ML20206F691

Forwards 180-day follow-up Rept on 981102 Release of RQ for Sodium Hypochlorite

ML20206F691
Person / Time
Site:	Limerick
Issue date:	04/28/1999
From:	Gallagher M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Suevo D PENNSYLVANIA, COMMONWEALTH OF
Shared Package
ML20206F695	List: ML20206F691
References
NUDOCS 9905060209
Download: ML20206F691 (1)

Text

b Michael P. Gallagher, P.E.

Plant Manager Limznck Generating Station PECO NUCLEAR ecco sa 'av campa"v Limerick Generating Station

.'. A Unit of PECO Energy Q23PA 19464 0920 610 718 2000 April 28,1999 l

Ms. Donna Suevo PA Department of Environmental Protection Division of Storage Tanks Lee Park, Suite 6010 555 North Lane

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Conshohocken, PA 19428

Dear Ms. Suevo:

.- On November 2,1998, the Umerick Generating Station reported the release of an RQ for l

sodium hypochlorite. The National Response Center Case Number is 462231. The attached 180-day follow-up report is being sent to meet the requirements set forth in Section 304 (c) of EPCRA (42 U.S.C.11004 (c), and Section 206 (d) of the Hazardous Material Emergency Planning and Response Act (35 P.S. 6022.206 (d)).

If you have any questions regarding this issue please contact Anthony Filippino at (610) 718-2509, Sincerely, Michael P. Gallagher Plant Manager l

MPG:AJF l

ec.

M. Alfonso, Manager Chemistry /Radwaste W. Coyle, Manager Radwaste/ Environmental.

A. Filippino, Environmental Coordinator i

'J. Rogan, PECO Corporate Environmental Affairs i

-Q3 H.J. Miller, US Nuclear Regulatory Agency Document Control Desk, US Nuclear Regulatory Agency

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.e 9905060209 990428 9 DR ADOCK 0500 2

LIMERICK GENERATING' STATION Sodium Hypochlorite Spill and Clean-up Final Report April 1999 4

Approved by:

Prepared by:

/

Anthony J. Filippino LGS Environmental Coordinator Michael'P. Gallagher Plant Manager

I i-Table of Contents Section Title

- 1.0

' Introduction 2.0 :

. Site Description and Location 3.0 Site Assessment -

'3.1-Immediate Response 3.2 Cleanup and Restoration 3.3 Final Restoration 3.4 Waste Removal 4.0 Conclusion and Recommendation Appendix A-Site Map l

Appendix B Site Photos l :.

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F FINAL REPORT SUBMITTED BY THE LIMERICK GENERATING STATION 1.0 Introduction in response to a small leak discovered on the LGS Unit i sodium hypochlorite tank, the decision was made to remove and replace the existing tank. A temporary tank and containment system were rented and the contents of the leaking tank were transferred to the temporary tank. The task was ccmpleted on Tuesday, October 27,1998. On November 1,1998 at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br />, the tank -

level indicator recorded a steady drop in product level within the temporary tank. The product level in the tank did not drop below the low-levol indicator limit and no alarms were sounded. The release was detected by Station personnel on November 2,1998 at 0618 hours0.00715 days <br />0.172 hours <br />0.00102 weeks <br />2.35149e-4 months <br />.

The release, which was caused by a chem;cally incompatible fitting, occurred from the Unit 1 temporary sodium hypocNoiite storage tank. The tank was located 10 ft south of the Unit 1 acid / chlorination building on a paved surface. Secondary containment was constructed around the tank. However, due to existing holes in the containment 350 gallons of the total 500 gallons

- of a 12.5% solution of sodium hypochlorite lost from the tank was released to the environment.

A total of 437 pounds of sodium hypochlorite was released to the environment.

- The product flowed along a crack in the asphalt until reaching the grass swale along the eastem edge of the asphalt. Following tt.e path ofleast resistance the product tiowed along this swale and into a culvert. Traveling through the culvert the product was halted at its '

northern end by existing debns and soil. Approximately 120 gallons of product was recovered from the culvert.

' 2.0 Site Description and Location -

The Umerick Generating Station is nuclear electric generating facility.' The Station has been in f

operation since the late 1980's. The Station is located 1.2 miles west of the Sanatoga Exit off

']

route 422 in Montgomery County.

To aid in maintaining and operating the closed cooling system at the Station, various chemicals j

are added to the circulating water to prevent corrosion and control biological growth and j

- scaling. Of these chemicals, sodium hypochte is used extensively.

1

- The temporary tank described in section 1.0 was centrally located within the property, less than 200 feet south of the Unit 1 Cooling Tower. The temporary tank was erected on an existing asphalt area adjacent to the Unit 1 Acid Feed House.- The tank was equipped with emergency containment, as requested by PECO personnel 4

A J

S.0 Site' Assessment 3.1 Immediate N:;-:-ae.

The release was caused by a cheTA4y incompatible camlock fitting which was,

attached to the temporary tank. To isolate the fitting and the leak, the valve upstream of this fitting was closed. Booms and spHI pads were used to contain and redirect the flow as it exited the seconday contenment A load of earth and stone was dumped at

the pavement-grass interface to stop flow to the grass area.' The tarpaulin placed beneath the tank and containment during construction acted as a partial catch-basr1 for preventing the product from leaking through the secondary containment The LGS Control Room was contacted by a Station Chemet on 11/2/98. LGS made the following notifications for a reportable release of sodium hypochlortie:

PADEP USCG NationalResponse Center

- Report # 462231-Pennsylvania Emergency Management Agency Nuclear Regulatory Commission Resident 3.2 Cleanup and Restoration Lewis Environmental was contracted to perform the Site cleanup and restoration. SpHI pads and booms were deployed to absorb the remaining free product that collected in cracks and depressions in the pavement, containment basin, tarpaulin and grass.

Dec0nniiination and removal of all free product from the spil area was completed on 11/2/98, excluding the downstream culvert. Containment was placed beneath the valve and fitting to prevent further contaminant release.

To prevent release to waterways and other non-contaminated areas due to rain or catastrophic tank faRure, an earthen berm was constructed at the downstream end of the release.

On the moming of 11/3/98 excavation was coirGLJ to a depth of 6 inches along the entire length of the spHI (excluding par;ement). Excavabon greater than 6 inches began the aftemoon of 11/3/98. SoH removal was allowed to proceed at 3 to 6 inch -

intervals due to potential underground interferences. Sou color and odor were used as indicators for hypochlorite contamination. _ 20 g sol samples were taken at increasing depths and from the excavation side walls unti contamination levels were found to be

<0.02 ppm residual oxidant.

The spill was found to temiinate at the end of a 50 ft culvert running beneath a site l

road. Initial con 6Tsi6 tion levels in the culvert were 740 ppm residual oxidant. Lewis Environmental pumped approximately 120 gallons of product from the culvert and -

performed the first of three 300 gallon water flushes through the pipe. Contamination levels were reduced to 37 ppm residual oxidant upon wn ytebun of the initial flush.

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Excavation continued on the grass area on 11/4/98 and the contaminated pavement area was cut and prepared for excavation later that day. Excavation reached depths bp to 21 inches in low-lying grass areas to achieve contamination levels below 0.02 ppm residual oxidant.

1he south end of the culvert (upstream) was excavated to a point where further excavation would impact the road support and was halted. Contamination levels were i

less than 1 ppm residual oxidant in this area. The north end of the culvert (downstream) was excavated the evening of 11/5/98. Upon removal of the soil and acphalt, free product was found at a depth of 10 Inches. Excavation continued around the face of the pipe and eventually exposed 16 inches of the pipe and to a depth of 14 inches. At this point soil contamination levels were found to be less than 1 ppm residual oxidant and the excavation was halted due to road support impact.

1 The second flush of the culvert was performed 11/6/98. 300 gallons of water was

)

pumped into the south end of the culvert and collected at the north end. The levels j

were reduced to 11 ppm residual oxidant, in the rinsate.

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The third and final flush included a wash with 100 gallons of a 5% sodium sulfite solution and rinse with 200 gallons of water on 11/6/98. Sodium sulfite was used to j

neutralize any remaining sodium hypochlorite solution. Contamination levels were reduced to <0.02 ppm residual oxidant, completing remediative activities in the culvert.

Asphalt removal continued at a width of 5 feet and depth of 6-9 inches to where soil samples came back less than 0.02 ppm residual oxidant. Initially, low levels of contaminant (less than 15 ppm residual oxidant) were found in the pavement underlayers.

Backfilling operations commenced immediately upon completion of sampling due to nuclear plant restrictions on excavation.

3.3 Final Restoration j

Paving operations were performed in December,1998. The operation was completed in one j

day.

Excavated sod and grass in the areas upstream and downstream of the culvert pipe were filled with topsoil and seeded. Stormwater diversion fencing was constructed upstream of the culvert piping to prevent erosion of the new fill material and seed.

Both the Unit 1 and Unit 2 sodium hypochlorite tanks were replaced as a result of this incident.

3.4 Waste Removal The following list details the types and quantities of wastes generated during the project:

contaminated soiland asphalt 12 tons ppe and other solids 300 pounds contaminated liquid 400 gallons Form U Residual Waste determination was perfomied on all solid, contaminated wastes. The wastes were classified as residual and accepted for disposal at the Pottstown Landfill.

Liquid wastes were pumped to the cooling system, as intended during normal operation.

N

r 4.0 Conclusion and Recommendation The fittirigs on the temporary tank were found to be aluminum and were not compatible with sodium hypochlorite, in addition to faulty fittings, the containment basin supplied by an outside vendor was not water tight. Hydrostatic testing was not pafeirred on the containment.

PECO determined the failure to ensure compatibility of components and the failure to perform adequate testing of new or temporary systems as the root cause of the release PECO has venfied component compatibility on existing tanks, fill / distribution lines and fittings, in addition, testing and component compatibility analysis will be pafefired on all new or temporary tanks, lines and containment systems.

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