Draft Notes from Site Visit at Duke Ener gy's Catawba Nuclear Station on October 19, 2009

EPA conducted a site visit at Duke Energy’s Ca tawba Nuclear Station (Catawba) located in York, SC on Monday, October 19, 2009 to learn about the operations at the plant and the wastewaters generated at the plant. Table 1, lo cated at the end of this memorandum, identifies the site visit participants. The presentation that the Catawba pers onnel gave during the site visit is provided as Attachment 1 to this memorandum . An overall water balance diagram for the plant

is included within Attachment 1.

This memorandum describes the information collected during the site visit and the pre-site visit phone call, which was held on October 13, 2009.

Plant Overview

 The Catawba plant is located on a 500-acre site next to Lake Wylie. Lake Wylie has a total surface area of 13,443 acres with 325 miles of shoreline. The plant intake from the lake is approximately 110 MGD.

 Catawba operates two identical nuclea r-fueled electric generating units.

Information on the two nuclear units is summarized in the table below.

Unit Installation

Date Gross Capacity

(MW) Reactor Type Fuel

1 1985 1,129 Westinghouse

Pressurized water

reactor (PWR) Uranium dioxide

2 1986 1,129 Westinghouse PWR Uranium dioxide

 Units 1 and 2 are both fueled by uranium dioxide. Both reactors are refueled approximately every 18 months. Units 1 and 2 are refueled on staggered intervals, refueling one unit approximately every 9 months so that only one unit is nonoperational at a time.

 Catawba stated that the next refueling cycle is scheduled to begin in late November 2009 and takes approximately 30 days to complete. During refueling outages, the plant may have as many as 1,800 contractors on site.

 Catawba stated that the analog equipment in the control room of Unit 1 will be upgraded to a digital control system dur ing the upcoming refueling outage. The digital control system will be the first of its kind in the United States. Catawba plans to upgrade Unit 2 to a digital system in Fall 2010.

 Each unit has a separate spent fuel pool and fuel storage area.

 Catawba has 1,270 employees. The plant typically has an additional 450-500

contractors on site.Page 2

Nuclear Service Water (NSW) and Low-P ressure Service Water (LPSW) Systems

 Catawba stated that there are two servi ce water systems at the plant, both of which use water from Lake Wylie. The low-pressure service water (LPSW) system is the primary water system that is used to provide cooling for the steam turbine cycle. The nucl ear service water (NSW) sy stem provides cooling to nuclear safety components and heat exch angers. The NSW system is not a backup system. The NSW system typically pulls off Lake Wylie and the NSW pond is a backup water source to the lake. The NSW system is always in service providing cooling to the nuclear safety components in the plant. The LPSW system provides cooling water to the non-nuclear safe ty related components in the plant.

 As an added safety measure, the NSW sy stem has the capabili ty of withdrawing intake water from either Lake Wylie or the plant’s standby nuclear service water pond (SNSWP). The SNSWP is maintained by the plant and th e plant uses water from Lake Wylie to keep the pond at an acceptable level in case of emergencies. Therefore, if the water level in Lake Wy lie was too low for the plant to withdraw water, then the plant woul d use the water reserve in the SNSWP. The volume of the SNSWP is 18.8 million gallons. Catawba stated that they have never had to

use the SNSWP water as a result of an emergency involving the loss of Lake Wylie. However, the intake pumps are te sted periodically. The plant has an outfall for the transfer of water from the SNSWP to Lake Wylie in case the SNSWP becomes too full, which is Outfall 006.

 Catawba operates cooling towers to recirc ulate the steam turbine cooling water in the Recirculating Cooling Water (RC) system. Catawba operates six cooling towers, three for each unit. The blowdown from the cooling towers flows almost continuously at approximately 5,000 gp m via internal Outfall 005, which

combines with other waste streams into Outfall 001 and is discharged to Lake Wylie.

 Catawba stated that they add sodium hypoc hlorite and/or Stabrex biocides to the NSW systems and at the SNSWP intake st ructure. Sodium hypochlorite is added

at the LPSW intake structure.

 Catawba adds sodium hypochlorite and/or Stabrex to the NSW system up to four hours per day, three to four days per wee k. Sodium Hypochlorite is added to the LPSW system up to 4 hours per day, 2 days per week. The sodium hypochlorite and/or Stabrex prevent biofouling an d sludge formation on heat exchanger surfaces. Polyacrylic acid is not used for bi ofouling control. It is used to control solids deposition. Biocides and the dispersa nt are used together to prevent/reduce fouling of piping and heat exchangers.

 Catawba adds a dispersant to the NSW system at the SNSWP intake structure. The dispersant increases the efficiency of the biocides. Biocide could be added to the NSW system up to 4 hours per day for up to 4 days per week depending on the amount of biofouling. Dispersant is added continually.Page 3

 Catawba stated that hydrazine or carbohydr azide are used to lay-up Secondary components during refueling outages. This practice prevents corrosion in the steam generator tubes due to their abili ty to act as oxygen scavengers. Catawba uses carbohydrazide due to the toxicity of hydrazine. Catawba uses sodium hypochlorite to break down the hydrazi ne or carbohydrazine when wet layup

chemicals are drained to conventional waste systems. Sodium hypochlorite is added upstream of Outfall 002 for hydrazine control and /or for algae control in the conventional wastewater ponds. This wa stewater is then discharged through

Outfall 002 when it is verified that th e wastewater is in specifications.

 The plant adds sodium bisulfite at Outf all 001 to dechlorinate the water before discharging into Lake Wylie. Catawba opera tes two sodium bisulfite pump trains, one of which is a back up system. Catawba has oxidation reduction potential probes that are used to determine the am ount of sodium bisulfite needed. Catawba stated that the required contact time for the dechlorination reaction is 30 minutes.

 Catawba stated that during biocide additi on to the cooling towers (RC system), the plant isolates the blowdown from the cooling towers (i.e., they do not discharge cooling tower blowdown until the chlorine has dissipated).

Nuclear Unit Operations and Wastewaters

 The energy from fission of uranium dioxide fuel heats the primary reactor cooling system. The primary cooling system is pre ssurized to ensure that the coolant in the primary loop does not boil. Pressure, te mperature, and flow rate are adjusted

to enable the efficient transfer of heat fr om the reactor to the coolant. The primary cooling system then transfers heat to th e secondary system which generates steam. The steam is used to generate electricity and then Catawba uses water from Lake Wylie to condense the steam via RC (reticulating Cooling system).

 Boron is a neutron moderator and is us ed in the primary cooling system to

maintain the desired rate of fission within the reactors. As the uranium fuel starts slowly losing its reactivity, the plant begins diluting some of the boron from the system because less is needed to control the reaction.

 The source of boron is boric acid. The concentration of boron in the primary cooling system at the beginning of the fuel cycle varies from about 1600 to 1800 ppm depending on core design. The concentrat ion at the end of the fuel cycle is less than 50 ppm. Boron is purged from the system by adding water to reactor coolant to maintain the desired temperat ure. The boron is dilu ted and the system volume is maintained by draining the reactor coolant to the recycle hold up tanks. Where approximately 80% is reclaimed using an evaporator. The remaining 20% is drained to the liquid waste system to control on-site inventory of tritium.

Wastewaters from Outfall 004 contain bor on. These wastewaters are treated using

demineralizers and filters.Page 4

 Catawba’s reactor cooling system and ra diological liquid waste processing system are designed to minimize the release of radi oactive liquids to unr estricted parts of the plant.

 The liquid radiological wast es generated at Catawba include wastewaters from

drains from the contained nuclear react or area including reactor cooling system equipment drains, floor drains, decontam ination drains, and laundry and shower facility drains. Radioactive liquid waste is segregated. The bulk of the reactor coolant drainage is reclaimed and used as makeup to the Reactor Coolant system. The remaining radiological wastewaters are transferred to storage tanks in the auxiliary building and waste monitor tank building, adjacent to the reactor

containment area. This radioactive li quid waste system processes the water through demineralizers and filters.

 Catawba monitors the radioactivity of th e wastes stored in the waste collection tanks. Catawba then processes the liquid radiological wastes through

demineralizers and filters to the releas e tanks. The tanks are then sampled and verified in specification for release. Radi oactive liquid waste is segregated. The bulk of the reactor coolant drainage is reclaimed and used as makeup to the reactor coolant system. The remaining ra diological wastes are processed through

demineralizers and/or filters. Periodica lly 1-2 liters of hydrogen peroxide per 5,000 gallons of wastewater are added to the liquid radiological waste system.

 The treated liquid radiological wastes are then discharged via internal Outfall 004 to Outfall 001, which discharges to Lake Wylie. The liquid ra diological wastes generated at the plant are di scharged in batches. Catawba performs calculations to

determine the amount of waste which can be released to the discharge canal according to NRC regulations. Catawba stat ed that because they discharge into a cove, they need to limit the amount of wastes discharged at one time because of

limited dilution due to disc harging into a cove.

 Catawba stated that they typically discha rge a batch of liquid radiological wastes twice a week; however, it is more fre quent during outages because they are draining a lot of the equipment. During i nnage periods Catawba typically has one discharge of approximately 20,000 gallon per week. During an outage Catawba has 2-3 discharges of approximately 5,000 gallons per week in addition to the 20,000 gallon per week discharge.

Metal Cleaning Wastes

 Catawba has performed two metal cleani ng operations on the let-down piping of its reactor coolant system. Catawba used nitric acid and EDTA to perform the cleaning. This cleaning was last pe rformed in May 2008 and September 2007, and each occurrence generated approximately 500 gallons of wastewater, which were treated by a portable demineralizer. These cleaning are not normal activities.

 Catawba performed a one time metal cleaning operation on the Nuclear Service water side of the NS heat exchanger. Catawba used phosphoric acid to reducePage 5

fouling in the heat exchanger. This cl eaning operation was last performed in 2000 or 2001 and generated approximately 14,000 gallons of wastewater. The waste that did not contain radioactivity was discharged through th e conventional waste system in small batches to ensure all parameters remained in spec. A second portion of the waste was draine d to radwaste system due to a leaking fitting on the pump skid. This waste was treated and tr ansported to a vendor for processing.

 The spent resins from the demineralizer are monitored for radioactivity and

treated as non-hazardous waste. The demineralizers were only used on the cleaning of the letdown pipi ng not the heat exchangers cleaning using phosphoric

acid.

 Some of the wastewaters generated by me tal cleaning were discharged in small batches from Outfall 002 (conventional wast ewater treatment plant effluent) or Outfall 004. The effect of discharging in ba tches is that the plant can dilute the metal cleaning wastewater and not ex ceed its permit limits. (Phosphoric Acid cleaning of Heat exchanger)

 Catawba does not perform metal clea ning operations on the turbines.

Other Plant Wastewaters and Treatment Systems

 Outfall 001 is the largest flow outfall at the plant and disc harges once-through cooling water, nuclear service water, cooling tower blowdow n (via internal Outfall 005), and liquid radiological wastes (via internal Outfall 004) to Lake Wylie. There are no dilution spec ifications for Outfall 001.

 Catawba operates a conventional wastewater treatment system to treat the wastewaters collected in sumps at the plan t that are not located within the nuclear

containment area.

 The conventional wastewater treatment system consists of two ponds, each 5 million gallons in volume. The ponds alte rnate between discharging and receiving

wastewater. Catawba stated that the plant switches between the ponds every one

to two weeks. Catawba stated that it ta kes approximately three and a half days to drain one of the ponds and the flow ra te from the pond is approximately 1,500

gpm.

 The conventional wastewater treatment sy stem batch discharges to Lake Wylie via Outfall 002. Catawba can add sodium hydr oxide or sulfuric acid to adjust the pH in the ponds. Sodium hydroxide may also be used to control algal growth in the ponds.

 Catawba stated that Outfall 002 has “m onitor and report” requirements for a number of pollutants, includi ng cadmium, zinc, hydrazine, and pentachlorophenol. Catawba stated that th e plant is required to monitor for cadmium even though the plant has never detected cadmium in the effluent. During Catawba’s permit application Form 2C data collection requirement, theyPage 6

reported cadmium as less than the detect ion limit. However, the detection limit

was not less than the concentration nece ssary to avoid the requirements for monitoring and reporting cadmium as de termined by the permit writer. The detection limit used by the plant for cadmium is 0.1 ug/L. Per the rational for the current permit there was only one data point to consider in the evaluation and an insufficiently sensitive PQL. Therefore, additional data is being obtained to perform a reasonable po tential evaluation.

 Catawba operates two final hold-up basins adjacent to the two conventional wastewater treatment ponds. Catawba stat ed that stormwater runoff from the plant’s three yard sumps are typically tr ansferred to the hold-up basins. Catawba monitors the effluent from the ponds for pH and radiological ac tivity (curies). The discharge of the hold-up basins is co mbined with the discharge from the conventional wastewater treatment ponds and discharged via Outfall 002. Catawba stated that the plant only disc harges from the hold-up ponds when the plant is also discharging from the c onventional wastewater treatment ponds.

 Catawba performs whole effluent toxici ty (WET) tests on Outfalls 001 and 002 quarterly and must meet discharge limitations on Ceriodaphnia dubia survival from these outfalls as required by the plant’s permit. In the summer of 2008,

Catawba had a failure in its WET test fo r Outfall 002. Catawba stated that the issue didn’t occur in September of 2008, but they failed another WET test in the summer of 2009. At the time, Catawba believ ed that blue-green algae growth in the hold-up ponds is likely responsible for these difficulties. Prior to these recent failures, Catawba had not experienced a toxicity failure for 10-15 years.

 Catawba stated that the hold-up ponds ar e aerated to keep the ponds from being stagnant. Additionally, Catawba is using sodium hypochlorite to reduce the amount of blue-green algae in the ponds.

 Catawba stated that they used to discharg e treated sanitary wastewater via Outfall 003; however, the plant now transfers the sa nitary wastewater to the county for

treatment.

 Outfall 006 discharges water from the SN SWP into Lake Wylie in the event of

overflow.

Landfill

 Catawba operates a landfill for the storage of low-level radiological wastes and sludges and asbestos from old piping insulation. The landfill is not lined and therefore does not collect leachate. Additionally, the landfill is relatively small and flat, compared to coal combustion waste landfills at coal-fired power plants.

 Radioactive wastes are stored in cont ainers and buried in the landfill. The

contaminated resins and car bon materials were buried either in steel drums or B25s. IHP sludge was not containerized.Page 7

 Low-level radioactive wastes consist of ma terial that has become radioactive due to neutron radiation at any point duri ng plant operations and meet low-level criteria established by the Nuclear Regul atory Commission (NRC) . This includes material previously classified as high-lev el radioactive waste that has been stored on site long enough for the material to decay to low-level classification. The SCDHEC RP Group reviews the lab analyses and pre-approves each burial.

 Catawba stated that the wastes stored in the landfill are not significantly more radioactive than the background ra diation levels found in nature.

 Catawba is required to monitor the groundwater around the perimeter of the landfill semi-annually (during March and Oc tober). However, there are no water quality requirements for the groundwater. The monitoring parameters are defined by SC Reg 61-107.19 Solid Waste Management: Solid Waste Landfills and

Structural Fill. While CNS has historica lly been required to analyze for Appendix III constituents, in 2009 the site was requi red to analyze all wells for Appendix V constituents as well. After analyses fr om a minimum of two sequential samplings

showed minimal contamination from Appendix V constituents, the site and SCDHEC have agreed the Appendix V sa mpling is no longer required for the existing wells. This subject is disc ussed in detail in the 2009-2010 Annual Report.Page 8Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailTara MyersCatawba (803) 701-3940 tara.myers@duke-energy.comDarrell Davies Catawba(803) 701-3023 Darrell.Davies@duke-energy.comSteve Rodgers Catawba(803) 701-3370 Steven.Rodger@duke-energy.comGary Sain Duke Energy(704) 382-3819 Gary.Sain@duke-energy.comDavid Vaught Duke Energy(980) 373-5302 David.Vaught@duke-energy.comKim Hamm* Duke EnergyNA NARobert Wylie Duke Energy(704) 382-4669 Robert.wylie@duke-energy.comMarshall Huffstetler Duke Energy(803) 701-3334 david.huffstetler@duke-energy.comJosh HallEPA/Office of Water(202) 566-1003 hall.josh@epa.govJezebele AliceaEPA/Office of Water(202) 566-1755 alicea.jezebele@epa.govTJ FinsethERG (Contractor to EPA)(703) 633-1698 thomas.finseth@erg.comKurt BlohmERG (Contractor to EPA)(703) 633-1675 kurtis.blohm@erg.comDonna HillUWAG(205) 257-5234 dbhill@southernco.com*Kim Hamm was a co-op student during EPA’s site visit. She is, currently, not employed by Duke Energy.