
The LHC took 13 years to build and was shut down after just nine days
The European Organization for Nuclear Research (Cern) said that as a result, 53 magnet units will have to be removed from the LHC's tunnel to be cleaned or repaired.
It is estimated the final magnet will be reinstalled by the end of March, with the LHC ready for tests in June.
Dr Evans, back in his native south Wales, said he was "optimistic" the experiment would be carried out successfully.
"I think we have done not only investigating the cause of the incident but making sure it can never happen again and I think that's an essential thing," said Dr Evans, who is from Aberdare, Cynon Valley.
"We now have developed a means to be able to spot such things before they create any damage so when the machine comes back up again it will come on safely and it will have a long and productive life."
He added there was never any risk of the LHC malfunction injuring people but that it would cost a lot of money - almost £14m - to repair.
However, he said the experiment, when finally carried out, would be worth it in order to try to answer some of the "profound questions" in science.
"There're whole questions about the dark matter and dark energy in the Universe, for instance; that we now know we can only see 4% of our Universe - 96% we don't know what it is," he said.
"Of course, coming along with the fundamental questions is pushing the frontiers of technology and knowledge."
The LHC was built to smash protons together at huge speeds, recreating conditions moments after the Big Bang.
The fault occurred just nine days after it was turned on in September.
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