Draft Notes from Site Visit at Progress Energy's H.B. Robinson Steam Electric Plant on 

October 21, 2009

EPA conducted a site visit at Progress Energy’s H.B. Robinson Steam Electric Plant (HB 

Robinson) located in Hartsville, SC on Wednesday, October 21, 2009 to learn about the 

operations at the plant, specifically the operations and wastewaters generated by the nuclear 

electric generating unit and the ash handling system associated with the coal-fired electric 

generating unit. Table 2, located at the end of this memorandum, identifies the site visit 

participants. An overall water balance diagram for the plant is provided as Attachment 1. 

This memorandum describes the information collected during the site visit and the pre-site visit 

phone call, which was held on October 14, 2009.

Plant Overview

• HB Robinson operates one coal-fired unit (Unit 1) and one nuclear unit (Unit 2). 

The table below contains some general information for the two units.

Table 1. HB Robinson Units Description

Unit Type of 

Fuel

Installation 

Date

Capacity 

(MW)

Particulate 

Control

NOx 

Control SO2

1

Control

Bituminous 

Coal 1960 174 Cold-side ESP

Low-NOx 

burner; 

Overfire air 

separator

None

2 Nuclear 

(Uranium) 1971 710 N/A (no air emissions)

N/A (no air 

emissions)

N/A (no air 

emissions)

• Unit 1 was installed in 1960 by Carolina Power & Light. The unit has a capacity 

of 174 MW. Carolina Power & Light also constructed Lake Robinson, a 1,200-

acre lake, for the unit. The lake is used as a cooling pond for the once-through 

cooling water.

• Carolina Power & Light initially had plans to build three additional coal-fired 

units, but in the late 1960s nuclear energy became available and the company 

decided to build a nuclear unit instead.

• Unit 2 began operation on March 7, 1971. The unit has a capacity of 710 MW.

• HB Robinson was the first nuclear plant built in the southeastern United States.

• HB Robinson stated that the plant also has 13 internal combustion turbines on site 

with a combined capacity of 812 MW. These turbines are operated as swing units 

to provide stability to the grid and the nuclear unit. [QUESTION FOR HB 
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ROBINSON: Are the internal combustion turbines owned by Progress Energy?]

• HB Robinson stated that they have dry fuel storage on site (i.e., spent fuel). The 

fuel is initially stored in a spent fuel pool and is then transferred to a storage area 

outside of the containment area.

• HB Robinson operates once-through cooling water systems for both Units 1 and 

2. The plant also has a service water system that is used to cool various 

equipment components for Unit 2.

• HB Robinson uses a 14% sodium hypochlorite solution for biofouling control of 

on both Units 1 and 2. HB Robinson stated that sponge balls are also used to 

mechanically clean the biofouling of the condenser tubes. [QUESTION FOR HB 

ROBINSON: What ultimately happens to the sponge balls?]

• HB Robinson stated that they usually chlorinate the cooling water at the same 

time that they use the sponge balls. Additionally, the plant stated that they 

chlorinate more frequently in the summer (5 cleanings per week) than in the 

winter (3 cleanings per week).

• The once-through cooling water from the plant is transferred to the discharge 

canal. The discharge canal (Outfall 001) is 4.2 miles long.

• There are two intake structures at the plant that separately serve the coal-fired and 

nuclear units at the plant. In September of 2009, water usage at the plant was 836 

MGD on average.

Nuclear Unit Operations and Wastewaters 

• HB Robinson operates a 3-loop Westinghouse pressurized water reactor. 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. Typically, 

the temperature and pressure inside the primary loop are 574o F and 2,235 psi. 

The primary cooling system then transfers heat to the secondary system which 

generates steam. The steam is used to generate electricity and then HB Robinson 

uses water from Lake Robinson to condense the steam.

• HB Robinson’s reactor cooling system and radiological 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 HB Robinson include wastewaters 

from equipment drains, chemical laboratory drains, shower drains, 

decontamination area drains, and demineralizer regeneration. These radiological 

wastewaters are transferred to one of three 25,000-gallon chemical and volume 

control system (CVCS) hold-up tanks. 
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• HB Robinson monitors the radioactivity of the liquids in the CVCS hold-up tanks 

and will hold liquids in the tanks for as long as possible to allow short-lived 

radiological isotopes to decay. 

• HB Robinson transfers the liquids in the CVCS hold-up tanks to the demineralizer 

system for treatment. 

• The demineralizer system consists of filtration and treatment by ion exchange. 

The ion-exchange resins consist of charcoal and anion/cation resins, which are 

specialized to remove radionuclides. HB Robinson sends spent ion exchange 

resins to an off-site disposal facility. 

• The effluent from the demineralizer system is sent to waste monitoring tanks. HB 

Robinson tests for pH, TSS, and oil and grease in the waste monitoring prior to 

diluting the wastewater with the plant’s service water via Outfall 006. The 

service water is then commingled with the plant’s once-through cooling water and 

transferred to the discharge canal. Additionally, HB Robinson monitors the 

radioactivity of the treated water. If the liquids do not meet NRC standards they 

are returned to the CVCS hold-up tanks for reprocessing.

• Liquid radiological waste is discharged in batches (approximately 8,000 gallons 

pre discharge). HB Robinson performs calculations to determine the amount of 

waste which can be released to the discharge canal according to NRC regulations. 

HB Robinson personnel stated that the frequency of discharges increases towards 

the end of each fuel cycle. For example, at the beginning of the fuel cycle the 

plant may not discharge any radiological wastes for two or three months, but 

towards the end of the fuel cycle the plant may need to discharge radiological 

wastes every XX days/weeks. [QUESTION FOR HB ROBINSON: How 

frequent is the discharge towards the end of the fuel cycle?]

• HB Robinson stated that the reactor is refueled approximately every 18 months. 

The plant was last refueled in October 2008 and is scheduled to refuel again in 

April 2010. 

• 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 fuel starts 

slowly losing its reactivity, the plant begins purging some of the boron from the 

system because less is needed to control the reaction. HB Robinson uses boric 

acid as the source of boron in the primary reactor cooling system. HB Robinson 

stated that the initial concentration of boron in the system at the start of the fuel 

cycle is 15,000-16,000 ppm. This concentration approaches zero at the end of the 

fuel cycle. [QUESTION FOR HB ROBINSON: Please describe how the boron is 

purged from the system? Which wastewaters generated at the plant contain 

boron? How are these wastewaters treated?]

• HB Robinson stated that approximately 10,000 kg of boric acid were used by 

plant in 2008.
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Coal-Fired Unit Operations and Wastewaters

• HB Robinson receives its coal via rail. The coal is stored in an outdoor coal pile.

• HB Robinson keeps approximately 20 days worth of coal on site at the plant.

• The coal pile runoff generated from stormwater that contacts the coal pile is 

collected in a settling area near the coal pile. The plant does not have a discharge 

from the coal pile runoff collection area because the soil in the area is sandy and 

drains easily; therefore, the coal pile runoff either evaporates or infiltrates to the 

groundwater.

• HB Robinson stated that they tested the use of SynFuel in the coal-fired unit 

because there was a tax incentive associated with using the fuel. HB Robinson 

described SynFuel as recycled coal fines that are combined together using a 

binder. [QUESTION FOR HB ROBINSON: When did the plant test the SynFuel 

and for how long?]

Ash Handling Operations

• HB Robinson operates a cold-side electrostatic precipitator (ESP) on the coalfired unit to collect the fly ash from the flue gas.

• The fly ash from the ESP is collected dry in the hoppers and a hydroveyor system 

pulls a vacuum to remove the fly ash from the hopper. The fly ash is pulled by 

vacuum to the hydroveyor junction where the fly ash is mixed with the sluice 

water. The fly ash sluice is then sent through an air separator to remove and vent 

the air present in the fly ash sluice.

• HB Robinson operates a wet bottom ash handling system.

• The bottom ash sluice and the fly ash sluice waters are combined together and 

pumped to the plant’s ash pond.

• HB Robinson stated that they usually sluice the fly ash and the bottom ash once 

per shift. The combined ash sluice flow rate is approximately 2 MGD.

Ash Pond

• The ash pond at HB Robinson receives fly ash sluice, bottom ash sluice, metal 

cleaning wastes associated with the coal-fired unit (internal Outfall 007) and 

stormwater from the Darlington County internal combustion turbines area of the 

plant. [QUESTION FOR HB ROBINSON: Are the metal cleaning wastes 

associated with the coal-fired unit only or both coal-fired and nuclear units?]

• The ash pond has a footprint of approximately 55 acres. 

• HB Robinson stated that the ash pond was designed to maintain a minimum 

embankment freeboard capable of preventing overflow during a 50-year storm 
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event. [QUESTION FOR HB ROBINSON: What is the freeboard design basis for 

the pond (e.g., 50-year storm)?]

• The height of the pond embankment has been increased three times (in 1982, 

1992, and 2003). The current height of the pond embankment is approximately 31 

feet.

• The ash pond has an outfall pipe (internal Outfall 005) into the discharge canal. 

However, the plant does not typically discharge from the ash pond. [QUESTION 

FOR HB ROBINSON: When was the last time the plant discharged from the ash 

pond?]

• HB Robinson stated that the pond is not lined and that the soil below the pond is 

sandy and drains easily.

• Portions of the ash pond are completely filled with ash and the ash appears to be 

completely dried out. HB Robinson operates a sprinkler system on the pond for 

dust control. The sprinkler system is used 2-3 times per week on average.

• HB Robinson has three groundwater monitoring wells around the ash pond. The 

groundwater wells were placed in order to monitor the groundwater as it migrates 

away from the pond and towards Lake Robinson. Additionally, there is a 

“control” monitoring well located on the west side of the ash pond. There is also 

a monitoring well located near the retention basin. 

• HB Robinson is required to monitor the groundwater semi-annually at all four of 

its wells. HB Robinson monitors for the following parameters: water level, 

turbidity, acid digestion (liquids), arsenic, zinc, sulfate, specific conductance, total 

dissolved solids, cadmium, chromium, copper, and pH. The two most recent 

groundwater monitoring reports are included as Attachments 2 and 3 of this 

memorandum.

Furnace Sorbent Injection System and Dry Fly Ash System

• HB Robinson does not operate a FGD system for sulfur dioxide control; however, 

the plant did install and operate a furnace sorbent injection (FSI) system 

temporarily in 2008 to test the technology. [QUESTION FOR HB ROBINSON: 

When and how long did the FSI system operate at the plant?] The FSI system 

consists of injecting lime into the boiler to control sulfur dioxide emissions. 

[NOTE TO HB ROBINSON: Please provide a copy of all FSI engineering reports 

and/or summary reports.]

• As part of the study, HB Robinson installed a dry fly ash handling system to 

capture the fly ash and transport it to a storage silo.

• The dry fly ash handling system uses vacuum pumps that were installed that pull a 

vacuum on the ESP hoppers and pull the fly ash to the transfer hoppers. These 

transfer hoppers are needed to move from a vacuum system to a pressure blower 
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system. From the transfer hoppers, the fly ash falls by gravity to another hopper 

where the blowers push the fly ash approximately 1,500 feet to the fly ash storage 

silo. [QUESTION FOR HB ROBINSON: In the transfer hoppers, how are the 

particles collected prior to falling into the hoppers below? Baghouse filters? What 

happens to the exhaust gas?]

• The fly ash storage silo has enough capacity to store approximately five days 

worth of ash when operating at full load. The plant has the capability to load 

open trucks with fly ash. Additionally, they have the capability to add water to 

condition the fly ash. HB Robinson does not have the capability to load closed 

trucks with fly ash. [QUESTION FOR HB ROBINSON: What is the source of 

water used to condition the fly ash?]

• HB Robinson stated that the FSI system was installed only for the purposes of 

testing the technology; however, the plant is still considering the technology for 

full time operation. HB Robinson stated that they are also considering several 

other technologies for sulfur dioxide controls. Additionally, HB Robinson is 

considering operating the dry fly ash handling system full time. However, 

because the plant does not currently have a contract set up to market the fly ash 

and the plant does not have a landfill on site to dispose of the fly ash, they will 

continue to use the wet fly ash handling system. 

• HB Robinson stated that the installation of the FSI system did not require any 

major modifications to the existing wet fly ash handling system.

• The major pieces of equipment included in the FSI/dry ash handling system are: 

three lime storage silos, lime injection nozzles, two vacuum pumps, two blowers, 

two transfer hoppers, 1,500 feet of high-pressure piping, and one fly ash storage 

silo. [QUESTION FOR HB ROBINSON: What was the cost for installing the FSI 

injection equipment? Additionally, what was the cost of installing the dry fly ash 

handling equipment?]

• HB Robinson stated that the FSI system reduces the efficiency of the boiler. 

[QUESTION FOR HB ROBINSON: How much does the FSI system reduce the 

efficiency of the boiler?]
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NPDES Outfalls

• Outfalls 008 and 009 are internal outfalls for the plants east and west retention 

basins, respectively. The east retention basin receives the yard drain stormwater 

from the coal-fired unit (Unit 1) and the west retention basin receives the yard 

drain stormwater from the nuclear unit (Unit 2). Both basins store approximately 

800,000 gallons. 

• The effluents from the two retention basins (Outfalls 008 and 009) are combined 

and transferred to the discharge canal. The pH of the retention basins is typically 

between 4.5 and 5.2 S.U.; therefore, the plant has an automated neutralization 

system which controls the pH by adding sodium hydroxide prior to water entering 

the discharge canal. 

• The retention basins do not have a synthetic material lining. [QUESTION FOR 

HB ROBINSON: Please describe the design and any linings of the retention 

basins.]

• Outfall 011 is the discharge from a ditch that flows into Black Creek. The 

discharge consists of stormwater runoff from the parking lots and administration 

buildings. 

• Outfall 013 discharges steam generator blowdown. HB Robinson operates three 

steam generators. The blowdown rate is approximately 25-50 gpm per generator, 

which is approximately one percent of the water volume in the steam cycle. 

• Outfall 014 is the discharge from the discharge canal to Lake Robinson and the 

outfall is located at the head of the discharge canal. 

• The on-site sanitary treatment plant discharges to the discharge canal via Outfall 

003. Sludge from the sanitary plant is sent off site by a waste disposal company. 

Metal Cleaning

• Metal cleaning of the nuclear unit’s steam generators consists of adding chemicals 

to the steam generators to maintain a pH of 9.8 to 10.1. HB Robinson adds ETA 

(ethanolamine) and hydrazine to increase the alkalinity within the steam 

generators and prevent corrosion.

• Adding alkalinizing chemicals generates sludge piles in the heat exchanger tubes 

within the steam generator. During plant outages, contractors perform sludge 

lancing to remove the accumulated sludge. Sludge lancing consists of using a high 

pressure water wash to remove sludge deposits. HB Robinson stores the 

wastewater from sludge lancing (which includes the sludge and the water used in 

lancing) in frac tanks. A waste disposal vendor ships the wastewater off site. HB 

Robinson stated that they must prove to the vendor that the waste is nonhazardous.
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• HB Robinson performs metal cleaning operations on the coal-fired unit’s boiler 

tubes by adding several chemicals, including citric acid or EDTA. 

• Metal cleaning on the coal-fired unit cooling system is performed every 7-10 

years and generates approximately 58,000 gallons of wastewater. The last two 

metal cleaning operations occurred in 1998 and 2007. In both cases, the metal 

cleaning wastes were sent to the ash pond.

• In 2007, the metal cleaning operation generated wastes that contained 1,520 

ponds of iron, 239 pounds of copper, and 2,110 pounds of iron oxide. 

• HB Robinson does not perform washes on the fire side of the boiler.
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Table 2. Site Visit Attendees

Name Organization (Representing) Telephone E-mail

Ken Kirkland H.B. Robinson

Willy Gilbert H.B. Robinson

Garrett Sanders H.B. Robinson

Ken Hatchel H.B. Robinson

Andy Kohl H.B. Robinson

Fred Holt Progress Energy

Robin Bryson Progress Energy (919) 546-3962 robin.bryson@pgnmail.com

Donna Hill UWAG (205) 257-5234 dbhill@southernco.com

Josh Hall EPA/Office of Water (202) 566-1003 hall.josh@epa.gov

Jezebele Alicea EPA/Office of Water (202) 566-1755 alicea.jezebele@epa.gov

TJ Finseth ERG (Contractor to EPA) (703) 633-1698 thomas.finseth@erg.com

Kurt Blohm ERG (Contractor to EPA) (703) 633-1675 kurtis.blohm@erg.com

[NOTE TO HB ROBINSON: Please provide contact information for all personnel for which information is missing.]