The Nuclear Regulatory Commission (NRC) on Monday began a special inspection of damage to the containment vessel at Unit 2 of SCANA’s Summer nuclear plant, which is under construction in South Carolina.  

The inadvertent damage stems from an incident during the week of Feb. 9, the NRC said. “Chicago Bridge & Iron (CB&I) workers cut some safety-related rebar and damaged the containment vessel bottom head while drilling into concrete.”

The actual damage appears to have been “minor,” but the NRC said it wanted to make sure it completely understands its potential impact and “the apparent breakdown in controls that might have prevented it.”

The federal regulatory body is also concerned about CB&I’s delay in reporting the issue. The firm reportedly alerted SCANA to the damage nearly a week afterwards on Feb. 16.

SCANA has one reactor in operation and two under construction at its V.C. Summer power plant located near Jenkinsville, S.C..

In a Feb. 19 earning conference call, company officials said SCANA is in discussions with the construction consortium to identify strategies that could accelerate the substantial completion date of Unit 2 to earlier in the first half of 2019, or to the end of 2018, with Unit 3 following about 12 months later.