Lesson Learned Statement:To help ensure the safety of personnel and the safe operation of potentially dangerous equipment, it is extremely important that manufacturer's operations and maintenance instructions are strictly adhered to. Manufacturers instructions may include: periodic maintenance and testing of equipment, training of personnel, equipment configuration, and proper operating parameters (ie. air pressure, temperature, etc.). In addition, when manufacturers make administrative changes to the operation and/or equipment modifications, site specific operational procedure changes may be necessary.
Discussion:On December 3, 2001, while performing an in place leak test using polyalphaolefin (PAO) in a Nucon F-1000-DG thermal aerosol generator, a small fire erupted at the generator outlet. The fire appeared shortly after the operator observed PAO dripping from the generator outlet port and closed the vapor adjust valve. The fire did not spread and was safely extinguished, however, the operator received second degree burns on his right hand. The burns occurred when he grabbed the thermally hot generator and re-directed the flames away from the PAO inlet piping.
In April 1999, WVNSCO had a similar fire using PAO and the same type of aerosol generator. Corrective actions from that event resulted in design changes to the unit which were expected to prevent similar events. Those design changes included both heater replacement and vapor adjust valve modifications which were to prevent complete closure of the valve.
Analysis:During the event investigation, it was determined that although the modifications were completed on the generator that was used, the generator was not operated per the current manufacturers operations and maintenance manual. First, a pipe nipple was being used on the generator outlet. Although this nipple was at one time recommended by the manufacturer, its use was specifically prohibited in the latest manufacturers operations and maintenance manual.
Secondly, the generator was operated using only 55 PSI of compressed air. The most current manual states operating pressure between 60-115 PSI.
Lastly, the operating procedure did not include a checklist to ensure that the generators valves and switches were properly aligned prior to equipment start-up. Although each item was addressed in the latest manufacturers operations and maintenance manual, they were not properly incorporated into the facility specific operating procedure.
Recommended Actions:One action that resulted from this event is to designate a Cognizant System Engineer to be responsible for the overall PAO testing program. This person's responsibilities would include being able to identify and maintain all PAO related equipment, procedure changes and be able to make the determination whether additional training is necessary after such changes.
Secondly, WVNSCO will revise and update the procedure for in place leak testing HEPA Filters and the PAO training program. This revision will incorporate the latest changes to proper personal protective equipment requirements, in addition to including the latest cautions, warnings and operational steps for the Nucon F-1000-DG thermal aerosol generator as provided by the manufacturer (latest manufacturer manual to date is Nucon Manual NIM 11-PAO, Rev. 1, dated December 11, 2002).
Third, training needs to stress the importance of properly opening and adjusting the "vapor adjust valve" on the thermal aerosol generator.
When new or updated operations and maintenance manuals are received from the manufacturer, site specific operational procedures should be reviewed for applicability to help ensure the equipment is being operated safely and properly.
Originator:West Valley Nuclear Services, Larry Myszka (716)942-4727
Validator:Joe Marek (716)942-4370
Contact:Joe Marek (716)942-4370
Name Of Authorized Derivative Classifier:N/A
Name Of Reviewing Official:N/A
Priority Descriptor:Yellow / Caution
Keywords:HEPA; PAO Testing
References:OccurRence Report No. OH-WV-WVNS-CF-2001-0003
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DOE Function / Work Categories:Conduct of Operations - Work Control
Maintenance - HVAC
Training & Qualifications
ISM Category:Perform Work
Hazard:Fire / Smoke / NFPA
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