1 Site Visit Report Brunswick Steam Electric Plant Highway 87 North Southport, NC 27562 January 28 , 200 8 1.0 Background and Objectives The Environmental Protection Agency (EPA) is in the process of revising the 316(b) Phase II regulation. As part of this process, EPA staff is visiting several electric generators to better understand the cooling water intake structure (CWI S) technologies in use at typ ical facilities, including the site

- specific characteristics of each facility

and how these affec t the selection and performance of CWIS technologies. Brunswick Steam Electric Plant ( Brunswick) was selected for a site visit due to its use of fine mesh traveling screens with a fish return and its relativel y large intake flows
. 1 2.0 Facility Description Brunswick is a two unit nuclear facility in North Carolina 40 miles south of Wilmington . Unit 1 is a 938 MWe General Electric Type 4 boiling water reactor that began operations in September 1976
. Unit 2 is a 937 MWe General Electric Ty pe 4 boiling water reactor that began operations in December 1974. The s ource waterbody for co oling is tidal water (salinity typi cally 15 to 30 parts per thousand) obtained from Walden Creek near the Cape Fear River estuary . The owner Carolina Power & L ight (Progress Energy) employ s about 900 employees . Brunswick permit number is NC0007064 , expire d as of November 30, 2006
. 3.0 Electricity Generation and Transmission Total generating capacity is approximately 1580 MW of nuclear fueled power for baseload electric ity with a capacity utilization rating of 94.7 percent . Scheduled outages that include refueling occur every year alternating between units 1 and 2
. Outages are usuall y for 20 to 30 days. 4.0 Cooling Water Intake Structure The Cape Fear River Estuary is an elongated shallow bay with a narrow dredged deep ship’s channel. Above the narrow constriction at Sunny Point, the estuary

is highl y stratified with salt water intrusion along the bottom and freshwater flow out along the surface. Below Sunny Point the es tuary

is well mixed and characterized b y a large ocean exchange rate of about 80 percent of the water over a 12
- h period. Brunswick obtains cooling water from the lower reach, with approximately

0.74 pe rcent of the tidal excursion withdrawn by the intake c anal
. 1 EPA was unable to provide a copy of this report to the facility for review prior to publication.2 Brunswick has vertical turtle bar s (bar racks ) at the c anal entrance . A dditional fish diversion structure with 3/8 inch (9.4 mm) screens installed in 1982
. The diversion structure is located near the confluence of the intake canal and Walden Creek. Copper

- nickel screen panels are set between reinforced concrete pilings. Mechanical grass rakes keep debris out of the canal. The canal is dredged 18 feet deep with frequency

dictated by

annual storm events. Design intake flow is 1.9 billion gallons daily , with the actual intake (3

- ye ar average) reported as 1.427 billion gallons daily

with an intake velocit y of 0.98 feet per second. A fine mesh and a fish return handling s ys tem was installed in 1983. After the 2.7 mile long intake canal, water flows to each generating unit’s cooling s ys tem consisting of four intake bay s and pumps
. Originally , vertical traveling screens installed in each bay

were fitted with 9.4 mm mesh screens. Eight fine mesh FMC screens were retrofit on the traveling screens to reduce entrainment of larvae 2

. The third fine

- mesh screen per unit was installed in 1987. As of a 2000 study , three of the four traveling screens f or each unit were fitted with 1 mm fine

- mesh screens. Currentl y, an alternative configuration is being studied where 1 mm f ine mesh overlay is installed on 2 of 4 screens creating a 50/50 panel on the two bay s. The other two bay s have fine mesh screens on all panels
. The traveling screens have two operating speeds, where the higher speed is triggered b y a pressure drop across the screens. The screens are visually inspected twice daily
. Impinged organisms are washed off the screens into a 1.4

- km fiberglass fish return
. The organisms are transported to a constructed holding pond that is open to a tributary of Walden Creek , allowing impinged organisms a full return route to the sourcewater
. December through March flow reduction management is utilized for further protec tion of larval fin fish. Cooling water fl ow is reduced from 31.1 cm/unit to 26.1 cm/unit . Normally , all flow is through traveling screens fitted with fine mesh. The cooling water flow for one unit onl y is allowed to be increased to 34.8 cm during July , August, and September b y using a forth intake pump fitted with 9.4

- mm mesh screens. Seasonal algae has been observed to foul the intake. Biocontrol is conducted by a ddition of hypochlorite and brome into the service water bay s every other hour, and to the sa lt water pumps twice a day . A silicone coating on the main cooling water s ys tem further reduces bio fouling. The return canal is a 5 mile open canal that is eventually piped under the Intra

Coastal Waterway

and remains submerged into the Atlantic Ocean. The returned warm water is dispersed 200 feet offshore the Oak I sland area. Water is returned less than 4 degrees F higher at the ocean. Permit conditions allow for a 2 acre mixing zone, with a 2,000 acre grid monitored for compliance.

2 Prior to installation of fine

- mesh screens, all entrained larvae we re returned to the ocean rather than back to the estuary, therefore they were considered 100 percent mortality.3

5.0 Impingement and En trainment Information Brunswick has conducted a representative species approach to population level effects as part of the demonstration to the state that there is no adverse environmental impact ; population modeling is not required by the state
. Brunswi ck has conducted some form of monitoring for more than 30 y ears. Brunswick staff indicated their data shows that the species composition, seasonality , and abundance of organisms has not changed as a result of operation of the plant. As earl y as 1968, base line studies were designed to collect preliminary biological and environment data prior to simultaneous operation of both units. In itial studies were conducted when plant operations commenced in the 70’s. Detailed I& E studies were conducted weekl y in the m id

- 80s . Sampling was conducted 3/day and 3/night over a 24 hour period, with data stratified by the tide conditions. Two nets in the discharge canal are used to collect organisms to show comparative density of entrainment. Overall abundance was generall y found to be lower in the fall. Brunswick performance data showed 84 percent reduction s in entrainment with the fine mesh over regular mesh (9.4 mm) . I mpingement mortality reductions ranging from 40 to 9 2 percent were observed depending on species and mes h configuration
. Currently monitored species of interest include Atlantic menhaden, spot, blue crab, and shrimp. Other previously monitored species include croaker, flounder, mullet, bay anchovy , and sea trout. Potential impacts to threatened and endange red (T&E) species include short

- nosed sturgeon and turtles. 6.0 Additional Information The base for a natural draft wet cooling was built, but the tower was not completed due to projected adverse impacts to air.
List of attendees : Charles Nelson, Thomas Thompson Attachments: Please see DCN 10

- 6559A through Q accompanying this document for photos from the site visit.