ML20059D210

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Intervenor Exhibit I-MFP-196,consisting of Mgt Summary, DCO-91-MM-N067 D6, Asw Pump Vault Drain Check Valves, 910115
ML20059D210
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 08/23/1993
From:
AFFILIATION NOT ASSIGNED
To:
References
OLA-2-I-MFP-196, NUDOCS 9401070067
Download: ML20059D210 (12)
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SUMMARY

On August 8, 1991, the check valves in the drain lines of the Auxiliary Saltwater (ASW) pump 1-1 and 1-2 vaults were removed to perform routine periodic inspection and refurbishment. The as-found condition-of both check valves was partially stuck open on trash,-e.g. tie wraps, cigarette butts, etc. No clearance was approved for the check valve removal. The operability'of the ASW pumps with both vault-drain check valves removed or inoperable has been evaluated. NECS - Engineering and Operations concur that the ASW pumps were not inoperable during this event, therefore this event is not a*non-conformance (ref. 6). Design document updates, work instruction corrections and  ! personnel error issues will be addressed via AR evals and l QEs, as appropriate. , NUCLEAR RECULATORY C0' AMISS 10N 

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                                                                                            's DCO-91-MM-N067 D6 January 15, 1991 ASW PUMP VAULT DRAIN CHECK VALVES
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I. Plant Conditions Units 1 and 2 were in Mode 1 (Power Operation) at 100% power. II. Descriotion of Event A. Event: On August 8, 1991, at approximately 1000 PDT Mechanical Maintenance removed the Auxiliary Saltwater-(ASW). Pump 1-1 and 1-2 vault. drain ~ check i valve s for routine periodi:11nspection'and refurbishment. No~ clearance was-requested cnr approved for the work. Operations was informed on August 8', 1991,nat-approximately 1400 PDT, that the check valves were degraded (ref. 1). At approximately 1600'PDT. . Operations' contacted the Mechanical' Maintenance 1 Foreman and determined that both check valves were. physically removed from the' system. Operations requested NECS - Engineering to determine the operability of the ASW pumps with the vault drain check valves removed inLAEL#.01 to 

                        - reference 1.      In AE # 02.to reference 1:,                         4 Operations requested Regulatory. Compliance to                        '

determine the reportability;of.this event. ! The ball float check valves also in these drain l lines have.had their internals removed since 1989.. l The as-found condition'of both check valves.was partially stuck open on trash, e.g. tie wraps,. l cigarette butts, etc. Pitting noted on the valve i discs (ref. 5) has been determined not to' affect l ' operability.' Investigative actions on page 7 below have been assigned to determine if-the ASW pumps were inoperable due to the stuck-open check valves. l l 91NCRWP\91MMN067.JCN Page 2 of 12 i 

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f I s I-DCO-91-MM-N067 D6 l January 15, 1991 i B. Inoperable Structures, Components, or Systems that Contributed to the Event: I None. C. Dates and Approximate Times for Major Occurrences.

1. August 8, 1991; 1000 PDT: Mechanical Maintenance removes the ASW pump vault drain check valves.
2. 1400 PDT: Operations became aware that the check valves are degraded.
3. 1600 PDT: Operations contact MM Foreman and determines both check valves are removed.
4. August 9, 1991; 1000 PDT: Mechanical Maintenance reinstalls the check valves.

D., Other Systems or Secondary Functions Affected: None. E. Method of Discovery: Operations was contacted by the System Engineer who had been reviewing an AR (ref. 2) and was curious why the Shift Foreman informed block had an "N". The System Engineer felt operations should be aware of the degraded condition of the ASW pump vault drain check valves. Operations investigated and determined that Mechanical Maintenance had removed both check valves without a clearance. F. Operators Actions: Operations issued an AR (ref. 1) to document the 91NCRWP\91MMN06'i.JCN Page 3 of 12

e T DCO-91-MM-N067 D6 January 15, 1991 condition and to request evaluations regarding operability and reportability. G. Safety System Responses: None required. III. Cause of the Event A. Immediate Cause:

1. Both ASW pump vault drain check valves were removed from ASW pump 1-1 and 1-2 vault drains simultaneously for maintenance.
2. Check valves were found partially stuck open due to debris.
3. The system configuration did not match current design drawings, i.e., the ball float check  ;

valves had been removed.

4. Mechanical Maintenance Department policies were not followed during the course of the work.

B. Determination of Cause:

1. Human Factors:

8 i

a. Communications: There was no I communications between i Mechanical Maintenance and l the operations Shift Foreman (SFM) prior to the start of the work. There was no tailboard prior to the work. The Maintenance Engineer was not contacted for evaluation of the "as-found" condition. The Journeyman did not contact anyone to resolve anomalies in the Wo.
b. Procedures (work instructions): The prerequisites in the Wo were misleading.

91NCRWP\91MMN067.JCN Page 4 of 12

e I DCO-91-MM-N067 D6-January _15, 1991 l

c. Training: The. Maintenance Foreman and the Journeyman were not-aware of the requirements of AP C-47 j and C-6.  :

1

d. Human Factors: . The Foreman was too busy to provide a tailboard or to visit thefjob.

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e. Management System: LThe WOs were scheduled for the same day for a 16 hour per train job.

No clearance was required byithe Wo.

2. Equipment / Material:

I

a. Material Degradation: No. y I
b. Design: No. -)
c. Installation: No.-
d. Manufacturing: No. I
e. Preventive' Maintenance: No.
f. Testing: No. 4
                                                                                                  .I
                ,        g. End-of-life failure:        No.

C. Root Cause: Since it has been determined that this event was ~ not a non-conformance, identification of a root cause is not applicable. D. Contributory Cause:

1. "he Wo prerequisites included a: Verification of clearance points but.no clearance was requested.

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2. The WO prerequisites incorrectly specified.  !
                         " MARK 'N/A' IN "SFM'AUTH"..."
3. No tailboard was held with the~ System Engineer j contrary to prerequisite C of the work order.

91NCRWP\91MMN067.JCN Page 5 of 12 

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DCO-91-MM-N067 D6 J* January 15, 1991-

4. The Maintenance Engineer was contacted.too late to permit: evaluation of the: "as-found"-

condition of the valves.- 

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5. New gaskets were not installed during reinstallation-(none were initially found in -l the valve). i
6. The Journeyman did'not stop the-job to correct- l the Wo anomalies.  ;
7. There are no P& ids showing these, valves.- j

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8. It was not documented 1that these valves were I found stuck partially open due to debris.
9. The Foreman did~not visit;the' job site-during ,

the job. l 1 10..The Foreman'and-Journeyman were not1 knowledgeable regarding the: technical , configuration' management decision process..  :

11. Drawings were not updated'in a timely. manner ,

when the internals for the ball-float check were removed in 1989.

  • IV. Analysis of the Event t A ., Safety Analysis:

NECS - Engineering has determined-that the'ASW system was.not'outside;the design l basis with-both- l' ASW pump vault drain valves' removed during maintenance'(ref. 1 and'ref t 4). -SinceLthere was no variance from the' design 1 basis of.the ASW , system'during the 24 hour period that:theLvalves were in' maintenance, the ASW' system was operable. 1 Thus the' health and safety of the public were.not i adversely.affected by this condition.. z l B. Reportability:' l

1. Reviewed under'QAP-15.'B and' determined to.be i not non-conforming.  ;
2. Reviewed under 10 CFR 50.72 and 10 CFR 50.73-91NCRWP\91MMN067.JCN Page 6 of. '12 -j a
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1 3 i F. DCO-91-MM-N067JD6 January.15, 1991 j per NUREG 1022 and determined to be not reportable. Having both check. valves removed for 24 hours during maintenance was not reportable.  ;

3. This problem does.not require a 10 CFR 21
                                     ' report.
4. This problem does not require reporting via an.

INPO Nuclear Network entry.

5. Reviewed under 10 CFR 50.9 and determined to be not reportable since this event does not have a significant implication for'public health and safety or common defense and security.
6. Reviewed under the~ criteria 'ofi AP C-22 requiring the-issue and approval of a JCO and-determined that no JCO is required.

V. Corrective Actions A. Immediate Corrective Actions:-

1. Valves SW-1-987'and SW-1-988 were reinstalled.
2. Correct the error in' prerequisite A of-library work order R0051550~.-

RESPONSIBILITY: 5. Mellinger 1 ECD: Complete 1 DEPARTMENT: Work Planning Tracking AR: A0238710,'AE # 01 B. Investigative. Actions:

1. Document Operations Department determination that the ASW system was operable, based on NECS evaluations in AR A0238503, AE01 and memorandum from M. Tresler to R. Powers dated August 13, 1991 (CHRON 175456).

RESPONSIBILITY: S. Fridley ECD:- ' Complete DEPARTMENT: Operations Tracking AR: A0238710, AE # 02

2. Interview the journeyman for more information on'the as-found condition of the check valves. .

91NCRWP\91MMN067.JCN Page 7 of. 12 l l i 

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                                                                                  ~DCO-91-MM-N067 D6-January 15, 1991 RESPONSIBILITY:     S., Allen _           _ ECD:1 Complete DEPARTMENT:    Mechanical Maintenance Tracking AR:     A0238710, AE.# 03'-
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3. Evaluate the bases for operability of the' check valves and ASW system in the as-found configuration.

RESPONSIBILITY: K. Smith ECD: Complete DEPARTMENT: NECS. Mechanical Tracking AR: A0238710, AE # 04.

4. Provide the classification of valves SW-1-987, SW-1-988,.SW-2-987 and SW-2-988.-

RESPONSIBILITY: T. Lee ECD: Complete DEPARTMENT: NECS - Engineering,.Nuc-Systems Tracking AR: A0238710,-AE,# 05

5. Issue design drawings showing the valves SW 987, SW-1-988, SW-2-987 and SW-2-988'and their classification.

RESPONSIBILITY: D. Tateosian . -ECD: 02/28/92 DEPARTMENT: NECS - Mechanical?(NCEM) Tracking AR: A0238710, AE / 06-

6. Update the resource database' based on-the~NECS classification of the'ASW pump vault drain
                               ,         check valves in investigative action number three above.

RESPONSIBILITY: 'S. Furnis-Law._TECD: 03/15/92 DEPARTMENT: Reliability Engineering (PTRE).'  :; Tracking AR: A0238710, AE # 07 l

7. Provide housekeeping provisions'for the ASW pump vault drain check valves'to preclude recurrence of the trash =found in them.

RESPONSIBILITY: 'C. Seward ECD: 02/28/92: DEPARTMENT: Mechanical" Maintenance (PGMC)' Tracking AR: A0238710, AE # 08 VI. Additional Information l A. Failed Components: 91NCRWP\91MMN067.JCN .Page- 8 of 12 l

6' 'I Y= DCO-91-MM-N067 D6 January 15, 1991 None. B. Previous Similar Events: None. C. Operating Experience Review:

1. NPRDS:

Not applicable.

2. NRC Information Notices, Bulletins, Generic Letters:

None.

3. INPO SOERs and SERs:

None. D. Trend Code: Not applicable. E. Corrective Action Tracking:

1. The tracking action request is A0238710.
             , 2. The corrective actions are not outage related.

F. Footnotes and Special Comments: None. G.

References:

1. Initiating Action Request A0238503.
2. Personnel statement "ASW Pump 1-1 and 1-2 Vault Drain Check Valves Event" from J. Molden dated 8/11/91.
3. Recurring Task Work Order R0051550.
4. Memorandum from Diablo Canyon Project Engineer (M. Tresler) to Diablo Canyon Maintenance Manager (R. Powers) dated August 13,-1991 91NCRWP\91MMN067.JCN Page 9 of 12

1 l i l 1 DCO-91-MM-N067 D6 January 15, 1991 (CHRON 175456).

5. Action Request A0238347.
6. Action Request A0238710.

H. TRG Meeting Minutes:

1. On August 14, 1991, tne initial convention of the TRG took place in Room 327 of the Administration Building at 1:00 pm PDT. The TRG discussed the problems with the work package to determine the impact on Maintenance. The design of the ASW pump vault drains was discussed to determine operability of the ASW system and reportability of the event.

The key points of the event were:

a. The Shift Foreman was not informed that this maintenance was underway.
b. The Journeyman made design configuration decisions independently.
c. No clearance was requested or implemented for the job.

A prerequisite in the WO to verify clearance points was not complica with. This is a generic step in most WOs. No tailboard with 

          ,     the System Engineer or the Maintenance Engineer was held prior to the work.being performed. No verbal tailboard was held; the Journeyman was given the package and instructed to read it.

The job progressed past removal and cleaning of the check valve without involving the cognizant Maintenance Engineer, preventing documentation of the "as-found" condition of the valves. The sequence of steps in the WO were not followed. No gasket was found when the valves were removed. The Journeyman independently determined that no gasket would be used for reinstallation of the valves. The work package could not be performed as written but the Journeyman did not stop work to have the 91NCRWP\91MMN067.JCN Page 10 of 12

l .' r DCO-91-MM-N067 D6 January 15, 1991 work package corrected. The WO specifies A-107 bolting for the check valves but the "as-found/as-left" bolting was brass. No torque wrench was used'on the bolting, the Journeyman used' independent judgement. The policy on when a Journeyman can use independent judgement and when an Engineer must be consulted prior to taking some field action should be established and communicated to all personnel. The Foreman did not visit the job site at any time during the job. The "as-found" condition of the check valves was partially stuck open by debris (tie. wraps, , paint chips, cigarette butts, etc.). The TRG will reconvene on Friday, August 23, 1991, at 10:00 a.m. PDT. l l 2. On August 23, 1991, the TRG reconvened and discussed the following: l l Operations was notLin attendance, but verbally agreed that during the 24 hour period.that'the check valves were removed, the ASW system was operable. This is based on NECS evaluation in y a memo from M. Tresler to R. Powers dated August 13, 1991 (wiRON 175456). Based on the , low probability of flooding events and the l recognized need for periodic maintenance, NECS ' concluded that the plant was not outside its l design bases for the 24 hour period of concern. An AE will be assigned to Operations j l to formally document their concurrence. (See Investigative Action #1 on p. 7 above.) j The TRG discussed a second operability issue:  ; was the ASW system inoperable in the as-found l condition (stuck (?) open approx. 30%)? The l last maintenance on these valves was August, l 1988. As the journeyman involved has been unavailable, Investigative Action #2 was l assigned to interview him for more information on the as-found conditions. Investigative Action #3 was assigned to NECS to evaluate the l 91NCRWP\91MMN067.JCN Page 11 of 12 l

e x DCO-91-MM-N0671D6' January 15, 1991 bases'for operability of the valves and.ASW system in the as-found condition. The TRG recommended that Operations needs.to clarify the policy on; clearing theseLyalves (Perhaps add them to Tech. Specs. (nr Equipment - Control Guidelines?) The'TRG determined an additional Immediate1 Corrective Action (see.p. 7:above). This TRG will. reconvene on Wed. August 28,: 1991 at 3:00 pm to further discuss this problem. 

                                       '3. On August 28, 1991, in Room 425 of.the'       ..

Administration Building the TRG reconvened at 1:00.pm PDT to discuss 1the determination of cause of the event and root cause. No root cause has been: agrees on'yet~but.a. barrier analysis showed four distinct barrier that should have prevented the event were broken through. Additional investigative actions were identified as' included above.- The TRG'will reconvene on or about' September-- 6, 1991 at 10:00'am.PDT.

4. On October- 23,.1991, at'1:00 pm PDT'in Room 533 of t'.u Administration Building to discuss the classification of the event. .. Based on the NECS - Engineering classificationfof the ASW.

pump vault' drain check valves as class II (ref. 6)-{and the Operations determination'that the.ASW pumps were operable during the period when the ASW pump vaultzdrain check valves were removed (ref. 6), it was agreed.that the event was not a non-conformance. This writeup will.be submitted to the-PSRC for , concurrence and subsequently. closed. I. Remarks: , None. l 91NCRWP\91MMN067.JCN Page 12 of 12 j 

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