IR 05000528/1994001
| ML17310B037 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 01/28/1994 |
| From: | Ang W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML17310B036 | List: |
| References | |
| 50-528-94-01, 50-528-94-1, 50-529-94-01, 50-529-94-1, 50-530-94-01, 50-530-94-1, NUDOCS 9402230035 | |
| Download: ML17310B037 (26) | |
Text
U. S.
NUCLEAR REGULATORY COMMISSION
REGION V
~dd Docket Nos.:
License Hos.:
Licensee:
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~l<<d d:
50-528/94-01, 50-529/94-01, and 50-530/94-01 50-528, 50-529, and 50-530 NPF-41, NPF-51, and NPF-74 Arizona Public Service Company P. 0.
Box 53999, Station 9012 Phoenix, AZ 85072-3999 Palo Verde Nuclear Generating Station Units 1, 2, and
Palo Verde Nuclear Generating Station, Mintersburg, Arizona Ins ection date:
January 3 through 7, 1994
~lns ecto':
D. Acker,'eactor Inspector, Region V
"dd Ins ection Summar M. P. Ang, Engineering Branch Chief l-26-e Date Signed
,,e dd Ins ection durin the eriod Januar 3 - 7 1994 Re ort Nos.
50-528 94-01 50-529 94-01 and 50-530 94-01 Areas Ins ected:
This routine announced inspection reviewed the licensee's maintenance program for General Electric Magne-Blast circuit breakers in accordance with Inspection Procedure 62705, "Electrical Maintenance (Components and Systems)."
The inspector also performed on-site followup of open items in accordance with Inspection Procedure 92700,
"Onsite follow-up of Mritten Reports of Nonroutine Events at Power Reactor Facilities," and Inspection Procedure 92702,
"Followup of Corrective Actions for Violations and Deviations."
Safet Issues Mana ement S stem SINS tern:
Hone.
9402230035 940128 PDR ADOCN 05000528
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Results:
General Conclusions and S ecific Findin s:
The licensee's program for maintenance of Class lE General Electric (GE)
Magne-Blast circuit breakers appeared to be adequate except for control of shims.
The licensee's procedure for overhaul of Class lE GE Magne-Blast circuit breakers allowed craft personnel to change shims on circuit breaker shafts without documentation or engineering review.
The licensee's procedures for maintenance and 'overhaul of Class 1E GE Magne-Blast circuit breakers did not include a check for crank shaft end play recommended by GE.
The licensee was actively pursuing correction of Class lE degraded voltage problems and had been technically thorough in calculations performed to date.
Si nificant Safet Matters:
None.
Summar of Vio1ation or'Deviations:
None.
0 en Items Summar
One unresolved item was opened.
One LER and two enforcement items were closed.
Revisions 0 and l of another LER were closed by in-office review.
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Detail s Persons Contacted Arizona Public Service Com an
- T. Fitzpatrick, Supervisor, Unit 2 Electrical Maintenance R. Fountain, Supervisor, guality Audits and Monitoring
- D. Gable, Supervisor, guality Control
- B. Grabo, Supervisor, Nuclear Regulatory Affairs
- H. Hypse, Supervisor, Site Technical Services
- D. Kanitz, Senior Engineer, Nuclear Regulatory Affairs
- S. Kesler, Supervisor, Nuclear Engineering, Electrical
- W. Montefour, Senior Representative, Management Services
- K. Roberson, Senior Engineer, Nuclear Regulatory Affairs
- C. Russo, Manager, guality Control
- R. Stevens, Manager, Regulatory and Industry Affairs
- H. Stewart, Supervisor, Unit I Electrical Haintenance
+J.
Thompson, Technical Assistant, Plant Support Others
- J. Draper, Southern California Edison Site Representative
- F. Gowers, El Paso Gas and Electric Site Representative
- R. Henry, Salt River Project Site Representative U. S. Nuclear Re ulator Commission
- K. Johnston, Senior Resident Inspector The inspector also held discussions with other licensee and contractor personnel during the course of the inspection.
- Denotes those attending the exit meeting on January 7,
1994.
Electrical Maintenance 62705 In April, 1993, the licensee reported the failure of a General Electric
{GE) Hagne-Blast circuit breaker due to misalignment of the close-latch reset spring.
The details of this misalignment were discussed in Information Notice 94-02, "Inoperability of General Electric Hagne-Blast Breaker Because of Misalignment of Close-Latch Spring."
Subsequently, another Region V licensee reported a separate maintenance related failure of a Hagne-Blast circuit breaker.
An inspection was performed to ascertain whether preventive maintenance activities relative to Hagne-Blast circuit breakers were being conducted in accordance with licensee-approved procedures and that these procedures met the requirements of technical specifications (TS), committed industry codes and standards, and vendor requirement ~
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a.
Licensee Procedures Nuclear Administrative and Technical Manual Procedures 32HT-9ZZ34, Revision 2, "Maintenance of Medium Voltage Circuit Breakers Type AM-4.16-250,"
and 32MT-9ZZ38, Revision 2, "Overhaul of AM-4.16-250-9H G.E. Hagne-Blast Circuit Breakers,"
were the licensee's procedures for Class lE 4.16 kilovolt (kV) GE Magne-Blast circuit breaker maintenance and overhaul.
The licensee scheduled Procedure 32MT-9ZZ34 to be performed every other refueling outage.
The licensee scheduled Procedure 32HT-9ZZ38 to be performed every fifth refueling outage.
b.
Technical S ecifications Committed Industr Standards and Vendor Re uirements The inspector reviewed the technical specifications and final updated safety analysis report and did not identify any specific requirements for overhaul or repair of Hagne-Blast circuit breakers.
The inspector determined that vendor requirements for Class 1E Hagne-Blast circuit breakers were contained in GE Publication GEH-1802X,
"Metal Clad Switchgear,"
and GE Publication GEK-41902 C,
"Hagne-Blast Circuit Breaker."
Additional GE requirements and recommendations were contained in service advisory letters.
c, Review of Maintenance Procedure 32HT-9ZZ34 The inspector reviewed the procedure to check compliance with vendor instructions.
The inspector had the following observations.
(1)
aintenance Interval The inspector determined that this procedure was based on GE requirements in Publications GEH-1802X and GEK-41902 C.
Publication GEK-41902 C recommended that the applicable maintenance steps be accomplished yearly, but noted that individual users could determine maintenance intervals based on breaker operating history.
The inspector asked the licensee for their rationale on performing the GE recommended maintenance every other refueling outage, approximately every three years.
The inspector determined that licensee personnel had previously reviewed the
'perating history of these circuit breakers and determined that every other refueling outage was the proper maintenance interval.
The inspector reviewed the licensee's records of failed Hagne-Blast circuit breakers and did not identify any trend of circuit breaker failures due to lack of maintenance.
The inspector concluded that the licensee's maintenance interval was reasonabl I f
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(2)
(3)
Com liance to Vendor Publications The inspector compared the instructions in the GE publications and service advice letters with Procedure 32HT-9ZZ34.
The inspectot identified that all vendor instructions except one were incorporated in the licensee's maintenance procedure.
The exception was a measurement of crank shaft end play specified on page 12 of Publication GEK-41902 C.
The inspector discussed measurement of crank shaft end play
'ith licensee engineering personnel.
The licensee determined that measurement and adjustment of crank shaft end play was beyond the limited maintenance scope of Procedure 32MT-9ZZ34, but should be accomplished in Procedure 32HT-9ZZ38.
The licensee committed to include crank shaft end play measurement in their next revision of 32MT-9ZZ38 via resolution of Instruction Change Request 66453.
The inspector noted that the GE instructions were written with the word "should," therefore, the inspector concluded that the licensee was not required to accomplish every vendor recommended step.
The inspector reviewed the records of Hagne-Blast circuit breaker failures for the last five years and did not identify any failures related to crank shaft end play.
The inspector concluded that the licensee actions were reasonable.
Circuit Breaker Installation Instructions The inspector determined that Procedure 32MT-9ZZ34 contained the vendor's instructions for taking measurements to ensure proper circuit breaker installation into its associated cubicle.
The inspector determined that the licensee had recently added the requirement to take the installation measurements after having a number of circuit breaker installation problems.
The inspector noted that Procedure 32HT-9ZZ34, Section 3.5, did not require installation measurements be made if a circuit breaker was being reinstalled in the same location it was removed from.
The inspector considered that if a circuit breaker were overhauled that measurement and adjustments may be required to properly reinstall the circuit breaker, even in a location were it had previously been satisfactorily installed.
The inspector discussed circuit breaker installation with licensee engineering and maintenance personnel.
The licensee stated that their normal method of circuit breaker overhaul was to overhaul spare circuit breakers and install them in new locations, while the removed circuit breakers were made spare
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and routinely overhauled for installation later in new locations.
Procedure 32HT-9ZZ34 required installation measurements be made for circuit breakers being installed in a new location.
The licensee acknowledged that the inspector's concern was valid, in that a circuit breaker could be removed, overhauled and reinstalled in the same location in accordance with Procedure 32HT-9ZZ34 without making installation measurements.
The licensee issued Instruction Change Request 66454 to evaluate the procedure.
Since the licensee was normally installing circuit breakers in new locations and making installation measurements, the inspector concluded that the licensee's actions were adequate.
d.
Review of Overhaul Procedure 32HT-9ZZ38 The inspector reviewed the procedure to check compliance with vendor instructions.
The inspector determined that there were no vendor instructions used in the procedure.
The licensee stated that they had been unable to obtain vendor overhaul instructions and had developed their own.
The licensee stated that engineering, maintenance and training personnel had disassembled and reassembled training circuit breakers and had developed the procedure from this experience.
The inspector reviewed the licensee's procedure for proper control of materials, checks for wear and damage, sufficient instructions to direct proper reassembly of the circuit breakers, and adequate testing.
The inspector determined that the procedure had adequate checks for wear and damage and adequate testing.
The inspector also determined that the procedure had adequate material control and sufficient instructions to direct proper reassembly except for one potential problem discussed below.
(I)
Control of Shims During review of Magne-Blast circuit breaker maintenance at other sites the inspector had determined that circuit breaker shaft shim (mostly flat washers)
locations were not shown in vendor drawings and varied from circuit breaker to circuit-breaker.
A vendor technical representative informed the inspector that shims were installed differently on each individual circuit breaker during construction to account for slight manufacturing differences.
Procedure 32MT-9ZZ38, Section 3.4.8 stated,
"Shims, washers, etc.
may be added or removed as necessary to allow free
movement of the breaker without excessive play.
Each breaker
<<lzth
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Ihh yb diff'
th dimensions shown in Appendix 8 as per EER 90-PB-013."
The inspector determined that the procedure required the electricians overhauling a circuit breaker to clearly document the as found shim locations, but allowed the changing of shims without even recording the changes made.
The procedure had no quality control oversight and required no engineering review of completed data.
The inspector obtained data from two recent Unit 1 Hagne-Blast circuit breaker overhauls and determined that there was no quality control oversight of these two circuit breaker overhauls.
In addition, a review of quality assurance records indicated that there had been no quality assurance review of Hagne-Blast circuit breaker overhauls in the last year.
The inspector concluded that the licensee procedure allowed their craft personnel to make undocumented changes to Class lE.
circuit breakers with no quality control, quality assurance, or engineering oversight.
Since vendor verbal information indicated that each circuit breaker was apparently unique, changing the shim arrangement may constitu'te a design change requiring conformance with 10 CFR 50, Appendix A, III, Design Control and
CFR 50.59.
The inspector reviewed shim control with the licensee.
The licensee stated that their procedure was adequate because:
Changing the shims was within the skill of the craft.
The shims were not shown on vendor drawings, therefore, specific material control of the shims was not required.
The circuit breakers were tested for proper operation after overhaul.
This item is left unresolved pending further NRC staff review of the applicability of 10 CFR 50 requirements for shim control in GE Hagne-Blast circuit breakers (Unresolved Item 50-528, 50-529, 50-530/94-01-01).
Witnessin of Overhauls The inspector did not witness any craft work because the licensee stated that there was no work being accomplished on Class 1E GE Hagne-Blast circuit breakers during the inspection wee '
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Review of Data The inspector reviewed the completed data for Procedures 32NT-9ZZ34 and 32HT-9ZZ38 for Unit 1 work orders 605378 and 606174.
All data met the associated acceptance criteria.
'he inspector observed that steps 4.9 through 4. 18 of work order
'606174, which required that each step be initialed complete, were initialed after the fact by supervisory review.
Although in this case records existed to allow for subsequent verification, the inspector considered that failure to complete required verifications as they were performed could lead to missed requirements.
The
'icensee acknowledged the need to sign required verifications as the associated steps were performed.
The inspector reviewed the last five years of failure information for these circuit breakers.
The inspector did not identify any trend of failures associated with maintenance errors or omissions.
g.
Conclusion Based on a review of procedures, a review of failure information, a
review of a sample of completed data, and licensee committed actions, the inspector considered that the licensee's program for maintaining GE 4.16 kV Class 1E Hagne-Blast circuit breakers appeared to be acceptable, pending resolution of the need to maintain shim control.
No violations or deviations from NRC requirements were identified.
3.
Onsite Followu of Written Re orts 92700 Closed Voluntar Licensee Event Re ort 50-528 93-Oll-LO:
Potential Safet -Related E ui ment Problems Due to De raded Grid Volta e Licensee's Re ort On December 19, 1992, licensee engineering personnel determined that with switchyard voltage at its design.basis minimum of 95X of 525 kilovolts (kV) and with maximum operating load, downstream voltages could be lower than degraded voltage relay settings.
This scenario would result in shedding of Class 1E 4.16 kV loads and automatic start and sequential loading of the emergency diesel generators (EDGs).
On January 14, 1993, a licensee preliminarj analysis indicated that, with switchyard voltage between 95X and 100X, voltages below the 90X value specified for continuous operation could occur in Class lE 480 volt equipment, without a trip of the degraded voltage relays.
Licensee's Actions The licensee obtained a load dispatcher commitment to administratively control the grid voltage above 100X.
The licensee performed new load
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voltage calculations, raised tap settings on selected 480 volt transformers, installed new degraded voltage relays with improved tolerances and submitted a Technical Specification (TS) change request to
'reset the degraded voltage relays to a more optimum value.
Ins ector's Actions Durin the Present Ins ection The inspector reviewed LER 50-528/93-011, Revision 0, supporting calculations, supporting computer programs, test data, and the TS change request, letter 102-02772-WFC-RAB-GEC of December 30, 1993.
The
.inspector also discussed the licensee's plans for further actions with cognizant engineering and management personnel.
Discussion and Conclusion The inspector determined that the licensee had developed their own computer program for determining load voltages.
The inspector reviewed the validation of this program with licensee engineering personnel.
The licensee checked the accuracy of the program to model the electrical distribution system by performing sample hand calculations, comparing their computer calculations to calculations from a commercially recognized program (AC-ELMS), obtaining a software quality assurance review, and by comparing program predicted values with actual test data.
The inspector reviewed the validation data and concluded that the checks were adequate to validate the acceptability of the program.
The inspector also determined that the methodology used as the basis for the computer program was technically acceptable for modeling electrical distribution systems.
The inspector reviewed the degraded voltage trip value,
>3744 volts, selected by the licensee as their basis for their TS change request.
The inspector determined that the licensee plans to set the relays at 3744, therefore, any negative relay drift will put the licensee outside their TS requirements.
The inspector considered that thi.s information was adequately described in the TS change request, which will be evaluated separately by NRR.
'he inspector also determined that the licensee plans to evaluate a
number of design changes that would improve their safety margins associated with degraded voltage and allow for potentially larger variations of grid voltages.
The inspector concluded that the licensee actions on degraded voltage to date have been technically adequate and that there was reasonable assurance that the licensee would continue to pursue further improvements.
Therefore, this voluntary LER is closed.
No violations or deviations from NRC requirements were identifie l
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Followu of Corrective Actions for Violations and Deviations 92702 a.
Closed Enforcement Item 50-530 92-15-02:
Im ro er Maintenance of Reactor Tri Circuit Breakers Ori inal NRC Enforcement Item An inspector determined that the licensee had not properly maintained their reactor trip circuit breakers.
This issue was discussed in an Enforcement Conference and cited as Violation A of a Notice of Violation and Proposed Imposition of Civil Penalty, dated August 13, 1992.
Violation A had three parts which were:
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Improper lubrication of both General Electric (GE)
and Westinghouse reactor trip circuit breakers.
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Failure to comply with a Westinghouse inspection bulletin which described potential failure of reactor trip circuit breakers to properly open and adjustments which would ensure proper operation.
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Failure to incorporate GE maintenance procedures for undervoltage and shunt trip devices.
Licensee's Actions in Res onse to the Enforcement Item The licensee, in their response to the Notice of Violation (NOV) on September 14, 1992, committed to:
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Determine and use the proper lubricant.
The licensee also determined that the use of the improper lubricant would have little effect on circuit breaker operation.
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Incorporate the Westinghouse inspection bulletin into Westinghouse reactor trip circuit breaker maintenance procedures.
Strengthen review processes for vendor information.
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Incorporate GE maintenance procedures for undervoltage and shunt trip devices into GE reactor trip circuit breaker maintenance procedures.
The inspector monitored reactor trip circuit breaker performance subsequent to the NOV.
The inspector noted that the licensee continued to have problems with adjustment of undervoltage trip units on the GE reactor trip circuit breakers.
The licensee kept NRC Region V management appr aised of these, and other reactor trip circuit breaker problems, including any potential for circuit breakers failing to open.
Although equipment failures outside of
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the circuit breakers made the circuit breakers partially inoperable in the test position and GE circuit breakers experienced failures to stay closed, no further failures of reactor trip breakers to open were noted by the licensee.
However, due to continuing maintenance problems with the existing reactor trip circuit breakers, the licensee decided to replace these circuit breakers, which were in limited use in the nuclear industry, with Westinghouse type DS-416 circuit breakers, which have more widespread industry use.
Ins ector's Actions Durin the Present Ins ection The inspector reviewed the associated procedures, Procedures 32NT-9SBOl, Revision 8, "Naintenance of Westinghouse Reactor Trip Switchgear,"
and 32NT-9SB02, Revision 6, "Naintenance of G.
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Reactor Trip Switchgear," to ensure that the licensee's committed actions were properly completed.
The inspector reviewed the status of the replacement of the existing types of reactor trip circuit breakers.
Discussion and Conclusion The inspector determined that the licensee had incorporated the committed items in their procedures.
The inspector determined that the licensee will complete replacement of the subject type of reactor trip circuit breakers by the end of 1994 in all three units.
Therefore, the inspector considered that any concerns regarding the long term acceptability of circuit breakers which were improperly lubricated will be resolved by replacement of these circuit breakers.
Based on the licensee immediate actions to resolve procedure problems and long term action to install reactor trip circuit breakers with industry known operating characteristics, the inspector concluded that this violation has been adequately resolved.
This item is closed.
Closed Enforcement Item 50-529 93-15-01:
Procedure Com liance Problems with Desi n Chan es Ori inal NRC Enforcement Ite An NRC inspection of design changes identified three separate procedure compliance problems with Unit 2 design changes.
The three parts of the violation were:
Failure to identify and update key drawings affected by a design change.
Failure to identify and update an operating procedure affected by a design chang l
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Failure to complete specified retest instructions for a design change.
Licensee's Actions in Res onse to the Enforcement Item The licensee, in their response to the Notice of Violation (NOV) on June 8, 1993, committed to:
Update the drawing and procedure noted in the violation.
Complete the missing retest.
Review all critical system design changes completed in the last two years for similar problems.
Change the structure of the engineering organization to allow for more dedicated engineering oversight of design changes.
Update the Station Information Hanagement System (SIHS) to include drawing and procedure cross references to equipment tag numbers.
Ins ector's Actions Durin the Present Ins ection The inspector reviewed the updated drawing and procedure and the completed retest information.
The inspector reviewed a sample of SIHS information for drawings and procedures.
The inspector reviewed the engineering organizational changes.
Discussion and Conclusion The inspector concluded that the licensee had updated the specified drawing and procedure and completed the required retesting.
The inspector also concluded that information was available on SINS to aid in determining which drawings and procedures could be effected by design changes.
The inspector determined that additional engineering organizational changes had taken place since the NOV response and that more were being planned.
Due to the potential for additional changes, the inspector did not attempt to ascertain if the organizational changes would assist in design change oversight.
However, the inspector concluded that the licensee had resolved the original problems and had updated SIHS to provide additional information to correctly identify drawings and procedures effected by design changes.
The inspector considered these actions adequate to resolve the violation.
This item is closed.
No violations or deviations from NRC requirements were identifie J
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5.
In-Office Review of Licensee Event Re orts 92712 Licensee Event Report 50-528, 50-529, 50-530/89-12, Revisions 0 and 1 are closed based on in-office review, noting that Revision 2 of this LER was closed by on-site review in Inspection Report 50-528, 50-529, 50-530/93-46.
'o violations or deviations from NRC requirements were identified.
6.
~Ei The inspector conducted an exit meeting on january 7, 1994, with members of the licensee staff as indicated in Section 1.
Ouring this meeting, the inspector summarized the scope of the inspection activities and reviewed the inspection findings as described in this report.
The licensee acknowledged the concerns identified in the report.
The licensee did not identify as proprietary any of the information reviewed by the inspector during this inspection.
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