NC0007064_Monitoring (Report)_20240314

Brunswick Steam Electric Plant (BSEP) Supplemental Information for Thermal Plume:
A. (1) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS [Outfall 001]
[15A NCAC 0213.0400 et seq., 15A NCAC 02B.0500 et seq.]
Criteria:
TEMPERATURE —Cooling-water system facilities shall be effectively maintained and operated to meet
the temperature standards assigned to the Atlantic Ocean: 0.8°C (1.44°F) increase above ambient water
temperature during the months June through August; 2.2°C (3.96°F) increase above ambient water
temperature during the months September through May. In no case should the temperature exceed
32°C (89.6'F) due to the discharge of heated liquid measured three (3) feet below the water surface
except within the following defined mixing zones:
(a). The temperature increase above ambient water temperature shall not exceed 7°F outside an area of
120 acres included within the plume extending from the point of discharge.
(b). The temperature increase above ambient water temperature shall not exceed 0.8°C (1.44°F)
increase above ambient water temperature during the months of June through August; 2.2°C (3.96°F)
increase above ambient water temperature during the months of September through May. In no case
should the temperature exceed 32°C (89.6°F) outside an area of 2000 acres.
(c). The temperature increase above ambient water temperature at the bottom (defined as one foot
above the ocean floor) shall not exceed 7°F for more than 1000 feet from the point of discharge, nor for
an area of more than four (4) acres.
Temperature monitoring at the ocean discharge shall be conducted semiannually, once during the
months of April - November and once during the months of December - March. Reactor power levels
should be at least 85% for each unit on the date of monitoring. If it is determined by this Division that
the water quality standards or conditions of this permit are being violated or being threatened (within
90% of the limitations or standards), additional monitoring may be required.
Temperature shall be monitored within a 2320-acre rectangular mixing zone defined by two (2) sampling
grids; one near the ocean surface (three feet below the water surface) and the second near the bottom
(one foot above the ocean floor). Temperatures shall be recorded at locations sufficient in number to
establish compliance with Water Quality Standards. The Permittee shall likewise establish and report
ambient temperatures beyond each grid by averaging four (4) temperature measurements -- each
measurement to be taken approximately 1500 feet beyond a different mixing -zone corner on a baring
approximately 1352 relative to each sampling grid except for the corners closest to the shoreline which
are to be taken 1500 feet from the grid parallel to the shoreline.
Conclusion:
Monitoring was performed on 3/14/2024.
All measured parameters were within the guidance specified by the BSEP NPDES permit.
Temperature monitoring is performed by plant procedure OE&RC-3227, Thermal Plume Monitoring.

Note:
Conditions at the time of monitoring were below the suggested Reactor power levels on Unit 1 due to
an emergent safety related shutdown and subsequent refuel outage. This impacted the original
schedule window to conduct the monitoring in February before the annual refuel typically scheduled in
March. At the time of monitoring, the unit was in startup at 20% (below the recommended 85% power
level). Recognizing that the unit would experience numerous power level changes during the next week
during unit recovery in addition to accounting for the unpredictable marine conditions, the team
proceeded with the monitoring.
DAP
3/14/2024

THERMAL PLUME MONITORING OE&RC-3227
Rev. 6
Page 14 of 18
ATTACHMENT 4
<< BNP Thermal Plume Monitoring Log >> Page 1 of 2
Date
3/14/2024
Wind Direction
NW Unit 1
Wind Speed
5 MPH Unit 2
Air Temperature
64 Tide Stage
Power
20.0
100.0
Rising, High, Falling
Station
Time
Surface Temp
Bottom Temp.
1
N/A
N/A
N/A
2
11:02
58.9
58.3
3
11:01
58.9
N/A
4
10:59
59.0
N/A
5
10:58
59.3
N/A
6
10:56
59.8
N/A
7
10:55
59.6
N/A
8
10:53
59.5
N/A
9
10:51
59.5
N/A
10
10:50
59.5
N/A
11
10:48
59.5
N/A
12
10:45
59.7
58.0
13
N/A
N/A
N/A
14
10:43
59.7
N/A
15
11:22
60.2
N/A
16
11:20
60.9
N/A
17
11:18
60.2
N/A
18
11:17
60.5
N/A
19
11:15
60.3
N/A
20
11:13
60.1
N/A
21
11:12
60.2
N/A
22
11:10
59.9
N/A
23
11:08
60.1
N/A
24
11:06
60.1
N/A
25
11:37
60.6
N/A
26
11:36
60.8
N/A
27
11:34
61.0
N/A
28
11:33
61.0
N/A
29
11:32
61.2
N/A
30
11:30
61.7
N/A
31
11:29
60.2
N/A
32
11:27
59.9
N/A

THERMAL PLUME MONITORING OE&RC-3227
Rev. 6
Page 15 of 18
<< BNP Thermal Plume Monitoring Log >> Al 1 AUHMEN 14
Page 2 of 2
Station
Time
Surface Temp.
Bottom Temp.
33
11:26
60.0
N/A
34
11:24
60.3
N/A
35
10:40
59.7
N/A
36
N/A
N/A
N/A
37
10:36
59.7
58.9
38
10:34
59.8
N/A
39
10:33
60.3
N/A
40
10:31
60.3
N/A
41
10:30
61.4
N/A
42
10:28
62.2
N/A
43
9:49
59.7
N/A
44
9:47
60.1
N/A
45
9:45
59.5
N/A
46
9:44
59.5
N/A
47
9:41
59.6
59.8
48
N/A
N/A
N/A
49
10:01
N/A
59.1
50
10:00
N/A
58.5
51
10:04
N/A
58.2
52
9:58
N/A
58.1
53
9:55
N/A
59.3
54
10:18
N/A
58.6
55
10:14
N/A
58.0
56
9:53
N/A
60.1
57
10:22
63.2
N/A
58
10:19
61.5
N/A
59
10:15
59.5
N/A
60
9:52
62.7
N/A
61
j 10:09
69.1
63.8
Ambient Temperature
Temperature Meter Serial Number:
Calibration Due Date:
Data Collected by:
Reviewed by:
Surface: 59.5 Bottom:
CP288734 Probe Serial Number: CP395923
1/24/2025
Wirth Wells, Ammon Babson, Kelli Davis
Drew A Petrusic, Environmental Field Support

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