ML20064N073

Notifies of 820803 Release of Sodium Hypochlorite Solution Into Yard Drainage Sys.Cause Not Stated.Release Terminated on 820804.Monitoring Performed Until Diffusure Gate Discharge Returned to Compliance

ML20064N073
Person / Time
Site:	Sequoyah
Issue date:	08/31/1982
From:	Elashry M TENNESSEE VALLEY AUTHORITY
To:	Morlar J ENVIRONMENTAL PROTECTION AGENCY
References
NUDOCS 8209080220
Download: ML20064N073 (3)

Text

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TENNESSEE VALLEY AllillORITY K NOXVIL L l'. 'i t;NNI.*WI i t / "' d TVA Mailroom q AUG 311982 a 0Md p Mr. John Harlar, Chief Facilities Performance Branch U.S. Environmental Protection Agency Region IV 345 Courtland Street, NE Atlanta, Georgia 30365

Dear Mr. Marlar:

NOTIFICATION OF NONCOMPLIANCE WITli EFFLUENT LIMITATIONS - NPDES PERMIT NO.

TN0026450 - SEQUOYAll NUCLEAR PLANT Description of the discharge--Discharge Serial No. 007 - Yard drainage pond effluent to the diffuser pond. Two samples collected on August 4, at 12 a.m.

and 5:15 p.m. exhibited pli values of 9.5 and 9.1, respectively, exceeding the maximum permit limitation of 9.0 standard units (s.u.). The flow rate for this discharge was 4.6 MGD.

i

Two samples collected on the same date at 5

20 p.m. and 10:45 p.m. from the l diffuser gate discharge (DSN 024) contained total residual chlorine (TRC)

concentrations of 0.3 mg/L and 0.4 mg/L, respectively, - exceeding the maximum i- instantaneous permit limitation of 0.1 mg/L. The flow rate for this discharge was 852.6 MGD.

Ca'use and period of the noncompliance--During startup operations, the product from our sodium hypochlorite genera tion system was released into the yard drainage system. Approximately 1080 gallons of four percent by weight sodium

hypochlorite splution were released over a 12-hour period from August 3 until i the morning of August 4. This release resulted in both the yard pond discharge pil noncompliance and .the diffuser gate discharge TRC noncompliance.

Samples collected from DSN 007 on August 3 at 12_a.m. and August 4 at 10:50 p.m. exhibited pil values of 8.5 and 8.9 s.u., respectively. Therefore, the possible period of pH noncompliance was less than 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br />.

Monitoring for TRC from DSN 024 on August 4 at 10:45 a.m. and on August 5 at 2 a.m. revealed concentrations of less than 0.1 mg/L in both - samples.

l Therefore, the possible period of TRC noncompliance was less than 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />.

l The Tennessee riverflow past SQN during the periods of noncompliance .was

! approximately 43,000 cfs. Since the diffuser gate discharge during this time t

' was 1,300 cfs, the effluent was diluted by a factor of 33, assumgg complete mixing. _2This would result in a TRC concentration of 9 x 10 mg/L and 1.2 x 10 mg/L, respectively, at the edge of the-mixing zone. Based on the above information, we do not believe the TRC noncomplia'nce had any significant environmental impact on the Tennessee River.

- During the above periods of noncompliance, a number of dead fish were observed in the diffuser pond. Details of our investigation are presented in the enclosure.

8209080220 820031 sPDR ADOCK 05000327 f.)

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AUG 311982

?!r. John flarlar, Chief Steps taken to reduce, eliminate, and prevent recurrence of the noncomplyig discharge--The release from the hypochlorite system to the yard drainage system was terminated at 3 p.m. on August 4. Monitoring of TRC was performed at an increased frequency until the diffuser gate discharge returned to compiiance.

Operation of the hypochlorite generation system iias been terminated due to the high cost of hypochlorite production as compared to the cost of offsite purchasing.

In the event future commercial hypochlorite solution cost it. creases above our production cost, operation of the hypochlorite system will he reinstated.

Iloweve r , steps have been taken to route product solution from future system startups (e.g., for testing) to storage tanks without a reicase.

Sincerely, Original Signed By 11 Paul Semaioroach flohamed T. El- Ashry, Ph.D.

Director of Environmental Quality Enc osure cc Enclosure):

Mr. Harold R. Denton, Director (5)

Office of. Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Washingtor , DC 20555 rir. Jack R. FicCormick, liasin tlanager Chattanooga Basin Office Division of Water Quality Cont rol 2501 Flilne Street Chattanooga, Tennessee 37406 rir. James P 0'Reilly, Director Office of Inspection and Enforcement il.S. Nuclea r Regulat ory Commiss ion Region 11 101 Flarietta Street Atlanta, Georgia 30303 Tennessee Department of Public llealth Division of Water Quality Control 150 Ninth Avenue, North TERRA Building Nashville, Tennessee 37203

. ~

ENC _l.0SllRE On the morning of August 4 approximately 1,000 deail fish of several species were observed in the diffuser pond. A sample collected at the pond discharge (DSN 007) to the diffuser ponil at approximately 12 a.m. contained a TRC concentration of 5.0 mg/L and exhibited a pil of 9.5 s.u. Grab samples from the diffuser gate discharge revealed the following TRC concentrations:

DATE Title NilflBER OF SAtlPl.ES CONCENTRATION August 4 10-10:45 a.m. 4 <0.1 mg/l.

August 4 5:20 p.m. 1 0.3 mg/L August 4 10:45 p.m. 1 0.4 mg/l.

August 5 2:00 a.m. 1 <0.I mg/L Additional monitoring at various locations within the dif fuser pond indicated dissolved oxygen values ranging f rom 4.0 to 4.6 mg/L, pil f rom 6 0 to 6.9, and water temperature from 102 F to 104 F. Temperat ure data on August 2 through August 4 indicate the maximum recorded di f fuser ut e temperature was 104.5 F, maximum change in upstream-downstream river temperature was 3.2 F, and the maximum downstream river t empe ra t u re was 82.3 F. The diffuser gate temperature from July 1-August 1, 1982 ranged liom 102.7 F to 105.2 F.

Based on the above data and observations by a biologist f rom our Office of Natural Resources, we believe the death of these fish cannot he contributed to a single factor but was a cumulative effect from heat stress and chlorine exposure. Based on this data, we also believe there was no significant environmental impact to the Tennessee River as a result of the above events.

The dead fish were collecteil, categorized, anil disposcil of following notification of EPA, the State of Tennessee (Division of Water Quality Control and Wildlife J{esource Agency), and the Nuclear Regulatory Commission (NRC).