ML20056G392

NPDES Noncompliance Notification:On 930710,13,14 & 25, Water Processing Facility (Wpf) Discharge Temp Exceeded Max Limitation of 74 Degrees F.Rev to NPDES Permit,Removing Temp Limits Approved & Wpf Chillers Removed from Svc

ML20056G392
Person / Time
Site:	Limerick
Issue date:	08/27/1993
From:	Boyce R PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Noll P PENNSYLVANIA, COMMONWEALTH OF
References
NUDOCS 9309030075
Download: ML20056G392 (5)

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PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION i P. O. BOX 2300  !

SANATOGA, PA 19464-2300 (215) 327-1200 EXT. 2000 ROBERT W. BOYCE tuNr u4u4aEs August 27 , 1993 UMERICK GENERATING STATION Mr. Peter G. Noll Department of Health Neshaminy Manor Center Doylestown, PA 18901

Subject:

Noncompliances with NPDES Permit Bradshaw Reservoir ,

NPDES Permit No. PA-0052221 j i

Dear Mr. Noll:

i During the month of July 1993, four noncompliances with NPDES Permit No. PA-0052221, Bradshaw Reservoir, occurred. All four ,

noncompliances resulted from the Water Processing Facility (WPP) 'I discharge temperature exceeding the permitted maximum limitaticn ,

of 74 degrees F. Each noncompliance is described below including i the causes and corrective actions.

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1. DESCRIPTION OF NONCOMPLIANCE NO. 1 r

On July 10, 1993, between 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> and 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, due to  !

extreme ambient conditions (heat wave), the WPF discharge 4 temperature exceeded the permitted limit of 74 degrees F.

The maximum temperature recorded during this time period has 75.2 degrees F. Discharge flow had been reduced as low as -;

possible in an attempt to maintain discharge temperature  !

below the permit limit. The minimum required East Branch '

Perkiomen Creek flow rate was maintained.  !

i CAUSE OF THE NONCOMPLIANCE -l The actual operating conditions on July 10, 1993,-were beyond the design basis conditions of the WPP. Prior to the i violation, the cooling equipment had been thoroughly checked -

and adjustments were made to ensure the full cooling capacity of the facility was being-achieved.

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1 Page 2 PREVENTION OF-A' FUTURE OCCURRENCE On July 29, 1993, a revision to the NPDES permit which removed all temperature limits was approved by the DER. On July 29, 1993, the WPF chillers were removed from service.

2. DESCRIPTION OF NONCOMPLIANCE NO. 2 At 1341 hours0.0155 days <br />0.373 hours <br />0.00222 weeks <br />5.102505e-4 months <br /> on July 13, 1993, the WPF chillers automatically shutdown due to a false low facility flow signal. Bradshaw flow was immediately reduced to the summer minimum East Branch Perkiomen Creek flow rate. During the next 1 1/2 hours attempts were made to restart the chillers; however the chillers tripped twice again on low facility flow. At 1510 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.74555e-4 months <br />, the low facility flow shutdown signal was bypassed, thereby allowing the chillers to continue to operate. As a result of this transient, the discharge temperature limit of 74 degrees F was exceeded for approximately two hours, with the maximum instantaleous temperature reaching about 83 degrees F.

CAUSE OF THE NONCOMPLIANCE The unexpected chiller shutdowns were caused by an erratic facility inlet flow signal. The cooling equipment automatically shuts down when measured inlet flow drops to 8000 gpm to prevent the evaporator pumps from emptying the facility reservoirs.

The erratic flow signal was believed to be due to debris on the paddlewheel of the inlet flow sensor. Several hours later the signal returned.to normal. Facility design did not adequately address this potential problem.

PREVENTION OF A FUTURE OCCURRENCE On July 14, 1993, a time delay was incorporated into the control system for low facility flow shutdown. This was done

.to prevent future shutdowns when the inlet flow signal drops below 8000 gpm momentarily. No additional unexpected shutdowns on low facility flow have occurred since the incorporation of this time delay. Since the NPDES permit was revised on July 29, 1993, the WPF chillers will no longer be operated and the erratic flow signal will no longer affect permit compliance.

3. DESCRIPTION OF NONCOMPLIANCE NO. 3 At 2231 hours0.0258 days <br />0.62 hours <br />0.00369 weeks <br />8.488955e-4 months <br /> on July 14, 1993, the Bradshaw Reservoir pumps tripped during an electrical storm and subsequently the WPF chillers shutdown by design on low facility flow. During the process of restarting the chillers after the Bradshaw Reservoir pumps automatically restarted, the discharge temperature exceeded the limit of 74 degrees F, with the maximum instan'taneous temperature reaching about 82 degrees

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F'. Temperature was stabilized below 74 degrees F by 2305 l hours. Shortly thereafter, it was recognized that the 3 Bradshaw Reservoir pumps would have to be shutdown in order j to select a different lead pump such that the required number of pumps could be operated.  ;

.i At 0030 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> on July 15, 1993, the Bradshaw Reservoir. pumps [

were shutdown, and the pumps were restarted at 0040 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br />. E While attempting to restart the WPP chillers as the Bradshaw .!

flow was gradually being increased, all three chillers

tripped immediately after starting. This caused a 30 minute restart lock-out for motor protection. As a result,  :

discharge temperature exceeded the 74 degrees F limit with a j maximum temperature of 82 degrees P from 0110.to 0220 hours0.00255 days <br />0.0611 hours <br />3.637566e-4 weeks <br />8.371e-5 months <br />, '

while the required summer minimum East Branch Perkiomen Creek '

flow rate was being maintained. -

CAUSE OF THE NONCOMPLIANCE:

The temperature limit violation on July 14, 1993, was due to i written instructions for the WPF system not being fully i followed. Contrary to recently provided training and written  !

instructions available in the Main Control Room, Bradshaw l flow was not gradually increased to match cooling capacity as l the chillers were being restarted. [

The causes of the chiller trips resulting in the July 15, 1993 temperature limit violation were spurious and are indeterminant. Each chiller subsequently restarted without j incident. '

PREVENTION OF A PUTURE OCCURRENCE: )

5 The individual involved in the July 14, 1993, violation was i counseled regarding the need for attention to detail when following instructions.

The cause of the chiller trips which resulted in the July 15, i 1993, violation is indeterminate. As stated previously, ,

operation of the WPP chillers is no longer required by the l NPDES permit as of July 24, 1993. Therefore, no long term - i corrective actions to prevent recurrence are planned. [

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4. DESCRIPTION OF NONCOMPLIANCE NO. 4:  :

r on July 25, 1993, while attempting to repair a communication-failure with one 10 cal control unit (LCU) at the WPF, numerous unexpected control system anomolies occurred. Large  ;

motors were unexpectedly shutting off and on, and valves were j cycling open and closed. In order to prevent serious i*

equipment damage and personnel injury, the entire facility had-to be temporarily shutdown at 1540 hours0.0178 days <br />0.428 hours <br />0.00255 weeks <br />5.8597e-4 months <br />. As a result, ,

discharge temperature exceeded the 74 degrees P limit with a  !

maximum temperature of 76.5 degrees P for about two hours l (from 1540 to 1740 hours0.0201 days <br />0.483 hours <br />0.00288 weeks <br />6.6207e-4 months <br />) while the summer minimum East  ;

Branch Perkiomen Creek flow rate was being maintained. By  ;

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Page 4 1740 hours0.0201 days <br />0.483 hours <br />0.00288 weeks <br />6.6207e-4 months <br />, the control system was returned to normal and the chillers were returned to service.

• This event is considered to be an allowable " bypass" (water ,

being diverted from cooling equipment) which met the criteria specified in Part B, Section 1.e(2) of the NPDES permit for ,

the following reasons:

i o The problems encountered requiring the facility shutdown could not have been reasonably anticipated.

o Serious equipment damage which would have jeopardized .

the ability of the cooling equipment to function f subsequently for permit compliance could have occurred. 'l o Operation of the WPF chillers on July 25, 1993,' required -

personnel to be physically in the vicinity of high ,

voltage and high speed rotating equipment. Therefore, -5 personnel were susceptible to injury.

CAUSE OF THE NONCOMPLIANCE:

i The cause of this noncompliance is believed to be a  !

combination of an equipment failure (i.e., LCU) and either errors made by technical personnel during the repair process i or an additional failure of the computer system during the 1 repair process.

PREVENTION OF A FUTURE OCCURRENCE:

As previously indicated, operation of the WPF chillers is no 'j longer required. However, we recognize the generic ,

implications of the LCU failure. Therefore, an investigation .

of the LCU failure and repair process problems will continue j since the Ozone Disinfection System utilizes LCUs and is ,

required to remain in operation. When the investigation is I complete, appropriate corrective actions will_be implemented ,

as necessary. 1 If you have any questions please contact Jim Kantner at 327-1200 extencion 3400. .

i Sincerely, l

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cc: U.S. Nuclear Regulatory Commission  !

Document Control Desk Docket-Nos. 50-352/50-353 ,

Washington, D.C. 20555 .

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'T. T. Martin i Administrator, Region I, USNRC [

Docket Nos. 50-352/50-353 i N. S. Perry l USNRC Senior Resident Inspector, LGS

Docket Nos. 50-352/50-353 l J. A. Feola -!

Pennsylvania Department of Environmental Resources '

Regional Water Quality Manager l Lee Park, Suite 6010 l 555 North Lane '

Conshocken, PA 19428 -

Program Management Section (3WM52)  ;

Permits Enforcement Branch Environmental Protection Agency

• Water Management Division Environmental Protection Agency Water Permits Section '

Region III 841 Chestnut Building Philadelphia, PA 19107 h

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