IR 05000295/1986026

Safety Insp Repts 50-295/86-26 & 50-304/86-26 on 861027-870217.Violations Noted:Failure to Provide & Follow Procedures & Failure to Perform Necessary Insps to Assure Quality

ML20211F891
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	02/18/1987
From:	Harrison J, Jeffrey Jacobson, Walker H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20211F781	List: IR 05000295/1986026 ML20211F776 ML20211F820 ML20211G026
References
50-295-86-26, 50-304-86-26, NUDOCS 8702250227
Download: ML20211F891 (10)

Text

U.S. NUCLEAR REGULATORY COMMISSION

REGION III

neport ho. 50-295/86026(DRS);50-304/86026(DRS)

Docket No. 50-295; 50-304 License No. DPR-39; DPR-48 Licensee: Comtronwealth Edison Company Post Office Box 767 Chicago, IL 60690 Facility Name: Zion Station, Units 1 and 2 Inspection At: Zion Site, Zion, Illinois

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Inspection Conducted: October 27, Novenber 6,11,12 14 and February 17, 1987 A b , and/m 20, 1986, Inspector: . M. Jacobson aflS O

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ye b / H. A. Walker 3-l19/61 4 Date

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. . O Approved By: . J. Harrison, Chief d-f/9!d7 Engineering Branch Date Inspection Summary Inspection on October 27, November 6, 11, 12, 14, and 20, 1986, and -

l February 17, 1987 (Reports No. 50-295/86026(DRS);50-304/86076(ifR5))

Areas Inspected: Unannounced, special safety inspection of the diesel engine failure and licensee corrective actions (30703B, 627008, 627028).

Results: Of the areas inspected, two apparent violations were identified (f ailure to provide and follow procedures - Paragraph 4.a; failure to perform necessary inspections to assure quality - Para 5raph 4.a).

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0702250227 B70210

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hDR ADOCK 05000295 PDR

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DETAILS Persons Contacted Commonwealth Edison Company (CECO)-

• J. Ballard, Quality Control Supervisor

• R. Budowle, Assistant Station Superintendent, Technical Services

• E. Fuerst, Superintendent Production

• A. Denenberg

-*J. Gilmore, Assistant Station Superintendent, Planning

' *R. Johnson, Assistant Station Superintendent,itaintenance

• W. Kurth, Assistant Station Superintendent, Operations

• A. Ockert

• G. P1imi,-Station Manage *C. Schultz, Regulatory Assurance Administrator

• D. Shuhan Institute of Nuclear Power Operations (INP0)

• G. Schweitzer US NRC

• M. Holzmer, Senior Resident Inspector

• L. Kanter, Resident Inspector

• Denotes those present during the exit intervie . Introduction and Overview of Event On October 24,1986, the 10 diesel generator at the Zion Station experienced a severe failure during a post maintenance run. This unit is a Cooper Bessemer KSV-16-T which has a 16 cylinder "V" configuration, four

' stroke. diesel engine. The diesel generator unit was placed in service on

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August 22, 1972. The most obvious result of the failure was the ejection

through the engine block of the articulating connecting rod and counter weight from the fourth cylinder in the left bank. No injuries or fires were produced by this failure and because Unit 1 was shut down for refueling, nc direct threat to the safe operation of Unit I was posed.

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On October 27, 1986, Region III issued a Confirmatory Action Letter related to this even The purpose of this report is to detail the NRC investigation into the

causes of this failure and to detail the NRC review of corrective actions to minimi.e the possibility of recurrence.

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, 3.- Review of Licensee Actions In response to the failure of the IB Diesel Conrnonwealth Edison initiated a program to determine the root cause and overall significance.of this

. event. Various parts of this program were discussed with NRC representatives prior to their implementation. The following sections of this. report discuss the important points of the licensee's progra The details of CECO's findings and conclusions are delineated in their formal report attached to their letter from P. .C. LeBlond, Ceco, to

> Mr. James G. Keppler, NRC, dated February 6,1987 (copy enclosed). Review of Maintenance History

i The maintenance history of the IB Diesel was reviewed to determine

. any abnormalities concerning this engine. These documents were also reviewed to determine compliance with the licensee's QA progra Review of the maintenance history did notishow any prior indicators of the type of failure experienced. The QA review did determine that

. certain aspects of the QA program were not being fcllowed, and that

the work instructions to the maintenance mechanics were not sufficien These inadequacies are discussed in more detail in Section 4 of

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' Description of Damage and Parts Mapping As a result of this event, three major areas of the 1B Diesel engine i

were damaged including:

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I (1) The left side cylinder block.

! (2) The explosion cover on the right side near the Number 4 cylinder.

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(3) The upper center frame.

I In addition to this structural damage, a number of engine parts were ejected from the engine including:

! 1) Articulating connecting Rod 4L.

2) Crankshaft throw counter weight and stu L l~

3) Misc. 4R explosion door and liner part (4) Explosion cover Flange 4 (5) Misc. Explosion Door 4R flange part (6) Engine block debri (7) Explosion cove (8) Explosion cover relief valve.

j The location of the ejected parts was mapped and photographed by the licensee as an aid in determining the sequence of events.

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! Work Package Review

As part of the licensee's evaluation, all work packages associated i

with repair or niodification of the IB Diesel during the October 1986

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outage were reviewed by the licensee's QA department. The licensee's l QA department made a number of findings including:

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(1) Inadequate work instructions were given to the Maintenance Mechanic concerning torquing requirements of the articulating connecting red bolt (2) The Maintenance Foreman had performed an inadequate review of the work packages involve (3) Certain " sign offs" had not been completed by the Mechani (4) Certain hold points were not signed off by the QC inspecto d. Metallurgical Review of Components The licensee's metallurgical experts reviewed the failed engine components for evidence of the cause of the failure. The following observations were made:

(1) The lower right bolt attaching the four left articulated rod to the four right cylinder and connecting rod had failed with a flat fracture morphology, indicative of fatigue induced crack propagatio (2) The lower left bolt attaching the four left articulated rod to the four right cylinder piston rod had failed in ductile overloa (3) The two bolts attaching the four left articulated rod to the piston pin exhibited reductions in cross section, tearing, and bending at a 45 angl (4) The Number 4 front end counter weight had fractured into four large identifiable piece (5) The toits attaching the counter weight to the crankshaft had failed. One bolt failed in shear and the other was bent at a 90 angle.

t (6) The lower portion of left piston and cylinder liner were

fractured.

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l A detailed m.etallurgical examination was performed of the bolt which appeared to fail in fatigue. This examination showed that the bolt material complied with the applicable specifications. In addition, the use of a scanning electron microscope showed a quasi-cleavage (i.e. transgranular) fracture morphology. The metallurgical review concluded that the bolt in question had failed due to fatigue.

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. ._ Licensee's Conclusion The licensee's interviews with the involved personnel determined that the bolt which failed in fatigue had been insufficiently torqued due to inadequate work instructions. In addition, the licensee's review of the engine parts determined that the bolt in question had failed in fatigue. Inadequately torqued bolts will result in increased susceptibility to fatigue crack initiation especially in applications which have alternating loads. For these reasons, it appeared that the insufficient torque applied to these bolts was the initiating cause of this failure.

4. NRC Review The NRC inspection was conducted to determine the cause and contributing factors to the failure of the IB Diesel on October 24, 1986, and to review the planned repairs and corrective actions. The inspection was perfonned by reviewing applicable procedures, work packages and records, conducting interviews, observing work activities to verify compliance with regulatory requircments and operations QA program connitments, and a review of metallurgical testin Inspection results are documented in the following section Maintenance and Maintenance Records In order to detennine if a lack of maintenance or improper maintenance contributed to the failure, 32 Nuclear Work Requests (NWRs) were reviewed. -Twenty-five NWRs were for the IB Diesel. Twenty-two of the NWRs were recently completed on the 18 Diesel just prior to the failure. Additional NWRs involving major maintenance were reviewed for other diesels, the residual heat removal, and auxiliary feedwater systems. The 22 NWR record packages for the recently completed IB Diesel repairs had not been final reviewed by QC or QA as required by Ceco procedures. These reviews had been completed for most of the other NWR record packages reviewe During the reviews, the following observations were made:

(1) Four NWRs, completed on the IB Diesel during the current Unit i refueling. outage, did not have work instructions appropriate to the circumstance (a) Z37930-1B Diesel - Disassembly, inspection and repair of the air control valv Detailed instructions and sign offs were not provided for torquing bolts to three separate valve (b) Z53220-1B Diesel - Repair 4L cylinde No instructions were provided for removal and replacement of engine internal (c) Z53240-18 Diesel - Repair SR cylinde No instructions were provided for removal and replacement of engine internal (d) Z53241-1B Diesel - Repair 7L cylinde No instructions were provided for removal and replacement of engine internal The failure to provide work instructions on NWR Z53220 directly contributed to the insufficient torque on the bolt which faile These failures to provide appropriate work instructions is an example of a violation of 10 CFR 50, Appendix B, Criterion V (295/86026-01A). (See Item (3) below.)

(2) Two NWRs completed on the IB Diesel during the current Unit I refueling outage had steps in the attached work instructions that were not signed off by the maintenance mechanic as being ccmplete (a) Z50444-1B Diesel - Perform refueling inspectio Nine of the ten steps for replacing a filter in Procedure P/0G 001/3-7A (Page 4) were not signed off by the maintenance mechanic as being complete (b) Z53241-1B Diesel - Repair 7L cylinde Step 11 on Page 4 of Ccpy No. 1 of Procedure DG001/3-4 was net signed off as being completed. Steps 1(d),

3.(a), 8.(1), 8.(2), 15, 16, 17 and 18 of Copy No. 2 Procedure DG001/3-4 were not signed off as being complete These failures to provide evidence that work was accomplished per documented instructions is an example of a violation of 10 CFR 50, Appendix B, Criterion V (295/86C26-018).

(3) In five 18 Diesel NWR packages, 22 QC hold points were not signed off as being complete (a) Z19730 18 Diesel - Move pressure switches to a vibration free location.

l Two QC hold points were not si The hold points

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were the last two (Step No. 7)gned off.2 of the Process en Sheet Control Sheet. The work was perfonned by a site contractor l

(Hunter Corporaticn) and the hold points constituted a l release of the work by llunter QC.

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(b) Z348901B Diesel - Replace turbo lube oil filter with Nugent type filter and housin Two QC hold points were not si The hold points were the last two (Step No. 7)gned off.2 of the process on Sheet control sheet. The work was performed by a site contractor (HunterCorporation)andtheholdpoints constituted a release of the work by Hunter Q (c) Z53220 1B Diesel - Repair 4L cylinde Five QC hold points for Steps 1(d), 13, 15, 16 and 18 of Procedure DG001/3-4 were not signed off. Licensee personnel provided the inspector with evidence that hold points for Steps (1)(d), 13, 16 and 18 were signed off on NWR 252659 for Step (1)DJ) and NWR Z50444 for Steps 13, 16 and 18. There were duplicate work instructions for these and other steps. No sign off could be located in other NWRs for the hold point in Step 1 (d) Z53240 IB Diesel - Repair SR cylinde Step (1)(d) QC hold point was not signed off. No sign off could be located in other NWRs for this hold poin ,

(e) Z53241 18 Diesel - Repair 7L cylinde Twelve QC hold points were not signed off in this NWR package. Four of these were in the copy of Procedure DG001/3-4 corrpleted October 24, 1986, and eight of the hold points (Steps (1)(d), (1)(c), 8.(1), 8.(2),

13, 15, 16 and 18) were in the copy of Procedure DG001/3-4 completed October 26, 1986. Five of the hold points from the latter procedure (Steps (1)(d), 8.(1), 13, 16, and 18)

had been signed off in other NWR packages containing duplicate work instructions. No sign off in other work instructions could be located for the other hold point In these five NWR packages, there were a total of 22 QC hold points which were not signed off. Of these 22 hold points, QC sign off for 9 hold points was located in other NWR packages where a duplicate of the steps was included. Sign

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off could not be located for 13 hold point In all cases, riaintenance mechanics performed the subsequent steps of the prccedure without QC sign off. 10 CFR 50, Appendix B, Criterion X defines a hold point as a point "beyond which work shall not proceed without the consent of its designated

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representative."

This failure to provide acceptable sign off for QC hold points and the completion of work beyond those hold points is a violation of Criterion X of 10 CFR 50, Appendix B (295/86026-02A).

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Activities affecting quality must be prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances. Issuing duplicate work instructions in more than one NWR added to the confusion in performing the work and contributed to the missing of QC hold points. This another example of the violation described above in Section 4.a.(1).

(4) Seven NWR packages for the IB Diesel had been completed and the diesel released for testing without sign off indicating that required repair work had been. inspected and.was acceptable. These NWR packages were as follows:

(a) Z19730 Move pressure switches to a vibration free locatio (b) Z34002 Repair lube oil lea ,

(c) Z348SO Replace turbo lube oil filter with a Nugent type filter and housin (d) Z39824 Replace main bearing and connecting rod high temperature trip (e) Z53220 Repair 4L cylinde (f) Z53240 Repair SR cylinde (g) Z53241 Repair 7L cylinde CFR 50, Appendix B, Criterion X requires that examinations, measurements or tests be performed where necessary to assure quality. Contrary to this requirerent there was no objective evidence that inspection was completed and acceptable for the above listed NWRs prior to running the 18 Diesel. This is a violation of 10 CFR 50, Appendix B, Criterion X (295/86026-028). Review of Metallurgical Tests

! The techniques and results of the metallurgical tests were reviewed

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by the HRC inspector. The techniques used in these tests were proper and the results of the tests were determined to acceptably support the licensee's conclusion Review of Corrective Actions

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As a result of the failure of the IB Diesel and the investigation, the licensee proposed a number of corrective actions to minimize the possibility of recurrence. These actions included: Checking the torque on similar bolts on the other diesel units.

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8 All QC inspectors were required to read and sign a policy statement on hold points and their importanc Every safety related work request was reviewed for adequacy of work instructions, Safety related NWRs that involve instructions covered by a vendor technical manual will have a traveler attached, which documents vendor instructions, No deviation from scope of work will be allowed without proper approva As a policy, work will not be considered finished for any reason until all " sign offs" are complet In addition, the licensee has formed a team to review the quality of maintenance at all CECO nuclear facilities. The purpose of this review is to strengthen maintenance activities in genera The NRC inspection team reviewed these corrective actions and believes these actions will help minimize the possibility of recurrenc In addition, the NRC team reviewed and monitored the repair processes used on the IB Diesel. Based en this review, the repair techniques were adequate and proper control of the repair was maintained. The review and results of the weld repair activities for the IB Diesel are documented in NRC Inspection Reports No. 50-295/86020; No. 50-304/86021.

6. Comonwealth Edison Company's Fonnal Report The NRC reviewed Ceco's report (dated February 6,1987) identifying the cause of the failure, findings, corrective actions, and conclusions and found this report (copy enclosed) to be acceptable.

7. (Closed) Confirmatory Action Letter (CAL-RIII-86-00Q Following the Diesel failure on October 24, 1986, CECO and the NRC agreed on October 25, 1986, that Ceco would take certain actions to determine the root cause of the failure and significance of this failur As a result, on October 27, 1986, the NRC issued the subject CAL. This CAL identified six specific actions that were required to resolve this failure. All six actions have now been completed; including the final requirement, issuance and acceptance of CECO's formal report. Therefore, all the required actions of the CAL have been completed by CECO and found acceptable by the NRC. This CAL is thereby close _ . - _ . _ __ . .

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. .. -. - . - -. Conclusion Based on the NRC review and the licensee's investigation, it appeared evident that inadequate work instructions caused insufficient torque to be applied to an articulating connecting red bolt. Due to the high alternating load on this bolt, it underwent a rapid fatigue failur This failure and subsequent related overloading of certain components caused the failure and ejection of components from the IB Diese This failure does not appear to be generic in nature and does not have implications for other Cceper Bessemer diesel engines. The failure does tend to highlight the importance of adequate work instructions and attention to detail. Also, this event en+hasizes the need to have proper implementation of RA and QC programs affecting safety related equipmen . Exit Interview The inspector met with site representatives (denoted in Person Contacted Paragraph) at the conclusion of the inspection. The inspector sumarized the scope and findings of the inspection noted in this report. The inspector also discussed the likely information content of the inspection report with regard to documents or processes reviewed by the inspector during the inspection. The licensee did not identify any such documents / processes as proprietary.

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