Additional safety features being added to the world's largest atom smasher will postpone its startup until the end of September, a year after the $10 billion machine was sidelined by a simple electrical fault, the operator said Tuesday.

The cost of the repairs and added safety features has yet to be determined, but it will be covered by the regular budget of the European Organization for Nuclear Research, spokeswoman Christine Sutton said.

The 20-nation organization, known as CERN, has said previously that repairs will cost at least 25 million Swiss francs ($21.5 million), but the amount appears to have risen since scientists could review the extent of the damage and devise new safety features.

"The costs will certainly have to come out of our normal budget," Sutton said.

• Click here for more photos.

• Click here to find out how the Large Hadron Collider works.

• Click here to visit FOXNews.com's Natural Science Center.

A faulty splice in the wiring shut down the Large Hadron Collider on Sept. 19, nine days after the machine started up with great fanfare.

The resulting electrical arc damaged a section of the equipment and punctured an enclosure holding the liquid helium used to keep the collider at a temperature colder than outer space for maximum efficiency.

It has taken months to determine the full extent of the damage, which was limited to one of the eight sectors in the collider housed in a 27-kilometer (17-mile) circular tunnel under the Swiss-French border on Geneva's outskirts.

Scientists have taken the setback in stride, saying that particle colliders always have such problems in the startup phase.

The massive machine was built to smash protons from hydrogen atoms into each other at high energy and record what particles are produced by the collisions, giving scientists a better idea of the makeup of the universe and everything in it.

They hope the collisions will show on a tiny scale what happened one-trillionth of a second after the so-called Big Bang, which many scientists theorize was the massive explosion that formed the universe.

The theory holds that the universe was rapidly cooling at that stage and matter was changing quickly.

After the shutdown, 53 of the massive magnets designed to guide and focus the beams of protons that whiz at the speed of light through the tunnel had to be brought to the surface to be cleaned or repaired.

To prevent a recurrence of the problem, CERN is installing a new, highly sensitive protection system to detect any unwanted increases in resistance on the electrical connections so that it can shut down the current before anything is damaged, a statement said.

"Enormous progress has been made in developing techniques to detect any small anomaly," it said.

Scientists also are installing new pressure relief valves for the liquid helium in two phases. The first set of valves will ensure that any damage would be minor should there be a repeat of the September failure.

The second set, to be installed this year and next year, "would guarantee" only minor damage "in all worst cases over the life of" the collider, according to a CERN statement.

The aim, said Sutton, is to "ensure that this machine is going to work beautifully for the coming decade or more."

"With these additional valves we should really be safe against this kind of incident. Any damage that will occur will only be minor and not anywhere near as disruptive," she said.

During the shutdown, around six tons of helium leaked out, overpowering the relief valves installed at the time and adding to the damage. The remaining 114 tons of liquid helium in the collider was unaffected by the leak, CERN said.

"What you have to try to think of is what can you do to protect yourself against things that you haven't thought of," Sutton said. "It's easy to protect yourself against things that you have thought of."