The NRC said engineers failed to develop proper testing protocol to ensure the membrane – used to waterproof areas near the reactor foundation – would perform properly, and also mentioned the use of an untested sealant used in membrane joints.
The violation was given a severity level of IV, the NRC’s least-serious category. The company has 30 days to respond.
The issues came to light during an Aug. 18 inspection to determine whether construction activities at the Burke County site were in compliance with the Early Site Permit and Limited Work Authorization granted by the NRC to allow some work to begin before the contruction of the new reactors was approved.
Activities allowed under that permit include construction of retaining walls, dirt and concrete backfill, and installation of the waterproof membrane in the foundation area.
“The violation was greater-than-minor because it represented a condition adverse to quality that rendered the quality of the waterproofing membrane system indeterminate,” inspectors wrote, noting that the issue could adversely affect future inspections, tests and acceptance criteria.
However, the report said, the violation does not meet the criteria to be greater than a Severity Level IV (least serious) violation.
Details of the inspection were outlined in a letter dated Friday and sent to Southern Nuclear executive vice president Joseph A. Miller from the NRC’s Construction Inspection Branch.