View source for ST-HL-AE-3913, NPDES Noncompliance Notification:On 911010,several Hundred Dead Fish Discovered at Circulating Water Discharge Structure.Caused by Possible Chlorine Toxicity.Fish Specimens Delivered to Texas A&M for Exam

{{Adams
| number = ML20079L607
| issue date = 10/31/1991
| title = NPDES Noncompliance Notification:On 911010,several Hundred Dead Fish Discovered at Circulating Water Discharge Structure.Caused by Possible Chlorine Toxicity.Fish Specimens Delivered to Texas A&M for Exam
| author name = Jump W
| author affiliation = HOUSTON LIGHTING &amp; POWER CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000498, 05000499
| license number = 
| contact person = 
| document report number = ST-HL-AE-3913, NUDOCS 9111070004
| document type = NPDES NONCOMPLIANCE NOTIFICATION, TEXT-ENVIRONMENTAL REPORTS
| page count = 6
}}

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e The Light company llouston Lighting & I,ower _ South Texas Project 1.lec'_ric Generating Station _ _ _ . _ P.
_ _O.
_ _Box
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___Wadsworth,
_                      Texas 77183 October 31, 1991 ST-liL- AE- 3913 File No..          C26 U. S. Nuclear Regulatory Cominission Attention:          Document Control Desk Washington, DC             20555 South Texas Project Electric Generating Station Unit 1 and Unit 2 Docket Nos. STN 50-498 and STN 50-499 Special Report Regarding the October 1991 Fish Mortality in the Main Coolinn Reservoir Pursuant to                 outh Texas Project Electric Generating Station Operating License g p ndix B, Environmental Protection Plan (Nonradiological),
llouston Lighting & Power submits the attached Special Report regcrding the October 1991 Fish Mortality in the Main Cooling Reservoir. Appendix B of the 0;erating License requires that any occurrence of an unusual or important event that indicates or could result in significant environmentel impact causally related to plant operation be recorded and reported to the Nuclear Regulatory Commission within 24 hours followed by a report within 30 days of the occurrence of the nonroutine event.
If you should have any questions on this matter, pluse contact Mr. C. A. Ayala at (512) 972-9628 or myself at (512) 972-7205, 1!illck .Q William J . Jump Manager, Nuclear Licensing JMP/aaip Attachm,nt: Special Report Regarding the October 1991 Fish Mortality in the Main Cooling Reservoir
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,          ER M 01-291.001                   A Subsidiary of Il0uston Industries lDCOrporated                                                                \
9111070004 91103:                                                                                                                          /  t PDR   ADOCK 05000498
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ST IIL- AE 3913 lloulton Ligt;:ing & Pow-
                                ^
ompany                                                                                                      File No,: G26 Sout}} Tesas Projett Eleo.   ,er.c ati g Station                                                                                         Paco 2 CC' Regional Administrator, Region IV                                                                                    Rufus S. Scott Nuclear Regulatory Commission                                                                                       Associate General Counsel 611 Ryan Pla::a Drive, Suite 4C0                                                                                    llouston Lighting & Power Company Arlington, TX 76011                                                                                                  P. o, Box 61867 llouston, TX 77208 George Dick, Project Manager U.S. Nucl nr Regulatary Commission                                                                                   1NPO Washington, DC 20555                                                                                                 Records Center 1100 circle 75 Parkway J. I, Tapia                                                                                                          Atlanta, CA 30339-3064 Senior Resident Inspector c/o U. S. Nuclear Regulatory                                                                                          Dr. Joseph M. llendric Commission                                                                                                          50 Bellport Lane P, O. Box 910                                                                                                        Bellport, NY 11713 Bay City, TX 77414 D. K, Lacker J. R. Newman, Esquire                                                                                                  Bureau of Radiation Control Newman & lloltzinger, P.C.                                                                                           Texas Department of floalth 1615 L Street, N.W.                                                                                                    1100 West 49th Street Washington, DC 20036                                                                                                  Austin, TX 78756 3189 D   E. Ward /T, M Puckett Central Power and Light Company P, O. Bo:c 2121 Corpus Christi, TX 78403 J. C. Lanier/M. B. Lee City of Austin Electric Utility Department P,0, Box 1088 Austin, TX 78767 K. J. Fledler/M. T. liardt C.ty Public Service Board r, O. Box 1771 San Antonio, TX 78296 Revised 10/11/91 L4/NRC/

Attachment i                                                                                          ST llL-AE-3913 Page 1 of 4 South Texas Project Electric Cenerating Station Units 1 and Un't 2 Decket Nos. STN 50-498 and STN $0-499 Special Report Regarding the October 1991 Fish Mortality in the Main QIml.l i;gleaf rvoir
: 1. Etscrintion of Event on September 30, October 1-3, and October 10 of 1991 Unit 1 was in Mode 1 ac 100% power and Unit 2 was in Mode 6 at On power for a refueling outage except for October 10, 1991, when Unit 2 was in no mode for the refueling outage. On October 2, 1991, at approximately 0930 hours, several hundred dead fish at the Circulating Water-(CV)
                                                              -discharge structure were reported to site environmental personnel.
Upon investigation by site personnel, an initial estimate of 50,000 -
100,000 dead fish was obtained. These fish were located in the vicinity of the CW discharge structure and tnroughout the western portion of the Main Cooling Reservoir (MCR). The majority of fish vore concentrated on the banks of the west shoreline and the west embankment   ,
of the diversion dike.      The Corporate Environmental Department was immediately notified at approximately 1100 hours.
Corporate Environmental personnel arrived onsite at approximately 1330 hours and accompanied site personnel on an inspection of the         -
affected area. A subsequent estimate of 250,000 affec,ed fish, the l-                                                             majority of which was determined to be Atlantic croaker, dirgropogoning undultatus, was-obtained. .Other species obserre's were sand seatrout l-                                                             (Cynoscion arenarius), spot (Lpiostorue xanthurus), and blue catfish (Ictalurcs nunctatua). The latter three species couprised.less than 1%
of the population of dead 11sh. All the de J fish appeared to be in a similar stat- of decay and were estimated to have been dead approximately 24 - 48 hours. There was no initial indication        of an unusual-disease or parasite ..rvolved.
l                                                              At 1615_ hours, due to. initial indications of possible chlorine toxicity as a contributor to the cause of death, the Unit 2 Control Room was 8
nstructed to discontinue sodium hypochlorito injections to the CW and
                                                              - Open-loop Auxiliary Cooling Water System (OLACW) on both units. The Senior FRC Resident inspector was verbally informed of this occurrence.
The Texas Parks and Wildlife Department was airo notified.
Several . random specimens of the affected fiah were collected for subsequent necropsy examination prior to the departure of Corporate Enviro'erstal personnel from the site at approximately 1830 houra that same day. These specimens'were placed in an ice chest and transported to the HLAP Cedar Bayou Marine Lab.
SRTr\91-291.001

Attachment ST.HL AE 3913 Page 2 of 4 4        South Texas Project Electric Generating Station Units 1 and Unit 2 Docket Nos. STN 50 498 and STN 50 499 Special Report Regarding the October 1991 Fish Mortality in the Main Cooline Reservoir On October 3, 1991, the Nuclear Regulatory Commission (NRC) Operations Center was notified at 1152 hours of this occurrance, The Corporate Environmental Department contacted the Texas A&M University Veterinary _
Medical Diagnostic Laboratory concerning examination of the specimens                          ;
collected from the MCR. At the request of Texas A&M University, the specimens were delivered for examination on October 15, 1991. Texas A&M University Medical Diagnostic laboratory has conducted a literature search /research into chlorine lethality.
Site en 4ronmental-personnel continued to monitor the MCR.                Sodium hypo chlorite injections to CW and OLACW of both units sere resumed on Octokse J, 1991.      No additional fish mortalities were noted until approximately 0930 hours on October 10, 1991, when approximately 1,000 fish of various species were discovered to be dead or in various states                        I
                     -of distress. The Corporate Environmental Department was contacted and                          !
                     .several specimens were collected and immediately transmitted to the                            !
Texas A&M University Veteriusry Medical Diagnostic Laboratory for                              j
                     -examination. Sodium hypochlorito injections to CW and OLACV were once again discontinued, -Corporate environmental personnel arrived on site at approximately 1630 hours on this dato to review this additional.
mortality occurrence.. Verbal supplemental notificati.an was provided to the NRC.
A chlorination test was performed on October 11, 1991, to verify that free residual chlorine lovels were within expected ranges,                Following receipt of acceptable test data, chlorination was then -re sumed on -
                      .0ctober 11, 1991 with no noted deleterious results. As of October 30,
                     ~1991, no additional morta11 ties had been noteu,
                     =Neither of the_two mortality occurrences affected any plant systems.or secondary functions. These occurrences did not involve nny plant safety systems.
l CREP191-291. 001
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Attachment ST !!L AE 3913 Page 3 of 4 South Texas Project Electric Cencrating Station Units 1 and Unit 2 Docket Nos. STN $0 498 and STN $0 499 Special Report Regarding the October 1991 Ebb Mortality in the Main Cooline Reservoir II.      Cause of Event At this time the cause of this ove.t cannot be readily or conclusively determined. Investigations by site and corporate personnel into various plant conditions which might have caused or contributed to this event are ongoing. Areas currently under investigation include possible chemical toxicity such as might be attributed t.o chlorine levels in the CW/01ACW discharge and possible low dissolved oxygen in                           '
the vicinity of the CW/Ol>CW discharge structure. A preliminary assessment from the Texas A&M University Medical Diagnostic Laboratory has indicated that death of the species submitted fot' examination on October 10 -1991, was due to gill damage of unknown cauno. Texas A&M University is enn**nuing to conduct addi tional tests to determine the cause of the gic.       image. Subsequent areas of investigation and appropriate corrective actions will be identified following the receipt-
                  - of results of- the necropsies conducted on specimens from each occurrence.                                                                                      -
III.      Analysis of Event STPECS Operating License Appendix B, Environmental Protection Plan (EPP) requires that "Any occurrence of an unusual or important event that indicates or could- result in significant environmental impact causally related to plant operation shall be recorded and reported to the-NRC within 24 hours followed by a written report..." The written report is required to be submitted to the NRC'within 30 days of.the occurrence of .the nonroutine event, These. occurrences did not involve any plant safety system; therefore, no safety consequences resulted from these eventra These events-solely involved an environmental impact to various fish species la the MCR of unknown cause at this time. The STPECS MCR is completely enclosed within the plant owner controlled boundary and is not used for.
recreational or other public activities at any timo. The MCR is used solely as a plant heat sink. As such, no' National Pollution Discharge Elimination _ System (NPDES)-limit applies to the circulating water
                   ~ discharge to . the reservoi r.
EREP)91-291.001

l Attachment             !
ST-lit.- AE- 3913      l Page 4 of 4 South Texas Project Electric Cencrat ing Station               l Units 1 and Urft 2                              l Docket Nos. STN 50 498 and STN $0-499                    l Special Report Regarding the October 1991                  1 Einh Mertality in_thc Jinin Cooling Rmngit l
l IV. Correctir Actiotig                                                       I
: 1. On October 2,1991, modiurn hypochlorite addit.lon t o the CW and O!ACW systems of both unit s was suspended until Oct ober 8, 1991, when addition wau resumed. Solium hypochlorite addition was ' gain suspended on October 10, 1991, when additional fish mortalit.ics were identified.
: 2. On October 11. 1991, testing for free residual chlorine levels was performed to verify that chlorine residuals at ths point of discharge were not excessive. Sodium hypochlorito injections were resumed on this dato upon roccipt of acceptable data. Chlorine measure;nents are being performed routinely to verify system performence.
Additionel orrective actions will be identified and initiated as aceded.
V. Mhtilinpal Infpac11nn No previous signifi<.e.t ilsh mortalities of a similar nature have bacn reported at STPEGS.
EREP\Ul*291,001}}