DCL-2025-508, 2024 Annual Report on Discharge Self-Monitoring
| ML25111A101 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/26/2025 |
| From: | Rebel T Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation, State of CA, Regional Water Quality Control Bd |
| References | |
| DCL-2025-508 | |
| Download: ML25111A101 (1) | |
Text
Pacific Gas and Electric Company*
Oiablo Canyon Power Plant P.O. Box 56 Avila Beach, CA 93424 PG&E Letter DCL-2025-508 February 26, 2025 California Regional Water Quality Control Board Central Coast Region Attn: Monitoring and Reporting Review Section 895 Aerovista, Suite #101 San Luis Obispo, CA 93401-7906 Electronic Submission CIWQS Web Application In accordance with Order 90-09, NPDES No. CA0003751, the 2024 Annual Report on Discharge Self-Monitoring at Diablo Canyon Power Plant (DCPP) is provided. This letter, accompanying overview, and annual data summary tables and plots, have been attached to the California Integrated Water Quality System (CIWQS) web application data submittal for the period. Annual Discharge Monitoring DMR Forms are additionally incorporated in the CIWQS submittal (Summary DMR).
Facility Name:
Address:
Contact Person:
Job
Title:
Phone Number:
WDR/NPDES Order Number:
Type of Report: (check one)
Quarter: (check one):
Year:
Violation(s) (Place an X by the appropriate choice):
Diablo Canyon Power Plant P.O. Box 56 Avila Beach, CA 93424 Trevor Rebel Manager, Environmental Operations (805) 441-5435 Order No. 90-09, NPDES No. CA0003751 1st QUARTERLY ANNUAL IE!
4th 2024 (Annual Reports for DCPP are Jan-Dec)
D No (there are no violations to report)
[RI Yes zfZ-5
PG&E Letter DCL-2025-508 CRWQCB Central Coast Region February 26, 2025 Page 2 If Yes is marked (complete a-g):
a) Parameter(s) in Violation:
b) Section(s) of WDR/NPDES Violated:
c) Reported Value(s) d) WDR/NPDES Limit/Condition:
e) Dates of Violation(s)
(reference page of report/data sheet):
f) Explanation of Cause(s):
(attach additional information as needed) g) Corrective Action(s):
(attach additional information as needed)
Violation ID 1134388 - Deficient Monitoring Missed Monthly Sample - 001 P (Seawater RO System Blowdown) pH and TSS (May 2024)
Monitoring and Reporting Program No. 90-09 Effluent Monitoring NIA NIA (If "YES", see overview section of attached report)
See Section A.4.b of attached report -
May 31, 2024 (If "YES", see overview section of attached report)
See Section A.4.b of attached report - Responsible personnel out of office. Sampling responsibilities were mistakenly marked as completed in plant tracking systems.
(If "YES", see overview section of attached report)
See Section A.4.b of attached report - A make-up sample was collected and analyzed on June 27, 2024, and results were found to be within permit limits. To mitigate and prevent future missed sample collections, the DCPP Chemistry department has implemented the use of a standalone sample verification data sheet that will be tracked by electronic work practice.
PG&E Letter DCL-2025-508 CRWQCB Central Coast Region February 26, 2025 Page 3 I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. The results of the influent and effluent monitoring presented are the observed results of the measurements and analyses required by the monitoring program and is neither an assertion of the adequacy of any instrument reading or analytical result, nor an endorsement of the appropriateness of any analytical or measurement procedure. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.
If you have any questions or concerns, or require additional information, please contact Trevor Rebel at (805) 441-5435 Sincerely, Name:
Trevor Rebel
Title:
Manager, Environmental Operations - Diab/a Canyon Power Plant 2025508/nrh/srp/tdr
PG&E Letter OCL-2025-508 CRWQCB Central Coast Region February 25, 2025 Page 4 cc:
Hardcopy Print-Out of CIWQS Application Submittal:
Mahdi Hayes NRC Senior Resident Inspector U.S. Nuclear Regulatory Commission Diablo Canyon Power Plant 104/5 Regional Administrator Licensing Assistant, Operations Branch U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011 -4511 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555-0001
CIWQS Web Application Submittal Print Out and Attached Supporting Documents
eSMR PDF Report Summary: Annual SMR ( MONNPDES ) report for 2024 Summary: Annual SMR ( MON NPDES ) report for 2024 submitted by Trevor David Rebel (Environmental Manager) on 02/26/2025.
Facility Name:
PG&E Diablo Canyon Power Plant Waterboard Office:
Region 3 - Central Coast Report Effective Dates:
01/01/2024 - 12/31/2024 No Discharge Periods Name Diablo M-001 Diablo M-0010 Diablo M-00lF Diablo M-00lG Diablo M-00lH Diablo M-001I Diablo M-00lJ Diablo M-00 l K Diablo M-00lL Diablo M-00lM Diablo M-00lN Diablo M-00l P Diablo M-002 Diablo M-003 Diablo M-004 Diablo M-005 Diablo M-008 Diablo M-009 Diablo M-013 Diablo M-015 Diablo M-016 Diablo M-017 Diablo M-INF Self-Determined Violations No Violat ions Entered Attachments File Name Description Order Number:
R3-1990-0009 Case Worker:
Sara h Crable Dates Comments 01/01/2024 - 12/31/2024 Plant Seawater Evaporators no longer in service.
01/01/2024 - 12/31/2024 Plant Condenser Tube Sheet Leak Detection Dump Tank no longer in service.
01/01/2024 - 12/31/2024 Bio Lab Seawater Supply Line Valve Box not drained during 2024. No effluent discharaed.
01/01/2024 - 12/31/2024 Seawate r RO System Blowdown Line not drained during 2024. Discharge rarelv used.
File Description Date Uploaded File Size - 2024 DCPP Annual Report Overview Section.pdf 2024 Annual Summary Report on Discharge Monitoring at Diablo Can on Power Plant.
02/26/2025 110588 bytes Page 1 of 3
File Name - 2024 DCPP Annual Rpt Appendix-1 NPDES Discharoes.odf - 2024 DCPP Annual Rpt Append ix-2 Tabular &
Graohical Data.odf - 2024 DCPP Annual Rpt Append ix-3 RWMP Summarv.odf Cover Letter application/pdf Data Summary Analytical Results No Analytical Data Measurements Available/ Reported Calculated Values No Ca lculated Data Measurements Ava ilable/ Reported Lab Batches No Lab Batch Data Available/ Reported Questionnaire No Questionnaire Available Certificate File Description Date Uploaded File Size DCPP NPDES Permit Order 90-09 Discharge Points Table.
02/26/2025 7489 4 bytes Tabular and Graphical Summaries of Influent and Effluent 02/26/2025 372 639 bytes Monitorinq.
Summary of Receiving Water Monitoring Program (RWMP) 02/26/2025 82907 bytes Activities.
Title I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.
I certify that I am Trevor David Rebel and am authorized to submit this report on behalf of PG&E Diablo Canyon Power Plant. I understand that I am submitting the following report(s):
- Annual SMR ( MONNPDES J report for 2024 (due 02/28/2025)
I understand that data submitted in this report(s) can be used by authorized agencies for water quality management related analyses and enforcement actions, if required.
I am also aware that my user ID, password, and answer to a challenge question constitute my electronic signature and any information I indicate I am electronically certifying contains my signature. I understand that my electronic signature is the legal equivalent of my handwritten signature. I certify that I have not violated any term in my Electronic Signature Agreement and that I am otherwise without any reason to believe that the confidentiality of my password and challenge question answers have been compromised now or at any time prior to this submission. I understand that this attestation of fact pertains to the implementation, oversight, and enforcement of a federal Page 2 of 3
environmental program and must be t rue to the best of my knowledge.
Name:
Trevor David Rebel
Title:
Environmenta l Manager Page 3 of 3
ANNUAL
SUMMARY
REPORT ON DISCHARGE MONITORING AT THE DIABLO CANYON POWER PLANT (NPDES NO. CA0003751) 2024
PG&E Letter No. DCL-2025-508 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant TABLE OF CONTENTS OVERVIEW
SUMMARY
OF MONITORING PROGRAM A.
Monitoring of Plant Influent and Effluent
- 1. Monitoring Data
- 2. Facility Operating and Maintenance Manual
- 3. Laboratories Used to Monitor Compliance
- 4. Review of Compliance Record and Corrective Actions B.
Monitoring of Receiving Water
- 1. Ecological Studies at Diablo Canyon
- 2. In-Situ Bioassay C.
Sodium Bromide Treatment Program NPDES Discharge Points PAGE 1
1 1
2 2
5 5
5 6
APPENDICES Appendix 1 -
Appendix 2 -
Appendix 3 -
Tabular and Graphical Summaries of Influent and Effluent Monitoring Summary of RWMP Monitoring for 2024
2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant OVERVIEW This annual summary report follows the format used in quarterly monitoring reports. Analytical results below the respective analytical detection limit (ND or non-detect) are plotted as a "zero" value in accordance with ELAP guidance. Results between the analytical detection limit and reporting (quantitation) limits are plotted at the value and shown as 'DNQ' in the tabular summaries as is done for CIWQS reports. Less-than results are typically reported to express an average of values that include non-detects and at least one result greater than the respective reporting limit (RL). These less-than results are plotted conservatively at the RL. During 2024, discharges occurred from all discharge paths except 0011, 001 K, 016, and 017.
California Ocean Plan Table B substances that were not analyzed for have not been added to the discharge stream. The substances listed in Table B in the California Ocean Plan were each analyzed for and reported in the permit renewal application and application updates for Diablo Canyon Power Plant (DCPP) submitted in October 1994, January 2001, and April 2011. There have been no changes in activities conducted at the plant that would have significantly affected the results previously reported in the above referenced documents.
SUMMARY
OF MONITORING PROGRAM A. Monitoring of Plant Influent and Effluent
- 1. Monitoring Data
- a. Appendix 1 provides a list of discharge path names for ease of reference. Report Appendix 2 contains monitoring data in tabular and graphical form.
- b. Discharge 001 D (Liquid Radioactive Waste Treatment System) annual grab samples for lithium, boron, and hydrazine were collected in September and analyzed in October. Results were ND (< 50 ug/L) lithium, 220 mg/L boron, and ND (< 0.003 mg/L) hydrazine.
- 2. Facility Operating and Maintenance Manual Pacific Gas and Electric Company (PG&E) maintains a multiple volume Plant Manual at DCPP that contains procedures used for operation and maintenance activities at the plant, including those activities that relate to wastewater handling, treatment, sampling, analysis and discharge.
Plant procedures are prepared and reviewed by DCPP Staff and approved by Plant Management. The facility conducts biennial internal audits that review NPDES procedures contained in the plant manual, as well as procedure implementation adherence by responsible workgroups. Ongoing reviews of plant procedures are conducted to assure that the manual remains valid, current, and complete for the facility.
1
- 3. Laboratories Used to Monitor Compliance The following laboratories were used during 2024 for monitoring compliance. The laboratories are certified by the California Environmental Laboratory Accreditation Program (ELAP) for the analyses performed. To satisfy requirements of the ELAP biannual certification process, these laboratories take part in annual performance evaluation testing.
- a.
PG&E Chemistry Laboratory, DCPP, Avila Beach, California (EPA Lab# CA01036)
- b. Aquatic Bioassay Consulting Laboratories, Ventura, California (EPA Lab# CA00021)
- c. ALS Environmental, Kelso, Washington (EPA Lab# WA01276)
- e. Abalone Coast Analytical, San Luis Obispo, California (EPA Lab # CA01543)
- f.
E. S. Babcock & Sons, Inc., Environmental Laboratories, Riverside, California (EPA Lab# CA00102)
- g. BSK Associates, Fresno, California (EPA Lab# CA00079)
- i.
Weck Laboratories, Inc., Industry, California (EPA Lab# CA00211)
- j.
TestAmerica, Inc., St. Louis, Missouri (EPA Lab# MO00054)
- 4. Review of Compliance Record and Corrective Actions
- a. Circulating Water Chlorination/Bromination Monitoring The 2024 quarterly NPDES reports discuss chlorination cycles when discharge monitoring was interrupted. These events are listed below, with brief descriptions of the cause and respective corrective action. When these monitoring interruptions occurred, engineering evaluations were performed (as approved by the CCRWQCB January 13, 1994; PG&E Letter No. DCL-94-002).
Descriptions of these evaluations are included in the respective quarterly reports as applicable.
The evaluations concluded that discharge chlorine limits were not exceeded during these events.
Date Unit and Number of Cause Corrective Action Readings Replaced 1 /19/24 Unit-1 Biofouling of monitor.
Cleaned monitor and 1 Readings restored flow.
2/4/24 -
Unit-1 Biofouling of monitor.
Cleaned monitor and 2/6/24 11 Readings restored flow.
3/23/24 -
. Unit-1 Biofouling of monitor.
Cleaned monitor and 3/25/24 11 Readings restored flow.
1/4/24 Unit-2 Biofouling of monitor Cleaned monitor and 1 Reading restored flow.
1/28/24 Unit-2 Biofouling of monitor.
Cleaned monitor and 1 Reading restored flow.
2/4/24 -
. Unit-2 Biofouling of monitor.
Cleaned monitor and 2/6/24 13 Readings restored flow.
3/3/24 Unit-2 Biofouling of monitor.
Cleaned monitor and 2 Readings restored flow.
2
4/5/24 to Unit-1 4/8/24 12 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
5/15/24 Unit-1 5/17/24 12 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/1/24 Unit-1 6/5/24 14 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/12/24 Unit-1 6/13/24 5 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/17/24 Unit-1 6/19/24 5 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/23/24 to Unit-1 6/24/24 8 Readings Stuck Chart Recorder.
Fixed chart recorder.
6/28/24 Unit-1 6/29/24 6 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/2/24 Unit-2 6/3/24 6 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
6/23/24 Unit-2 6/24/24 8 Readings Stuck Chart Recorder.
Fixed chart recorder.
6/29/24 Unit-2 6/30/24 6 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
8/12/24 Unit-1 8/20/24 13 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
8/24/24 Unit-1 8/26/24 12 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
9/1 1/24 Unit-1 9/12/24 2 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
7/27/24 Unit-2 7/29/24 9 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
9/14/24 Unit-2 9/17/24 4 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
9/22/24 Unit-2 9/23/24 6 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
9/30/24 Unit-2 1 Reading Sample pump failure.
Repaired and restarted sample pump.
10/6/24 Unit-1 10/7/24 6 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
11/7/2024 Unit-1 1 Reading Biofouling of monitor.
Cleaned monitor and returned to service.
10/3/24 Unit-2 10/11 /24 15 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
10/15/24 Unit-2 10/16/24 4 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
10/20/24 Unit-2 10/23/24 9 Readings Biofouling of monitor.
Cleaned monitor and returned to service.
3
11/1/24 Unit-2 Biofouling of monitor.
Cleaned monitor and 1 Reading returned to service.
11/7/24 -
Unit-2 Biofouling of monitor.
Cleaned monitor and 11/8/24 6 Readings returned to service.
11/18/24-Unit-2 Biofouling of monitor.
Cleaned monitor and 11/22/24 4 Readings returned to service.
12/1/24 -
Unit-2 Biofouling of monitor.
Cleaned monitor and 12/2/24 4 Readings restored flow.
- b. Deficient Monitoring Violation On June 27, 2024, the DCPP Chemistry department discovered that the May 2024 001 P (Seawater RO System Slowdown) pH and TSS analysis were not performed. A phone call was made to the Water Quality Control Board Region 3 (RWQCB) office to inform them of the missed samples.
A make-up sample was collected and analyzed on June 27, 2024, and results were found to be within permit limits. To mitigate and prevent future missed sample collections, the DCPP Chemistry department implemented the use of a standalone sample verification data sheet that will be tracked by a recurring work order.
After this sampling error was reported in the 2nd quarter 2024 report, the RWQCB determined that it qualified as a deficient monitoring violation and subsequently added a violation to the 02 2024 SMR report.
- c. Discharge Exceedance Events No discharge constituent or criteria exceedance events occurred during 2024.
- d. Discharge Bypass Events No discharge bypass events occurred during 2024.
- e. Closed Cooling Water Releases During 2024, maintenance activities that required draining of closed cooling water systems were performed and are summarized below. PG&E received concurrence from the CCRWQCB in response to letters dated July 19, 1995 (PG&E Letter DCL-95-156), May 23, 1996 (PG&E Letter DCL-96-522),
and May 19, 1997 (PG&E Letter DCL-97-533) regarding the use of glutaraldehyde and isothiazolin to control microbiological growth and corrosion in DCPP's freshwater closed cooling water systems. Any drainage from these systems is discharged at a flow-rate such that the chronic toxicity level is below the "No Observable Effect Concentration" (NOEC) at NPDES Discharge 001.
The volumes of cooling water drained in 2024 from the intake cooling water (ICW), component cooling water (CCW), and service cooling water (SCW) systems are presented below. The glutaraldehyde (Glut) and isothiazoline (Isa) concentrations presented in the table are system concentrations, not concentrations at the point of discharge to receiving water.
Other analysis as applicable included total suspended solids (TSS) and oil and grease (O&G).
4
Date System Volume Glut lso TSS O&G Reason &
(gallons)
(mg/I)
(mg/I)
(mg/I)
(mg/I)
Comments 03/16/24 Unit-1 sew 121.8 n/a 0.370 n/a n/a Routine Maintenance 04/11/24 Unit-2 sew 4,130 n/a 0.360
<2.0
<1.4 Routine Maintenance 09/10/24 Unit-1 CCW 2,284 n/a
<0.250 n/a n/d Routine Maintenance 09/18/24 Unit-1 ICW 3,303 n/a n/a n/a n/a Routine Maintenance 12/09/24 Unit-2 sew 50 n/a
<0.250 n/a n/a Routine Maintenance
- f.
Errata During preparation of the Attachment 3 of the annual report, an error was discovered in the reporting of 3Q24 Chromium at discharge point 001. The value reported was 9 ug/L. 9 ug/L is below the reporting limit of DCPP's metals analysis by ICP. The number should have been reported as DNQ(9) on the eSMR. The reported value is the same, but the qualifier used was incorrect. This has been corrected in Attachment 3 of the annual report.
B. Monitoring of Receiving Water
- 1.
Ecological Studies at Diablo Canyon Marine ecological monitoring was continued during 2024 under the Receiving Water Monitoring Program (RWMP) as requested in a letter from the Central Coast Regional Water Quality Control Board (CCRWQCB) dated December 9, 1998, and as detailed in a letter from PG&E dated January 8, 1999 (DCL-99-503). This program includes tasks from the Ecological Monitoring Program (EMP) with additional stations and increased sampling frequencies. This program replaces the EMP and the Thermal Effects Monitoring Program (TEMP). Several one-year-only tasks outlined in the above letters were completed in 1999 and were not requested to be performed in 2024. Results of 2023 RWMP data collection were submitted to the CCRWQCB on April 23, 2024. A table in Appendix 3 summarizes requirements and completed monitoring tasks for 2024.
- 2. In Situ Bioassay Results of the Mussel Watch Program are reported to the CCRWQCB directly by the Moss Landing Marine Laboratories (administered by San Jose State University) in their periodic report for this program.
C. Sodium Bromide Treatment Program DCPP continued an integrated sodium bromide and "foul release coating" strategy to control macrofouling in the Circulating Water System (CWS). Both circulating water conduits of each Unit can be chemically treated simultaneously. Routine treatment consists of six 20-minute injections per day (at 4-hour intervals) of a blend of sodium bromide and sodium hypochlorite into the plant seawater intake conduits. Each injection attempts to achieve a target concentration range of 250 to 300 parts per billion (ppb) Total Residual Oxidant (TRO) at the inlet waterbox of the main steam condensers.
In conjunction with the chemical treatment program, untreated portions of the cooling water system were previously painted with a non-toxic "foul release coating" to reduce or prevent attachment of fouling organisms.
Discharge TRO, measured at the plant outfall, remained below NPDES limitations throughout 2024.
Typically, unit discharge TRO values during conduit treatments were between 20 ppb and 60 ppb.
5
Annual Discharge Monitoring Report APPENDIX 1 (Attachment 2 to 2024 Annual SMR)
DIABLO CANYON POWER PLANT NPDES DISCHARGE POINTS DISCHARGE NUMBER DESCRIPTION 001 Once-Though Cooling Water 001 A Firewater Systems 001 8 Auxiliary Salt Water Cooling System 001 C Discharge Deleted 001 D Liquid Radioactive Waste Treatment System 001 E Service Cooling Water System 001 F Turbine Building Sump 001 G Make-Up Water System Waste Effluent 001 H Condensate Demineralizer Regenerant 001 I Seawater Evaporator Slowdown 001 J Condensate Pumps Discharge Header Overboard 001 K Condenser Tube Sheet Leak Detection Dump Tank Overboard 001 L Steam Generator Slowdown 001 M Wastewater Holding and Treatment System 001 N Sanitary Wastewater Treatment System 001 P Seawater Reverse Osmosis System Slowdown 002 Intake Structure Building Floor Drains 003 Intake Screen Wash 004 Bio Lab and Storm Water Runoff 005,008,009,013,014, 015 Yard Storm Drains 006,007,010, 011,012 Storm Water Runoff 016 Bio Lab Seawater Supply Pump Valve Drain 017 Seawater Reverse Osmosis System Slowdown Drain
Annual Discharge Monitoring Report APPENDIX 2 (Attachment 3 to 2024 Annual SMR)
TABULAR AND GRAPHICAL SUMMARIES OF INFLUENT AND EFFLUENT MONITORING
2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001 TEMPERATURE (DEG F)
FLOW (MGD)
INFLUENT EFFLUENT DELTAT Month hiSh low av!
hiBh low 3VG hiSh avG hi~h low av~
JAN 60.6 53.8 56.5 79.7 72.6 75.2 19.J
]8.8 2486 2486 2486 FEB 58.2 56.6 57.4 77.3 75.5 76.3 19.1 18.9 2486 2486 2486 MAR 58.J 51.0 54.7 77.0 70.0 73.5
]9.7 18.8 2486 2486 2486 APR 54.4 48.6 52.3 74.3 65.0 71.2 19.9 19.0 2486 1239 1505 MAY 54.0 48.5 51.2 72.8 61.6 69.l 19.9 18.0 2486
]239 1713 JUN 54.7 49.2 51.8 73.9 68.3 70.9 19.3 19.1 2486 2486 2486 JUL 55.0 50.6 53.4 74.5 69.9 72.9 20.0 19.5 2486 2486 2486 AUG 56.6 52.8 54.2 77.8 72.8 74.5 21.3 20.3 2486 2004 2470 SEP 59.1 52.0 55.9 79.1 73.2 76.2 21.3 20.3 2486 1891 2396 OCT 61.0 53.2 57.6 80.5 72.1 76.8 20.4
]9.1 2486 1874 2441 NOV 55.3 52.4 54.0 74.J 71.1 72.7 18.8 18.7 2588 2486 2489 DEC 55.7 52.9 54.9 74.8 72.1 73.9 19.5 19.0 2486 2486 2486 limi t:
22 2760 The Influ ent and Effluent "high" and "low" tcmpcrture values correspond to the highest and lowest daily average value for that month. The Influent high and low temperature docs not ncccssn.rily correspond to the same day as the Effluent high and low temperature for that month. The "a,*g" temperature for Influent and Efflu ent is the average fo r the entire month. The Month ly Delta T "high" is the highest Delta T for a day of the month based on daily average Influent and Effluent temperature va lues. The 11avg 11 temperatu re is calculated from Influent and Effluent monthly avg values.
DISCHARGE 001 TOTAL RESIDUAL TOTAL CHLORJNE CHLORINE (daily max. ug/1)
USED (lbs/day)
Month high low avg high low avg JAN 69 0
48 475 0
345 FEB 62 42 49 446 283 434 MAR 74 41 54 446 166 407 APR 64 0
38 396 202 244 MAY 103 0
38 343 0
184 JUN 93 0
38 454 0
365 JUL 56 0
26 454 0
339 A G 37 14 27 526 149 464 SEP 52 12 24 666 86 436 OCT 57 13 31 756 200 619
'OV 87 17 42 698 389 495 DEC 54 14 33 557 259 Sil Note: The residual ch lorine limits in Permit CA0003751, Order 90-09, is an instantaneous max of 200 ug/1, and includes a tim e-bascd limit (per the Ocean Plan) which depends on the length of the respective chlorination cycle.
Page 1 of22 internal
2024 Annual Summary Report on Discharge Monito.-ing at the Diablo Canyon Power Plant DISCHARGE 001 METALS (monthly avg. ug/1)
CilROMilJM COPPER NICKEL Month Influent Efflu ent InOuent Effluent InOuent Effluent JAN ND(5)
ND(5)
ND(5)
ND(5) 16 21 FEB 11'0(5)
ND(5)
ND(5)
ND(5) 15 17 J\\1AR DNQ(9) 11'0(5) 11'0(5) 11'0(5) 14 24 APR ND(5).
ND(5)
ND(5)
ND(5)
ND(5)
ND(5)
MAY ND(5)
ND(5)
ND(5)
ND(5) 11'0(5) l\\'0(5)
JUN 15 17 ND(5)
ND(5)
DNQ(5) 11'0(5)
JUL 11'0(5)
DNQ(7)
ND(5)
ND(5)
))
12 AUG ND(5)
ND(5)
ND(5) 11'0(5)
ND(5) 11'0(5)
SEP ND(5)
ND(5)
ND(5)
ND(S)
ND(5)
ND(S)
OCT ND(5) l'l'D(5)
ND(5)
ND(5)
DNQ(5) l\\'D(5)
NOV l'l'D(5)
ND(5)
DNQ(5)
DNQ(5)
DNQ(5)
DNQ(G)
DEC ND(5)
ND(5)
ND(S)
ND(S)
ND(S)
DNQ(6) 6-rn onth median limit:
10 10 30 Note: Influent results presented only for comparison to effluent.
Influent Cr, Cu, Ni, are analyzed monthly, but are only required to be reported quarterly by permit.
Influent zinc is analyzed monthly and reported quarterly, but only required annually by permit.
DISCHARGE 001 VARIOUS ANNUAL ANALYSES (ug/1) 6-Mo. Med.
Parameter Influent Effluent Arsenic 1.41 1.33 Cadmium 0.036 0.031 Cyanide l'l'D(0.5) l'l'D(0.5)
Lead l'l'D(0.020) l'l'D(0.020)
Mercury DNQ(0.00045) 0.001 43 Silver DNQ(0.006)
ND(0.004)
Titan ium ND(0.74) 0.89
- Phenolic Compounds ND(J.031)
ND(J.031)
(non-chlorinuted)
- Phenolic Com pounds ND(0.567) l'l'D(0.567)
(chlorinated)
"'**PCB's ND(0.196)
ND(0.196)
- Results for analysis of 8 target compounds. The sum of the 8 detection limits is 3.03.
- Results for analysis of 6 target com pounds. The sum of the 6 detection limits is 0.57.
Effluent Limit 30 JO 30 10 0.2 2.9 none 150 10 none
- Detection limits shown are the sum of individual detection limits for 7 target compounds.
DISCHARGE 001 AMMONIA (as N) (ug/1)
Month TnOuent JAN ND(0.02)
FEB MAR APR ND(0.02)
MAY JUN JUL AUG SEP 0.064 OCT ov l'l'D(0.02)
DEC 6-month median hm 1t:
Page2 o/22 internal Efflu ent l'l'D(0.02)
ND(0.02) 0.061 0.067 3,060
- ZINC Innuent Effluent 11'0(5)
ND(5) 11'0(5)
ND(5)
DNQ(5)
DNQ(7)
ND(5)
ND(5)
DNQ(7)
ND(5) 11'0(5)
DNQ(9)
ND(5)
ND(5)
DNQ(6)
ND(5) 11'0(5)
ND(5)
ND(5)
ND(5) l'l'D(5) l'l'D(S)
ND(S)
ND(5) 70
Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC limit:
Discharge:
Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant MONTHLY pH (averages) 001 002 003 004 Influent Effluent 8.1 8.1 8.0 7.9 7.9 8.1 8.1 8.0 8.0 8.1 7.9 8.0 7.8 7.9 8.3 7.7 7.7 7.7 7.8 7.7 7.7 7.7 7.7 7.8 7.9 7.9 7.8 7.8 7.8 7.7 7.8 7.8 7.6 7.7 7.7 7.8 7.6 7.7 7.6 7.6 7.8 7.7 7.7 7.7 7.5 7.7 7.7 7.6 7.7 7.8 7.6 7.6 7.5 7.6 7.6 7.6 7.6 7.6 7.7 7.6 Discharee 00lF SUSPENDED OIL & GREASE (mg/I)
SOLIDS (mg/I)
Month hiGh a,,G hiGh a,*c JAN DNQ(l.5)
DNQ(l.5)
DNQ(2)
DNQ(2)
FEB DNQ(l.8)
DNQ(J.8) 5 5
MAR 5.6 5.6 6
6 APR 4.8 4.8
<5
<5 MAY DNQ(2.7)
DNQ(2.7)
DNQ(3)
DNQ(3)
JUN DNQ(l.8)
DNQ(l.8)
DNQ(3)
DNQ(3)
JUL DNQ(3.0)
DNQ(3.0)
DNQ(3)
DNQ(3)
AUG 6.3 6.3 DNQ(4)
DNQ(4)
SEP DNQ(J.9)
DNQ(l.9)
DNQ(2)
DNQ(2)
OCT DNQ(J.6)
DNQ(J.6) 6 6
NOV ND(J.4)
ND(J.4)
DNQ(4)
DNQ(4)
DEC DNQ(2.6)
DNQ(2.6)
JO JO limit:
20 15 100 30 OOJP 7.7 7.6 7.6 7.6 7.4 7.5 7.3 7.4 7.5 7.4 7.4 Note: "high" limits based upon Daily Maximum limits.
11avg" limits based upon Monthly A,*eragc limits.
DISCHARGE 001N (Monthly Summary of Weekly Data)
SUSPENDED GREASE & OIL (mg/I)
SOLIDS (mg/I) high low avg high low avg high ND(l.5)
ND(l.5)
ND(l.5) 15 6
10 DNQ(O.l)
DNQ(J.5)
ND(J.5)
DNQ(l.5) 4 3
4 DNQ(0.1)
ND(J.5)
ND(J.5)
ND(l.5) 9 5
7 DNQ(0.1)
ND(J.5)
ND(l.5)
ND(J.5) 16 4
12 DNQ(O.l)
DNQ(J.5)
ND(l.5)
DNQ(J.5) 33 14 24 DNQ(0.1)
DNQ(l.5)
ND(J.5)
DNQ(J.5) 16 8
11 DNQ(O.I)
DNQ(J.5)
ND(l.5)
DNQ(l.5) 8 5
6 DNQ(O.I)
DNQ(l.5)
ND(l.5)
DNQ(J.5) 19 4
9 DNQ(0.1)
DNQ(l.5)
ND(J.5)
DNQ(l.5) 14 8
11 DNQ(O.J)
ND(l.5)
ND(l.5)
ND(J.5) 18 6
12 DNQ(0.1)
DNQ(J.5)
ND(l.5)
DNQ(l.5) 13 7
10 DNQ(O.J)
DNQ(l.7)
ND(l.5)
DNQ(l.5) 11 8
9 DNQ(0.1) 20 15 60 3.0 Note: "high" limits based upon Daily Maximum limits. "avg" limits based upon l\\1onthly Average limits.
Page3 o/22 Jnternal SEITLEABLE SOLIDS (ml/I) low avg DNQ(O.l)
DNQ(O.J)
DNQ(0.1)
DNQ(0.1)
DNQ(O.l)
DNQ(O.l)
DNQ(0.1)
DNQ(O.l)
DNQ(O.J)
DNQ(0.1)
DNQ(O.l)
DNQ(O.I)
DNQ(O.l)
DNQ(O.l)
DNQ(O.J)
DNQ(O.J)
DNQ(O.l)
DNQ(O.J)
DNQ(0.1)
DNQ(O.J)
DNQ(0.1)
DNQ(0.1)
DNQ(0.1)
DNQ(O.l) 1.0
2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001D, H, L, F, METALS (avg. ug/1) 00!D oorn 00JL Month Ag Cd Cr Cu Ag JAN NO(0.39)
DNQ(0.11)
ND(2.6)
DNQ(J.J)
ND(5)
FEB MAR APR ND(0.39)
DNQ(0.14)
ND(2.6}
l9.0 ND(5)
MAY JUN JUL ND(0.39)
DNQ(0.20)
ND(2.6) 5.ll ND(5}
AUG SEP OCT ND(0.39)
DNQ(0.19)
ND(2.6)
DNQ(4.0)
ND(5}
'OV DEC limit: none Note: 001D, 001 Hand 00JL analyses performed on quarterly composites.
00lF analyses performed quarterly on a composite of weekly samples.
Cd Cr Cu Ag Cd Cr ND(5) 25 58 ND(5)
ND(5)
ND(5}
ND(5}
26 54 DNQ(5}
ND(5}
ND(5}
ND(5}
<10 28 15
'0 (5)
ND(5)
ND(5)
DNQ(8) 26 ND(5}
ND(5)
ND(5)
DISCHARGE 001D, II, L, F, METALS (avg. ug/1) 00!D Month Hg Ni Pb Z n Hg JAN ND(0.080)
ND(J.8}
DNQ(0.97)
JO DNQ(0.083)
FEB MAR APR ND(0.080)
ND(t.8)
DNQ(2.J}
71 ND(0.080)
MAY JUN JUL ND(0.080)
DNQ(l.9)
DNQ(!.2}
77 ND(0.080)
AUG SEP OCT ND(0.080)
DNQ(2.5)
DNQ(t.4}
99 ND(0.080)
NOV DEC lim it: none Note: 001D, 00JH and O0IL analyses perform ed on qua rterly composites.
00JF analyses performed quarterly on a composite of weekly samples.
oorn Ni Pb 24 ND(5) 19 DNQ(5) 11 DNQ(5}
DNQ(7}
ND(5)
Page4 o/22 Jnternal Zn 26 23 JJ 10 00lL Hg Ni Pb ND(0.080) ND(5)
ND(5)
ND(0.080) DNQ(S}
ND(5}
ND(0.080) DNQ(7}
ND(5)
ND(0.080)
ND(S}
ND(S) 00JF Cu Ag Cd Cr Cu N D(5}
ND(5}
- 0(5) 39 18 ND(5)
ND(5)
ND(5) 12 10 ND(5}
ND(5}
ND(5)
DNQ(9}
ND(5)
ND(5)
ND(5)
ND(5}
DNQ(5) DNQ(5) 00JF Zn Hg
'i Pb Zn NO(5}
ND(0.080) 45 ND(S}
67 ND(5)
ND(0.080)
ND(5)
ND(5) 42 ND(5)
N0(0.080) 36 ND(5) 15 ID(S}
ND(0.080)
ND(5}
ND(S) 14
Month OOID*
OOJG JAN
<5 ND(2)
FEB
<5 ND(2)
<5 ND(2)
APR
<5 ND(2)
MAY
<5 ND(2)
J1JN
<5 1D(2)
JUL
<5 ND(2)
AUG
<5 1D(2)
<5 1D(2)
OCT
<5 ND(2)
NOV DNQ(2) l\\'D(2)
<5 1D(2)
Limit:
30 30 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant MONTHLY TOTAL SUSPENDED SOLIDS Averages (mg/I)
OOIB 0011 OOJJ OOJ K OOIL ND(2)
ND(2)
ND(2)
ND(2)
ND(2)
ND(2)
ND(2)
ND(2) 1D(2)
ND(2) 1D(2) 25 1D(2)
ND(2)
ND(2)
ND(2)
ND(2) 7 ND(2) 1D(2) 1D(2)
DNQ(2)
ID(2)
DNQ(3) 1D(2)
DNQ(2)
DNQ(2) 30 30 30 30 30
- Discharges from 001D arc batched. l\\1onthly averages are now weighted.
Note: No discharges occu rred from OOll and OOJK during 2024.
Blank spots for other discharge points indicate that no discharge occurred during that particular month.
GREASE & OIL Averages by Month (mg/I)
Month OOID*
OOIG OOIB 0011 OOJJ OOJK OO!L JAN DNQ(l.4}
l\\'D(l.4}
l\\'D(l.4}
l\\'D(J.4)
FEB MAR ID(J.4)
APR ND(l.4)
ND(J.4)
ND(l.4)
ND(!.4)
ND(J.4)
MAY JUN JUL ND(l.4)
ND(l.4)
ND(J.4)
ND(l.4)
AUG SEP OCT ND(J.4)
ND(!.4)
ND(l.4) l\\'D(l.4)
15 JS 15 15 JS 15 JS OOIM DNQ(2)
ND(2) 1D(2)
D 'Q(2) 30 OOIM ND(l.4)
ID(l.4)
ND(l.4)
ND(l.4) 15
- Discharges from 00JD are batched. Averages are flow-weighted and calculated monthly. l\\1onthly averages arc averaged for quarter and reported.
Note: No discharges occurred from OOJJ and 001K during 2024.
Pages o/22 internal OOJP 002 003 ND(2) 21 JS 19 lJ 16 DNQ(2)
DNQ(2) 8 14 ND(2)
DNQ(2)
DNQ(2)
DNQ(2)
ND(2)
DNQ(2) 8 JI
<5 8
6 1D(2)
DNQ(2)
DNQ(2)
DNQ(2)
DNQ(3) 14 DNQ(2)
D Q(4)
ND(2)
DNQ(3)
]3 DNQ(2) 1D(2) 8 30 30 OOIP 002 003 004 ND(J.4) l\\'D(J.4)
ND(J.4)
ND(J.4)
ND(l.4) l\\'D(l.4)
ND(J.4)
ND(l.4)
ND(l.4)
ND(J.4) l\\'D(l.4)
ND(J.4) l\\'D(J.4)
ND(J.4)
ND(J.4)
ND(J.4) 15 15 15 15
2024 Annual Summary Report on Discharge Monitoring atthe Diablo Canyon Power Plant QUARTERLY ACUTE AND CHRONIC TOXICITY TESTING (toxicity units, tu. and tuJ ACUTE Test 6-Month Month Result Median JAN FEB 0.00 0.00 MAR APR MAY 0.00 0.00 J1JN JUL AUG 0.00 0.00 SEP OCT
'OV 0.00 0.00 DEC 6-rnonth median limit:
0.26 This parnmeter is monitored for the State Ocean Plan instead of the 1'TDES Permit. A value of 1.0 indicates no chronic toxicity.
Sludge Parameter Percent 1\\foisturc Total Kjeldahl Nitrogen Ammonia (N)
Nitrate (N)
Total Phosphorous pH Oil and Grease Boron Cadmium Copper Chromium Lead Nickel Mercury Zinc Volume DISCHARGE 00IN ANNUAL ANALYSES Result 98.7%
90000 mg/kg dry 13000 mg/kg dry DN Q(96) mg/kg dry 12000 mg/kg dry 7.3 s.u.
21 mg/L 650 mg/kg dry 1.9 mg/kg dry 720 mg/kg dry 8.9 mg/kg dry 8.0 mg/kg dry 17 mg/kg dry ND(0.63) mg/kg dry 800 mg/kg dry 0.30 tons dry Note: Annual samples were collected in October.
- STLC = Soluble Threshold Limit Concentration Page 6 of22 internal
l0XSTLC J0XSTLC J0XSTLC lOXSTLC lOXSTLC lOXSTLC None
90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001 INFLUENT Temperature (
0F}
-High
___._ Average
-Low 0.0 +-----+-----+-----+------l----+----+-----+-----+-----+----1---------1 JAN 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2024 The Innuent and E rnuent "high" and "low" temperture values correspond to the highest and lowest daily average value for that month. The Innuent high and low temperature does not necessarily correspond to the same day as the Ernuent high and low temperature for that month. The "avg" temperature for Ionuent and Ernuent is the average for the entire month. The Monthly Delta T "high" is the highest Delta T for a day of the month based on daily average Innuent and Ernuent temperature values. The "m*g" temperature is calculated from Innuent and Ernuent monthly avg values.
DISCHARGE 001 EFFLUENT Tempcratnre (
0 F}
-High
-Average
-Low FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2024 Page 7 o/22
.Internal
3000 2500 2000 1500 1000 500 0
JAN FEB MAR 15 10 5
2024 Annual Summary Report on Discharge Monitoring at the APR Diablo Canyon Power Plant DISCHARGE 001 EFFLUENT Flow{MGD)
MAY JUN JUL 2024 DISCHARGE 001 EFFLUENT Montbly Delta T (
0F)
AUG SEP Llmit
-High
--+--Average -Low OCT NOV DEC Limit 0+----+----+----+----+-----t-----t-----t-----t----+-----+---------1 JAN FEB MAR APR MAY JUN 2024 Page 8 o/22 internal JUL AUG SEP OCT NOV DEC
120 100 80 60 40 20 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001 Totll Chlorine Residl11ll, ug/1
--High
-+-- Average
-Low 0 N---------+-----+------n-----n----t".1------<,.,::::.---+-----+----+-----+-------l 800 700 600 500 400 300 200 100 JAN FEB MAR APR MAY JUN JUL 2024 Note: Values plotted at zero were below the reporting limit.
DISCHARGE 001 Totll Chlorine Used, pouads per dlly AUG SEP OCT NOV
--High
,-+--Average
-Low DEC 0l'f-------+-----+-----+---~----t".----~---+-----+-------+-----+-------l JAN FEB MAR APR MAY JUN 2024 Page 9 o/22
.Internal JUL AUG SEP OCT NOV DEC
12 8
6 4
2 2024 Annual Summary Report on Discharge Monitoring attbe Diablo Canyon Power Plant DISCHARGE 001 Copper (mont/Jly average, ug/1)
Pmnit Limit and R<portiDi Limit
-llflluent o------ ------------ ----------- -----------,- ----111,--------------+----*
JAN 35 Jan FEB MAR APR MAY JUN JUL AUG 2024 Note: The analyte was not detected at or above the detection limit for values plotted at zero.
The 6-month median limit (the most conservative limit) is plotted on this chart (this is also the analytical reporting limit).
The daily maximum limit for Copper is 50 ug/1.
Feb Mar Apr DISCHARGE 001 Nickel (monthly average, ug/1)
May Jun Jul 2024 Aug Note: The analyte was not detected at or above the detection limit for values plotted at zero.
The 6-month median limit (the most conservative limit) is plotted on this chart.
The daily maximum limit for Nickel is 100 ug/1.
Note: Several data points on this chart overlap.
Page l0o/22
.Internal SEP OCT NOV DEC Di&chargc -
Limit Allalytical Reporting Limit Sep Oct Nov Dec
80 60 50 40 30 20 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001 Zinc (moothly average, ug/1)
DiJchargcPcrmitLimit
--Efllucot
-- Analytical Rt:porting Limit 0,._ ___....,==----+----==~.-:::::::....--.,,:=------=::,,,,.,,._ __
.::::::.,~ =------<._-.....::::::::..,i~ ---..,_---~----6 18 16 14 12 8
6 4
2 JAN FEB MAR APR MAY JUN JUL AUG 2024 Note: The aualyte was not detected at or a hove the detection limit for values plotted at zero.
DISCHARGE 001 Chromium (moothly average, ug/1)
SEP OCT NOV DEC 6-Month M<dian and Analytical Rt:porting Limit 0 ------- ----- ----- ----a----+----__.r------n------ ---.....ca----------
JAN FEB MAR APR MAY JUN JUL AUG 2024 Note: The aualyte was not detected at or above the detection limit for values plotted at zero.
The 6-month median limit and the analytical reporting limit are the same (10 ug/1) and are plotted on this chart.
The daily maximum limit for chromium is 40 ug/1.
Note: Several data points on this chart overlap.
Page 11 o/22
8.4 8.2 7.8 7.6 7.4 7.2 7.0 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant pH
-001 lnllumt -001 Eflluml 6.8 +-----+-------+----+-----+-----+----+------+------+----+-----+-----;
JAN FEB MAR APR MAY Note: Several data points on this chart overlap.
3500 JUN JUL 2024 Discharge OCH Ammonia (as N, ug/1)
AUG SEP OCT NOV 6-MOnlh Median Llmit
-Efflumt 3000 a----- ----r- ---n~--- ---~ ----1:>-----r:-----r:11-----ID---~ ---n 2500 2000 1500 1000 500 0&-----,----------------6-----,--------4>------3----ft----G JAN FEB MAR APR MAY JUN JUL AUG SEP 2024 Note: The analyte was not detected at or above the detection limit for values plotted at zero.
Page 12 o/22 lnternal OCT NOV DEC DEC
25.0 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE OOlF Oil& Grease (Maximum, mg/1)
Daily MllimumLimit
-<>-MoDlllly AYcr3i"C Limit Sample Rt<ult (Maximum)
-Amlytial Rqxn:tin1 Limit 15.0 n-----n -----c>-----:>----*n -----<>-----<>-----D------o -----c>-----J----o 10.0 0.0 +------l-----l--------l----+-----+----+----+-----+-----l---=::,,...,,,::::........._---1 JAN 120 80 60 40 20 FEB MAR APR MAY JUN JUL 2024 Note: Values plotted at zero were below the detection limit.
DISCHARGE OOlF Suspended Solids (Maximum, mg/1)
AUG SEP OCT NOV DEC Daily Mllimum Limit
-<>- Mon1hly AYm,gc Limit Sample 11,:suh (Maximum)
Amlytial Rqx,rtioi Limit 0 l=~:::j~==t===:::t:~:=:::::::t=::::::3~===:::t:':""'::==~:':'::::=::::=E:::='.:::::j~==::t~=::!
JAN FEB MAR APR Note: Maximum values are plotted.
MAY JUN 2024 Page 13 o/22 internal JUL AUG SEP OCT NOV DEC
25 10 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001N Oil & Grease {mg/1)
-D2ily Mmnmml.imit
- MaDll,ly Avenge Limit
-DililyMmnmm
~
Avenge Analytical R<poJ'tini Limit 0 ~===~::::::::=-....--..-,===~~==~====~==~~==~::::::::~...-===~~==~
JAN 70 FEB MAR APR MAY JUN JUL AUG 2024 ote: Daily maximum and monthly average values overlap at several points on this plot.
DISCHARGE 001N Suspended Solids {mg/1)
SEP OCT NOV DEC Mmtthly Average Limit D2ily Maximum
-Average 60 13-----ffl------i;- ----n-----rn----- ---------n----:.-----o----- ----
50 40 30 20 10 ~---::::::~---=:$===:::-----
0 +-----+-------1----+-----+------11-----+-----+----l------+------+--------l JAN FEB MAR APR MAY JUN JUL AUG SEP 2024 Note: There is no limit for daily maximum values. The average values are below the monthly average limit.
Page 14 o/22 internal OCT NOV DEC
3.5 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001N Settleablt: Solids (m.J/1)
-Daily MnimumLimit
--0-- Mombly Av=ge Limit
-Daily Maximum
-+-- Average 3-----------------------------------------------------
2.5 2
1.5 1 o -----< >-----<>----<>-----<>-----<>----< >-----<>----<>----*<>-----< J1------o 0.5 o-===:::$===-===~===-===~===~==~===$:::==::::llit:::===~==~
JAN FEB MAR APR 25 20 15 10 5
MAY JUN JUL 2024 DISCHARGE 001D Quarterly Metals (ug/1)
AUG SEP OCT NOV DEC Silver Cadmium Chromium IIICopper 0 +-----'--,--------,-----,-~--""
......... -----,----"T'""--.,__J---.-------,,..........----,-~--
JAN FEB MAR APR MAY JUN JUL AUG 2024 Note: The aoalyte was not detected at or above the detection limit for values plotted at zero.
Page 15 o/22 Jnternal SEP OCT NOV DEC
300 250 200 150 100 50 2024 Aaaual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE 001D Quarterly Metals {ug/1)
Nickel Lead CZinc IIMercwy 0 +--
....... -f-----+----t-~--..._+---+----1--..... '-J..-t----+------+---
........__+----+---~
140 120 100 80 60 40 20 JAN FEB MAR APR MAY JUN JUL AUG 2024 Note: The analyte was not detected at or above the detection limit for values plotted at zero.
DISCHARGE OOlF Quarterly Metals {ug/1)
SEP OCT NOV DEC Silver Cadmium Chromium Copper 0 +--....... ~ ----+----+---'....... -+---+---~----L....L,_-+----+----+--'-..... 4----1----------l JAN FEB MAR APR MAY JUN JUL AUG 2024
'ote: The analyte was not detected at or above the detection limit for values plotted at zero.
Page 16 o/22
180 160 140 120 100 80 60 40 20 0
120 100 80 JAN FEB MAR 2024 Annual Summary Report on Discharge Monitoring at the APR Diahlo Canyon Power Plant DISCHARGE OOlF Quarterly Metals (ug/1)
MAY JUN JUL 2024 AUG SEP Note: The aoalyte was not detected at or above the detection limit for values plotted at zero.
JAN FEB MAR APR DISCHARGE 001H Quarterly Metals (ug/1)
MAY JUN JUL 2024 AUG Note: The aoalyte was not detected at or above the detection limit for values plotted at zero.
Page 17 o/22 lnternal SEP OCT NOV OCT NOV Mercury Nickel Lead Zinc DEC Silver Cadmium CJChromium II Copper DEC
50 45 40 35 30 25 20 15 10 5
0 25 20 15 5
JAN FEB 2024 Annual Summary Report on Discharge Monitoring at the MAR APR Diablo Canyon Power Plant DISCHARGE 001H Quarterly Mef1lis (ug/1)
MAY JUN 2024 JUL AUG SEP Note: The analyte was not detected at or above the detection limit for values plotted at zero.
DISCHARGE OOlL Quarterly Mef1lis (ug/1)
OCT NOV Mercury Nickel Lead Zinc DEC Silver Cadmium CJCbromium Copper 0 +----+----+------~------------1~ ----+-----+-----+-----+----+-----<
JAN FEB MAR APR MAY JUN JUL AUG 2024 Note: The analyte was not detected at or above the detection limit for values plotted at zero.
Page 18 of 22 lnternal SEP OCT NOV DEC
25 20 15 IO 5
2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant DISCHARGE OOlL Quarterly MetJls (ug/1) 0+-- ---1-----+----J----J 40 35 JAN FEB MAR APR MAY JUN JUL AUG 2024 ote: The analyte was not detected at or above the detection limit for values plotted at zero.
MONTHLY TOT AL SUSPENDED SOLIDS (A veragr:, mg/1)
SEP OCT NOV Mercury Nickel Lead Zinc DEC Moll!hly Avenge Limit
-OOID
-DOIG
-OOIH 30 -----~ ----t.,---- ---------ti----
- ----;a----- ----ut----------,111 25 20 15 IO 5.,.. ___...... ___.....,.,------,..----..... ---..... ---.......-----:::,,,""'-,~""-<,--+-----,A,---
0 L----<l-----<')----0-----<1>-----n-------n::::::::::=~-
_=:::::~-====dt:::::::::t::::::::i JAN FEB MAR APR MAY JUN JUL AUG 2024
'ote: Points on chart may overlap. Values plotted at zero were below the detection limit.
Page 19 of22 lnternal SEP OCT NOV DEC
40 35 2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant MONTHLY TOT AL SUSPENDED SOLIDS (Average, mg//)
MoD!bly Avenge Limit
-oou
-OOIL
-OOIM 30 ------------ -------------------------
25 20 15 10 5
0 b-====:::::::::~===:::::::..-0----6----0-----b----o----o---o----c.__-
---ci-===~
JAN 40 35 FEB MAR APR MAY JUN JUL AUG 2024 Note: Points on chart may overlap. Values plotted at zero were below the detection limit.
MONTHLY TOTAL SUSPENDED SOLIDS (A veragr:, mg/1)
-MoD!bly Av=ge Limit (OOIP & 002)
-OOIP
-002
-003 30 ----------- ----,--------------- ----- ---------mt-------t1- ---l'!II 25 20 15 6-~-...::-r<:~
10
~ ~---+- ---=~~:::::::sl:=~~~~=t;~===::::;;;;:~~~1::§:=-=!i:-==~~~=:6 JAN FEB MAR APR MAY JUN JUL AUG 2024 Note 1: Points on chart may overlap. Values plotted at zero were below the detection limit.
Note 2: Monthly average limit only applies to 001P and 002. 003 has no monthly average limit.
Page 20 o/22 lnternal SEP OCT NOV DEC
18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 18 16 14 12 10 8
6 4
2 0
18 16 14 12 10 8
6 4
2 0
2024 Annual Summary Report on Discharge Monitoring at the Diablo Canyon Power Plant QUARTERLY OIL & GREASE (Average, mg/1)
IJI JAN FEB MAR APR MAY JUN JUL AUG SEP 2024 Note: Values plotted at zero were below the detection limit. Less than values are plotted at the value.
QUARTERLY OIL & GREASE (Average, mg/1)
El II Ill
[I
[I Cl ll1 JAN FEB MAR APR MAY JUN JUL 2024 Note: Values plotted at zero were below the detection limit.
QUARTERLY OIL & GREASE (Average, mg/1)
Ill II r2 II All values were 0 JAN FEB MAR APR MAY JUN JUL 2024 Note: Values plotted at zero were below the detection limit.
Page 21 o/22 internal a
-OOIG OOIH
-Monlbly Average Limit II OCT NOV DEC 00IJ
-OOIL OOIM
-Momhly A-=gcLimit OCT NOV DEC OOIP
-002 003 004 MoD!bly Average Limit OCT NOV DEC
1.20 1.00 0.80 0.60 0.40 0.20 0.00 JAN
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FEB 2024 Annual Summary Report on Discharge Monitoring at the MAR Diablo Canyon Power Plant ACUTE AND CHRONIC TOXICITY APR
( 6-Month Mewan)
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MAY JUN JUL 2024 Page 22 o/22 internal
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AUG SEP c:::::::J Chronic Bioassay Results
_,_ 6-mo. Median Acute Limit
_.,_ Acute Bioassay Results Acute 6-month Median
~...
Annual Discharge Monitoring Report APPENDIX 3 (Attachment 4 to 2024 Annual SMR)
SUMMARY
OF RWMP MONITORING FOR 2024 RWMP 1st Survey 2nd Survey 3rd Survey Study Stations/
Completion Completion Completion Surveys Stations/
Stations/
Stations/
per Year Dates Dates Dates Horizontal Band Transects 14 / 4x Mar 8 May 29 Oct 20 Vertical Band Transects 5 I 4x Mar 8 May 11 Jul 23 Benthic Stations 8 I 4x Apr24 Aug 13 Oct 21 Fish Observation Transects 12 / 4x Apr19 Aug 27 Sep 9 Bull Kelp Census
- /1x n/a n/a n/a Temperature MonitorinQ 24 I **
Jan-Mar Apr-Jun Jul-Sep Diablo Cove census.
4th Survey Completion Stations/
Dates Dec 3 Nov 18 Nov27 Dec 10 Oct 29 Oct-Dec Temperature measured throughout the year at 20-minute intervals (14 intertidal and 10 subtidal stations).
CIWQS Web Application State DMR Forms (eDMR)
Incorporated with Annual CIWQS eSMR Report Submittal
NPDES Permit #: CA0003751 DMR NODls Feature - LS Monitoring Period 005-Y 01/01/2024 - 12/31/2024 008-Y 01/01/2024 - 12/31/2024 009-Y 01/01/2024 - 12/31/2024 013-Y 01/01/2024 - 12/31/2024 016-Y 01/01/2024 - 12/31/2024 017-Y 01/01/2024 - 12/31/2024 DMR Parameters Feature - LS:
001-Y Loe Sea Param Param Text Ql Q2 Cyanide, total 1
0 00720 (as CN)
Arsenic, total 1
0 01002 (as As)
Cadmium, total 1
0 01027 (as Cd)
Lead, total (as 1
0 01051 Pb)
Generated on 03/18/2025 at 07:03 PDT eSMR PDF Summary: DMR Facility: PG AND E DIABLO CANYON POWER PLANT NODI Code NODI Description B
Below Detection Limit/No Detection B
Below Detection Limit/No Detection B
Below Detection Limit/No Detection B
Below Detection Limit/No Detection C
No Discharge C
No Discharge Monitoring Period: 01/01/2024 - 12/31/2024 Cl C2 C3 Excur Analy Sample Count Freq Type NODI: B NODI: B 6 Month lnstantaneou Median s Maximum 1.33 ug/L 1.33 ug/L 6 Month lnstantaneou Annual GRAB Median s Maximum 0.031 ug/L 0.031 ug/L 6 Month lnstantaneou Annua l GRAB Median s Maximum NODI: B NODI: B 6 Month lnstantaneou Median s Maximum Page 1 of 6
NPDES Permit#: CA0003751 Facility: PG AND E DIABLO CANYON POWER PLANT Feature - LS:
001-Y Monitoring Period: 01/01/2024 - 12/31/2024 Loe Sea Param Param Text Ql Q2 Cl C2 C3 Excur Analy Sample Count Freq Type Silver, total (as NODI: B NODI: B 1
0 01077 6 Month lnstantaneou Ag)
Median s Maximum Titanium, total 0.89 ug/L 0.89 ug/L 1
0 01152 (as Ti) 6 Month lnstantaneou Annua l GRAB Median s Maximum Chlorinated NODI: B NODI: B 1
0 34034 phenols 6 Month lnstantaneou Median s Maximum Polychlorinated NODI: B NODI: B 1
0 39516 biphenyls 6 Month lnstantaneou (PCBs)
Median s Maximum Mercury, total 0.00143 ug/L 0.00143 ug/L 1
0 71900 (as Hg) 6 Month lnstantaneou Annual GRAB Median s Maximum Phenolic NODI: B NODI: B 1
0 78218 compounds, 6 Month lnstantaneou u nch lori nated Median s Maximum Generated on 03/18/2025 at 07:03 PDT Page 2 of 6
NPDES Permit#: CA0003751 Facility: PG AND E DIABLO CANYON POWER PLANT Feature - LS:
015-Y Monitoring Period: 01/01/2024 - 12/31/2024 Loe Sea Param Param Text Ql Q2 Cl C2 C3 Excur Analy Sample Count Freq Type 11.5 mg/L 11.5 mg/L 1
0 00556 Oil & Grease 30 Day Daily Annual GRAB Averaqe Maximum Generated on 03/1B/2025 at 07:03 PDT Page 3 of 6
NPDES Permit#: CA0003751 Facility: PG AND E DIABLO CANYON POWER PLANT Feature - LS:
01D-Y Monitoring Period: 01/01/2024 - 12/31/2024 Loe Sea Param Param Text Ql Q2 Cl C2 C3 Excur Analy Sample Count Freq Type Boron, total (as 220.0 mg/L 1
0 01022 B)
Daily Annual GRAB Maximum Lithium, tota l NODI: B 1
0 01132 (as Li)
Daily Maximum NODI: B 1
0 81313 Hydrazine Da ily Maximum Ge nerated on 03/18/2025 at 07:03 PDT Page 4 of 6
NPDES Permit#: CA0003751 Facility: PG AND E DIABLO CANYON POWER PLANT Feature - LS:
INF-Y Monitoring Period: 01/01/2024 - 12/31/2024 Loe Sea Param Param Text Ql Q2 Cl C2 C3 Excur Analy Sample Count Freq Type Cyanide, total NODI: B G
0 00720 (as CN)
Daily Maximum Arsenic, total 1.41 ug/L G
0 01002 (as As)
Daily Annua l GRAB Maximum Cadmium, total 0.036 ug/L G
0 01027
{as Cd)
Daily Annual GRAB Maximum Lead, total {as NODI: B G
0 01051 Pb)
Daily Maximum Silver, total (as NODI: Q G
0 01077 Ag)
Daily Maximum Zinc, total {as NODI: Q G
0 01092 Zn)
Daily Maximum Chlorinated NODI: B G
0 34034 phenols Daily Maximum Mercury, total NODI: Q G
0 71900 (as Hg)
Daily Maximum Phenolic NODI: B G
0 78218 compounds, Daily unchlorinated Maximum Generated on 03/18/2025 at 07:03 PDT Page 5 of 6
Certificate I certify under penalty of law that all data submitted, including attachments, were prepared under my direction in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of a fine or imprisonment, for knowing violations. I certify that I am Trevor Rebel and am authorized to submit this report on behalf of PACIFIC GAS and ELECTRIC COMPANY.
I understand that I am submitting an NPDES Discharge Monitoring Report (DMR) for the period ending 12/31/2024 and I understand that data submitted in this report can be used by authorized agencies for water quality management related analyses and enforcement actions, if required.
Entry of my name and title below indicate my certification of this report of my understanding of the above conditions.
Name: Trevor Rebel
Title:
Environmental Manager Date: 02/26/2025 - 16:22:55