DCL-2006-509, Request for Concurrence on Proposed Re-Routing of Storm Water at Diablo Canyon Power Plant

Request for Concurrence on Proposed Re-Routing of Storm Water at Diablo Canyon Power Plant

ML060790089
Person / Time
Site:	Diablo Canyon
Issue date:	03/03/2006
From:	Becker J Pacific Gas & Electric Co
To:	Briggs R Office of Nuclear Reactor Regulation, State of CA, Regional Water Quality Control Bd
References
DCL-2006-509
Download: ML060790089 (3)

Text

F 7I. Pacific Gas and Electric Company' Diablo Canyon Power Plant P.0. Box 56 Avila Beach, CA 93424 March 03, 2006 Certified Return Receipt

1. 7003 3110 0005 7002 5345 PG&E Letter DCL-2006-509 Roger Briggs Executive Officer California Regional Water Quality Control Board Central Coast Region 895 Aerovista, Suite #101 San Luis Obispo, CA 93401-7906 Request for Concurrence on Proposed Re-routing of Storm Water at Diablo Canyon Power Plant (DCPP)

Dear Mr. Briggs:

As required by DCPP's NPDES Permit Order No. 90-09, DCPP requests Executive Officer concurrence in the proposed re-routing of storm water described below. DCPP has started the preliminary steps in the construction of the site Independent Spent Fuel Storage Installation (ISFSI). One component of the project is to provide for the relocation of existing roadways immediately North of the DCPP South Warehouse (Warehouse B Building) further inland. The current intersection of the plant site access roadway, and the roadway that leads to the ISFSI area, is located near South Cove (Patton Cove), an area subject to degrading soils stability caused by a slow slide of earthen material toward Patton Cove. The roadway relocations being implemented as part of the ISFSI project should provide additional stability to this area.

As part of the overall effort to stabilize the Patton Cove area, DCPP proposes to re-route storm water run-off from the majority of the ridgeline watershed that currently outfalls at Discharge 006 to Discharge 005. The change will significantly reduce the volume of storm water currently directed to, and through, the Patton Cove bluff. Furthennore, with the potential for increasing soils instability in the area and associated potential for damage to engineered structures located within the Patton Cove bluff, reduction in the volume of transiting storm water would reduce the possibility for significant erosion and further destabilization of the bluff in the event of culvert or conduit degradation.

In accordance with Order No. 90-09, NPDES No. CA000375 1, Section D. Provisions, 6., Re-routing of in-plant waste streams identified in Finding No. 4 or shown on Attachment "C" may be made with the concurrence of the Executive Officer. Both storm water Discharge Points 005 and 006 are identified in Order No. 90-09 Finding No. 4 and on Attachment C.

The current DCPP NPDES Permit description for Discharge 005, Yard Storm Drains, Flow Variable, is:

"Storm water runofffromn the plant yardon the Unit 2 side of the radwvaste buildings and the vest side of the turbine buildings is dischargedto South Cove. This may occasionally include some firewater (see note 1), vashivater andstored water releases. Rain water and ivashwvaterfrom the rotorwvarehouse and adjacent areas is collected in a sumip and routed into this drainagesystem."

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PG&E Letter DCL-2006-509 Mr. Briggs, CCRWQCB March 03, 2006 Page 2 The current DCPP NPDES Permit description for Discharge 006, Storm Water Runoff, Flow Variable, is:

"Storm water runofffromn the Pacific Ocean side of the ridge to the southeast of the plant is discharged to South Cove. Storm water runofffrom the south warehouse, the shooting range, and a temporary parking lot also drains to this discharge."

The proposed re-routing will result in the "runofffroin the Pacific Ocean side of the ridge to the southeast of theplant" from Discharge 006 being re-directed to Discharge 005. The other components of

-Discharge&006-will re-main' utnchlang6d. B6th Discharge 005 iand Discharge 006 flow into Patton Cove.

Thus, there is no change to the receiving water for either discharge point. Further, the re-routing will not impact Permit Monitoring and Reporting Program requirements. Currently, Discharge 005 is subject to grease & oil analysis through an annual grab sample. This requirement would remain unchanged.

DCPP requests your concurrence with the proposed re-routing of a portion of storm water flow from Discharge 006 to Discharge 005. An enclosed statement has been provided to record and communicate your concurrence. A self-addressed, stamped envelope for return of the document has also been provided.

If you have any questions or concerns regarding this matter, or require additional information, please contact Bryan Cunningham of my staff at (805) 545-4439.

Si cerel James R. ecker Vice President- Diablo Canyon Operations andStation Director 2006509/bkc/kmo Enclosures

Pacific Gasand ng x Electric Company*

Diablo Canyon Power Plant P.0. Box 56 PG&E Letter DCL-2006-509 Avila Beach, CA 93424 Mr. Briggs, CCRWQCB March 03, 2006 Page 3 cc: w/ encl. Peter von Langen Environmental Scientist CCRWQCB 895 Aerovista, #101 San Luis Obispo, CA 93401-7906 w/o encl. California Department of Fish and Game

- -- 20 Lo wer Ragsdale, Suite 100 Monterey, California 93490 Resident Inspector, Terry Jackson U.S. Nuclear Regulatory Commission Diablo Canyon Power Plant 104/5 Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Dr., Suite 400 Arlington, TX 76011-4005 Director, Division of Reactor Projects U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Dr., Suite 400 Arlington, TX 76011-4005 U.S. Nuclear Regulatory Commission Document Control Desk

__Washington, D.C. 20555-