Fort Madison Water Treatment Plant - Executive Summary |
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Chlorine is utilized as the Fort Madison Water Treatment Plant (WTP) to purify water for drinking. Chlorine equipment and related procedures are designed to maintain the safe handling and use of chlorine. In the Fort Madison WTP five-year accident history, no off-site accidental releases of chlorine have occurred. Chlorine is stored in quantities up to 8,000 pounds in a Program 3 process. The Fort Madison WTP operates with two chlorine ton containers connected to the chlorine manifold. Also, located in close proximity are two additional ton containers. The chlorine process, as defined under RMP requirements, includes vessels that are interconnected and co-located. The worst-case scenario assumes that 2000 pounds of chlorine are released from a ton container as a gas in a ten minute period. However, the release rate of chlorine from the chlorine building is estimated to be 55% if the release rate from the container due to the passive mitigation of the chlorine building. The rel eased plume is estimated to travel 0.9 miles before no longer posing a hazard to the public. The alternative scenario assumes the release of chlorine from a ton container due to a valve failure, bad flexible tubing connection, or flexible tubing failure. Any of these events could release chlorine gas through the 5/16 inch diameter valve body opening. Over a 60 minute period, 318 pounds of chlorine are estimated to be released. This release is predicted to travel 0.31 miles before no longer posing a hazard to the public. The Fort Madison WTP uses a variety of equipment and procedures to prevent accidental releases. The process is a vacuum system for gas feed of the chlorine. Among this equipment are monitors to detect releases, vacuum regulators on the chlorine flow from the chlorine containers, the chlorine building with its fire prevention design, and chlorine containers in conformance with ASME code. Procedures include the safe storage of chlorine containers, periodic inspe ctions and maintenance of the chlorine equipment, maintenance that requires regular part replacement, the review of proposed chlorine process changes to preserve the safe operation of the chlorine process, the periodic review of process hazards, and steps to investigate releases that do occur in order to prevent reoccurrence. These procedrues and more have been developed through the OSHA PSM abd RMP Program 3 requirements. Recent chlorine process equipment replacements at the Fort Madison WTP signficantly improve the potential for safe plant opertions. In the event of an accidental release, the Fort Madison WTP has coordinated and pre-planned response activities with offsite responders. Fort Madison WTP employees will evacuate the site and notify these responders according to the Fairfield WTP emergency action plan. |