Conesville Power Plant - Executive Summary
The Conesville Plant is a coal-fired electric utility that incorporates six units to generate electricity. The plant is owned by American Electric Power and is located in Conesville, Ohio. The plant has operating under a Title V operating permit issued by the Ohio Environmental Protection Agency in 1998. Anhydrous ammonia is the only chemical identified in the Risk Management Program is utilized above a threshold quantity in a process at the facility. The anhydrous ammonia system is used on Unit 4 at the plant to improve the efficiency of collecting coal combustion by-products in the electrostatic precipitator. |
To prevent an accidental release of anhydrous ammonia, the plant uses a system that incorporates employee training, system inspections, and a facility wide emergency action plan. The employee training program includes a general awareness of the hazards and associated emergency action plan related to anhydrous ammonia for all employees at the plant. While for employees tha
t work with the system, more specific training is provided related to maintenance, inspections, safety, and operation of the system. Additional awareness and emergency action information is provided to contractors that or working on or adjacent to the anhydrous ammonia system.
The mechanical integrity program at the plant involves inspecting the system at various frequencies and in various detail to assure that the system safe and meets design specifications. In addition, the emergence action plan for the plant can be applied to the anhydrous ammonia system if an accidental release occurred. This plan is organized to mitigate a potential release and protect the safety of the employees and the public. The program incorporates a plan for notifying the Coshocton County LEPC and other responders that may be needed. Only one accidental release has occurred in the last five years (May 1996). The momentarily accidental release of a small amount resulted from the system not being corr
ectly vented. As a result, drawings, procedures, and clearance standards were updated and additional operator training was provided.
Using the EPA's OCA Guidance Reference Tables, an evaluation of a worst case and alternative case release was performed. The worst case release evaluated would occur if the entire contents of a full storage tank were release during atmospheric conditions conducive to producing minimum dilution and maximum dispersion. Although the potential for a release of this type to occur during these atmospheric conditions is very rare, the evaluation determined that the release could potentially impact public receptors nearby such as recreation areas, schools, and residences.
The alternative case release scenario evaluated was the same as the worst case release scenario, but it considered more realistic atmospheric conditions would be present if a release from the storage tank occurred. As with the worst case, the potential for this type of release to occur
is very rare. Compared to the worst case release, the alternative case would allow for the release to be diluted more rapidly and as a result have the potential to impact a smaller area could only possibly include a lesser amount of recreation areas and residences.
The combination of training, frequent inspections, and an established emergency action plan has produced a system that operates in safe and efficient manner. In addition, the plant adheres to the Process Safety Management requirements set forth by OSHA for the anhydrous ammonia system that adds additional safety and awareness to the system. As an action item from a recent process hazard analysis of the system, the plant is going to begin researching the potential for removing anhydrous ammonia from the plant and replacing it with a substance that does not fall under the Risk Management Program. Results of the evaluation should be completed by the end of 1999.