ML082050385

Special Report: Technical Specification 4.1, Appendix B, Unusual Fish Kill

ML082050385
Person / Time
Site:	Calvert Cliffs
Issue date:	07/23/2008
From:	Gaines J Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML082050385 (3)

Text

Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby , Maryland 20657 o NUcle: ~enera~ion Grouprg July 23, 2008 U. S. Nuclear Regulatory Commission Washi ngton, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos . 1 & 2; Docket Nos . 50-317 & 50-3 18 Spec ial Report: Technical Specification 4. 1, Appendix B, Unusua l Fish Kill REFER ENCE : (a) Calvert Cliffs Nuclear Power Plant, Environmental Protection Plan (Non-Radiological) Technical Specifications, Section 4.1 In accordance with Reference (a), Calvert Cliffs Nuclear Power Plant is submitting the following report as described in Attachment ( 1). This report documents the occurrence of a fish kill in the intake embayment.

The most probable cause of the death of the fish was low oxygen conditions in the intake .

Shou ld you have questions regarding this matter, please contact Mr. Jay S. Gaines at (4 10) 495-5219.

Very truly yours,

-:J?"\.S(-.><- ~---"

J~ . Gaines Director -- Licensing JSG/CAN/bjd

Attachment:

(I) Unusual Fish Kill Event at Calvert Cliffs Nuclear Power Plant cc: D. V. Pickett, NRC S. Gray, DNR S. J. Collins, NRC T. Boone, MDE Resident Inspector, NRC

ATTACHMENT (1)

UNUSUAL FISH KILL EVENT AT CALVERT CLIFFS NUCLEAR POWER PLANT Calvert Cliffs Nuclear Power Plant, Inc.

July 23, 2008

ATTACHMENT (1)

UNUSUAL FISH KILL EVENT AT CALVERT CLIFFS NUCLEAR POWER PLANT On June 23, 2008 Calvert Cliffs Nuclear Power Plant personnel identified a large number of dead fish impinged on the trash racks in the intake. The trash racks were cleaned and approximately 480 dead cow-nosed rays, Rhinoptera bonasus, were removed from the intake. This was determined to be a "significant event that indicates or could result in significant environmental impact causally related to station operation" thus was reported to the Nuclear Regulatory Commission (NRC) within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in accordance with Calvert Cliffs Nuclear Power Plant, Environmental Protection Plan (Non-Radiological)

Technical Specifications, Section 4. 1.

1. Describe, analyze, and evaluate the event, including extent and magnitude of the impact and plant operating characteristics.

An unusual number of dead fish on the trash racks in the intake was discovered at approximately 06:30 am on June 23, 2008 during normal operator rounds. Approximately 480 dead cow nosed rays, Rhinoptera bonasus, and a smaller number of other fish, were removed from the trash racks. The plant was operating at full power under normal conditions. The fish kill had no impact on power plant operation.

2. Describe the probable cause ofthe event.

The most probable cause of the death of the fish was low oxygen conditions in the intake.

3. Indicate the action taken to correct the reported event.

The fish were dead when found, no attempts were made to resuscitate. The dead fish were removed from the trash racks.

4. Indicate the corrective action taken to preclude repetition of the event and to prevent similar occurrences involving similar components or systems.

Calvert Cliffs Nuclear Power Plant has previously implemented a number of practices to reduce the potential for fish kills during periods of low ambient dissolved oxygen in Chesapeake Bay bottom waters which are typical during summer. These practices include:

• Removal of five panels in the baffle wall and replacement with 'screens' to allow surface water with higher dissolved oxygen concentration into the embayment area. These screens extend only a short distance (approximate ly two feet) below the surface of the water, providing a pathway for fish to escape the embayment area.

• Monitoring of dissolved oxygen levels in the intake.

• Continuous operation of the traveling screens during periods of low dissolved oxygen to improve fish survival.

• Operation of installed spray aeration pumps during periods of low dissolved oxygen to create areas of higher oxygen where fish can recover from the effects of the low oxygen.

These actions were in place on June 23rd, at the time of the observed fish kill. No additional actions were taken to preclude repetition of the event.

5. Indicate the agencies notified and their preliminary responses.

No other agencies were formally notified . The site's National Pollutant Discharge Elimination System permit, Special Condition N, requires the Maryland Department of the Environment and the Department of Natural Resources to be notified of fish kills only if they are substantial enough to cause modifications to plant operations. As stated above, no change to plant operations resulted from this event.