ML20245G897

NPDES Noncompliance Notification:On 880801,dead Fish Discovered in Intake Forebay & Sample of Intake Water Analyzed for Total Residual Chlorine.Caused by Release of Sodium Hypochlorite to Water.Levels within NPDES Limits

ML20245G897
Person / Time
Site:	Sequoyah
Issue date:	04/26/1989
From:	Schmierbach M TENNESSEE VALLEY AUTHORITY
To:	Stewart P TENNESSEE, STATE OF
References
NUDOCS 8905030258
Download: ML20245G897 (5)

Text

e j TENNESSEE VALLEY AUTHORITY KNOXVILLE, TENNESSEE 37902 APR 201989 Mr. Philip L. Stewart, Manager Chattanooga Field Office Tennessee Division of Water Pollution Control 2501 Milne Avenue Chattanooga, Tennessee 37406-3399 1

Cear Mr. Stewart:

SEQUOYAH NUCLEAR PLANI (SQN) - REPORTED DISCHARGE OF SODIUM HYPOCHLORITE - l AUGUST 1, 1988  !

lhe purpose of this letter is to document events related to the release of sodium hypochlorite at SQN which was reported to you on August 2,1988. The event was also reported to the National Response Center (Center) on the same day. The Center assigned report number 10465 to the event.

At 0240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />, on August 1, 1988, SQN Operations called the SQN Chemistry Laboratory Shift Supervisor to report that dead fish were found in the intake l forebay and to request that a sample of the intake water be collected and

, analyzed for total residual chlorine (TRC). Operations was initially concerned about the possible relationship betwee" W dying fish in the intake forebay and chlorination of the Essential Raw Cooling water (ERCW) system.

The requested sample was collected at 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> and measured 0.15 parts per i million (ppm) of TRC. At 0541 hours0.00626 days <br />0.15 hours <br />8.945106e-4 weeks <br />2.058505e-4 months <br />, Operations notified the Laboratory that the ERCW hypochlorite feed was aligned to the 2A and 28 strainers and to the 1B pump pit. The ERCW pumps were not taking suction from the 1B pit. This raised the question of where this hypochlorite was going. At 0609 hours0.00705 days <br />0.169 hours <br />0.00101 weeks <br />2.317245e-4 months <br />, l Operations reported that the hypochlorite feed to the 18 pit was being

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discontinued and that an ERCW pump was being started to evacuate the pit.

We do not know exactly when the hypochlorite addition to the 1B pit was begun. Based on entries in the Assistant Unit Operator (AU0) journal, pu ips P7 and PS (used to inject the hypochlorite) could have been aligned to the 1B pit for up to 57.56 hours6.481481e-4 days <br />0.0156 hours <br />9.259259e-5 weeks <br />2.1308e-5 months <br /> and 50.06 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, respectively. Both of these feed pumps are rated to deliver 35.0 gallons per hour at full stroke; however, P7 {

was set at 20 percent stroke and PS was running at 25 percent stroke during  !

this period. Both pumps were feeding a 10 percent solution of sodium hypochlorite which has a specific weight of 1.2. Based on the above  !

information, the maximum quantity of sodium hypochlorite which could have been released is 842 pounds, or 351 pounds per day. With a flowrate of 1000 million gallons per day through the intake forebay and without allowing for any of the chemical to be consumed, the release of this amount of hypochlorite to the intake would result in a TRC concentration of about 0.04 ppm in the intake. Therefore, the TRC value of 0.15 ppm became questionable.

1 8905030258 890426 [j PDR ADOCK 05000327 S PNU An Equal Oppoi tunity imployer j

APR 261989 Mr. Philip L. Stewart Ann McGregor of the Tennessee Division of Water Pollution Control visited the site on August 2,1988, to investigate the reported hypochlorite discharge and the fishkill incident. Relative to the hypochlorite incident, Ms. McGregor was given copies of the Chemistry Laboratory and AVO journals for the period of July 29 through August 1, and copies of design drawings 37W201-2 and 37W201-3 for the ERCW pumping station. Evaluation of the ERCW pump pit arrangement during her visit revealed that any hypochlorite escaping the inactive pump pit would be drawn into the active pump pits on either side (i.e., the hypochlorite would be drawn into the ERCW system and would not ese. ape into the river or intake forebay).

Analysis of the intake water on August 2, 1988, approximately 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> after the hypcchlorite was realigned, still indicated that TRC was present at 0.3 -

G.35 ppm. A sample was also collected from the dif fuser discharge on August 2; because, if chlorine were present in the intake forebay, the normal method of demonstrating TRC compliance in the diffuser discharge would not detect this chlorine. This sample was 0.15 ppm indicating that the discharge limitation for TRC was exceeded. Based on these results, TVA verbally a reported this as a noncompliance. These values and those reported for the W-0300 sample on August 1, were undoubtedly incorrect, but an explanation was not obvious.

During this same time period Chickamauga Reservoir was stratified and the water in the bottom of the reservoir was void of dissolved oxygen. Since the intake structure is designed to draw water of f the bottom of the reservoir, the water in the intake forebay was also void of oxygen. It is the absence of oxygen that has been credited with killing the fish. This conclusion was documented in an October 20, 1988 letter to you.

When reservoirs lack oxygen in the lower depths, manganese is released from organic matter in the sediment. An intake water sample collected during the week of August 2, 1988, contained 1.5 ppm of manganese. Because of documentation that manganese interferes with the N,N-diethyl-p-phenyl-endiamine titration method for TRC, it was concluded that the erroneous TRC results were caused by manganese interference with the analysis method.

Samples collected at the heat exchangers and analyzed for TRC showed that TRC values were within the National Pollutant Discharge Elimination System Permit limits. A copy of the TRC analysis and computation results for the period of July 24 through August 13 are enclosed. We have concluded that all of the chlorine injected at the ERCW station during this time period was drawn into the ERCW system and consumed. There was no unpermitted release of sodium hypochlorite. Therefore, a Notice of Noncompliance for the August 2 event was not submitted with the August 1988 Discharge Monitoring Report.

l APR 261989 I Mr. Philip L, Stewart l

4 If you or your staf f have any questions or comments regarding this letter, please contact Abraham V LoudermilE, Jr. , at (615) 632-6656 in Knoxville.

Sincerely, 1 1 - lh '

M. Paul Schmierbach, Manager Environmental Quality l

Enclosure cc (Enclosure):

Mr. Bruce R. Barrett, Director Water Management Division U.S. Environmental Protection Agency, Region IV 345 Courtland Street, NE. j Atlanta, Georgia 30365 Ms. S. C. Black, Assistant Director for Projects TVA Projects Division '

U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20952 1

Mr. F. R. McCoy, Assistant Director '

for Inspection Programs TVA Projects Division U..S. Nuclear Regulatory Commission ,

Region 11 101 Marietta Street, NW., Suite 2900 Atlanta, Georgia 30323 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 Mr. Garland P. Wiggins, Manager Industrial Facilities Section Division of Water Pollution Control Tennessee Department of Health and Environment Bureau of Environment TERRA Building 150 Ninth Avenue, North Nashville, Tennessee 37219-5404

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' APR 261989 Mr. Philip L Stewart

\ 1 cc (Enclosure):

U.S. Nuclear __ Regulatory Commission 1 Attention: Document Control ~ Desk ~ l Washington, D.C. 20555 i

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1 ENCLOSURE

, MEASURED AND CALCULATED TOTAL RESIDUAL CHLORINE AT SEQUOYAH NUCLEAR PLANT, I

TOTAL RESIDUAL CHLORINE .

TOTAL RESIDUAL CHLORINE DATE AT HEAT EXCHANGER (Measured) AT DIFFUSER (Calculated) 1988 (ma/L) (ma/L)

July 17 0.78 <0.10 July 18. 0.83 <0.10 3 July 19 0.80 <0.10 J July 20 0.68 <0.10 .I July 21 0.60 <0.10 f July 22 0.63 '<0.10 July 23 0.50 <0.10 July 24 0.70 <0.10 July 25 10.53 <0.10 July 26 0.60 <0.10  ;

July 27 0.15 <0.10 July 28 0.98 <0.10 July 29 1.00 <0.10 H July 30 0.24 <0.10 July 31 0.43 <0.10 August 1 0.66 <0.10 August 2 0.10 <0.10' August 3 0.11 <0.10 August 4 0.10 <0.10 August 5 0.10 <0.10 August 6 0.10 <0.10 During this time, the total residual chlorine (TRC) at the diffuser was calculated using an Essential Raw Cooling Water (ERCW) flow of 39.4 million gallons per day (MGD) and a Condenser Cooling Water. (CCW) flow of 1015.2 MGD. ,

The calculation is made by multiplying the ERCW flow times the TRC at the heat 'i exchanger and dividing by the CCW flow.

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