NCS000020_4th Quarter 2022 Zn Benchmark Exceedance_20230111

DUKE
ENERGY
January 5, 2023
Mr. Zahid Khan, Regional Engineer
NC DEQ DEMLR — Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, North Carolina 28115
Reference: Duke Energy Carolinas, LLC — McGuire Nuclear Station
Industrial Stormwater NPDES Permit No. NCS000020
Tier 2 Required Response/Action
Mecklenburg County, North Carolina
Certified Mail: 7021 1970 0002 0904 7003
Dear Mr. Khan,
McGuire Nuclear Station
12700 Hagers Ferry Rd
Huntersville, North Carolina 28078
Please accept this email as the written two week notification as required by Part D, Condition D-6,
Table 3(iii), regarding the industrial stormwater system serving the McGuire Nuclear Station.
On December 14, 2022, quarterly stormwater samples were collected and analyzed in accordance
with NCS000020. Analytical results for ISW004 (ROS) were received by Duke Energy on December
29, 2022. Upon review of the results, it was observed that benchmark for Zinc was exceeded. The
benchmark for Zinc is 126 ug/L and the analytical result was 165 ug/L. Duke Energy will document
this exceedance and our response/actions within our SWPPP per Part D, Condition D-6. We will also
increase our monitoring frequency of all parameters to monthly (qualitative and quantitative) and
document within our SWPPP the other obligations addressed in Table 3.
If any questions or if further discussions are needed, please do not hesitate to contact Mr. Greg
Beaver, McGuire Environmental Field Support Professional, (704-642-6845 Cell or
[e-mail]).
Sincerely,
jX,
Brent Bare
Plant Manager
McGuire Nuclear Station
cc: Mr. Greg Beaver, DEC MNS
Mr. Don Safrit, P.E., Carolinas Permitting & Compliance