SWEPCO Wilkes Power Station - Executive Summary
RMP DATA ELEMENT - Executive Summary |
SWEPCO Wilkes Power Station
Wilkes Power Station is one of five natural gas fueled power generating facilities in the Southwestern Electric Power Company (SWEPCO) subsidiary, which includes a total of nine generating facilities throughout East Texas, Louisiana and Arkansas. This site is located in Marion County near the city of Avinger, TX. The facility has 34 full time employees.
Southwestern Electric Power Company (SWEPCO) is an investor-owned utility. The company's common stock is held by Central and South West Corporation, a registered public holding company headquartered in Dallas, Texas and Tulsa, Oklahoma.
The facility is a three-unit steam electric power station with a total generation of approximately 800 mw. It burns natural gas as the primary fuel. Units 2 and 3, rated at 323 mw each, were installed in 1970 and 1971 respectively. Unit 1, rated at 160 mw was installed in 1964. All three units have General Electric turbines. One Combu
stion Engineering and two Babcock and Wilcox boilers provide steam.
The following information is part of a complete Risk Management Plan (RMP) that was prepared for the SWEPCO Wilkes Power Station. The information includes accident prevention and safety programs, emergency preparedness and response programs, chemical description, five year accidental release history, alternative release scenario and the worst case scenario. The sharing of this type of information is a means to improve community safety, not a prediction of the probability that either a worst case or more likely scenario would ever occur. These scenarios are estimates required by the Environmental Protection Agency and are used to illustrate the importance for risk reduction, safety, prevention and emergency preparedness and response.
The Wilkes Power Station has been producing electricity for over 35 years. During this time, there has not been any chlorine release that adversely impacted the plant or the surroundin
The release scenarios, a worst case scenario and an alternative release scenario, are designed to be exercises which calculate the potential impact on the community based upon extreme conditions defined by the governing agency, the Environmental Protection Agency (EPA). A worst case scenario is defined as the complete release of the largest inventory of the chemical over 10 minutes under weather conditions that would allow the chemical to travel as far as possible. The distance(s) used in this plan are from the EPA Offsite Consequence Analysis Guide (April 1999). It also assumes that none of the site's mechanical controls or safety systems is operational for this theoretical exercise. However, the laws of physical science do not allow a complete release of the chemical as described in the worst case scenario.
The worst case scenario for the Wilkes Power Station involves a cylinder containing 2,000 pounds of chlorine. The entire quantity is released and vaporizes over a
10 minute period and the resulting vapor cloud travels down wind. A level of concern to the community extends 3.0 miles down wind.
Given these unrealistic guidelines of a worst case scenario, more realistic scenarios or alternative release scenarios were also developed. These scenarios involve smaller releases and allow a site's safety systems to work. The alternative release scenario may be used by local government and industry to prepare emergency response plans.
The alternative release scenario for the Wilkes Power Station involves the failure of a one-fourth inch pigtail or similar connection releasing chlorine for a duration of 60 minutes. The resulting cloud extends 0.3 miles down wind.
SWEPCO chlorinating systems are built and installed with safety controls designed to prevent accidental releases. Some of the typical safety equipment and systems used at the plant include:
- Storage cylinders meeting American Society of Mechanical Engineering requirements
- Automatic sh
- Interlocks and relief valves
-Specifically designed pressure gauges, fittings, connections, tubing and piping.
Plant employees, including plant operators, electricians, mechanics, and laboratory technicians, receive training in the operation and maintenance of the chlorination system. This training includes emphasis on:
- Specific safe work practices
- Routine operating procedures
- Audit and inspection procedures
- Emergency operation including shut down
- Alarms and emergency notification procedures.
SWEPCO has an established Preventative Maintenance Procedure specifically developed for the chlorination system. This procedure requires:
- Periodic inspection and testing of all mechanical systems
- Detailed documentation of all inspection and maintenance activity
- Documentation of equipment deficiencies
- Timely and appropriate repair of all deficiencies.
A Process Safety Management System has been specifically developed for the chlorination syste
m at this plant in compliance with the Occupational Safety and Health Act Process Safety Management rule. This management system requires:
- An initial and periodic analysis of engineering and administrative controls
- Investigation procedures designed to resolve and correct potential incidents
- Formal audits performed by trained individuals with knowledge of chlorination systems.
All Plant personnel handling chlorine are specially trained. This training includes:
- Emergency shutdown
- Emergency operation of the chlorinator
- Hazards of chlorine
- Safety procedures to be followed during normal operations
- Emergency Response Procedures
- Notification procedures
- Evacuation procedures.
Periodic inspection of the equipment is mandatory. Repairs are required on all items identified as defective during inspections.
If a release occurs, only trained Emergency Response Personnel will respond to assess and stop the leak. In all cases, necessary actions will be taken to con
trol the release of chlorine.
- The Plant Control Room will be notified immediately if a chlorine leak is detected.
- Control Room personnel will coordinate emergency response procedures.
- Emergency response procedures may include:
- Notification of authorities
- Evacuation of plant personnel
- Evacuation of public
- Notification of plant and/or company managers.
Southwestern Electric Power Company (SWEPCO) is committed to providing electricity to South Texas. We understand our responsibility to follow federal, state and local regulations in the most effective manner possible. SWEPCO is doing its part to provide a safe environment for the residents in our community.