The discovery of some 40-year-old bad math about the building housing the Fort Calhoun nuclear reactor in Nebraska is being scrutinized and could further delay resumption of operations at the plant.

The plant, which has been closed since 2011, is subject to strict oversight from the Nuclear Regulatory Commission because of ongoing problems.

So it was worrisome when utility officials said they’d discovered that supports for some heavy equipment in the containment building might not withstand extreme stress.

Critics say the Omaha Public Power District should consider shutting down Fort Calhoun for good because of the mounting costs.

But the utility believes Fort Calhoun is worth salvaging because significant improvements have already been made — and it’s the only power plant it owns that produces electricity without greenhouse gases.