ML13116A303
| ML13116A303 | |
| Person / Time | |
|---|---|
| Site: | Byron, South Texas  |
| Issue date: | 04/23/2013 |
| From: | Horner T Engine Systems |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| 48960 | |
| Download: ML13116A303 (9) | |
Text
0412312013 U.S. Nuclear Regulatory Commission OperationsCenter Event Report Page I Part 21 (PAR) Event# 48960 Rep Org: ENGINE SYSTEMS, INC Notification Date I Time: 04/23/2013 16:32 (EDT)
Supplier: ENGINE SYSTEMS, INC Event Date / Time: 04/19/2013 (EDT)
Last Modification: 04/23/2013 Region: 1 Docket #:
City: ROCKY MOUNT Agreement State: Yes County: License #:
State: NC NRC Notified by: TOM HORNER Notifications: DAVID HILLS R3DO HQ Ops Officer: HOWIE CROUCH JACK WHITTEN R4DO Emergency Class: NON EMERGENCY 10 CFR Section:
21.21 (d)(3)(i) DEFECTS AND NONCOMPLIANCE PART 21 REPORT - ESI REFURBISHED EMERGENCY DIESEL GENERATOR CYLINDER HEADS MAY HAVE VALVE KEEPER SEALS MISSING The following information is a summary of a report faxed to the Operations Center from Engine Systems, Inc. (ESI) concerning a condition reportable under 10 CFR 21:
"Engine Systems Inc. (ESI) began a 10 CFR 21 evaluation on 02/19/13 following the failure analysis of a cylinder head returned by South Texas Project (STP). The cylinder head had been installed on an emergency diesel generator set at STP and, during routine prestart checks, oil was found leaking from the Kiene valve while barring over the engine. This cylinder head had been previously refurbished in 2004 under ESI's 10 CFR 50 Appendix B program. ESI's investigation revealed that the refurbished cylinder head was returned to the customer without keeper seals installed.
"The evaluation was concluded on 04/19/13 and it was determined that this issue is a reportable defect as defined by 10 CFR 21. Omission of the keeper seals from the cylinder head of the KSV emergency diesel generator set could allow engine lubricating oil to migrate through the cylinder head and into the combustion chamber during engine standby conditions. Presence of this oil could damage the engine to the point that it is unable to perform its safety related function."
ESI began dedicating refurbished cylinder heads in 2001 but the refurbishment scope did not include valve train components. Refurbishments that included valve train components were first shipped in 2003. Procedure steps were included in 2007 to verify valve keepers were installed. Therefore, only cylinder heads refurbished between 2003 and 2007 are affected. A review of purchase orders have determined that the following plants received a total of 26 cylinder heads that may not have valve keeper seals installed:
04/23/2013 U.S. Nuclear Regulatory Commission OperationsCenter Event Report Page Part 21 (PAR) Event # 48960 Byron Station - 3 heads South Texas Project - 21 heads Cooper Nuclear Plant - 2 heads Affected cylinder head part numbers are 10-KSV-1 1-3-RR, 12-KSV-1 1-3-RR AND 13-KSVR-1 1-6-RR.
ESI will be notifying affected customers.
04-23-13;04:43PM; # 1/ 7 ENGINE SYSTEMS., INC.
-S1 175 Freight Road Telephone: 252/977-2720 Rocky Mount, NO 27804 Fax: 252I446-1134 TELEFAX Date: April 23, 2013 Company: NRC Operations Center Fax Number: 301/816-5151 Verification No.: 301/816-5100
Reference:
Report No. 10CFR21-0108, Rev. 0 From: Tom Homer Page: 1 of 7
Dear Sir:
Following this cover is a copy of our report 10CFR21-0108, Rev. 0, for a 10CFR21 reportable notification on a KSV cylinder head with missing keeper' seals, cylinder head part numbers 10-KSV-i 1-3-RR, 12-KSV-1 1-3-RR, and 13-KSV-11-6-RR.
A copy of this report will be mailed to the NRC Document Control Desk and to our affected nuclear customers.
Should you have questions, please let us know.
Sincerely, ENGINE SYSTEMS, INC.
Tom Homer Quality Assurance Manager Quality Performance With Pride
04-23-13;04:43PM; # 2/ 7 ENGINE SYSTEMS, INC.
175 Freight Road, Rocky Mount, NC 27804 Telephone: 252/977-2720 Fax: 252/446-1134 Report No. 10CFR21-0108 Rev. 0: 04/23/13 10CFR21 REPORTING OF DEFECTS AND NON-COMPLIANCE COMPONENT: KSV Cylinder Head with Missing Keeper Seals Head Part Numbers 10-KSV-1 1-3-RR, 12-KSV-11-3-RR, and 13-KSV-1 1-6-RR SYSTEM: Emergency Diesel Generator CONCLUSION: Reportable in Accordance With IOCFR21 Prepared By: Date:
" Engineer!g Manager Reviewed By: Date:________
Quality Assurance Manager Quality Performance With Pride
04-23-13;04:43PM; # 3/ 7 Report No. 10CFR21-0108 Record of Revisions Page: 1 of I REV DATE PAGE DESCRIPTION 0 04/23/13 Initial issue.
04-23-13;04:43PM; # 4/ 7 Report No. IOCFR21-0108 Revision: 0 Date: 04/23/13 Page: 1 of 4 Component:
KSV cylinder head with missing keeper seals, cylinder head part numbers 10-KSV-1 1-3-R1, 12-KSV-11-3-RR, and 13-KSV-11-6-RR.
Summary:
Engine Systems Inc. (ESI) began a 10CFR21 evaluation on 02/19/13 following the failure analysis of a cylinder head returned by South Texas Project (STP). The cylinder head had been installed on an emergency diesel generator set at STP and, during routine prestart checks, oil was found leaking from the Kiene valve while barring over the engine. This cylinder head had been previously refurbished in 2004 under Engine Systems Inc. 10CFR50 Appendix B program. ESI's investigation revealed that the refurbished cylinder head was returned to the customer without keeper seals installed.
The evaluation was concluded on 04/19/13 and it was determined that this issue is a reportable defect as defined by 10CFR21. Omission of the keeper seals from the cylinder head of the KSV emergency diesel generator set could allow engine lubricating oil to migrate through the cylinder head and into the combustion chamber during engine standby conditions. Presence of this oil could damage the engine to the point that it is unable to perform its safety related function.
Discussion:
STP returned a cylinder head, P/N 12-KSV-11-3, S/N 8M1608, due to oil present in the power cylinder. It was reported that during routine prestart checks, STP opened all Kiene valves and manually barred over the engine. Excess lube oil was found leaking from the Kiene valve of this one cylinder head. This cylinder head had been remanufactured by Cameron Compression in Bethlehem, PA in 2004, under ESI's 10CFR50 Appendix B Quality Program.
During the failure analysis investigation performed at the current Cameron facility in Casper, WY, it was noted that the intake and exhaust valve keeper seals, P/N W30C-1 #1, were not installed. The purpose of the keeper seals is to deflect lube oil from draining into the cylinder head, and possibly the combustion chamber, during standby conditions. The source of this lube oil is the intake and exhaust rocker arms that are pressurized with heated lube oil during standby conditions to maintain the engine's fast start capability. The quantity of oil that travels through the rocker arms to the valve keeper area is dependent upon the component clearances within the rocker arm components. The absence of the valve keeper seals could allow a small amount of this lube oil to drain past the keepers, down the valve stem, through the valve guides and into the intake and exhaust ports of the cylinder head. In this particular case, the intake or exhaust valves were sufficiently open to allow oil to enter the cylinder (which is dependent upon the engine's position when it stops rotating following a shutdown). One or more cylinders on an engine will have open valves at any given position of the crankshaft, though not all cylinders are affected at the same time.
The seals are made of an elastomeric material in the form of a rectangular block and they are replaced during a rebuild as standard practice. Each cylinder head has eight seals (with two required for each valve and there are four valves per head). The seals are installed between the keeper halves on opposite sides of the valve stem. See figure and photo on the following page for a visual representation of the seal location.
04-23-13;04:43PM; # 5/ 7 Report No. 10CFR21-0108 Revision- 0 Date: 04/23113 Page: 2 of 4 Figure 1: Showing Location of Keeper Seals Photo 1: Showing Location of Keeper Seals
04-23-13;04:43PM; # 6/ 7 Report No. 10CFR21 -0108 Revision: 0 Date: 04/23/13 Page: 3of4 Impact on Operability:
Absence of the keeper seals could allow lube oil to leak through the valve guides, into the cylinder head, and into the combustion chamber during standby conditions. Excess oil in the combustion chamber could prevent the piston from stroking its full length during a compression or exhaust stroke causing hydraulic lock. This could cause catastrophic damage to the engine's power assembly components and render the engine inoperable, Affected Users:
ESI began dedicating remanufactured KSV cylinder heads starting in October 2001. The scope of many of these head rebuilds did not include the valve train components (valves, springs, keepers, keeper seals, etc); therefore these orders are not affected by this notification. After a review of each sales order that included the valve train components, ESI has determined there is a remaining quantity of 26 cylinder heads that may have been reassembled without the keeper seals. These are shown in the table below (note that the part numbers listed are the only part numbers affected by this notification).
Date Customer Shipped ESI IWO Customer PO#N SIN TY.
9M0507 May 2003 97227 Exelon-Byron 38571 1O-KSV-1 1-3-RR DM2103 2 May 2004 110077 STP - South Texas 49208 12-KSV-1 1-3-RR 8M1608 1
__________ ________Project _ _ _ _ _ _ _
8K1102 8J1603 8L3001 7D2102 902703 8K2307 9A1 310 8K2803 STP - South Texas 8M0407 March 2005 8000117 Project 58227 12-KSV-11-3-RR DM1109 19 PSM 1604 DM1101 8J1606 8K2008 DM2106 DM0409 8M1108
-M2803 8M1105 March 2005 8000229 STP - Project South Texas 58227 10-KSV-11-3-RR 1A1702 1 Feb 2006 8000389 Exelon-Byron 84798 10-KSV-11-3-RR 8J1306 1 Feb 2007 8000857 NPPD-Cooper 4500069477 13-KSV-1 1-6RR 7A2108 2 1 Nuclear I 6B1901 Total Affected Cylinders Heads 26
04-23-13;04:43PM; # 7/ 7 Report No. 10CFR21-0108 Revision: 0 Date: 04/23/13 Page: 4 of 4 Corrective Action:
ESI's current repair procedure includes a step to verify the keeper seals are installed and all orders since 2007 have included installation of the keeper seals; therefore, the issue has been corrected and is no longer active.
The STP cylinder head had been in-service for a number of years prior to this occurrence and this is the only instance of this type of oil leakage reported to ESI. Even though the probability for excessive oil leakage as a result of missing keeper seals appears to be quite low; any engine with an affected cylinder head could be subject to the same phenomenon. Depending upon the component clearances within the rocker arms (which provides the source of oil to the keeper) and the position of the camshaft (and thus the valve train) following an engine shutdown, oil could leak into the combustion chamber during standby, As a result, ESI has the following recommendations:
For those customers with affected cylinder heads already installed:
Inspect the valve keepers for presence of the keeper seals. If seals are installed, no further action is required. If seals are not installed, it is recommended that a borescope inspection be performed to ensure no engine lube oil is in the combustion chamber. This inspection could be performed through the fuel injector bore or the Kiene valve passage (if equipment will allow).
If no oil is present, then there is assurance that oil is not being introduced into the combustion chamber during standby conditions. As a result, engine operability is not affected and any further work could be postponed until the next engine run. This inspection can be repeated after each engine run ifdesired until keeper seals are installed.
If oil is present, then immediate action is required to remove the oil and rework or replace the cylinder head. Reworking the head can be performed on-engine as follows: With the Kiene valve open, the engine should be barred over until the piston is at top dead center. By doing this the oil will be pushed out of the Kiene valve. Lock the barring device to maintain the piston at TDC and connect a pressure test set to the Kiene valve. This pressure will be used to hold the valves against the fire deck of the cylinder head. An applied pressure of 50 psig should be used; however higher pressures may be utilized as required to maintain the valve against the fire deck. Remove the rocker arms to access the top of the valves. Using a valve spring compressor (such as P/N LS-44-AA#7), compress the spring retainer enough to loosen the keepers and insert the keeper seals. Replacement keeper seals are available from ESI as dedicated components. Relieve the spring compressor and ensure the keeper seals are fully inserted between keepers and flush with the top of the keepers. Repeat for the remaining valves.
If desired, the entire cylinder head may be removed and replaced with a head that has the keeper seals installed. In this case, the removed head may be returned to ESI for rework.
- For those customers with affected cylinder heads that are not installed:
Inspect the valve keepers for presence of the keeper seals. If seals are installed, no further action is required. Ifseals are not installed, these heads must be reworked prior to installation.
Customers may elect to perform rework in-house using replacement seals provided by ESI or the head may be returned to ESI for rework.