ML20236R825
| ML20236R825 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 07/16/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20236R805 | List: |
| References | |
| 50-440-98-11, NUDOCS 9807220299 | |
| Download: ML20236R825 (22) | |
See also: IR 05000440/1998011
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U.S. NUCLEAR REGULATORY COMMISSION
REGION lil
Docket No:
50-440
License No:
Report No:
50-440/98011(DRS)
Licensee:
Centerior Service Company
Facility:
Perry Nuclear Power Plant
Location:
P. O. Box 97, A200
Perry,OH 44081
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Dates:
May 18 - 22,1998
inspectors:
Z. Falevits, Reactor Engineer, Team Leader, Rlll
S. Alexander, Reactor Engineer, NRR
A. Pal, Electrical Engineer, NRR
T. Tella, Reactor Engineer, Rill
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Approved by:
Ronald N. Gardner, Chief,
Engineering Specialists Branch 2
Division of Reactor Safety
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EXECUTIVE SUMMARY
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Per:y Nuclear Power Plant
. NRC Inspection Report 50-440/98'111(DRS).
A team insoection was conducted using the guidance of Temporary instruction (TI) 2515/137,
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. Revision 1, " Inspection of Medium-Voltage and Low-Voltage Power Circuit Breakers." issued
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March 1998. The purpose of this inspection was to verify the adequacy of licensae programs,
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procedures, training, equipment and supporting documentation for the mainte'1ance of
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medium-voltage and low-voltage power circuit breakers. The inspection team was comprised of
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Region lil and Headquarters personnel. The following observations were made.
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Calculatic.a PRDC-0007, " Voltage Drop of DC Control Circuits," dated May 18,1998,
lacked rigor in terms of design inputs and conclusions. In addition, design control
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measures were ineffective in that design reviews failed to identify these deficiencies. A
safety assessment, performed during the inspection, was acceptable to support an
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interim operability determination. The licensee indicated that a long term resolution
would be developed to conservatively demonstrate on a continuing basis that the DC
system could perform its intended function. A violation was cited. (Section E2.1)
The licensee initiated aggressive corrective action to address NRC concems identified in
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1994 relative to inadequate breaker maintenance. Subsequently, in 1995/1996 all AC
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power circuit breakers were refurbished. However, most safety related DC bruakers
had not yet been refurbished despite their age and the observed hardened grease in
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most of the ABB low voltage breakers. The licensee committed to accelerate the
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refurbishment plan for the DC breakers. (Section M2.1)
The preventive maintenance procedures for the low-voltage power circuit breakers
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reviewed were generally of a type appropriate to the circumstances and included
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appropriate qualitative and quantitative acceptance criteria. However, various errors
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were identified in test reports reviewed for solid state trip devices. Similar errors were
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identified by the licensee as a result of the team's request to review additional test
reports. The instantaneous trip function of circuit breaker EF1804 was tested for
instantaneous pickup at 2270 amps instead of the upper limit of 2160 amps. A violation
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was cited. (Section M3.1)
The licensee was using an unevaluated cleaner on the 5 kV and 15 kV medium power
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circuit breakers. The maintenance procedures specified an ammonia-based glass
cleaner to clean the breaker's electrical components. The licensee used "Windex Glass
Cleaner" which was not an evaluated cleaner. (Section M3.2)
The team concluded that lack of training on the Gels contributed to the inadequate
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implementation of the test procedures and considered this a weakness. (Section M5.1)
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There was very good evaluation and disposition of NRC, vendor, INPO, and other
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industry experience information. The operating experience reviews (OER) program
' procedures were generally comprehensive and workable and the OER database was
complete with respect to circuit breaker information identified beforehand by the team.
The individual OER evaluations were generally thorough and the resolution of issues
expressed in NRC generic communications, operating experience reports, Part 21
reports and vendor letters was very good. This area was considered a strength.
(Sections M6.1)
Treatment of medium and low-voltage power circuit breakers under the Maintenance
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Rule was satisfactory. (Section M6.3)
No specific audits or self assessments were performed in the areas of breaker
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maintenance or operations. This area was considered a weakness. (Section M7.1)
The implementation of the vendor manual control and vendor interface program in the
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past was not effective. The program was suffering from inadequate involvement by
equipment-knowledgeable staff, insufficiently aggressive or tenacious follow up with
uncooperative vendors, and out-of-date vendor contact information. The latest version
of the vendor manual control and vendor interface program shou'd improve the state of
switchgear vendor manuals. This area was considered a weakness. (Sections M8.1)
No documented breaker failures were recorded that could be directly attributed to
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breaker problems after the licensee refurbished all AC breakers in 1995/1996. The
team noted that since breakers had been swapped between switchgear cubicles and
breaker serial numbers were not being consistently recorded on work orders, the
repetitive breaker failure data could not be easily obtained. The team also noted that
the licensee had not yet established a program for trending breaker repeat failures and
routine maintenance deficiencies. (Sections M8.2)
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II. Maintenance
M2
Maintenance and Materiel Condition of Facilities and Equipment
M2.1 Low Voltage Breaker Maintenance
a.
Insoection Scooe
The team reviewed the licensee's maintenance and refurbishment program for low
voltage breakers.
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b.
Observations and Findings
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The team noted that a violation (Perry report 50-440/94006) had been issued by NRC in
1994 for inadequate and untimely corrective actions to address the grease hardening
concems in ABB breakers. Grease hardening in ABB breakers was a known problem
since at least 1989, when a 10CFR Part 21 Notice was issued. The team also noted
that most of the breakers refurbished by the licensee during 1995 indicated severe
hardening of grease and several other problems. All the safety related AC low voltage
breakers (except the spares) had been refurbished and appeared to be in good working
condition. However, there were twelve safety related DC breakers in Unit 1 and eight
safety related DC breakers in Unit 2 yet to be refurbished.
The team noted that the DC ABB breakers were approximately 20 years old and the
vendor recommended complete refurbishment of these breakers, at intervals to not
exceed a maximum of 10 years. Further, four DC breakers refurbished recently also
exhibited hardened grease. In view of these facts, the team was concerned about the
condition of the remaining DC breakers in service.
In response to this concem, the licensee informed the team that the refurbishment
schedule for the DC breakers would be accelerated and that the safety related DC
breakers would be refurbished by September 30,1999. The previous completion date
was April 17,2001 for safety related ABB K-Line DC breakers.
c.
Conclusion
The team determined that corrective actions, taken to address the concems noted by
the NRC with the AC breakers in 1994, were effective. However, the team was
concerned that the safety related DC breakers had not yet been refurbished in view of
their age and the observed hardened grease in most of the ABB low voltage breakers.
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-M3
Maintenance Procedures and Documentation
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M3.1 Review of Maintenance Procedures for Low-voltage Power Circuit Breakers
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a.
Insoection Scone
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The team reviewed the preventive maintenance procedures for the low-voltage power
circuit breakers. The procedures were compared to the maintenance section of the
manufacturer's instruction manuals and to the recommendations in Electric Power
Research Institute (EPRI) Nuclear Maintenance Applications Center (NMAC) Publication
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NP-7410, Volume I, " Low-voltage Circuit Breaker Maintenance," Part 1," ABB K-Line.
The procedures were reviewed in light of the team's knowledge of good industry practice
- for breaker maintenance, as well as specific guidance in Tl 2515/137. These
documents and concepts provided a framework for assessing the quality of the
- maintenance procedures. The ultimate acceptance criterion applied by the team was
that the procedures were of a type appropriate to the circumstances and included
appropriate qualitative and quantitative acceptance criteria.
The team reviewed the following low-voltage circuit breakers procedures:
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General Electric Instruction (GEI)-0009, ABB Low-Voltage Power Circuit Breaker
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Types K-600 & K-600s Through L-3000 & K-3000s Mainter'ance, Revision 4.
gel-0124, Types SS-3, SS-4, and SS-5 Solid State Trip Devices Testing and
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Calibration Using Multi-Amp CB-8160 Test set, Revision 4.
gel-0102, Maintenance and Calibration of Gould/ITE Solid State Trip Cue'ces
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Type (SS-3, SS-4, SS-5), Revision 2.
gel-0115, Maintenance and Calibration of DC Over current Trip Device Type
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OD-3 and OD-4, Revision 2.
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gel-0012, Cleaning of Electrical Equipment, Revision 2.
b.
Observations and Findings
The team observed that the maintenance procedures were clear, detailed, incorporated
sign-offs on individual steps by craft persons and overall by approver and supervisor.
Data sheets provided a good record of the results of all measurements made and
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breaker condition at time of maintenance.
The preventive maintenance procedures reviewed were generally of a type appropriate
to the circumstances and included appropriate qualitative and quantitative acceptance
criteria. Breaker maintenance was done at a five year frequency. However, some
breakers depending on operating experience, might be maintained at three years
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frequency.
(1)
The team reviewed procedure gel-0009, Revision 4, in detail, and made the
following observations:
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The procedure included the maintenance and testing recommendations
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from the manufacturer's instruction book and the NMAC K-line
Maintenance Guide. In addition, the procedure had been revised to
' include industry experience.
The breaker closing and tripping operation at 90 Vdc were included in the
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procedure. However, the vendor maaual recommended a minimum
voltage for tripping of 70 Vdc. Also, the verification at 90 Vdc was not
performed on all breakers. The team was informed that the closing and
tripping operations at the minimum and maximum operating volhnes
were performed at the service center during refurbishment. (Operating
breakers below the minimum control voltage that might be expected -
under the worst-case design basis condition and operation for tim
- particular breaker provided some assurance of opening or closing
operability at those voltages.) Opening and closing breakers electrically
at the minimum and maximum rated voltage for the device of concem
(i.e., trip coils, closing solenoids, closing spring release coils, and closing
spring charging motors) provided qualitative indication that there was
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some margin to degraded mechanical condition of the breaker for-
diagnostic screening purposes.
(2)
The team reviewed procedures gel-0102 and 0124 for testing and calibration of -
solid state trip devices on K-line breakers and identifed that the limits for the
solid state trip device long and short time delays were not in agreement with the
vendor manual recommendations. The time delays are tabulated below:
Lona Time Delav (seconds) Vendor Manual Data
Perry Procedure Data
Min.
8 - 12
8 - 12
int.
20 - 32
19 - 32
Max.
60 - 98
57 - 98
Short Time Delav (seconds)
Min.
0.08 - 0.17-
0.08 - 0.17
Int.
0.20 - 0.32
0.20 - 0.32
Max.
0.35 - 0.50
0.35 - 0.50
CR 98-1148 was written to address this cormem.
(3)
Additionally, the team reviewed a sample of actual testing using these
procedures a'x! identified that the instantaneous trip function of circuit breaker
EF1804 used for emergency closed cooling pump motor 1P42C001 A was
inadequate. The team reviewed a data sheet from work order R93-683, dated
. November 14,1994, and identified that the electrician who determined the test
current values, based on data provided by engineering, made several errors in
computing the test current values which were used during performance of the
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test. First, the electrician applied the long-time trip pickup multiplica, tion factor
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(1.1) in addition to the instantaneous trip multiplication factor (12) to the trip unit's
nominal full-load current value of 150 amperes, yielding a nominal instantaneous
trip pickup value of 1980 amperes (150x12x1.1) instead of the correct value of
1800. amperes (150x12). Second, the electrician applied a previously used field
test tolerance of 15 percent to his incorrectly computed instantaneous pick up
value of 1980 amperes instead of the *20 percent tolerance prescribed in the
revision of the procedure in effect at the time. This yielded a minimum
instantaneous trip test current value of 1683 amperes (1980x0.85) instead of the
correct value of 1440 amperes (1800x0.8) and an upper test limit of
2277 amperes (1980x1.15)instead of the correct value of 2160 amperes
(1800x1.2).
. The electrician tested the trip device for no-pickup at 1685 amps (lower limit) and
instantaneous pickup at 2270 amps (upper limit). Because the trip function was
tested at a value higher than the maximum allowable trip current (and tripped at
that level, but not below it), the test did not provide assurance that the breaker
would trip at current levels within the allowable band. This potentially impacted
circuit coordination and circuit protection. The fact that the breaker did not trip
when tested at a current level within 15 percent of the lower limit was actually
conservative (although not in accordance with the current procedure), indicating
that this breaker was not likely to tilp prematurely. The team determined that the
errors made in the test report were not identified by the reviewer / approver that
signed off the test report. Other completed tests with similar errors were
identified as a result of the team's request to review additional completed tests.
The team considered the as left instantanooto trip test current of circuit breaker
EF1B04 to be inadequate.
Criterion XI, " Test Control," of 10 CFR Part 50, Appendix B, requires, in part, that
components be tested in accordance with written test procedures that .
incorporate the requirements and acceptance limits of applicable design
documents. The failure to ensure that testing of circuit breaker EF1804 was in
accordance with design requirements is considered an example of a violation of
Criterion XI (50-440/98011-01(DRS)).
Condition report (CR) 98-1140 was written to address this concem and an
operability evaluation was performed. The operability evaluation determined that
the circuit pivw. tion and coordination would not be affected and the tested value
would not degrade the safety function of systems, structures or components.
The team agreed with the conclusion of the operability evaluation.
(4).
In response to the team's concem about the use of 20 percent tolerance for
instantaneous pickup inriend of 15 percent as indicated in the vendor manual,
the licensee provided an ABB letter dated September 22,1992. The team noted
that the ABB letter indicated a 10 percent tolerance according to ANSI
C37.17-1979Property "ANSI code" (as page type) with input value "ANSI</br></br>C37.17-1979" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process. for long time pickup and longer waiting timr= between tests. These
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were not included in the plant procedures gel 0102 and 0124. CR 98-1166 was
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. written to address this finding. This item was considered unresolved pending
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licensee completed corrective action following clarification from the vendor of use
' of the 15 percent tolerance for long time trip during single phase primary injection
testing and the vendor recommended cooling periods between short time and
instantaneous tests. (50-440/98011-02(DRS)).
c.
Conclusions
The preventive maintenance procedures reviewed were generally of a type appropriate
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to the circumstances and included appropriate qualitative and quantitative acmptance
criteria. However, the team identified various errors in test reports for solid state trip
devices. Similar errors were identified by the licensee as a result of the team's request
to review additional test reports. As a result of the noted test errors, the team identified
that the instantaneous trip function of circuit breaker EF1B04 was tested for -
instantaneous pickup at 2270 amps instead of the upper limit of 2160 amps. The
breaker was subsequently evaluated and the evaluation determined that circuit
protection and coordination would not be affected.
M3.2 Review of I nhriu. tion and Cleaners used Durina Mahtenance of Power Circuit
Breakers
a.
Inspection Scope
The team reviewed preventive maintenance procedures used to perform maintenance
activities on the power circuit breakers. The team focused on lubrication requirements -
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delineated in the procedure and compared them to vendor recommended and approved
lubricants and cleaners.
b.
Observations and Findings
Generic Electric Instruction, gel-0135, "ABB Power Breakers 5 KV Types 5HK250 and
5HK350 Maintenance," Revision 0, dated March 25,1994, section 4.2, item 9 specified
that a~ monia-based glass cleaner, or equivalent SC 1152404 Chemical Permit 284 was
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an acceptable cleaner for 5 KV breakers. Section 5.4.4b stated, " Wipe the outside of
the arc chute with a clean cloth and a mild ammonia-based glass cleaner," Similarly,
gel-0136, "ABB Power Breakers 15 KV Types 5HK1000 Maintenance," Revision 0,
dated March 25,' 1994, section 4.2, item 10 also specified that ammonia-based glass
cleaner, or equivalent was an acceptable cleaner for 15 KV breakers. The team noted
that Chemical Permit 284 was issued on June 6,1996, for use of "Windex Glass
Cleaner" which contained butoxyethanol and isopropyl alcohol; however, the permit did
not allow use of this cleaner specifically on breaker components. The team determined
that the use of "Windex Glass Cleaner" was not approved by the breaker manufacturer.
ABB manual MS3.2.1.9-1D used, in part, for maintenance and surveillance of
medium-voltage breakers type 5HK250 and 350 stated in section 1.a that the
recommended lubricants for breaker mechanisms was Anderol 757 and for electrical
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contacts, NO-OX-lD. The manual further stated that, "use of other lubricants risks
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incompatibility with original materials or unproven performance." In addition, ITE Gould
instructions, IB-8.2.7-2, issue H "5 KV power circuit breakers type 5HK75,5HK150,
5HK250 and 5HK350, " stated in section 5.12 " Lubrication" that, "if grease should
become contaminated or parts are replaced, lubrication should be done with NO-OX-ID
or Anerol as applicable. Use of other greases have not been proved by test and are not
recommended."
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The licensee could not provide the team with an engineering evaluation that concluded
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that use of the "Windex Glass Cleaner" to clean the breaker arc chutes was acceptable.
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The licensee informed the team that the use of Windex would be discontinued, the
procedures would be revised to match the vendor manual and an acceptable product
would be used. The licensee, however, did not issue a condition report, to determine
the effect this cleaner had on the breakers it was used on, until questioned by the NRC.
The team was concemed since use of unapproved sprays in the nuchar industry on
safety related breakers has resulted in breaker operational problems.
The licensee was evaluating the acceptability of the use of "Windex Glass Cleaner" to
clean safety related electrical breaker components. This issue is considered unresolved
pending licensee evaluation results. (50-440/98011-03(DRS)).
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c.
Conclusions
The team concluded that the licensee was using an unevaluated cleaner on the 5 KV
and 15 KV medium power circuit breakers. The maintenance pror*d:r,c5 specified are
ammonia-based glass cleaner to clean the breaker's electrical components. The
licensee used "Windex Glass Cleaner," which was not evaluated for this application and
was not an approved cleaner by the vendor.
' M3.3 . Review of Medium Voltaos Breaker Testino
a.
Inspachon Scope
The team reviewed licensee's maintenance procedures for medium and low voltage
breakers to verify adequacy of testing.
b.
Observations and Findings
The team noted that procedure gel-135, Revision 0, "ABB Power Circuit Breakers 5 kV
Types 5HK 250 and 5HK 350 Maintenance," Section 5.6.2, specified bumishing the
main contact surfaces with a fine Scotch-Brite or bumishing stone, prior to measuring
~ the contact resistances to compare with values (60 micro-ohms) specified in Table 1
(Section 5.8.1) of the procedure. The team was concemed that the as-found contact
resistances were not measured, prior to cleaning and bumishing, and prior to severci
. closing operations and thus the as-found data was lost and could not be trended.
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The team noted that ABB vendor manual for HK type Breakers (186.2.1.7D) specified a
maximum contact resistance as 40 micro-ohms for optimum performance. The vendor
manual specified that the main and arcing contacts be dressed with a fine file if the
contact resistance (and the milli-volt drop) exceeded 150 percent of the specified value.
The vendor manual also stated that the contact pressures be adjusted, if these values
were still over 150 percent of specified values, after the contacts were dressed.
However, the procedure specified only one contact resistance of 150 percent (60
micro-ohms) as the acceptance criteria instead of the twa step process specified in the
vendor manual. The licensee's maintenance procedure also specified several breaker
closing operations prior to meastfg 2 wotact resistances.
The licensee's methodology which did not take as found data and include provisions for
assuring that prerequisites (i.e. measuring contact resistances prior to cleaning and
bumishing) wete met was a concem since this data could be evaluated and trended by
engineering to determine if changes were needed to the maintenance frequency.
c.
Conclusions
The team was concerned that the as-fou'nd contact resistances were not measured,
prior to cleaning and bumishing, and prior to several closing operations and thus the
as-found data was lost and could not be trended. Procedure, gel-135, Revision 0, did
not include provisions for measuring the contact resistances (and milli-volt drops) of
breakers prior to cleaning and bumishing these contact surfaces.
M5
Maintenance Staff Training and Qualifications
M5.1 Training in Breaker Maintenance
a.
Inspection Scope
The team reviewed the licensee's program, procedures and lesson plans for training
maintenance personnel in electrical breaker maintenance.
b.
Observations and Findinas
The team selected three electricians to review their training in detail. The electrical
training coordinator and the selected electricians were interviewed. The training was
acceptable overall. However, the team noted that training was given to the electricians
on administrative procedures and on new Gels, but no training was given on the
subsequent revisions to the Gels. The team noted that gel-0124, " Types SS-3, SS-4
and SS-5 Solid State Devices Testing," Revision 4, changed the acceptance criteria for
instantaneous pickup from 15 percent variation toi20 percent. The team noted that
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eight procedure instruction changes were issued to this procedure since it was revised
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in June 1998. The team noted that during the testing of solid state devices using
gel-0124, the electricians made several errors (as mentioned in Section M3.1.b(3)). It
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appeared that some engineering functions were delegated to the electricians. The team
- determined that lack of adequate training on these procedure revisions could have
contributed to the errors made by the electricians in implementing these procedures.
The team also noted that Section 5.1.5 of Perry's quality assurance (QA) plan stated, in
part, that training was not required for revisions to instructions. This might have
contributed to inadequate training.
c.
Conclusion
The team concluded that lack of training on the revisions to Gels contributed to the
inadequate implementation of the test procedures, and considered this a weakness.
M6
Maintenance Organization and Administration
M6.1 Evaluation of Ocaratina Exoerience Reoort (OER) Prociem and ImO smentation
a.
Inspection Scope-
The team reviewed procedures for obtaining, tracking, reviewing, disseminating, and
dispositioning industry operating experience information, including information from the
NRC, The Institute for Nuclear Power Operations (INPO), other licensees and vendors.
The team reviewed a printout of the Perry OER computer database entries pertaining to
circuit breakers in general, comparing the plant information to the team predetermined
list. Finally, the team reviewed the files for selected OER items including NRC
information notices (IHs) pertaining to medium-voltage circuit breakers in general and
Perry's ABB HK and GE Power-Vac type breakers in particular.
b_
Observations and Findinos
Review of NRC generic communications indicated that there were ten ins that were
either generically or specifically applicable to Perry ABB medium-voltage Type HK circuit
breakers. In most cases (only one exception identified), the review by OER personnel
for applicability of the information to Perry was thorough. With only two exceptions
among the selected items reviewed, the dispositions of the information were complete,
appropriate and timely. For example, IN 83-84, dealing with problems with puffer
pistons in ABB HK breakers was appropriately determined to be applicable to Perry
equipment. Although the team did not verify that all affected breakers were immediately
inspected for the reported problem, the licensee had incorporated instructions for
inspecting for the problem on a routins basis into HK breaker preventive maintenance
procedures.
The exception to appropriate determination of applicability involved the licensee's review
of IN 80-13 and GE riuclear anergy (NE) service information letter (SIL) 155 regarding
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GE SBM type switches. The information notice, SIL 155 and several service advice
letters (SALs) from the GE product department that manufactured the switches,
reported problems with age induced cracking of the contact cam followers that were
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made of GE's polycarbonate material called Lexan@, used in SBM switches that were
made between 1972 and 1976. The review focused on switches received through GE
NE in the NSSS scope of supply and the licensee determined that none of those -
switches were affected. However, the OER and technical reviewers failed to recognize
that the switches had been widely used by switchgear original equipment manufacturers
including ABB. During the review of the ABB HK breaker vendor manuals, the team
found SBM control switch information and confirmed with the licensee and through the
walkdowns that the local breaker control switches on the ABB HK breaker cubicles were
GE SBM types. In response to this finding, the licensee committed to reevaluate the
applicability of the IN, SIL and SALs pertaining to SBM switches, determine whether any
of the switches installed or in the warehouse were among the affected date codes or
showed signs of degradation and to take appropriate corrective action.
IN 84-46 reported problems with breaker position verification and was determined to be
generically applicable to Perry. System operating instruction sol-R22 (Revision 4), for
medium-voltage switchgear and FTI-F0036 (Revision 2), the post maintenance test
manual indicated that unless the equipment being supplied power by the breaker
needed to be operated for some other reason (e.g... surveillance, operations, etc.) the
breaker would typically not be cycled (closed and opened) after being retumed to the
connected position. If maintenance had been performed on a breaker removed from its
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cubicle or even from the connected position to the test or disconnect positions within the
cubicle, the breaker was functionally tested (closed and opened) in the test position.
- However, industry experience (including experience with HK breakers) has shown that
there are various things that can occur when moving a breaker back into the connect
position (i.e., with primary disconnects connected to the bus) that can lead to loss of the
ability for the breaker to be closed once reconnected, opened once closed, or the
closing spring recharged. Should this occur, a safety-related load might be rendered
inoperable, but this condition remain undetected for an extended period.
The team discussed the practice of operating the breaker as soon as possible after
reconnection to the bus (which runs the load equipment if the bus is energized),
consistent with or as allowed by plant conditions and operations, with the Perry electrical
maintenance engineer. The engineer agreed that as infrequently as breakers were
actually disconnected relative to the frequency of routine operation of most load
equipment, or bus switching operations, that the poct-reconnection retest should not
unduly tax the equipment. He agreed, therefore, to consider adopting this good
engineering practice which the team pointed out was generally subscribed to by
members af the circuit breaker users groups as well as EPRI-NMAC.
IN 91-78 reported problems with circuit breaker status (closed or open) indication in
which control power to the breaker closing or spring release coils and trip coils was
fused separately from power to the status indicating lights. In this situation, if a control
power fuse blew the indicating lights that were on could remain on and not alert control
room operators that control power for remote electric or automatic operation of the
- breakers was no longer available. According to the file, this IN had been correctly
screened as potentially applicable to Perry and referred to engineering for review. After
I
several iterations of review, the licensee ultimately determined that in all cases, breaker
,
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control power and indicating light power had common fuses. However, during the
team's review, it appeared that one of the licensee engineer's questions in an internal
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memorandum had not been adequatdy addressed. In the course of examining the
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affected control and indication schematic drawings, the team discovered a feature of the
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plant design that would require further review. The diagrams revealed that although trip
and closing coils and indicating lights did have common fuses, the red indicating lights
(breaker closed), at least in the control room, were wired in series with the trip coils such
that the control room red light (not necessarily the one on the local panel) not only
indicated that the breaker was closed and tripping power was available, but also that
there was circuit continuity through the trip coil. However, the drawings indicated that
the green indicating lights (breaker open) were not wired in series with the breaker
closing spring release coils. These lights when illuminated would then indicate that the
breaker was open and that closing power was available (common fuse), but would not
confirm continuity through the spring release coil branch circuit. The licensee could not
offer an explanation of why the closing and opening circuits were or should be wired
differently.
The team found the OER program to be very good; however, the following weaknesses
were noted:
IN 96-44 and 96-44, Supp.1 were not reviewed adequately for generic impact at
.
Perry. Procedure PAP - 1607, Rev.1 required generic implication svaluation.
OER review request was reissued to review for generic implication.
OMR-387 regarding missing retaining rings was not reviewed adequately.
-
Documentation indicated only Unit 1 breakers were reviewed for the missing
<
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retaining rings. In response to the teams concem, OER review request was
reissued to include Unit 2 breakers.
Resolution of NRC generic communications and Part 21 reports on the subject of circuit
breakers was good. As a result of the OER Program, some procedures had bean
modified to incorporate the lessons leamed. For example:
As a result of the review of IN 88-75, operating procedures gel-0135 and gel-
.
0136 were modified to place the breaker control switch in OFF/STOP position in
order to reset the anti-pump seal-in as applicable and allow the breaker to close.
As a result of the review of IN 93-91, the appropriate maintenance procedure
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was modified to add visual verification to ensure correct positioning of the
auxiliary switch contacts with the breaker racked in and closed.
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c.
Conclusions.
j
The team concluded that, in general, there had been very good evaluation and
3
disposition of NRC, vendor, INPO, and other industry experience information. The OER
{
program procedures were generally comprehensive and workable, the OER database
was complete with respect to circuit breaker information identified beforehand by the
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team (and, in fact, included some information of which the team was previously
unaware). With only one exception identified, the individual OER evaluations were
typically thorough and looked for the message in the information rather than dismissing
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some pertinent information on the basis of Perry not having the exact type of equipment
used as an example in the information. The items selected for detailed review of their
ultimate disposition that had been determined, in the OER screening process, to be
applicable to Perry medium-voltage circuit breakers were typically appropriately and
promptly incorporated in plant procedures or other documents as applicable. This area
was considered a strength.
M6.2 - Reviewer and Anorover Raouirement for Comolated Maintenance Activities
a.
Insoection Scope
- The team reviewed selected completed maintenance work orders related to breaker
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maintenance and testing activities.
b.
Observations and Findings
The team noted that some of the work packages were reviewed and approved by the
i
same individual. The team determined that reviewer and approver responsibilities for
completed electrical and mechanical maintenance work activities were not clearly
delineated in administrative procedures but were management ' expectations." In
contrast, the inspectors noted that instrument and control (l&C) maintenance procedure
mal-0504 clearly documented in Sections 6.9.2 and 6.9.3 the review and approval sign
off requirements. The l&C procedure required that the review be performed by the l&C
supervisor and that the approval be performed by an independent maintenance support
engineer. The licensee informed the team that the electrical and mechanical reviewer
and approver requirements will be reexamined and action will be taken to address this
concem. In addition, the review of completed work orders also revealed inconsistent
filling of identifying information on all pages. Some required signatures and breaker
serial numbers were also missing.
c.
Conclusions
The team concluded that reviewer and approver responsibilities for completed electrical
and mechanical maintenance work activities were not clearly delineated in
administrative procedures. The licensee informed the team that the electrical and
mechanical reviewer and approver requirements will be reviewed and the concem
addressed.-
M6.3 Treatment of Circuit Breakers Under 10 CFR 50.65. The Maintenance Rule
a.
Inspection Scope
The team reviewed the licensee's treatment of medium and low-voltage power circuit
breakers under 10 CFR 50.65, the Maintenance Rule (MR). The team reviewed
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scoping, classification of breakers according to system or as separate class of
components, treatment under 50.65(a)(1), or (a)(2), maintenance preventable
functional failures (MPFFs), and use of industry information as required by (a)(3).
b.
Observations and Findings
The team found that there was adequate justification for exclusion of those breakers not
included within the scope of 10 CFR 50.65 activities. For in-scope breakers, the scoping
bases considered were comprehensive. In general, at Perry, breakers that supplied
busses, supplied transformers for lower-voltage systems, and tied busses together were
treated as part of the electrical distribution system or subsystem of which they were a
part. Breakers that supplied power directly to components of other systems (e.g.,
mechanical fluid systems) or to load centers or motor control centers for those systems
were generally treated as part of the system to which they supplied power. The licensee
did not treat breakers as separate components for (a)(1) performance issues, however,
the licensee did elect to include " monitoring" of all safety-related 13.8 kV,4.16 kV and
480 Vac breakers under the electrical component group, to enhance the MR (a)(2)
performance criteria which were established for train or system functions.
The licensee hcd included the failere in 1996 (an unexpected trip on apparent overload
documented in PlF 96-2958) of breaker EF1D09 (fuel handling building HVAC supply
fan B), in its MR monitoring database. Although the failure was attributed to a
manufacturing defect (overcurrent trip unit phase sensor current transformer lead
reversal), which was also the subject of NRC IN 98-18, and hence, was not treated as
an MPFF per se, the licensee's MR procedure, PAP-1125, Revision 2, called for basing
performance criteria on all functional failures. The follow up corrective action described
in PlF 96-2958 with the vendor to prevent recurrence was satisfactory.
c.
Conclusions
Treatment of medium and low-voltage power circuit breakers under the MR was
satisfactory. In addition, the practice of including safety-related AC breakers in the
electrical component group to enhance performance criteria and the licensee's proactive
position in which functional failures attributable to other activities such as operations and
engineering, in addition to maintenance, formed the basis for performance criteria were
considered strengths.
M7.1 Self-Assessments. Audits and Surveillance
a.
Insoection Scoce
The team reviewed the licensee's self-assessments, audits and surveillance in the
areas of low and medium power electrical breakers.
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'b.
Observations and Findinas
,
The team noted that the licensee did not perform specific self-assessments, quality
'
audits, and surveillance of Perry's breaker maintenance program. One QA audit
conducted during January 1996 in the area of maintenance did not evaluate breakers
but included reference to field observations to evaluate the preparation of breakers for
planned replacement during RF05.
c.
Conclusion
The team determined that no specific audits or self-assessments were performed in the
areas of breaker maintenance or operations. This was considered a weakness.
M8
Miscellaneous Maintenance issues
M8.1 Vendor Manuals and Vendor Interface
,
a.
Inspection Scope:
l
. The team reviewed procedures goveming vendor manuals and other vendor
information, including periodic recontact to ensure that all pertinent information has been
received. The team reviewed the binders of approved vendor technical manuals and
other technical documents compiled by the licensee under its system to determine if
they were complete and up to date relative to medium- and low-voltage safety-related
switchgear.
b.
Findinas and Observations:
I
The program as currently described by the latest revision to the procedures should
improve the state of vendor manuals for Perry switchgear and better ensure receipt and
!
appropriate disposition of updates to manuals and other technical information.
However, the program implementation has not been fully effective, particularly in the
area of periodic contact of Non-NSSS vendors of key safety-related equipment, in
l.
particular, switchgear. There was evidence that vendors had not been very cooperative
i'
in this effort in the past, but this fact was recognized by the licensee and documented in
several CRs, for example in 1992 and again in 1995, the result of which was the present
vendor manualimprovement program.
However, the efforts thus far under this initiative to contact vendors and receive timely
replies has not been effective. The writing of form letters once a year or in intervals of
several months with no response was clearly not a sufficiently aggressive approach. It
appeared that the licensee did not always write to the most appropriate vendor locations
or personnel. The effort suffered from a lack of adequate involvement by equipment-
knowledgeable personnel and did not comprise tactics that have proven more effective.
For example, the licensee did not establish the several vendor contacts (at different
locations) who were currently cognizant of the equipment of interest and familiar with the
associated technical documentation and conduct detailed comprehensive reconciliations
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of all applicable equipment and information. Written responses that were received from
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vendors indicating that the requested information was not available at that location, did
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ot receive adequate follow up.
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Several switchgear manual binders reviewed did not contain the most recent applicable
revisions; although, safety-related circuit breaker manuals had recently been more
completely updated than those for non-safety-related switchgear. For example,
File 162, the binder for safety-related ABB 4160-Vac Type 5HK breakers and associated
equipment contained an outdated renewal parts bulletin. An old version (different
number series, published by one of the previous manufacturing company names, of the
instruction book for the switchgear itself (i.e., cubicles, busses, etc.)) was in the file
whereas the new version (published by ABB) has been out since about 1991.
Revisions 3 and 4, adding manuals for a GE and ITE protective relay, respectively, were
entered incorrectly in that non-safety-related switchboard designators were listed as
applicable instead of the safety-related ones (i.e., % R22 S001 through S005 instead of
% R22 3007,' S006 and S009). In File 160 for safety-related low-voltage ABB K-line
breakers, and K3000 and K4000 breakers, only old versions of the switchgear
^ instruction books were in the file, in File 424 for the GE Power Vac medium-voltage
breakers, one change was not properly entered. The several binders for non-safety-
related breakers had similar, but more numerous, deficiencies.
c.
Conclusions:
The latest version of the vendor manual control and vendor interface program should
improve the state of switchgear vendor manuals. Implementation in the past was not
always effect!ve, suffering from inadequate involvement by equipment-knowledgeable
staff, insufficiently aggressive follow up with uncooperative vendors, and out-of-date
vendor contact information This area was considered a weakness, but improving.
M8.2 Review of Breaker Failun History and Trendina Prooram
a.
Insoection Sr2DR:
The team attempted to review data of failures of low and medium-voltage circuit
breakers over the last three years.
b.
Findinas and Observations:
The team requested breaker failure history data; however, the licensee could not easily
retrieve the information and the team could not effectively assess this area. The team
noted that safety related breakers were swapped between switchgear cubicles and
' breaker serial numbers were not consistently being recorded on work orders, thus the
repetitive breaker failure data could not be easily obtained.' Based on interviews with
engineers and maintenance staff and review of completed maintenance procedures, the
team concluded that no documented breaker failures were recorded that could be
directly attributed to breaker problems after the licensee refurbished all AC breakers in
1995/1996,
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The team noted that the high pressure core spray pump (HPCS) 1E22C001 breaker
failed to close in January 1998 during testing. PIF 98-0125, dated January 26,1998,
)
- documented that HPCS pump 1E22C001 failed to start on demand during a surveillance
when breaker EH1304 failed to close. Troubleshooter g did not identify the cause of this -
failure. The breaker closed satisfactorily after it was racked back into the cubicle. The
I
as found condition of the breaker was not preserved after the pump failed to start and
the breaker was racked out before the engineers could inspect the breaker and record
the as found condition in order to determine the root cause. The team also noted that
the licensee had not yet established a program for trending breaker repeat failures and
routine rnaintenance deficiencies.
c.
Conclusons
' The team concluded that no documented breaker failures were noted that could be
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directly attributed to breaker problems after the licensee refurbished all AC breakers in
<
1995/1996. The team determined that, since breakers had been swapped between
switchgaar cubicles and breaker serial numbers were not being consistently recorded on
{
work orders, the repetitive breaker failure data could not be easily obtained. The team
also noted that the licensee had not yet established a program for trending breaker
repeat failures and routine maintenance deficiencies.
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lit. Engineering
E2
Engineering Support of Facilities and Equipment -
E2.1
Breaker Control Power issue
a.
Inspection Scope
The team performed an inspection to determine whether breaker operation was assured
at minimum operating voltage as specified in the vendor's manual or minimum
calculated voltage, whichever is the lowest as stated in TI-2515/137.
b.
Observation and Findinas
Calculation PRDC 0007, " Voltage Drop of DC Control Circuits," Rev. 4, dated May 18,
1998,'was reviewed to verify that electrically operated breakers (both medium and
low-voltage) were operable at the calculated minimum available voltage at the closing
and tripping coils. The design basis of the calculation was loss of offsite power with loss
of coolant accident. Since all emergency core cooling systems load breakers would
change state within the first minute, the battery terminal voltage at first minute was used
in this calculation. However, for a station blackout (SBO) recovery, battery discharge
- voltage (voltage at the end of four hours which is 105 Vdc) was used for circuits '
associated with preferred supply breakers and attemate preferred supply breakers. The
calculation indicated available voltage at the closing, tripping, and spring charging
circuits for 4 kV and 480 V power circuit breakers was above 90 Vdc. Testing at 90 Vdc
was included in the latest revision of both medium and low-voltage power circuit breaker
s
18
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.
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maintenance procedures. However, very few breakers were tested at 90 Vdc at the
plant. The team was told that all AC breakers were tested at the minimum operating
voltage during refurbishment at the ABB service center. The voltages used were: (1)
for 4 kV and 15 kV HK type breakers 90 Vdc for breaker close coil and charging motor
and 70 Vdc for tripping coil, and (2) for 480V K-line breakers-100 Vdc for closing coil
and 70 Vdc for tripping coil and 85 Vdc for charging motor. All DC breakers were
manually operated.
in reviewing the calculation, the team noted the following concems:
Inverter DC current input was not calculated properly. The inverter was a
.
constant kVA device and current was dependent on the available voltage at its
terminals.
The battery terminal voltage calculation did not consider the effect of aging factor
.
(1.25), temperature correction factor (1.04), and design margins (1.1).
Non-conservative control circuit lengths were used.
.
The calculation did not address the emergency diesel generator (EDG) output
.
breaker closing coil voltage during SBO recovery (i.e., at the end of SBO
duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />).
The calculation did not address 13.8 kV breakers trip coil voltage.
.
The preliminary recalculation of two circuits (emergency service water pump
1P45-C0001B and EDG output breaker EH-1102) indicated inat the available voltage at
closing and trip coils will be below 90 Vdc. As a result, CR 98-1167 was initiated.
Criterion ill, " Design Control," of 10 CFR Part 50, Appendix B, requires that the design
basis be correctly translated into specifications, procedures, instructions, or drawings.
The failure to: (1) properly calculate inverter DC current input, (2) consider the effect of
aging factor, temperature correction factor and design margins in the calculation, (3) use -
correct control circuit lengths, (4) address the EDG output breaker voltage during SBO
recovery and (5) consider the 13.8 kV breakers trip coil voltage is considered a violation
of Criterion lli(50-440/98011-04(DRS)).
,
Based on the present condition of the divisional batteries, as demonstrated by required
- service and capacity tests, an initial assessment of affected circuit breakers indicated
that no immediate operability concems existed. The minimum calculated DC control
voltage at the circuit breakers was estimated to be 93 Vdc under design basis
,
requirements. The licensee committed to perform a detailed calculation to fully
substantiate this initial assessment.
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c.
Conclusions
The team identified that calculation PRDC-0007," Voltage Drop of DC Control Circuits,"
Revision 4, dated May 18,1998, lacked rigor in terms of design inputs and conclusions.
In addition, design control measures to provide verification of adequacy of design were
ineffective in that design reviews failed to identify these deficiencies. Based on review
of selected calculations, the team was concemed about the adequacy of design basis
calculations in general. A safety assessment, performed during the inspection in
response to the team's concems about the voltage calculation, was acceptable to
support an interim operability determination. The licensee indicated that a long term
resolution would be developed to conservatively demonstrate on a continuing basis that
the DC system could perform its intended function. A violation was cited.
V. Manaaernent Meetinos
X1
Exit Meeting Summary
On May 22,1998, the inspection results of the team inspection were presented to the licensee
at an exit meeting. The i.ansee did not identify any material provided during the inspaction
report period as proprietary.
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PARTIAL LIST OF PERSONS CONTACTED
Licensee
N. Bonner, Director, Maintenance /First Energy
R. Collings, Manager, QA, First Energy /QAS
L. McGuire, Supervisor, PNMD/MSPU
- S. Moffitt, Manager, PNED/First Energy
L. Myers, Site Vice President
S. Sanford, Compliance Engineer, PNSD/ PAS /CU
R. Schrauder, Director, PNED, First Energy
D. Watkins, Maintenance Engineer, PNMD/CEI
M. Zeal, PES /NSSS, PNED/CEI
.
NBCL
J. Clark,' Resident inspector
' C. Lipa, Senior Resident inspector
INSPECTION PROCEDURE USED
Tl 2515/137 Inspection of Medium-Voltage and Low-Voltage Power Circuit Breakers
Effectiveness of Licensee Controls in Identifying, Resolving and Preventing
Problems
ITEMS OPENED, CLOSED,~ AND DISCUSSED
Opened
50-440/98011-01
Inadequate calculated test parameter values and as left
instantaneous trip test current of circuit breaker EF1B04.
50-440/98011-02
URI - (1) Limits for the solid state trip device long and short time delays
were not in agreement with the vendor's manual
recommendations, (2) use of 20 percent tolerance for
instantaneous pickup instead of 15 percent as indicated in the .
. Vendor Manual, and (3) 10 percent tolerance for long time pickup
and longer waiting time between tests not in procedures.
50-440/08011-03
Use of an unapproved cleaning agent such as Windex Glass
Cleaner to clean safety related electrical breaker components.
50-440/98011-04.
VIO ' Failure to: (1) properly calculate inverter de current input (2)
consider the effect of aging factor, temperature correction factor
and design margins in the calculation, (3) use correct control
circuit lengths and additional calculational deficiencies.
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LIST OF ACRONYMS USED
Altemate Current
CR
Condition Report
Direct Current
-EPRI
Electric Power Research Institute
gel
Generic Electric Instructions
GENE
General Electric Nuclear Energy
l&C
Instrumentation and Control
IN
information Notice
-INPO
Institute of Nuclear Power Operation
kV-
Kilo Volts
Maintenance Preventable Functional Failures
,
Maintenance Rule
l
NMAC
Nuclear maintenance Applications Center
NRC
Nuc' ear Regulatory Commission
!
Operating Experience Reports
Quality Assurance
Service Advice Letter
SBO-
Station Blackout
i
Service Information Letter
Tl
Temporary Instruction
j
Unresolved item
'
Vdc
Voltage in direct current
!
' VIO
Violation
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