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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 54506 | 31 January 2020 06:00:00 | 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | Part 21 - Unknown Tightness of Cam Thrust Lock Nut Assembly | The following information is a summary of information received via facsimile: On January 31, 2020, Fairbanks Morse (FM) submitted information of a defect or failure of the unknown tightness of the opposed piston (OP) diesel engine cam thrust lock washer and lock nut assembly for emergency diesel generators (EDGs). FM assembled and completed a factory acceptance test on a 1000 rpm new opposed piston diesel engine generator set. Upon post-test inspection it was discovered that the lock nut and lock washer had fallen off of the camshaft. The failure did not prevent the engine from starting, accelerating to rated speed as well as accepting and sustaining rated load. The failure does not result in an immediate engine shutdown or load rejection. The timing chain restrains the camshaft adequately for the engine to perform its emergency function. However, it cannot be concluded that the engine would continue to operate for the entire duration of its safety function. This Part 21 notification is being issued for subject engines with less than 98 hours of operation since the camshaft lock nut assembly was tightened. This Part 21 notification is being applied only to engines with less than 98 operating hours since the cam lock nut assembly was tightened for the following two reasons: 1) There are no known occurrences of cam lock nut assembly failures on any 900 rpm FM OP engines. All FM OP engines in service as EDGs in the United States are 900 rpm and 2) A laboratory analysis of the failed components conclusively shows this failure is an infant mortality. In the event the cam lock nut is loose, the lock washer will fail very quickly upon engine operation. FM has defined the appropriate tightening value to the cam lock nut assembly in Service Information Letter SIL-40 and has provided this guidance to all licensees that possess FM OP engines. FM has updated all internal engineering specifications and manufacturing instructions to include the newly specified tightening requirements. There are no 10 CFR 50 Appendix B FM OP engines being newly constructed. A list of affected customers are: Exelon - Peach Bottom Nuclear Generating Station and Southern Nuclear / Georgia Power - Hatch Nuclear Power Plant FM Notification Report Serial Number 20-01 | Emergency Diesel Generator | |
| ENS 48850 | 28 January 2013 05:00:00 | 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | Part 21 Report - Foreign Material Inside Edg Air Start Piping | Facility Affected: Xcel Energy - Prairie Island Nuclear Generating Plant (PINGP). Component Affected: OP Engine- Air Start Piping Assemble (p/n 11879060*00) shipped after October 23, 2012. Supplier: Fairbanks Morse Engine, 701 White Ave., Beloit, WI 53511. Nature of Defect: During a routine emergency diesel generator (EDG) test on 1/28/2013, one of the two redundant air start systems was isolated from the other and the single air start system failed to start the EDG due to the foreign material in the solenoid valve. The foreign material removed from the solenoid valve during failure analysis appears to be liquid pipe sealant used to seal threaded pipe joints during assembly. Safety Hazard Which Could Be Created By Such Defect: Foreign material within both of the redundant air start piping systems could become lodged in both of the solenoid valves. Simultaneous failure of the two solenoid valves would prevent the emergency diesel generator from starting. Corrective Action: PINGP has completed disassembly and cleaning of both piping systems to ensure no foreign material remains within the piping system. FM will create a workmanship standard for pipe sealing, hydrostatic testing, and pressure testing that will include a foreign material exclusion program to ensure cleanliness of assemblies. This will be completed by June 30, 2013. FM has issued Corrective Action No. 2609 in its Quality Assurance Program. | Emergency Diesel Generator | |
| ENS 48359 | 28 September 2012 05:00:00 | 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | Part 21 - Fairbanks Morse Opposed Piston Edg Fuel Oil Pump Leak | The following information was received via fax and email: Utilities operating Fairbanks Morse (FM) Opposed Piston (OP) Emergency Diesel Generators (EDG) are as follows: Constellation Energy - Calvert Cliffs; Dominion - North Anna, Millstone; DTE - Fermi II; Entergy - Vermont Yankee; Arkansas Nuclear One; Exelon - Limerick, Peach Bottom, Three Mile Island; Next Era Energy - Duane Arnold; Progress Energy - H.B. Robinson, Crystal River 3; Southern Company - Georgia Power (Plant Hatch), Alabama Power (Plant Farley); Xcel Energy - Prairie Island. The defect is a significant oil leak from the fuel oil pump shaft. Leakage will occur if the mechanical seal area within the pump is displaced by an impact to the pump shaft during shipment and handling. Even with a significant leak the pump has sufficient capacity to provide the proper operating pressure and volume of fuel oil to start the engine / EDG within the design specifications and continue operating the EDG at 100% load. However, the significant amount of fuel oil leaking while the system is under pressure, during standby and operating conditions, could potentially result in having an inadequate volume of stored fuel for the EDG to fulfill the seven day operating mission. FM has instituted the following corrective actions which will be effective on all shipments after September 28, 2012: 1. Hydrostatic testing will be performed at FM during the dedication. 2. Outgoing shipments will be packaged in accordance with a new packaging procedure which requires the pump be secured to a piece of wood or directly to a skid, thus prevents an impact to the shaft during shipment. Customers should perform a visual inspection after installation to ensure the fuel pump has no leaks. Defective pumps will have an immediate and significant leak. All installed pumps that are free of leaks are acceptable for continued operation. Fairbanks Morse Report Number 12-01 - Issued Sept 28, 2012 | Emergency Diesel Generator | |
| ENS 46598 | 7 February 2011 06:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Potential Emergency Diesel Generator Bearing Failures | The following information was received via e-mail: Linear indications (hot tears) were observed on one main bearing by the FM (Fairbanks Morse) production inspector. The indications were only on one edge of the bearing. The indications went across the entire edge and extended about 1 inch deep into the bearing, being visible on the outside diameter and the inside diameter for about 1 inch. Subsequent 100% liquid penetrant inspection (PT) of all finished bearings in stock has found linear indications on 13 of 454 bearings (3% reject rate) made from permanent mold castings. No bearing failures in engines have been linked to linear indications. The root cause of the problem occurs during the casting of the aluminum material in the permanent mold. The linear indications occur only on one edge of the casting, which has been identified as the bottom of the casting. During the cooling and solidification of the molten material poured into the permanent mold tool, the material shrinks and must be continuously replenished with molten material from the top of the casting. If the top of the casting solidifies before the bottom, there is no additional molten material available from the top to feed the bottom as it cools and shrinks, resulting in tears (hot tears) to the material on the bottom of the casting. It is suspected these hot tears are occurring due to improper cooling of the mold tool core. Because there are no cooling passages within the solid mold tool core, the core becomes progressively hotter throughout the production run until the core reaches a temperature hot enough to cause the hot tears. Affected plants are: Limerick, Peach Bottom and Prairie Island. | Emergency Diesel Generator | |
| ENS 44178 | 29 April 2008 05:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Part 21 Notification Regarding Identification of Defect Alco Snubber Valve Micro-Cracking | The reporting organization provided the following information via facsimile: Name and address the individual or individuals informing the Commission. Mr. Dominic Dedolph, Manager, Quality Assurance, Fairbanks Morse Engine, 701 White Avenue, Beloit, WI 53511. Identification of the facility, the activity, or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect: Facility- Entergy (Indian Point). Basic component which fails to comply or contains a defect: ALCO Fuel Snubber Valve P/N 2402466-1. The snubber valves in the Emergency Diesel Generator are installed in the high pressure fuel line between the fuel injection pump and the injection nozzle and serve as a pulsation dampener. Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply. Nature of defect: Fairbanks Morse Engine (FME) evaluation has determined that a potential safety hazard exists for ALCO fuel injection snubber valves due to micro-cracking in the tip of the snubber valve created during the material surface hardening process when the tips of the snubber valve were quenched in water. Safety hazard which could be created by such defect: Micro-cracking in the tip of the snubber valve could potentially lead to material flaking . It has been postulated that the flakes (or particles) could be flushed downstream and become lodged in the nozzle, causing excessive fuel to enter the combustion space and wash the cylinder liner dry and lead to a piston seizure. The date on which the information of such defect or failure to comply was obtained. Deviation discovered on February 29, 2008. Evaluation completed on April 28, 2008. The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action. Root cause analysis was performed and found that water quenching during the heat treatment process resulted in approximately 40% of the tips of the snubber valves to have micro-cracking present. When oil was substituted for the quenching medium, no snubber valves showed any signs of micro-cracking. The heat treatment process documentation has been updated to specify the quenching medium as oil. Oil has been used exclusively in the heat treatment process of all snubber valves produced by FME since March 1, 2008. Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees. FME is notifying Entergy (Indian Point) of the twelve (12) suspect pieces. | Emergency Diesel Generator | |
| ENS 43235 | 13 March 2007 17:00:00 | 10 CFR 21.21 | 10 Cfr 21 Notificaton - Identification of Defect Woodward Governor Pivot Pin Defect | This Part 21 was received via facsimile Pursuant to 10 CFR 21.21 (d)(3)(ii), Fairbanks Morse Engine is submitting a written notification on the identification of a defect that is considered to be a substantial safety hazard. (II) Identification of the facility, the activity, or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect. Facility: Duane Arnold Energy Center Basic component which fails to comply or contains a defect: Woodward governor actuator model EGB13P, part number 16403190, Woodward part number 9903-561 for Fairbanks Morse Engine Emergency Diesel Generator (EDG). (iii) Identification of the firm constructing the facility or supplying the basic component which fails to comply or contains a defect. Fairbanks Morse Engine 701 White Avenue Beloit, WI 53511 (IV) Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply. Nature of defect: Per Woodward service bulletin 01393 dated January 2007, a pivot pin within the governor actuator was manufactured from incorrect material. The subsequent case hardening of the pivot pin made from incorrect material resulted in through hardening, making the pivot pin more brittle. Safety hazard which could be created by such defect: Per Woodward service bulletin 01393, a potential for pivot pin fracture exists which would result in the governor actuator going to the minimum fuel setting. The EDG would not be capable of carrying load under this condition. The inability of an EDG to carry a load during a design basis event would be considered a loss of safety function. (v) The date on which the information of such defect or failure to comply was obtained. Fairbanks Morse Engine received Woodward service bulletin 01393 on 1/11/07. Duane Arnold Energy Center was notified of this situation via e-mail dated 1/12/07. (vi) In the case of a basic component which contains a defect or fails to comply, the number and location of all such components in use at, supplied for, or being supplied for one or more facilities or activities subject to the regulations in this part. The list of potentially affected governor actuators identified in Woodward service bulletin 01393 contains only 3 units (serial numbers 14693610, 14687576 and 14699005) that were purchased by Fairbanks Morse Engine on purchase order 1079037-I. All 3 units were sold to Duane Arnold Energy Center and had not been assembled to the EDGs. (vii) The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action. The 3 units were repaired at Woodward on 1/18/07 by replacing the though hardened pivot pin with one that was from a lot that was verified via destructive analysis to be hardened to the properly case depth. All future lots of pivot pins will have case depth measurements taken to ensure proper case depth. (viii) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, Is being, or will be given to purchasers or licensees. The need for repair of the 3 units was communicated to Duane Arnold Energy Center on 1/12/07. The repaired governor actuators were returned to Duane Arnold Energy Center on 1/26/07. | Emergency Diesel Generator |