Draft Notes from Site Visit at Duke Energy's Catawba Nuclear Station on October 19 , 200 9

EPA conducted a site visit at Duke Energy ’s Catawba Nuclear Station ( Catawba ) located in
York

, S C on Mond ay, October 19 , 2009 to learn about the operations at the pla nt and the wastewaters generated at the plant . Table 1, located at the end of this memorandum, identifies the site visit participants. The presentation that the Catawba personnel gave during the site visit is provided as Attachment 1 to this memorandum. A n overall water balance diagram for the plant i s 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 1 3 , 2009.

Plant Overview

**•** The Catawba pl ant 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 nuclear

- fueled electric generati ng 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 Uraniu m dioxidePage 2

**•** 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

, refuel ing one unit approximately every 9 months so that only one unit is non

operati onal 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 during 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 digit al system in Fall 2010.

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

**•** Catawba has 1,270 employees. The plant t ypically has an additional 450

- 500
contractors on site.

Nuclear Service Water (NSW) and Low

- Pressure Service Water (LPSW) S ystems

**•** Catawba stated that there are two service water systems at the plant, both of which use water from Lake Wylie. The l ow

- pressure service water (LPSW) system is the primary water system that is used t o provide cooling for the steam turbine cycle and cooling water for the nuclear reactor. The nuclear service water (NSW) system is a back up water system that can be used if there are issues with the LPSW system. Although the NSW system is a back

- up, the system operates continuously, but not at full cap acity. [QUESTION FOR CATAWBA: Please confirm that the NSW is primarily used as a back

- up system . Is the NSW used to as cooling water for processes that the LPSW system does not cool? ]

**•** As an added safety measure, the NSW system has the capability of wit hdrawing intake water from either Lake Wylie or the plant’s standby nuclear service water pond (SNSWP) . The SNSWP is maintained by the plant and the plant uses water from Lake Wylie to keep the pond at an acceptable level in case of emergencies.
Therefor e, if the water level in Lake Wylie was too low for the plant to withdraw water, then the plan would use the water reserve in the SNSWP . Catawba stated that they have never had to use the SNSWP water as a result of an emergency. However, th e intake pumps are tested periodically

. The plant has an outfall for the transfer of water from the SNSWP to Lake Wylie in case the SNSWP becomes to full, which is Outfall 006. [QUESTION FOR CATAWBA: What is
the volume of the SNSWP? ]

**•** Catawba operates cooling towers to recirculate the steam turbine cooling water in the LPSW system. Catawba operates six cooling towers, three for each unit. The blowdown from the cooling towers flows almost continuously at approximatelyPage 3

5,000 gpm via i nternal Outfall 005, which commingles with other waste streams
into Outfall 001 and is discharge d to Lake Wylie

.

**•** Catawba stated that they add sodium hypochlorite and/or sodium bromide
biocides to the LPSW and NSW systems and at the SNSWP intake structure.

**•** Catawba adds s odium hypochlorite and/or sodium bromide to the LPSW system approximately four hours p er day, three to four days per week. The sodium hypochlorite and/or sodium bromide prevent bio fouling and sludge formation on heat exchanger surfaces. Catawba stated that d uring biocide ad dition, the plant
isolates the blowdown from the cooling towers (i.e., they do not discharge cooling tower blowdown)

. [QUESTION FOR CATAWBA: Is polyacrylic acid also used for biofouling control?]

**•** Catawba adds a dispersant at the NSW and SNSWP intake stru ctures. The dispersant increases the efficiency of the biocides. [QUESTION FOR
CATAWBA: What is th e frequency and duration of biocide addition for the NSW system?]

**•** Catawba stated that hydrazine or carbohydrazide are used to prevent corrosion in
the boiler tubes due to their ability to act as oxygen scavengers. Catawba stated that the Occupation Safety and Health Administration (OSHA) recommended the use of carbohydrazide as an alternative to hydrazine due to hydrazine’s toxicity. Catawba uses sodium hypoch lorite to break down the hydrazine or carbohydrazine. [ QUESTION FOR CATAWBA: Does the plant add sodium hypochlori t e at Outfall 002 or elsewhere within the plant ? ]

**•** The plant adds sodium bisulfite at Outfall 001 to dechlorinate the water before discharging into Lake Wylie. Catawba operates two sodium bisul fi te pump trains

, one of which is a back up system

. Catawba has oxidation reduction potential probe s that are used to determine the amount of s odium bisul fi te needed . Catawba stated that the required contac t time for the dechlorination reaction is 30 minutes.

Nuclear Unit Operations and Wastewaters

**•** The energy from fission of uranium dioxide fuel heats the primary reactor cooling system. The primary cooling system is pressurized to ensure that the coolant in the primary loop does not boil. Pressure, temperature

, and flow rate are adjusted to enable the efficient transfer of heat from the reactor to the coolant. The primary cooling system then transfers heat to the secondary system which generates steam.
Th e steam is used to generate electricity and then Catawba uses water from Lake Wylie to condense the steam.

**•** Boron is a neutron moderator and is used in the primary cooling system to
maintain the desired rate of fission within the reactors. As the uranium f uel starts slowly losing its reactivity, the plant begins purging some of the boron from the system because less is needed to control the reaction. [ QUESTION FOR
CATAWBA: What is the source of boron (e.g. boric acid)? What is the
concentration of boron in the primary cooling system at the beginning of the fuelPage 4

cycle? Please describe how the boron is purged from the system? Which wastewaters generated at the plant contain boron? How are these wastewaters
treated? ]

**•** Catawba’s reactor cooling system and ra diological liquid waste processing system are designed to minimize the release of radioactive liquids to unrestricted parts of the plant.

**•** The liquid radiological wastes generated at Catawba include wastewaters from
drains from the contained nuclear reacto r area including reactor cooling system equipment drains, floor drains, decontamination drains, and laundry and shower facility drains. These radiological wastewaters a re transferred to storage tanks in the auxiliary building and waste monitor tank buildin g, adjacent to the reactor
containment area.

**•** Catawba monitors the radioactivity of the wastes stored in the tanks

. Catawba then transfers the liquid radiological wastes to the radiological waste treatment system , which consists of demineralization and fil tration

. [QUESTION FOR
CATAWBA: Does the plant treat all the radiological wastes through the
demineralizers and/or filters? D oes the plant perform any chemical treatments on the liquid radiological wastes? If so, what chemicals and amounts are used? ]

**•** Th e treated liquid radiological wastes are then discharged via internal Outfall 004 to Outfall 001, which discharges to Lake Wylie. The l iquid radiological waste s generated at the plant are discharged in batches

. Catawba performs calculations to
determine t he amount of waste which can be released to the discharge canal according to NRC regulations. Catawba stated that because they operate a recirculating cooling water system, they need to limit the amount of wastes discharged at one time because they don’t have as much dilution water as a once

through plant.

**•** Catawba stated that they typically discharge a batch of liquid radiological wastes twice a week; however, it is more frequent during outages because they are draining a lot of the equipment. [QUESTIO N FOR CATAWBA : How does the frequency of the discharge vary from the beginning of the fuel cycle to the end of the fuel cycle? What are typical volumes discharged? ]

Metal Cleaning Wastes

**•** Catawba performs metal cleaning operations on the let

- down piping of its electrical system. Catawba uses nit ric acid and EDTA to perform the cleaning. This cleaning was last performed in May 2008 and September 2007, and each occurrence generated approximately 500 gallons of wastewater, which were treated by the demine ralizer. [QUESTION FOR CATAWBA: Please confirm the information is correct.]

**•** Catawba performs metal cleaning operations of t he heat exchangers from the

reactor primary cooling system

. Catawba uses phosphoric acid to reduce fouling in the heat exchangers. This cleaning operation was last performed in 2000 orPage 5

2001 and generated approximately 14,000 gallons of wastewater, which wa s diluted significantly and then haul ed off site by a vendor

.

**•** The spent resins from the demineralizer are monitored for radioact ivity and
treated as hazardous waste.

**•** Some of t he wastewaters generated by metal cleaning are discharged in small
batches from Outfall 002 (conventional wastewater treatment plant effluent) or Outfall 004. The effect of discharging in batches is that the plant can dilute the metal cleaning wastewater and not exceed its permit limits.

**•** Catawba does not perform metal cleaning operations on the turbines.

Other Plant Wastewaters and Treatment Systems

**•** Outfall 001 is the largest flow outfall at the plant and discharges once

- through cooling water, nuclear service water, cooling tower blowdown (via internal Outfall 005), and liquid radiological wastes (via internal Outfall 004) to Lake Wylie. There are no dilution specifications for O utfall 001.

**•** Catawba operat es a conventional wastewater treatment system to treat the wastewaters collected in sumps at the plant 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 alternate between discharging and receiving wastewater. Catawba stated that the plant switches between the ponds every one to two weeks. Catawba stated that it takes approximately three and a half days to drain one of the ponds and the flow rate from the pond is approximately 1,500

gpm.

**•** The conventional wastewater treatment system discharges directly to Lake Wylie via Outfall 002. Catawba can add sodium hydroxide or sulfuric acid to adjust the pH in the ponds.

**•** Catawba stated tha t Outfall 002 has “ monitor and report ” requirements for a number of pollutants, including cadmium, zinc, hydrazine, an d pentachlorophenol

. Catawba stated that the plant is required to monitor for cadmium even though the plant has never detected cadmium in the effluent.
D uring Catawba’s permit application Form 2C data collection requirement, they reported cadmium as less than the detection limit. However, the detection limit
was not less than the concentration necessary to avoid to the requirements for
monit or ing and report ing cadmium as determined by the permit writer

. [QUESTION S FOR CATAWBA: What is the detection limit of cadmium for the method used by the plant? What was the concentration required by the permit writer?]

**•** Catawba operates two hold

- up basins adjacent to the two conventional wastewater treatment ponds. Catawba stated that stormwater runoff from the plant’s threePage 6

yard sumps are transferred to the hold

- up basins. Catawba monitors the effluent from the basins for pH and radiological activity (cur ies). The discharge of the
hold

- up basins is combined with the discharge from the conventional wastewater treatment ponds and discharge via Outfall 002. Catawba stated that the plant only discharges from the hold

- up ponds when the plant is also dischargin g from the conventional wastewater treatment ponds.

**•** Catawba performs whole effluent toxicity (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 p ermit. In the summer of 2008,
Catawba ha d a failure in its WET test for 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 believed that blue

- green alg ae growth in
the hold

- up ponds is likely responsible for these difficulties. Prior to th ese recent failures , Catawba had not experienced a toxicity failure for 10

- 15 years.

**•** Catawba stated that the hold

- up ponds are aerated to keep the ponds from being

sta gnant. Additionally, Catawba is using sodium hypochlorite to reduce the
amount of blue

- green algae in the ponds.

**•** Catawba stated that they used to discharge treated sanitary wastewater via Outfall
003 ; however, the plant now transfers the sanitary wastewat er to the county for

treatment.

**•** Outfall 006 discharges water from the SNSWP into Lake Wylie in the event of
overflow.

Landfill

**•** Catawba operates a landfill for the stor age of low

- level radiological wastes and sludges and asbestos from old piping insulat ion . 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

.

**•** R adioactive wastes are stored in containers (barrels ) and buried in the landfill.

**•** Low

- level radioactive wastes consist of material that has become radioactive due
to neutron radiation at any point during plant operations and meet low

- level criteria established by the Nuclear Regulatory Commission (NRC). Th is includes material previously classified as high

- level radioactive waste that has been stored on site long enough for the material to decay to low

- level classification.

**•** Catawba stated that the wastes stored in the landfill are not significantly more radioactive than the background radiation levels found in nature

.

**•** Catawba is required to monitor the groundwater around the perimeter of the
landfill semi

- annually (during March and October) . However, there are no water quality requirements for the ground water. [QUESTION FOR CATAWBA: WhatPage 7

parameters is the plant monitoring? Please provide the five most recent groundwater monitoring reports.]Page 8

Table 1. Site Visit Attendees

Name Organization (Representing) Telephone E

- mail

Tara Myers Catawba (704) 747

- 5001 tara.myers@duke

- energy.com

Darrell Davies Catawba

Steve Rodgers Catawba

Gary Sain Catawba

David Vaught Catawba

Kim Hamm Duke Energy

Robert Wylie Duke Energy (704) 382

- 4669 Robert.wylie@duke

- energy.com

Marshall H uffstetler Duke Energy (864) 630

- 7856 david.huffstetler@duke

- energy.com

Josh Hall EPA/Office of Water (202) 566

- 1003 hall.josh@epa.gov

Jezebele Alicea EPA/Office of Water (202) 566

- 1755 alicea.jezebel e @epa.gov

TJ Finseth ERG (Contractor to EPA) (703) 633

- 1698 thomas.finseth@e rg.com

Kurt Blohm ERG (Contractor to EPA) (703) 633

- 1675 kurtis.blohm@erg.com

Donna Hill UWAG (205) 257

- 5234 dbhill@southernco.com

[QUESTION FOR CATAWBA: Please provide the missing phone numbers and e

- mail addresses.]