ML20151X745

Rev 3 to PGE-1063, Trojan Nuclear Power Station,Suppl to Applicant Environ Rept

ML20151X745
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	09/10/1998
From:	PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20151X721	List: ML20151X717 ML20151X745
References
PGE-1063, PGE-1063-R03, PGE-1063-R3, NUDOCS 9809170232
Download: ML20151X745 (3)

Text

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1 PGE-1063 Portland General Electric Supplement to Applicant's Environmental Report 1

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Post Operating License Stage Trojan Nuclear Power Station Revision 3 9809170232 980910 PDR

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W ADOCK 05000344 PDR

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l List of Effective Pages  !

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Page Number Revision Title page - September 1998 Executive Sumary Original li through iv Original

.v September 1998 l 1 through 3 Original Figure 2.2-1 and 2.2-2 Original

' 4 through 9 Original Figure 2.3-1 through 2.3-3 Original l 10 and 11 Original L

Figure 2.4-1 through 2.4-3 Original l

l. 12 through 14 Original t.

l Figure 2.5-1 through 2.5-3 Original ,

l 15 Original l 16 and 17 September 1996 18 November 1996 l Figure 3.2-1 November 1996 19 through 22 Original 23 September 1998 24 through 35 Original i-f l

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v Revision 3

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,yl' EN11RONMENTAL REPORTSUPPLEMENT- POST OPERA TING LICENSE STAGE The plant's once through cooling system remains in service to provide makeup water for the I spent fuel storage pool. The shutdown of the plant has greatly reduced the demand for water l from this system. Chlorination of this system (and the neutralization of the residual chlorine) I continues at this time. The impact of this chlorination on the water discharged to the Columbia River is reduced from previous levels, however, due to the reduced flow requirements.

Discharges originating from blowdown of the reactor coolant system and miscellaneous steam leaks and drains from the plant secondary system have also been eliminated as a result of the I permanent shutdown of the plant.

With the plant permanently defueled, the water use is less than when the plant was operating. l Water is drawn from two wells on site and the Columbia River. The estimated maximum usage l from the wells is 26,925 gpd for potable water and for the demineralized water system, with plans to use an additional 43,200 gpd for potable water, backup fire protection, and air compressor bearing cooling water. The estimated maximum plant usage from the Columbia River is 42,600 gpm (40,000 gpm for the service water system,2,000 gpm for the fire system, and 600 gpm for the screen wash system).

The daily average minimum flow of the Columbia River at Trojan is approximately 120,000 ,

cubic feet per second. The discharge is at the bottom of the river in a manner providing an l average 120-fold dilution by the time the effluent reaches the river surface. Further dilution of

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the discharge occurs rapidly in the river. Within 12,000 feet of the discharge, complete mixing is j expected. i The original Trojan environmental report noted that chemicals from the plant, after dilution by river water, would cause only a slight increase in the concentration of elements and compounds which already existed in the river. The report concluded that the waste discharge from the Trojan plant would have a negligible effect on the chemical composition of the Rainier drinking water and cause no adverse effects on human health from this source. The report also concluded that chemical wastes from Trojan would have a negligible biological impact on the environment of the Columbia River or on the area surrounding the plant. These conclusions have subsequently been supported by the continuing monitoring of the environment in the vicinity of Trojan. The permanent shutdown of Trojan has further reduced any chemical discharges from the levels that resulted from plant operation. Any chemical discharges resulting from decommissioning activities will be made in accordance with the limitations and conditions of the NPDES Waste Discharge Permit issued to the plant.

During plant operation various chemicals were also present in the cooling tower drift. These consisted basically ofinsoluble salts. Chlorine was also present in the cooling tower drift within the cooling tower structure. An asbestos cement material was used for construction of portions of the cooling tower internals. As stated in the original Trojan environmental report, there were no measurable environmental effects expected due to operation of the cooling tower. However, since the cessation of plant operations, the cooling tower is no longer in use and release of any chemicals contained in the cooling tower drift has also ceased.

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