L-2019-051, Unusual or Important Environmental Event - Turtle Mortalities - February 4, 2019 and February 11, 2019

Unusual or Important Environmental Event - Turtle Mortalities - February 4, 2019 and February 11, 2019

ML19058A222
Person / Time
Site:	Saint Lucie
Issue date:	02/27/2019
From:	Snyder M Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2019-051
Download: ML19058A222 (2)

Text

FEB. 2 7 2019 L-2019-051 10 CFR 50.4 10 CFR 50.36.b EPP 4.1 U.S. Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: St Lucie Units 1 and 2 Docket Nos. 50-335 and 50-389 Environmental Protection Plan Report Event Dates: February 4, 2019 and February 11, 2019 Unusual or Important Environmental Event - Turtle Mortalities On February 4, 2019 and February 11, 2019, a dead juvenile green sea turtle (Che/onia mydas) was recovered from the St Lucie Plant intake canal. A necropsy was performed on both turtles, and the mortalities were determined to be causal to plant operation.

The attached report is being submitted pursuant to the requirements of Section 4.1 of the St Lucie Units 1 and 2 Environmental Protection Plans to provide the description of the reportable sea turtle mortalities.

~~p Michael J. Snyder Licensing Manager St. Lucie Plant MJS/rcs Attachment CC

FDEP Siting Office Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

St. Lucie Units 1 and 2 L-2019-051 Docket Nos. 50-335 and 50-389 Attachment Environmental Protection Plan Report Page 1 of 1 Event Dates: February 4, 2019 and February 11, 2019 Unusual or Important Environmental Event - Turtle Mortalities DESCRIPTION OF THE EVENT On February 4, 2019 and February 11, 2019, a dead juvenile green sea turtle (Chelonia mydas) was recovered from the St. Lucie Plant intake canal east of the five-inch turtle barrier net. The necropsies determined that the mortalities were causal due to forced submersion.

The turtle that was recovered on February 4, 2019 was found to be moderately decomposed, and the turtle that was recovered on February 11, 2019 was observed to be substantially underweight.

CAUSE OF EVENT The most likely cause of the mortalities is that the juvenile turtles were entrained at the end of a breath cycle, and did not have enough air reserves to traverse the intake pipe. A contributing mortality factor may have been the effects of low water temperatures that have an amplified effect on small volume turtles or turtles with low body weight.

CORRECTIVE ACTION Water temperatures and low visibility make it more difficult to monitor for turtles on the barrier net. As a result, divers were mobilized to maintain the net free of biota build up, and biologists were deployed for additional net observations as well actively attempting to dip net resident turtles.

ACTIONS TO PRECLUDE FUTURE EVENTS Aggressive turtle monitoring and removal protocols remain in place; hourly inspections of the five-inch net and constant observations on the tangle nets occur during daylight hours. When visibility allows, staff biologists perform hand, and dip net turtle captures in an effort to minimize turtle residence time. Net cleaning activities are performed periodically to minimize biota buildup on the barrier net.

AGIENCES NOTIFIED The Florida Fish and Wildlife Conservation Commission (FWCC) was contacted on February 4, 2019 and February 11, 2019 in accordance with Marine Turtle Permit MTP-125 and the Site Environmental Protection Plan.

Due to the moderate decomposition of the turtle that was recovered on February 4, 2019, causality determination was deferred to the necropsy. The FWCC was updated on February 7, 2019 once the necropsy determined that the mortality was causal to plant operation.

A notification was made to the NRC on February 7, 2019 and February 11, 2019 per the requirements of 10 CFR 50.72(b)(2)(xi).