LOS ALAMOS, N.M.—The contractor that runs Los Alamos National Laboratory says it will pay $10 million to cover some of the costs for fixing a faulty $213 million security system.

In a joint statement, the officials from the lab and the National Nuclear Security Administration say the money will cover "potentially unallowable costs" incurred in construction of the system, which was built around the only place in the country where nuclear weapon triggers can be made.

The money will come from Los Alamos National Security, the private contractor that runs the lab.

Officials have estimated it will take an additional $41 million and another six months to fix the system, which was supposed to be up and running this summer.