ML20115C584
| ML20115C584 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/09/1992 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9210190463 | |
| Download: ML20115C584 (2) | |
Text
.
k B ALTIMORE GAS AND ELECTRIC
+
CALVERT CLIFFS NUCLEAR POWER PLANT 1650 CALVERT CLIFFS PARKWAY
- LUSBY, MARYLAND 20657-4702 CHARLES V CRUSE PLANT GENERAL MANAGER cALVERT CLsFFS October 9,1992 U. S. Nuclear Regulatory Commission Washington,DC 20555 ATTENTION:
Docu.nent Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2: Docket Nos. 50-317 & 50-318 Technical Specification Annendix B Special. Report of Fish Kill Event Gentlemen:
1 Please find attached a special report required by our Technical Specification Appendix B, Section 4.1 i
describing a fish kill event that occurred on or about August 29,1992. The appropriate Maryland State and local authorities have also been notiGed of this event.
'?
Should you tave any further questions regarding this matter, we will be pleased to discuss them with
{
you.
Very truly yours, p
/
-?
/
g,,J. -
'/ s ;l1
,/t V
CHC/CDS/bjd Attachment cc:
D 3 rune, Esquire J. L', Silberg, Esquire
{
R. A Capra,NRC D. G. Mcdonald, Jr., NRC i
T. T. Martin, NRC 6
P. R. Wilson, NRC R. L McLean, DNR
?
J. H. Walter, PSC
{
Y i
b-fi M l;o d{
- ,p
, ' #p Lu0003 4
[.-(j/ }u />
)
h31v 9210190463 921009 r
g l
p,
$h PDR ADOCK 05000317 t
S PDR g
4-
"* ACllMENT(1)
TECilNICAL SPECIFICATION APPENDIX H SPECLAL REPORT OF FISil KILL EVENT On August 29,1902 striped bass (Morone saxatilis) began appearing on the trash racks of Calvert Cliffs Nuclear Power Plant. By the next day, approximately 250-260 striped bass we e removed from the racks. Most of the fish ranged from 20-36 inches in length. Very few fish weie collected after August 30,1992. The event had no impact on facility operations.
The event was investigated by Academy of Natural Sciences personnel.- We did not observe exactly when the Esh died. Ilowever, it ar pears the fish were dead for some time before drifting into the 9
trash racks. Prior to the event,larte numbers of striped bass were noticed in the embayment area. It appears the fish died due to low utssolved oxygen levels in the embayment area. On August 30,1992 oxygen levels were 0.8 ppm at the surface and 0.1 ppm at 3 meters below the surface. It is believed that the fish suffocated, sank to the bottom, then floated to the surface and drifted into the trash -
racks. Shoreline checks to determine if other areas around our plant were affected by the low dissolved oxygen event found only one dead fish. Again, these observations were made some time after the event actually began.
The plant embayment area is formed by curtain wall. Intake water for the plant is drawn under the bottom of the wall. During the summer months, some of the curtain wall panels are removed to allow the fish an egress to water with higher dissolved oxygen, if it exists, outside the embayment drCa. Ilowever, a Chain link fence covers a top section of these curtain wall openings to prevent debris from entering. Large fish cannot pass through this fence. During periods of declining dissolved oxygen levels it is rossible that the fish will not dive under the fence to escape the embayment area since they snd to seek higher dissolved oxygen levels near the water's surface.
Smaller fish able to pass through the fence ure much more likely to escape, thus accounting for the relatively large size of most of the fish found in the plant's trash racks. To address this problem, the fence on the curtain wall openings was cut off one foot below the mean low water level on September 1,1992. We anticipate that this modification will reduce the mortality rates of fish, especially large ones, during periods of declining dissol red axygen levels within the embayrnent area.
t.
1
_