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Choctaw County Generating Station

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Facility #1 : Choctaw County Generating Stat


Basic Facility Info facility_Basic_Facility_Info help link help link  
Facility ID100000181741
Deregistered (Yes/No)No
Facility NameChoctaw County Generating Station
Street Address Line 12446 Highway 407 West
CityFrench Camp
StateMS
Zip Code39745
CountyChoctaw County
113th Congressional DistrictMS01: Mississippi 1
Owner or Operator NameGenOn Wholesale Generation, LP.
Parent CompanyGenOn Wholesale Generation, LP
Second Parent CompanyNRG Energy, Inc.
Latitude33.288861
Longitude-089.419611
Number of RMP Submissions3

Most Recent Submission Info facility_Most_Recent_Submission_Info help link help link  
RMP ID1000033110
Submission Typerevised submission for facility
Submission Date02/20/2013
Reason For Submission5-year update (40 CFR 68.190(b)(1))
Process Toxic Amount Total (lbs)223,878
Process Flammable Amount Total (lbs)0
Process Amount Total (lbs)223,878
Number of Potential Offsite Consequence Processes0
Potential Offsite Consequence Toxic Amount Total (lbs)0
Potential Offsite Consequence Flammable Amount Total (lbs)0
Potential Offsite Consequence Amount Total (lbs)0
All Process NAICS221112
Exec Summary Submission Date02/20/2013

Executive Summary facility_Executive_Summary help link help link (Facility #1 : Choctaw County Generating Stat, executive summary: all)

Executive Summary
INTRODUCTION



Choctaw County Generating Station is a natural gas-fired, electric power generating station located near French Camp, Mississippi. This 192-acre facility is located 1.5 miles west of French Camp, MS and 90 miles northeast of Jackson, MS, near the intersection of Highway 407 and the Natchez Trace Parkway.



The station currently employs approximately 12 full-time staff and a few contract employees. The facility was constructed and began operations in 2003, but went into "mothball" status in 2004. The facility returned to commercial operation status in 2007 and has remained in operation since that time.



The facility generates 844 MW of power from three natural-gas fired turbines. Each turbine unit is equipped with a Heat Recovery Steam Generator (HRSG) and a Selective Catalytic Reduction (SCR) system. The SCRs employ aqueous ammonia injection technology to control emissions of oxides of nitrogen (NOx). Aqueous ammonia is classified as a toxic chemical subject to the requirements of the RMP Program. The aqueous ammonia used in these SCR systems is a 30% solution of ammonia in water.



It should be noted that this facility was originally incorrectly classified as a Program 2 facility. During the course of the 2008 5-year renewal, it was determined that the facility should be classified as a Program 1 facility. No changes were made to the aqueous ammonia process to necessitate this change, and no changes have been made to the aqueous ammonia process since the 2008 RMP renewal. The facility maintains procedures and practices that are designed to meet the requirements of a Program 2 facility, and continues to keep the public informed on the facility's prevention and protection efforts.





1. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES AT THE STATIONARY SOURCE



Corporate policy is to comply with all applicable regulatory requirements, including those for accidental release prevention and emergency response.





2. THE STATI
ONARY SOURCE AND REGULATED SUBSTANCES HANDLED



a. PRIMARY ACTIVITIES



This facility is a natural gas-fired, electric power generating station.



b. USE OF REGULATED SUBSTANCES



The aqueous ammonia injection system at Choctaw County Generating Station is designed to remove NOx from boiler flue gas by SCR. This is accomplished by injecting an approximately 30% ammonia solution into the flue gas.



No other toxic or flammable materials are stored at the facility in quantities above the RMP regulatory threshold.



c. QUANTITIES HANDLED OR STORED



The aqueous ammonia system at Choctaw County Generating Station is comprised of one storage tank, transfer pumps, piping, instrumentation, and controls. The piping terminates at the vaporizer for each unit, where the aqueous ammonia is atomized and vaporized. The storage tank has a capacity of 31,862-gallons. Administrative controls are in place to ensure that the tank is not filled beyond 85% of its capacity (i.e. 9'5" liquid height or 27,083 gallons). For purposes of RMP release calculations, a conservative potential release amount of 30,000 gallons has been used. The tank is equipped with a pressure relief valve and vacuum breaker, as well as pressure and level indicators. The tank is located in a concrete diked area for secondary containment. The aqueous ammonia tanker truck unloading connections are located within the same secondary containment as the storage tank.





3. THE WORST-CASE RELEASE SCENARIO



a. WORST CASE RELEASE SCENARIO



The worst case release scenario (WCS) assumes that the entire contents of the aqueous ammonia tank is spilled into the secondary containment area, over time. The WCS can include the effects of passive mitigation systems, and for Choctaw County Generating Station this is the use of secondary containment to minimize ammonia liquid spills. The potential quantity released is calculated using:



30,000 gallons * 7.4626 lb/gal = 223,878 lb



Per EPA guidance, because the h
orizontal surface area of the secondary containment system (1960 ft2) is less than that of the worst-case liquid pool (no secondary containment, one-centimeter deep pool), the rate at which the material is released is calculated as:



1.4 x LFA (0.026 lb/min/ft2) x 1960 ft2 = 71.3 lb/minute



b. DISTANCE TO ENDPOINT



The offsite consequences of this accidental release scenario were evaluated with a screening computer dispersion model (RMP*Comp, online version). Offsite consequence analysis of the worst-case scenario must include the following improbable weather conditions: a wind speed of 1.5 m/s (3.4 mph), "F" atmospheric stability class, a temperature of 77 deg F, and relative humidity of 50%. In addition, although the facility is located in a "rural" area, "urban" topography was used to model the dispersion created by the power plant buildings and surrounding forest.



The maximum calculated distance to the endpoint using the RMP*Comp model is 0.2 miles for the worst-case scenario for aqueous ammonia. This represents the maximum downwind distance that the catastrophic release (under worst-case weather conditions) could pose a hazard to the public. There are no public or environmental receptors within the radius of impact.





4. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS



The aqueous ammonia storage and handling system prevention program includes the following components:



- The ammonia storage tank is built to exacting standard;



- Ammonia tank trucks will only by unloaded during daylight hours on weekdays;



- A comprehensive plan covering all components of the aqueous ammonia system with respect to operation, maintenance, inspection, and training is in place at the facility;



- Internal compliance audits are conducted regularly;



- All incidents related to the aqueous ammonia system are investigated promptly.





5. FIVE-YEAR ACCIDENT HISTORY



No accidents as defined in 40 CFR Part 68 have
occurred during the past five years at this site.





6. THE EMERGENCY RESPONSE PROGRAM



In the unlikely event that an accidental release of ammonia would occur, an emergency response plan for the ammonia storage and handling system has been developed. This plan incorporates elements of the facility's Integrated Contingency Plan (ICP). Choctaw County Generating Station employees have been trained on this plan and would be first to respond in the event of an emergency. All Choctaw County Generating Station employees are trained and certified in HeartSaver First Aid and Class A, B, and C Fire Fighting. The French Camp Volunteer Fire Department would provide the first EMT response to the facility.





7. PLANNED CHANGES TO IMPROVE SAFETY



All station safety programs, including the emergency response program, are reviewed periodically for improvement opportunities. A hazard review of the aqueous ammonia storage and handling system at Choctaw County Generating Station was last conducted prior to start-up of the system in 2003. There are no planned changes to the system at this time.


Submission - Other Facility Info facility_Submission_-_Other_Facility_Info help link help link  
Number of Full Time Employees12
Owner or Operator NameGenOn Wholesale Generation, LP.
Owner or Operator Address Line 12446 Highway 407 West
Owner or Operator CityFrench Camp
Owner or Operator StateMS
Owner or Operator Zip39745
Parent Dun and Bradstreet Number0
Second Parent Dun and Bradstreet Number0
Number of Full Time Employees12
Number of FTE CBI FlagNo
Other Facility ID110009860962
Covered by OSHA PSM StandardNo
Covered by EPCRA Section 302Yes
Covered by CAA Title VYes
CAA Title V Air Operating Permit ID0400-00018
Last Safety Inspection Date11/06/2012
Last Safety Inspection ByState environmental agency
OSHA Star or Merit RankingNo
LEPC NameChoctaw County LEPC

Submission - Contact Info facility_Submission_-_Contact_Info help link help link (Facility #1 : Choctaw County Generating Stat, RMP submission #1 : 2013-02-20)
Owner or Operator Phone6625477001
Facility URLwww.nrgenergy.com
Facility Dun and Bradstreet Number0
RMP ContactHoward Holder
RMP Contact TitlePlant Manager
RMP Contact EmailHoward.Holder@nrgenergy.com
RMP Preparer NameJulia Parsons, PE
RMP Preparer Address Line 1Foster Plaza 6
RMP Preparer Address Line 2681 Andersen Drive, Suite 400
RMP Preparer CityPittsburgh
RMP Preparer StatePA
RMP Preparer Zip15220
RMP Preparer Zip Extension2749
RMP Preparer Phone4125034597

Submission - Additional Info facility_Submission_-_Additional_Info help link help link  
RMP DescriptionChoctaw RMP 2008 Revision
RMP Complete FlagYes
Predictive FilingNo
No RMP Accidents Last 5 YearsNo
Complete Check Date02/20/2013
Postmark Date02/20/2013
Anniversary Date02/20/2018
Confidential Business InformationNo

Submission - Lat/Long Info facility_Submission_-_Lat_Long_Info help link help link (Facility #1 : Choctaw County Generating Stat, RMP submission #1 : 2013-02-20)
Latitude33.288861
Longitude-089.419611
Valid Lat/LongYes
Lat/Long MethodInterpolation - Other
Lat/Long Location TypeStorage Tank
FRS Latitude33.28
FRS Longitude-89.41
FRS Lat/Long DescriptionSTORAGE TANK

Submission - Counts and Totals facility_Submission_-_Counts_and_Totals help link help link  
Number of RMP Accidents0
RMP Accident Flammable Total (lbs)0
RMP Accident Toxic Total (lbs)0
RMP Accident Amount Total (lbs)0
Number of RMP Accidents0
Number of Processes1
Number of Process Chemicals0
Number of Toxic Worst-case Scenarios1
Number of Toxic Alternate Case Scenarios0
Number of Flammable Worst-case Scenarios0
Number of Flammable Alternate Case Scenarios0
RMP Accident Flammable Total (lbs)0
RMP Accident Toxic Total (lbs)0
RMP Accident Amount Total (lbs)0
Total RMP Accident Deaths0
Total RMP Accident Injuries0
Total RMP Accident Evacuated/Sheltering In Place0
Total RMP Accident Property Damage$0

Processes facility_Processes help link help link (Facility #1 : Choctaw County Generating Stat, RMP submission #1 : 2013-02-20, process #1 : NH3 Storage and Handling)
Process DescriptionNH3 Storage and Handling
Program Level1
Confidential Business InformationNo
Toxic Amount Total (lbs)223,878
Flammable Amount Total (lbs)0
Process Amount Total (lbs)223,878
Number of Process Chemicals0
Number of Toxic Worst-Case Scenarios1
Number of Toxic Alternate Scenarios0
Number of Flammable Worst-Case Scenarios0
Number of Flammable Alternate Scenarios0

Process Chemicals facility_Process_Chemicals help link help link  
Process Chemical IDAmmonia (conc 20% or greater)
CAS number007664417
Chemical TypeToxic
Process Chemical Amount (lbs)223,878
Confidential Business InformationNo

Process Chemicals facility_Process_Chemicals help link help link (Facility #1 : Choctaw County Generating Stat, RMP submission #1 : 2013-02-20, process #1 : NH3 Storage and Handling, process chemical #2)
Process Chemical IDPublic OCA Chemical
CAS number000000000
Process Chemical Amount (lbs)0
Confidential Business InformationNo

Worst-Case Toxic Scenarios facility_Worst-Case_Toxic_Scenarios help link help link  
Percent Weight (Within Mixture)30
Physical StateLiquid
Model UsedEPA's RMP*Comp(TM)
Release Duration (minutes)3,139.9
Wind Speed (meters/sec)1.5
Atmospheric Stability ClassF
TopographyUrban
Passive Mitigation - DikesYes
Passive Mitigation - EnclosuresNo
Passive Mitigation - BermsNo
Passive Mitigation - DrainsNo
Passive Mitigation - SumpsYes
Confidential Business InformationNo

Process NAICS facility_Process_NAICS help link help link (Facility #1 : Choctaw County Generating Stat, RMP submission #1 : 2013-02-20, process #1 : NH3 Storage and Handling, process NAICS code #1 : 221112)
NAICS Code221112: Fossil Fuel Electric Power Generation

Emergency Response Plan Info facility_Emergency_Response_Plan_Info help link help link  
Facility In Community PlanNo
Facility Own Response PlanYes
Specific Facility Response PlanYes
Inform. Procedures in Response PlanYes
Emergency Care in Response PlanYes
Plan Review Date02/13/2013
Response Training Date02/13/2013
Local Response AgencyChoctaw Co. LEPC - Brent McKnight
Local Response Agency Phone6622857495
Subject To - OSHA EAPYes
Subject To - OSHA HAZWOPERYes
Subject To - CWAYes
Subject To - RCRANo
Subject To - OPANo
Subject To - State EPCRAYes


Search Criteria Used
RMP Facility ID100000181741

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