ML20116B007
| ML20116B007 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 04/03/1985 |
| From: | Root R WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| GO1-85-0066, GO1-85-66, NUDOCS 8504240675 | |
| Download: ML20116B007 (6) | |
Text
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y Washington Public Power Supply System P.O. Box 968 3000 George Washington Way Richland, Washington 99352. j509372:50 April 3, 1985 Responds to: N/A
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G01-85-0066 Response required by: N/A Mr. J.B. Martin Regional A'dministrator Nuclear Regulatory Commission Region V 1450 Maria Lane, Suite 210 Walnut Creek, Calif. 94596
Subject:
NUCLEAR PROJECTS N0.1 DOCKET N0. 50-460 REPORTABLE CONDITION 10CFR50.55(e)
EMERGENCY DIESEL GENERATOR CYLINDER BLOCK
Reference:
Telecon, C.R. Edwards, Supply System to R.T. Dodds, NRC, same subject, dated March 8, 1984.
In the noted reference, the Supply System informed your office of a
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reportable deficiency i_n accordance with the requirements of 10CFR50.55 (c). Attachment A provides a statement of the identified condition and a brief description of our planned actions to correct the identified deficiency. Based on the construction status at WNP-1, the Supply System will not be able to issue a final report at this time. An update will be provided at construction restart.
If you have an ions or desire further information, please advise.
fl l
R. W. Root, l
WNP-1 Program Director (821)
RWR:LCO:llw Attachments cc: Transamerica Delaval J.P. Laspa, BCI (862)
V.
Mani, UE&C (897)
E.C. Haren, UE&C (895)
NRC Document Control Desk, DC ORM (847)
FDCC (899)
BDCC (828) 8504240675 850403 PDR ADOCK 05000460 S
PDR p-g7
Attachment A Docket No. 50-460 POTENTIALLY REPORTABLE CONDITION PER -10CFR50.55(e)
EMERGENCY DIESEL GENERATOR CYLINDER BLOCK DESCRIPTION OF DEFICIENCY The Supply System's WNP,-l Project utilizes two Emergency Diesel Generators from Transamerica Delaval' Inc. (TDI) as its emergency power supply source.
The TDI Diesel Generator Owners Group issued a Phase I report (Letter 0GTP-631-N-53, C.L. Ray to H.R. Denton, Phase I Report -
Design Review of TDI R-4 and RV-4 Series Emergency Diesel Generator Cylinder Blocks, Revision 1, dated 12/13/84) which justifies the design and quality aspects of the cylinder blocks based on analysis, test, and inspection considerations. This report also discusses the effects on the cylinder blocks when Widmanstatten graphite is present.
A netallurgical sample from each of the four cylinder blocks was taken and only one cylinder block indicated the presence of Widmanstatten graphite.
Using the methodology described in the Phase I report, the consultant for the Owners Group determined that continued operation for this ' block is justified for only nine equivalent full power hours before a block inspection is required.
This restriction is unacceptable for continuous diesel generator availability. Attachment B is the TDI Owners Group report for the cylinder block.
ANALYSIS OF SAFETY IMPLICATION The resultant cracking of the block due to the reduced strength and duct'lity characteristics caused by the Widmanstatten graphite, could result in engine failure.
CAUSE OF DEFICIENCY Widmanstatten is a degenerate or abnormal form of graphite that occurs infrequently in heavy-section castings of gray cast iron as a result of slow cooling rate in conjunction with tramp elements and/or moisture or hydrogen contamination.
CORRECTIVC ACTION The Supply System has confirmed, using additional block samples, the presence of the Widmanstatten graphite in engine 18 left.
A Nonconfor-mance report (1-BNCR-53-ll) has been issued to document the deficiency.
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Further actions will now be taken to procure a suitable replacement cylinder block.
ACTION TO PREVENT RECURRENCE Replacement of the deficient cylinder block will ensure that WNP-1 engines are acceptable for operation.
Spare parts orders for replacement cylinder blocks will require a metallurgical analysis of the actual block to determine that Widmanstatten graphite is not present.
The vendor is being notified of this deficiency by copy of this letter.
No further action is deemed necessary.
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ATTACICiENT B s
- TOI OWNERS GROUP for WASHINGT0!1 PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO. 1 CYLINDER BLOCK COMPONENT PART NO. 02-315A I
INTRODUCTION The TDI Emergency Diesel Generator Owners Group Program for the Washington Public Power Supply System Nuclear Project No. 1 (WNP-1) requires Design and Quality Revalidation reviews of the cylinder blocks to determine the adequacy of design for the intended use at WNP-1.
The blocks are manufac-tured by TOI and are supplied under their part number 02-315-03-AE.
The cylinder block forms the framework of the liquid cooled engine and pro-vides passage for coolant and support for the cylinder liners and cylinder heads.
II OBJECTIVE The objective of this review was to c' valuate the structural adequacy of
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the cylinder block for its intended use at WNP-1.
III METHODOLOGY In order to meet the stated objective, the following methods were used:
Review of 'rniP-1 site, nuclear and non-nuclear experiences (see o
Appendix C).
Review of engine opera ting conditions at WNP-1 and identification of any differences from those at Comanche Peak.
Performance of dimensional check and evaluation of cylinder liner / block interaction.
Evaluation of steady state
- stresses, alternating stresses and stiffncss in key portions of the cylinder block.
Evaluation of crack growth rate for cylinder block landing and counterbore diameter by comparison with conservative Shoreham data and analysis.
Review of liquid penetrant inspections of WNP-1 OSRV-16-4 A and B engine blocks.
Revie.1 of metallurgical / microstructural analysis of cylinder block
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top miterial.
WN3G87/1
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e Page 2 of 4 Review of Component Quality Revalidation Checklist results for a
acceptability.
IV RESULTS AND CONCLUSI0tl5 A generic investigation of the structural adequatv of +he
-4 and RV-4 series diesel engine cylinder blocks for emt.,
. n oy service in nuclear power plants is summarized in Reference 1.
i..e investigation considers the cause, extent, and consequences of cylinder block cracking, and the inspections required to assure sufficient margin of safety during 7
continued operation under test and postulated accident conditions.
Evaluation of steady state stresses, alternating stresses, and stiffness in key portions of the cylinder block was accomplished as part of the strain gauge testing at Shoreham and the results were included in the cumulative damage and crack growth analyses.
The cumulative damage algorithm is explained in Reference 1.
Diesel generators A and B have had limited operational experience.
Engine hours accumulated to date consist of test hours performed by TOI at the factory.
The engine operating conditions at.WNP-1 were compared to those at Comanche Peak and Shoreham.
No significant dif ferences were found that
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would affect the structural integrity assessment of the WNP-1 blocks.
It is recommended that liner bore and mating block dimensions be checked in order to evaluate the interaction of the block and liner.
These re-suits are utilized in applying the cumulative damage methodology out-lined in Figure 5-1 of Reference 1.
For the purpose of analyzing the steady state and alternating stresses present, the cylinder block mat-crial is assumed to be characteristic of typical Class 40 grey cast iron and liner / block bore interaction is assumed to be similar to that pre-sent at Shoreham.
These assumptions must be verified prior to placing
+Mse engines into emergency standby service.
The power output for this engine is 7000 kW at 100 percent rated load.
The output required 'or a load profile enveloping both a LOOP and LOOP /
LOCA is 7376 kW for 1 huur 6893 kW for 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, 6485 kW for 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />, 6379 kW f or 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and 5890 kW for 142 hours0.00164 days <br />0.0394 hours <br />2.347884e-4 weeks <br />5.4031e-5 months <br /> (Ref. 3).
Strain gauge testing of the original Shoreham EDG 103 block, inspection data from before and af ter testing, and materials testing were used as a basis to predict adequate life for cylinder blocks.
The apparent rate of propaqation of cracks between stud holes in the original Shoreham EDG 103 block, when ccn. pared wi th the LOOP and LOOP /LOCA envelope requirements, indicates that even if the WHP-1, blocks 1B Right, 2A Right and 2A Lef t had ligament cracks, they are predicted to withstand with sufficient margin a LOOP or LOOP /LOCA event.
Engine block 1B Left has been shown to have degenerative
'!! d. nan s ta t te n Graphite.
Consequently, continued engine
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operation with sufficient maroin for a LOOP or LOOP /LOCA event is justified only if block tcp irr.pections result in no detectable block top Cracks.
WU36d2/2
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Page 3 of 4 To date, no inspection results for Engine A and B blocks tops have been reported.
It is recommended that, prior to placing the engines in emergency standby service, the visual and NDE examinations consistent with those identified in Appendix B be performed on Engines A and B to determine whether or not block top cracks are present.
Microstructural evaluations of hNP-1 engine 2A and 1B blocks have been performed and indicata that the left block of engine 1B contains degenerate Widmanstatten Leaphite.
Engine blocks 10 Right,2A ttight, and 2A Left are characteristic of typical Class 40 grey cast iron.
Application of the cumulative damage algorithm Figure 5-1 of Reference 1 shows that provided WNP-1 blocks have no detectable block top cracks continued operation without inspection is justified for the following time periods at full power (7000 Kw) or operation resulting in equivalent cumulative damaqe with sufficient margin for a LOOP or LOOP /LOCA event (Reference 2):
Engine 1B Left 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> Engine 1B Right 583 hours0.00675 days <br />0.162 hours <br />9.63955e-4 weeks <br />2.218315e-4 months <br /> Engine 2A Right and Left 583 hours0.00675 days <br />0.162 hours <br />9.63955e-4 weeks <br />2.218315e-4 months <br /> If block tnp inspection results for engine block 1B Left show the presence of block top cracks, there is no analytic basis for futher
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engine operations.
Block top cracks in the IB Right,2A Right, and 28 Lef t engine blocks will ef fect future inspection intervals as shown in Figure 5.1 of Reference 1.
Engine operation in excess of the time porieds listed above without inspection could be justified if the 1atique damage index since the it.,t inspection has not exceeded the allowable fatigue damage index before the last inspection.
In the future after additional engine operation without inspection has been accumulated, additional engine operation may be performed af ter removal of the cylinder heads and inspection of the block top for detectable ligament, stud-to-stud or stud-to-end cracks.
If none are found, then additional engine operation without inspection may be performed until the future fatigue damage index equals the allowable fatigue dc.vqe index accrued to the last inspection.
This process may be repeated indefinitely throughout the life of the engine.
Optionally, in the future, after additional engine operation without inspection has been accumulated and the fatigue damage index for future operations exceeds the allowable fatigue damage index, continued ennine operation without removal of cylinder heads and inspection of the block top will allow cuf ficient margin to withstand a LOOP or LOOP /LOCA event provided pnriodic eddy current inspections are pertormed.
The periodic eddy current inspections are dMcribed in Figure 5-1 of Reference 1.
The information prcvided on IER IP-003 has been reviewed and is consis tent m t h the f inal conclusions of this report.
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Page 4 of 4 Results of the Quality Revalidation Inspections performed to date have been reviewed and considered in the performance of this design review, and the results are consistent with the final conclusions of this report.
Based on the above review, subsequent completion and review of block top inspections, and cylinder liner / block bore dimensional check as identified in Appendix B for Engines A and B, and implementation of routine inspec-tions, it is concluded that the cylinder blocks are acceptable for their intended use at WNP-1.
IV REFERENCES 1.
Design Review of TDI-R4 and RV-4 Series Emergency Diesel Generator Cylinder Blocks.
FaAA-84-9-11.
2.
FaAA support Package Number SP-84-9-11(k).
3.
Telecon between S.
Rau (FaAA) and C.
Kinsel (United Engineers and Constructors) on 01/08/85.
(J.
)
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.h WH3682/4
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