ML15195A372

Response to NRC Request for Additional Information, Dated May 22, 2015 Regarding License Renewal Application, Environmental Review, MH-01 on Microbiological Hazards

ML15195A372
Person / Time
Site:	LaSalle
Issue date:	07/02/2015
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
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References
RS-15-179
Download: ML15195A372 (1)

Text

LaSalle Environmental Audit Response to Request for Additional Information Index #:

016 RAI #: MH-01 Category: Microbiological Hazards Statement of Question:

Section 4.5.2.3 of the ER states that water treatment additives are utilized for scale inhibition, silt dispersion, corrosion inhibition, and micro-and macro-biological control. Please provide a summary of Exelon's chlorination procedures for the circulating water and service water systems that includes the chlorine compounds used to treat each system as well as the concentrations and frequency of injection.

Response

LSCS utilizes a 15 percent by weight Sodium Hypochlorite, NaOCl, solution to provide biocide to the Circulating Water (CW) and Service Water/Emergency Service Water systems.

CW biocide injection is performed twice daily per unit. Injections times are limited to 120 minutes per day per unit as outlined in the NPDES permit. The biocide is injected into the discharge piping of the operating CW pumps. Free Available Chlorine (FAC) is monitored 3 times per week at the outlet, (via Amertap system) of each units main condenser. The goal for FAC is to achieve a value between 0.05 and 0.2 ppm. Sampling is performed during the midpoint of the injection period.

Service Water/Emergency Service Water, biocide injection occurs in the Service Water tunnel located in the lower elevation of the Lake Screen House (LSH). The injection quills are installed in the six 36-inch lines that convey lake water from the fore-bay area of the LSH into the tunnel.

Biocide injection for the tunnel is continuous, which allows for treatment of intermittently operated systems. Similar to CW, Service Water FAC is monitored 3 times per week with a goal value of 0.05 to 0.2 ppm.

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