DCL-21-037, Annual Nonradiological Environmental Operating Report

Annual Nonradiological Environmental Operating Report

ML21118B011
Person / Time
Site:	Diablo Canyon
Issue date:	04/28/2021
From:	Gerfen P Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-21-037
Download: ML21118B011 (7)

Text

Paula Gerfen Site Vice President Diablo Canyon Power Plant Mail code 104/6/605 P.O. Box 56 Avila Beach, CA 93424 805.545.4596 Internal: 691.4596 Fax: 805.545.4234 A member of the STARS Alliance Callaway

• Diablo Canyon

• Palo Verde

• Wolf Creek April 28, 2021 PG&E Letter DCL-21-037 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Power Plant, Units 1 and 2 2020 Annual Nonradiological Environmental Operating Report

Dear Commissioners and Staff,

Enclosed is the 2020 Annual Nonradiological Environmental Operating Report for Diablo Canyon Power Plant, Units 1 and 2. This report is being submitted in accordance with Subsection 5.4.1 of the Environmental Protection Plan, Appendix B of the Facility Operating License Nos. DPR-80 and DPR-82.

PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this letter.

If you have questions concerning this report, please contact Mr. David Cortina, Chemistry and Environmental Operations Manager, at (805) 545-3517.

Sincerely, Paula Gerfen armb/50941710 Enclosure cc:

Diablo Distribution cc/enc: Donald R. Krause, NRC Senior Resident Inspector Samson S. Lee, NRR Project Manager Scott A. Morris, NRC Region IV Administrator Matthew T. Keeling, Executive Officer, Central Coast Regional Water Quality Control Board m

Pacific Gas and Bectric Company*

Enclosure PG&E Letter DCL-21-037 2020 ANNUAL NONRADIOLOGICAL ENVIRONMENTAL OPERATING REPORT DIABLO CANYON POWER PLANT, UNITS 1 AND 2 Pacific Gas and Electric Company April 2021

Enclosure PG&E Letter DCL-21-037 page 1 of 5

1. Introduction Pacific Gas and Electric Company (PG&E) has prepared the 2020 Annual Nonradiological Environmental Operating Report in accordance with the Environmental Protection Plan (EPP), which is Appendix B of Facility Operating License Nos. DPR-80 and DPR-82 for Diablo Canyon Power Plant (DCPP), Units 1 and 2, respectively. The report describes implementation of the EPP per the routine reporting requirements of EPP Subsection 5.4.1. PG&E remains committed to minimizing the environmental impact of operating DCPP.

2. Environmental Monitoring 2.1. Aquatic Issues Aquatic issues are addressed by the effluent limitations and receiving water monitoring/reporting requirements contained in the DCPP National Pollutant Discharge Elimination System (NPDES) permit. The NPDES permit includes applicable requirements of the California State Water Resources Control Board's Ocean Plan and Thermal Plan.

2.1.1. Routine Influent and Effluent Monitoring During 2020, DCPP submitted quarterly NPDES reports containing routine influent and effluent monitoring data and permit compliance summaries to the Central Coast Regional Water Quality Control Board (CCRWQCB). The reports were submitted electronically during the month following the end of each calendar quarter via the California Integrated Water Quality System (CIWQS), an internet database application. DCPP also submitted an annual NPDES report for 2020 to the CCRWQCB in February 2021 via the CIWQS application. The annual report contained monitoring data summaries in tabular and graphical form, and a summary of permit compliance and corrective actions, as applicable, for 2020.

2.1.2. Receiving Water Monitoring Program (RWMP)

The NPDES RWMP, required by the CCRWQCB, included the ecological monitoring, temperature measurements, and State Mussel Watch activities.

Environmental monitoring programs have recorded biological changes in the discharge area since plant start-up. These programs monitor intertidal and subtidal communities of invertebrates, algae, and fish in the discharge cove and at stations north and south of DCPP. During 2020, environmental monitoring continued under the revised RWMP.

The revised RWMP continued historical monitoring tasks, including

Enclosure PG&E Letter DCL-21-037 page 2 of 5 temperature monitoring, State Mussel Watch activities, and intertidal and subtidal surveys (with additional stations and increased sampling frequencies).

DCPP submitted the NPDES Receiving Water Monitoring Program:

2019 Annual Report (PG&E Letter No. DCL-2020-513) to the CCRWQCB and the NRC on April 30, 2020. The 2020 Receiving Water Monitoring Program Annual Report will be submitted by the end of April 2021.

The NPDES permit remains under administrative extension. In 2000, DCPP reached a tentative agreement with the CCRWQCB addressing current and future impacts on receiving waters from the power plant cooling water discharge. This agreement, and the associated NPDES permit renewal application, did not receive the expected approvals from the CCRWQCB in July 2003. Based on the tentative agreement at that time, future receiving water monitoring requirements would be reduced or potentially eliminated upon approval of a renewed NPDES permit.

Power plant wastewater discharge effluent monitoring would continue under a revised NPDES permit.

Resolution of all outstanding issues related to receiving water impacts and NPDES permit renewal currently remain pending. During 2020, significant progress was made toward resolution of the plant discharge impacts concern resulting in the negotiation of an updated agreement between PG&E and the CCRWQCB. Judicial review and approval of a final thermal discharge settlement is expected in 2021.

2.1.3. Thermal Effects Study DCPP submitted the final thermal effects comprehensive assessment report (PG&E Letter No. DCL-1998-585) to the CCRWQCB and the NRC in 1998.

2.1.4. 316(b) Studies DCPP submitted the final 316(b) Report, entitled 316(b) DemonStration Report (PG&E Letter No. DCL-2000-514), to the CCRWQCB and the NRC on March 1, 2000.

2.2. Terrestrial Issues 2.2.1. Herbicide Application and Erosion Control Herbicides are used as one component of an overall land vegetation management program that includes transmission line corridors and

Enclosure PG&E Letter DCL-21-037 page 3 of 5 rights-of-way. The company continues to use only herbicides registered by the Environmental Protection Agency and approved by state authorities, and applies them in accordance with all applicable regulations.

Another component of the vegetation management program is mastication. Mastication is utilized to reduce fuel loads, create fire breaks, maintain line clearance, and increase line of sight in rights-of-ways. Mastication is a vegetation management tool that reduces ground disturbance and is effective at controlling vegetation when used in conjunction with herbicides.

PG&E continues to implement erosion control activities at the plant site and in the high voltage transmission line corridors as part of an overall land management program. These erosion control activities consist of routine maintenance and prevention efforts performed periodically on an as-needed basis, including seasonal storm activity and wildfire damage repair as applicable.

2.2.2. Preservation of Archaeological Resources A. CA-SLO-2 Site Management Archaeological site CA-SLO-2 is managed in compliance with the Archaeological Resource Management Plan (ARMP) and Operating Procedure EV1.ID2. All projects undertaken within site CA-SLO-2, or immediately adjacent, are reviewed to determine whether archaeological deposits associated with the site are present and, if so, an impact assessment is completed. PG&E would invoke the notification and mitigation procedures identified in the ARMP if a project-related impact were identified.

The annual photo-monitoring of CA-SLO-2 was completed on November 17, 2020, by the PG&E Senior Cultural Resource Specialist.

Two contract archaeologists with Applied Earthworks accompanied the PG&E Senior Cultural Resource Specialist during the photo-monitoring effort. The Applied Earthworks archeologists were on-site conducting pedestrian surveys and archaeological site record updates as part of the Diablo Canyon Decommissioning - Cultural Resource Inventory and Study Plan (Enright et al. 2021[1]).

[1] Enright, Erin, Jasmine Kidwell, Richard Hanes, Diane Douglas, and Dennis McDougal (2021). Diablo Canyon Decommissioning - Cultural Resource Inventory and Study Plan. Prepared by Applied Earthworks for Pacific Gas &

Electric Co.

Enclosure PG&E Letter DCL-21-037 page 4 of 5 The overall condition of site CA-SLO-2 remains stable in locations away from the coastal bluff, with only minor changes observed since the last monitoring event completed in late 2019. Monitoring indicates that the low soldier-pile retaining wall constructed during 2018 in the west-central portion of the site along a steep road cut is functioning as designed. No new earthen slumping or erosion was observed, and the impacted location has revegetated in the interim. Location specific photographs and a monitoring summary are on file with PG&E. Notable events related to the management of CA-SLO-2 are summarized below.

Applied Earthworks collected additional information necessary to update the archaeological site record for CA-SLO-2, including photography, mapping, and characterizing prior disturbances based on historical aerial imagery. The information is synthesized in Enright et al.

(2021) as well as the updated site record provided as an appendix to the referenced report.

Cultural resource monitoring and condition assessment also occurred at CA-SLO-2 in relation to resurfacing the existing paved road that passes through and adjacent to the site (North Access Road Project).

Preconstruction survey and archaeological monitoring was conducted at the site in compliance with cultural resource conditions of approval in the associated road upgrade project permit. With exception of filing the final archaeological report (which encompasses several cultural sites, not just CA-SLO-2), all project permit conditions were met. An interim report was provided by SWCA Environmental Consultants in January 2021 to document progress on fulfilling project permit Condition of Approval-26 related to submission of a final report on cultural mitigation. Completion of the final report is expected May of 2021.

Replacement of the tubular steel pole (TSP) (Diablo Standby PP 01/B 230kV Structure) located on the southern margin of the cultural site took place over the course of two days in October 2020. The TSP replacement utilized the pre-existing pole foundation and structure guy wire anchors, avoiding impacts to previously confirmed buried archaeological deposits within CA-SLO-2. Planning, site preparation and implementation considered protection of the cultural site. Analysis of archaeological material excavated in 2019 related to exploratory work for the TSP replacement project remains ongoing. Completion of a final report on findings is expected late April 2021.

B. Northern Chumash Correspondence Outreach and coordination with the yak tityu tityu yak tilhini Northern Chumash Tribe of San Luis Obispo County in 2020 related to the

Enclosure PG&E Letter DCL-21-037 page 5 of 5 management of CA-SLO-02 was focused on the North Access Road Project and Diablo Standby PP 01/B 230kV Structure replacement project (reference previous section). PG&Es Senior Consulting Scientist for Cultural Resources served as the primary point of contact for engagement with the tribe during project planning and implementation phases.

3. Unusual or Important Environmental Events There were no unusual or important environmental events during 2020.

4. Plant Reporting Requirements 4.1. EPP Noncompliance There were no EPP noncompliances during 2020.

4.2. Changes In Station Design There were no changes in plant design or operation, tests, or experiments that involved an unreviewed environmental question or a change to the EPP.

4.3. Nonroutine Reports There were no nonroutine events during 2020 per the EPP; therefore, no nonroutine reports were submitted to the NRC.