ML20197C895
| ML20197C895 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 09/04/1998 |
| From: | Barron H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-369-98-07, 50-369-98-7, 50-370-98-07, 50-370-98-7, NUDOCS 9809140277 | |
| Download: ML20197C895 (10) | |
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McGuire Nuclear Station 12700 Hagers Ferry Road lluntersville NC 28078-9340
- 11. B. Barron (704) 875-4800 omCE Vice President IION) 8I5*4009 MX September 4, 1998 U.
S. Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555
Subject:
McGuire Nuclear Station Docket Nos. 50-369, 370 NRC Inspection Report 98-07 Violations 50-369.370/98-07-07 and 50-369.370/98-07-09 Reply to Notice of Violation (NOV)
Pursuant to the provisions of 10 CFR 2.201, attached are Duke Energy Corporation's responses to Notice of Violations dated August 7, 1998 regarding inadequate vendor oversight associated with the rebuild of emergency diesel generator (EDG) cylinder heads and inadequate procedural controls associated with a degassing evolution on the Unit 1 Volume Control Tank (VCT).
Duke Energy Corporation acknowledges that these are violations of regulatory requirements. Please note that the inadequate controls associated with the Unit 1 VCT degassing evolution did not result in an effluent release in excess of allowed radiological limits.
Section 3 in each response lists the only regulatory commitments associated with the respective response.
Questions regarding the EDG or the VCT degassing violation responses should be directed to M.
R. Wilder at (704) 875-5362 or J. W.
Bryant at (704) 875-4162, respectively.
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9809140277 990904 PDR ADOCK 05000369 G
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U.S. Muslear Rrgulctgry Comuniccion Document Control Derk september 4, 1998 Page 2
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Very truly yours, S-H.
B.
Barron, Vice President McGuire Nuclear Station Attachments cc:
Mr. Luis A. Reyes Regional Administrator, Region II U.
S.' Nuclear Regulatory Commission Atlanta Federal Center i
61 Forsyth St.,
Suite 23T85 i
Atlanta, Georgia 30323 l
Mr. Frank Rinaldi U.
S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation One White Flint North, Mail Stop 9H3 Washington, D.C.
20555 i
Mr. Scott Shaeffer Senior Resident Inspector McGuire Nuclear Station i
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Attc:chment 1 cf 2 Pqo 1 of 4 McGuire Nuclear Station Reply to Notice of Violation 50-369.370/98-07-07 September 4, 1998 Restatement of Violation 50-369.370/98-07-07 10CFR 50 appendix B,
Criterion VII, Control of Purchased
- Material, Equipment and Services, as implemented by the licensee's approved Quality Assurance (QA) Topical Report (Duke-1-A),
Amendment 22, Section 17.3.2.4, Procurement
- Control, requires that measures be established for the procurement of services associated with the station's QA Condition 1,
Systems and Components, to assure the suitability of their intended service and that the safety and reliability of the station are not compromised.
QA Topical Report Section 17.3.2.5, Procurement Verification, further states that overall supplier performance evaluation is performed to a
depth consistent with the item or service's importance to safety, complexity, and the quantity and frequency of procurement.
Contrary to the above, measures were not established to assure the suitability of intended services contracted for the rebuild of emergency diesel generator (EDG) cylinder
- heads, which compromised the reliability of this QA Condition 1 equipment.
Additionally, the depth of the service supplier's performance evaluation was not consistent with the service's importance to
- safety, complexity, quantity, and frequency of procurement.
These deficiencies contributed to the EDG sub-component
- failures, which occurred on EDG's 1B and 2A on May 31 and June 4, 1998.
All failures occurred on sub-components within the cylinder i
heads, which were rebuilt by a licensee approved contractor i
during the 1997 EDG refurbishments.
- 1. Reason for the violation:
1.
McGuire's EDG procurement specification (MCS-1301.00-00-0007) contained inadequate controls, in that the vendor was not required to submit refurbishment plan or assembly procedures for Duke Energy Corporation review and approval.
2.
Vendor surveillance was inadequate to the degree that it did not identify deficient EDG vendor performance.
This deficiency allowed substitution of valve spring material without Duke's review and approval.
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Attechnent 1, P gs 2 of 4 McGuirt mac1ccr statica
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Reply to Violation 50-369.370/98-07-07 The specific events which lead to these deficiencies are described below.
The Original Equipment Manufacturer (OEM) (Nordberg) of the
.McGuire Nuclear Station emergency diesel generators (EDGs) discontinued OEM services in 1974.
Subsequently, the 10 CFR 50 Appendix B supplier of replacement parts and services for Nordberg diesels has been N.A.K.
Engineering Inc.
of Petaluma, California, i
In 1997, McGuire's EDGs were comprehensively overhauled. All l
rebuild services' were performed by Duke Energy Corporation
-personnel with the exception of the cylinder head rebuilds which were contracted to NAK Engineering.
The cylinder head rebuilds were out sourced because of Duke Energy resource limitations and the time constraints of the outages.
The McGuire Nuclear Station procurement specification (MCS-1301.00-00-0007) for replacement parts and services required that replacement parts comply with Nordberg's original manufacture specification (manufactured in 1970) unless otherwise specified by Duke.
In 1972, Nordberg completed a revision to decrease valve stem to valve guide clearances for the reason of reducing i
operating cost associated with oil consumption.
This revision increased the potential for tolerance accumulation to~cause a valve performance problem.
Typically the valve i
stem and valve guide dimensional changes would have been identified by assignment of new part numbers.
Nordberg personnel failed to assign new part numbers when completing this specific revision.
The root cause investigation searched and reviewed records, but a specific cause could not be determined for this failure.
Therefore, McGuire's record copy of the EDG vendor manual indicated the 1970 clearances values (3.5 to 5. 5 mils), while NAK records for the 197') Nordberg diesel part numbers had been revised by Nordberg to 1972 revision values (2 to 4 mils) without any documented Duke review and approval.
The 1970 Nordberg original valve spring material specification is AISI A6150.
The specification of the valve spring material is a
Nordberg part specification not typically provided to the purchaser and of which Duke had no i
record.
Unavailability of AISI I
' valve springs caused NAK to substitute ASTM A401 mater M or supply of Nordberg valve' springs.
McGuire was sup}
,d with the ASTM A401 j
valve spring material without an opportunity for review and i
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Attcchment 1, Poco 3 of 4 i
McGuiro Nuclocr Et tien
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Reply to Violation 50-369.370/98-07-07 approval in 1993 and in the 1997 ylinder head rebuilds.
The ASTM A401 valve spring material is an acceptable valve spring material.
The material has a
slightly reduced j
fatigue strength;
- however, it i s.
well within engine specification requirements.
Therefore, the substitution of the ASTM A401 valve spring material is not safety significant. Duke Energy considers this to be an isolated example of a vendor performance deficiency. Duke's vendor oversight was inadequate in that it did not identify this i
deficiency.
Vendor oversight was not adequate given the scope and complexity of the EDG overhaul.
4 2.
Corrective steps that have been taken and the results j
achieved:
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1.
Comparison of Duke to Vendor information concludes
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the valve stem clearance is the only dimensional deviation.
j 2.
Engine diagnostic data review:
a) identified characteristics of EDG-1B cylinder 8R stuck inlet valve j
b) identified EDG-1B cylinder 6L as sluggish i
3.
Replaced EDG-1B cylinder heads 8R and 6L.
- 4. Rebuilt all spare heads to larger valve stem to guide clearance.
5.
Completed a spring fatigue stress analysis.
- 6. Audit was performed of EDG Vendor Appendix B j
program in June 1998 with focus on areas in relation to recent EDG problems.
7.
Replaced all EDG springs with original Nordberg supplied springs with the exception of one inner spring.
8.
Completed a root cause failure analysis.
9.
Distributed a industry network message.
- 10. Reviewed vendor corrective actions for all parts and services supplied for the cylinder heads.
3.
Corrective steps that will be taken to avoid further violations:
- 1. The EDG procurement specification will be revised including adding a requirement for Duke review and approval of refurbishment plans and assembly procedures.
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Attechment 1, Pcco 4 of 4
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McGuiro Nuclocr Cteti~1 Reply to Violation 50-369.370/98-07-07 2.. Augmented oversight will be performed on procurement activities with NAK Engineering until satisfactory implementation of all corrective actions.
- 4. Date when full compliance will be achieved:
McGuire Nuclear Station is currently in full compliance.
l The implemented and committed corrective actions have l
restored the reliability of the EDGs, and provide the required vendor oversight to prevent reoccurrence for current and future EDG procurement activities.
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Att chment 2 cf 2 Pago 1 cf 4 McGuire Nuclear Station Reply to Notice of Violation 50-369.370/98-07-09 September 4, 1998 Restatement of Violation 50-369.370/98-07-09 Technical Specification 6.8.1, Procedures and
- Programs, requires that written procedures be established, implemented, and maintained to cover safety-related activities referenced in Appendix A of Regulatory Guide 1.33, Revision 2,
February 1978, which includes licensee procedures for control of radioactivity for limiting materials released to the environment and limiting personnel exposure.
Contrary to the above, on May 30, 1998, the licensee failed to establish procedural guidance for the abnormal vent path used for degassing the Unit 1 volume control tank to the environment.
This resulted in an unplanned release,of radioactivity (approximately 0.409 curies) that initiated an auxiliary building radiation gaseous monitor alarm.
- 1. Reason for the violation:
1.
Plant personnel involved in the VCT venting evolution failed to adequately verify or validate the existence of an adequate controlling procedure for the evolution.
On May 30, 1998, during a Unit 1 Reactor Coolant System (NC) degassing evolution, McGuire management requested recommendations from plant personnel on how to expedite completion of the degassing. One recommendation offered was to align the VCT gas space to the Nuclear Sample System (NM) sample hood. An NM sample valve would then be opened to atmosphere, venting the gas to the Auxiliary Building Ventilation System (VA) via the NM sink sample hood. This hood vents to the Unit vent which is monitored by a process radiation monitor (EMF). Chemistry management directed plant personnel to evaluate the feasibility of venting the VCT through the NM system as described above. They specified the need for a controlling procedure along with Operations (Ops) and RP concurrence of the proposed degassing method.
Chemistry personnel were contacted to determine if a
procedure existed for venting the VCT through the NM system.
They indicated that during past maintenance evolutions they
.---~~.-.---.-.-----m Attcchment 2, Pega 2 of 4-McGuiro Nuclocr Etetien Reply to Violation 50-369.370/98-07-09 used an NM sampling procedure to align the VCT gas space to the NM sample hood. A Removal and Restoration Form (R&R) was then used to open an NM sample valve to atmosphere. The VCT j
gasses were then routed to the VA system via the sample hood vent. Given that Ops and RP had approved the proposed VCT i
venting method and thinking that a procedure existed to adequately control the evolution, plant personnel were instructed to proceed with venting the VCT to the VA system through the NM sample hood. Approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> later, EMF-41 (VA Radiation Monitor) went into alarin. The VCT venting evolution was subsequently secured.
The root cause of the event was determined to be a fa U.ure to verify or validate the existence of an adequate controlling procedure.
Neither management nor staff personnel involved with the VCT venting evolution performed a review of the NM sampling procedure to verify that it contained the appropriate steps for performing the proposed evolution. In addition, chemistry personnel contacted about the NM sampling procedure failed to provide further details about the procedure (identified as a contributing cause to the event). A procedure review or further procedure details would have revealed that both the VCT and the Waste Gas system (WG) could be aligned to the NM sample hood when venting the VCT during degassing evolutions using the NM sample procedure. Consequently, when using this procedure in the past to vent the VCT, it was only partially implemented to help prevent this situation where the VCT and WG system were aligned to the sampling hood at the same time. Upon partial implementation of the procedure, an R&R would be issued to open an NM sample valve and vent the VCT to the VA system. However, since a procedure review was not performed and the chemistry personnel contacted did not provide further details of the NM sampling procedure, plant personnel performing the VCT venting evolution were unaware of the above past procedural practices. Consequently, when the NM sampling procedure was implemented, both the VCT and I
the WG system were aligned to the NM sample hood. Since the WG system is used to store fission gasses removed from the NC system during degassing, the xenon concentration of i
gasses in the WG system was much higher than that indicated in the NC system isotopic analysis used to support the degassing evolution. These fission gasses were subsequently routed to the VA system when the NM sample valve was opened to vent the gasses to the NM sample hood. Note that this NM sample valve was opened without utilizing an R&R as had been the practice during past maintenance evolutions. This was identified as a contributing cause of the event since the approval process associated with the issuance of an R&R i
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Attachament 2, P gs 3 of 4
e McGuiro Nuclocr Stction Reply to Violation 50-369.370/98-07-09 would have provided another opportunity for this evolution to be reviewed.
Additional contributing causes identified were a failure to 1
4 review flow diagrams and other system design documentation and inadequate interface between chemistry and RP personnel.
Review of system design documentation would have revealed that the WG system ties into the vent path utilized during the VCT venting evolution. The inadequate interfaces relates to chemistry contacting RP Surveillance and Control (S&C) personnel regarding the exjstence of a
controlling procedure.
S&C personnel have limited experience with effluent releases and therefore they did not recognize the potential radiological release consequences of this evolution. It would have been more appropriate to consult with RP Shift personnel who are more routinely involved in effluent release operations.
2.
Corrective steps that have been taken and the results achieved:
1.
McGuire management has reemphasized the need to verify and validate (V&V) actions asscciated with plant operations especially during infrequent, critical, or emergency evolutions.
This reemphasis included:
How to identify when a questionable condition or unusual plant evolution is about to be entered.
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Situations involving questionable conditions or unusual plant evolutions should be closely reviewed prior to execution.
Plant and system design documentation should be reviewed prior to executing plant evolutions.
j Procedures used during unusual plant evolutions e
i should be closely reviewed prior to execution to ensure they will provide adequate control over the evolution.
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Attnchment 2, P go 4 of 4
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McGuiro Nuclocr Etaticn Reply to violation 50-369.370/98-07-09 Communications between groups involved in plant evolutions should be clear and detailed.
The above corrective actions address the root cause of this event - failure to verify or validate the existence of a adequate controlling procedure.
3.
Corrective steps that will be taken to avoid further violations:
1.
A controlling procedure will be developed for venting the VCT to the VA system via the NM sample hood.
2.
Procedure changes will be implemented to ensure that all primary side venting activities are coordinated through RP Shift personnel who are more experienced with effluent release operations than RP S&C personnel.
3.
The need and the reasons for using tne R&R process will be stressed with plant chemistry personnel.
- 4. Date when full compliance will be achieved:
McGuire Nuclear Station is currently in full compliance.
The implemented and committed corrective actions will ensure that future VCT venting evolutions are performed satisfactorily using approved procedures.
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