ENS 47685
ENS Event | |
|---|---|
05:00 Feb 17, 2012 | |
| Title | Missing Upper Mounting Pads on Subcover Assemblies |
| Event Description | Engine Systems Inc. (ESI) began a 10CFR21 evaluation on 12/20/11 upon notification of an issue with four subcover assemblies at Perry Nuclear Power Plant. It was reported that Perry was performing a maintenance activity whereby they were replacing four cylinder head subcover assemblies on their Enterprise diesel engine. During installation, it was noted that qty. 2 of 11 bolt holes were missing an upper mounting pad. This was visually apparent once the customer attempted to install the bolts, which have a 6" length. The two areas missing the upper landing pad did not have an area for the underside of the bolt head to rest upon.
The evaluation was concluded on 2/17/12 and it determined that this issue is a reportable defect as defined by 10CFR21. DISCUSSION: Lack of the mounting pads alone will not result in a failure, however if a customer attempts to install the subcover without recognizing the missing material, there is the possibility that two of the eleven hold down bolts will provide no clamping function. This may result in loosening of the subcover mounting which could allow the cover to separate from the cylinder head. The subcover is a device that is fastened to the top of the cylinder head and provides support for the rocker arms and rocker shafts and encloses the valve stem area. There is one subcover per cylinder head and thus for a model DSRV-16-4 Enterprise engine there are 16 subcovers. Failure of a subcover would impact the ability of either of the corresponding rocker arms to provide the mechanical force to actuate the intake and exhaust valves. Without valve actuation, that particular power assembly would be unable to generate power which would reduce the output of the emergency diesel generator (EDG). Failure of the EDG to produce its nameplate rated power could prevent the safe shutdown of the nuclear power plant during an emergency situation. AFFECTED USERS AND SHIPMENTS: ESI has supplied subcovers with the incorrect mounting pad to the following customers [in USA]: Perry; Qty: 4; Date: October 2011. Note: The subcovers returned by Perry are the subject of this evaluation. CORRECTIVE ACTIONS: Customers may elect to justify use of a shorter bolt to facilitate installation of in-stock covers. Otherwise it is ESI's recommendation that customers return the subcovers for replacement. The root cause analysis determined that the cause of this issue was that the pattern for the casting is missing the portions that would ultimately form this upper mounting pad. In addition, the machining drawing was unclear in showing these locations. As a result, ESI's inspections did not specifically check for these locations and the non-conforming subcovers were shipped to the customer. The pattern is now being corrected to ensure the presence of the upper mounting pads. Also, ESI's dedication report is being revised to add specific checks to inspect for the presence of these pads. This will be completed prior to any future shipments of this item. |
| Where | |
|---|---|
| Engine Systems, Inc Rocky Mount, North Carolina (NRC Region 1) | |
| Organization: | Engine Systems, Inc |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+132.35 h5.515 days <br />0.788 weeks <br />0.181 months <br />) | |
| Opened: | Tom Homer 17:21 Feb 22, 2012 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Feb 22, 2012 |
| 47685 - NRC Website | |
Engine Systems, Inc with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 476852012-02-17T05:00:00017 February 2012 05:00:00
[Table view]10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Missing Upper Mounting Pads on Subcover Assemblies ENS 476352011-12-01T05:00:0001 December 2011 05:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation ENS 473472011-10-11T04:00:00011 October 2011 04:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 Notification - Emergency Diesel Generator Piston Delamination ENS 471122011-06-16T16:00:00016 June 2011 16:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 - Emergency Diesel Generator Failed Air Start Motor ENS 467602011-04-15T04:00:00015 April 2011 04:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Potential Defect in Magnetrol Level Switch from Engine Systems Incorporated ENS 453262009-08-17T04:00:00017 August 2009 04:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 - Faulty Emergency Diesel Generator Start-Up Solenoid Valve ENS 453352009-08-14T04:00:00014 August 2009 04:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 Involving Woodward Governors Using Unapproved Supplier Integrated Circuits 2012-02-17T05:00:00 | |