Pacific Oroville Power, Inc. - Executive Summary |
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EXECUTIVE SUMMARY DESCRIPTION OF ACCIDENT PREVENTION AND EMERGENCY RESPONSE POLICY This facility complies with ASME Boiler and Pressure Vessel Code, Section VIII, Pressure Vessels, Division I (1992 edition) requirements for Chlorine-Gas storage. The chlorine supplier complies with Cylinder and Ton Container Procedures for Chlorine Packaging, Edition 2, Revision 1, June 1994. It is our policy to adhere to all applicable federal, state, and local laws. Regular inspections of chlorine storage and piping systems ensure system integrity and provides for preventative maintenance and repairs. If an emergency were to occur, it is our policy to implement the emergency response procedures to mitigate damages, and to notify the Oroville Fire Department and request that they respond to the emergency. DESCRIPTION OF STATIONARY SOURCE This facility is a 22 MW electric power generation unit. Chlorine gas is used to prevent biofouling in the cooling tower and fire suppression pond and pumpin g system. The chlorine storage system at each process, consists of two, one-ton cylinders, with only one cylinder in service at any time. The system is designed to prevent rapid loss of chlorine gas. WORST CASE RELEASE SCENARIO The worst-case scenario is failure of one-ton cylinder when filled to the greatest amount allowed resulting in release of 2000 lbs. of chlorine gas. Sudden failure of the tank was assumed to release the contents, resulting in a cold vapor cloud that moves offsite under at 1.5 meters per second under stable atmospheric conditions that minimize mixing. The results of this analysis indicate that a worst case chlorine release results in a toxic endpoint (0.0087 mg/L) that extends 1.3 miles. Although the two chlorine processes are isolated with respect to each other, they are sufficiently proximate so that the affected area resulting from a worst case release from either process is the same. Therefore the worst case scenario is identical for both process locat ions. The possibility of an accident propagating to a second vessel was considered and rejected based on design tank integrity and nature of the materials. Only one tank is in service at any time in each process. The second tank is in storage with the valve bonnet attached. There is no foreseeable mechanism by which an accident could propagate to both tanks. ____________________________________________________________________________________ RMP*Comp Results of Consequence Analysis Chemical: Chlorine CAS #: 7782-50-5 Category: Toxic Gas Scenario: Worst-case Liquefied under pressure Quantity Released: 2000 pounds Release Duration: 10 min Release Rate: 200 pounds per min Mitigation Measures: NONE Topography: Urban surroundings (many obstacles in the immediate area) Toxic Endpoint: 0.0087 mg/L; basis: ERPG-2 Estimated Distance to Toxic Endpoint: 1.3 miles (2.1 kilometers) --------Assumptions About This Scenario--------- Wind Speed: 1.5 meters/second (3.4 miles/hour) Stability Cla ss: F Air Temperature: 77 degrees F (25 degrees C) _________________________________________________________________________________ ALTERNATE RELEASE SCENARIO An alternate release scenario was performed to evaluate the impact of a release caused by a broken main valve or loss of fusible plug. It was conservatively assumed that the controlled release under pressure would empty a full container in two hours at a rate of 16.7 lb/minute. The alternative scenario was evaluated at release rates up to 50 lb/minute for 40 minutes with the same endpoint result. The higher release rate may be possible with the loss of more than one fusible plug resulting from a fire proximate the chlorine container. Such a scenario would only occur in the event of a cooling tower fire with failure of the deluge fire control system, and failure to keep the cylinder cool in accordance with emergency response plan. Repair equipment is available at from the Kelly Ridge Fire Department that would likely resul t in repair prior to loss of the tank contents. The alternate scenario indicates that the endpoint distance extends 0.1 miles from the leak. Chlorine concentrations above the enpoint thesholds extend offsite and may affect industrial receptors to the North of the facility. No residences, schools, parks or other public receptors are within the endpoint distance of the alternate scenario. Any wind direction other than out of the south-southwest does not result in any offsite receptor exposure. The RMP*COMP model results of the highest alternate scenario release rate is shown. RMP*Comp Results of Consequence Analysis Chemical: Chlorine CAS #: 7782-50-5 Category: Toxic Gas Scenario: Alternative Release Duration: 40 minutes Release Rate: 50 pounds per min Mitigation Measures: NONE Topography: Urban surroundings (many obstacles in the immediate area) Toxic Endpoint: 0.0087 mg/L; basis: ERPG-2 Estimated Distance to Toxic Endpoint: 0.1 miles (0.2 kilometers) --------Assumptions About Th is Scenario--------- Wind Speed: 3 meters/second (6.7 miles/hour) Stability Class: D Air Temperature: 77 degrees F (25 degrees C) ------------------------------------------------ PREVENTION PROGRAM DESCRIPTION SAFETY INFORMATION This facility complies with EPA's accident prevention rule and all applicable state and local codes and regulations. The chlorine system is designed, installed, and maintained in accordance with ASME Boiler and Pressure Vessel Code, Section VIII, Pressure Vessels, Division I (1992 edition) requirements for Chlorine-Gas storage. The chlorine supplier complies with Cylinder and Ton Container Procedures for Chlorine Packaging, Edition 2, Revision 1, June 1994. Chlorine is a gas at normal temperatures and pressures. It is liquefied by storing it in a closed container at pressures higher than its equilibrium vapor pressure. PROCESS HAZARD ANALYSIS POPI utilized a professional consultant experienced in biomass power facilities and hazard analysis. A "Wha t-if" analysis was selected and utilized along with a checklist. The process hazard analysis was developed based on water treatment industry guidelines and process specific criteria. Certain initiating events were determined to pose a minimal risk. The facility is located outside of the 100 year flood plain (Zone X) and in an area if low-risk for seismic activity (Zone 3). Severe weather events are unusual, but a maximum wind speed of 80 MPH could occur in a severe thunderstorm or F-1 tornado. There are no flammables, explosives or incompatible organic chemicals in proximity to either chlorine process area that could cause, or contribute to, tank failure. Chlorine storage and use occurs at a location, remote from any roadways or railways, and is therefore not exposed to off-site traffic. Catastrophic failure of a tank was not identified as a likely scenario. The process hazard analysis identified scenarios that could cause equipment damage, or result in equipment failure with the worst case release being from a broken valve or failed fusible plug. Potentially catastrophic failures are adequately addressed by unit design and safety engineering integral to the cylinder and regulator unit. The PHA identified the need to modify several standard operating procedures, and identified labeling, flexible chlorinator line support and protection, and vehicle exclusion barriers as deficiencies to be addressed. OPERATING PROCEDURES Written operating procedures are in effect for general chlorine safety operations, container loading and unloading, normal startup, normal shutdown and emergency procedures. Supporting procedures apply for specific equipment operations such as crane safety procedures at SMP5. Chlorine cylinders are delivered by All Pure Chemical Company which operates in accordance with written Standard Operating Procedures. Procedures at the facility include off-loading delivery vehicle, mounting cylinders in operating position, removal and placemen t of cylinder shelters, installation of vacuum regulator, operation of manual shut-off valves, adjustment of chlorine eductor, maintenance and inspection of equipment and lines. Operating procedures are subject to routine review and modification. Qualified personnel in chlorine operations are trained in operating procedures and evaluated for competency. TRAINING Only trained personnel are authorized to operate equipment in chlorine service. Training includes chemical specific safety information, standard operating procedures, emergency response procedures, and equipment orientation. Supporting training programs include fork lift safety, vehicle safety, hazard communication, and fire safety, Each employee presently involved in operating or maintaining a process, and each employee before working in a newly assigned process, shall be trained in an overview of the process. At least every three years, and more often if necessary, refresher and supplemental training shall be provided t o each maintenance or operating employee and other workers necessary to ensure safe operation of the facility. Training certificates are maintained in employee records. Testing procedures are used to ensure competency in job skill levels and safe and healthy work practices. MAINTENANCE PROCEDURES The chlorine tank and associated piping and equipment are inspected on a regular basis with the objective of ensuring equipment integrity before breakdown occurs. The operation of valves and regulators are checked at each cylinder change. The gasket seal at the vacuum regulator is changed with each connection. Maintenance procedures are audited in accordance with the process safety management plan. INCIDENT INVESTIGATION POPI has established a written form for prompt reporting and investigating every incident which results in or could reasonably have resulted in a major accident. There has never been an accident resulting in injury or significant material release related to chlorine o perations. MANAGEMENT OF CHANGE POPI has established and implemented a written procedures to manage changes (except for "replacement in kind") to process chemicals, technology, and equipment, and changes to facilities. The chlorination process is relatively simple and process changes are not expected to occur unless alternative anti-biofouling chemicals are implemented or chlorine operations are consolidated at a new location. CONTRACTORS All visitors and contractors on site must register with the office. Contractors are informed of specific hazards in the areas they are assigned work, and are be accompanied by plant personnel for orientation. All contractors are required to produce proof of an adequate safety plan, and are required to conform to safety and environmental standards at the plant. Contractors that perform work at the facilities are required to participate in an orientation training session the first time that they are on site. The training includes site rules, ba sic safety requirements, handling of emergencies, fire protection information and hazardous materials present at the site. HOT WORK PERMITS A welding and cutting safety procedure is in effect. POPI has developed and implemented a written procedure for the issuance of "hot work" permits. No welding or hot work is required or authorized in the vicinity of the chlorine tanks. There are no welded fittings or pipelines. Repair of moveable shelters can be performed at a location remote from the tanks and pipelines. ACCIDENT HISTORY There have been no accidents related to the regulated equipment in the past five years, nor for the history of the facility. EMERGENCY RESPONSE PROGRAM POPI has developed and distributed a business plan for emergency response pursuant to subdivision (a) of Section 25503.5 and subdivision (b) of Section 25505 of the Health and Safety Code. A copy of the Business Plan is available in the Control Room and main office. Emergency response is based on recog nition and observation of potential emergency conditions, and immediate repair, or notification of the primary response agency. The policy for emergency response at Pacific Oroville Power is to immediately notify the hazardous materials response team (Kelly Ridge Volunteer Fire Dept.) of any emergency. The Kelly Ridge team is equipped to handle chlorine emergencies and maintains an inventory of repair parts including fusible plugs. POPI personnel are equipped only with escape breathing apparatus and will not respond to a significant leak or rescue situation. Small fires will be contained and mitigated with water sprays and fire extinguishing equipment onsite. Emergency notification is required for any release or threatened release of a hazardous material which poses a significant present or potential health, safety or environmental hazard. The plant manager is designated incident command when present. The senior operator is designated incident command when management is not pres ent. Incident command is transferred to emergency responders upon arrival. PLANNED CHANGES TO IMPROVE SAFETY A process hazard analysis was conducted on June 4, 1999 using a what-if and checklist analysis. Several deficiencies were identified that require modification. POPI is currently revising several standard operating procedures. Upon completion, these more detailed procedures will be implemented through training and review. The chlorine process areas were audited. Improved signs, vehicle exclusion barriers and general clean-up were identified as priorities. Improved lighting is to be installed for night operations. POPI is also in the process of evaluating leak detection and alarm equipment. Improved documentation of equipment being specifically approved for use in chlorine service is being obtained. |