IR 05000324/1993057
| ML20059G132 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/22/1993 |
| From: | George Macdonald, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20059G125 | List: |
| References | |
| 50-324-93-57, 50-325-93-57, NUDOCS 9401240012 | |
| Download: ML20059G132 (6) | |
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NUCLEAR REGULATORY COMMISSION UNITED STATES
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101 MARIETTA STREET, N.W., SUITE 2900 7,;
j ATLANTA, GEORGIA 303234199
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Report Nos.:
50-325/93-57 and 50-324/93-57 Licensee:
Carolina Power and Light Company P. O. Box 1551 Raleigh, NC 27602 Docket Nos.:
50-325 and 50-324 License Nos.:
DPR-71 and DPR-62 Facility Name:
Brunswick 1 and 2
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Inspection Conduc ed:
No er 29 - D ember 3, 1993 Inspector: )
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G. MacDonald Date Signed
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Approved by:
I,#[MW 42-J3 -M3 M. Shymlock, Chief Date Signed Plant Systems Section Engineering Branch Division of Reactor Safety SUMMARY Scope:
This special, announced inspection was conducted in the areas of electrical maintenance and modification.
Brunswick Unit 1 Startup Open Item F2 " Neutron Detector Repairs" was reviewed.
Inspector Followup Item 92-46-01 was reviewed.
Results:
In the areas inspected, one violation was identified. The licensee failed to maintain the design configuration of Whittaker hardline coaxial cables and connectors in Unit I modification 92-049.
The licensee completed the -
corrective action shortly following the inspection. The corrective action was reviewed and was acceptable.
Unit 1 Startup Open Item F2 was reviewed and is closed (Section 2.2).
Inspector Followup Item 50-325/92-46-01 was reviewed.
Corrective action was acceptable and this item is closed.
Inspector Followup Item 50-324/92-46-01 remains open for Unit 2.
Unit 2 corrective action was scheduled for the next refueling outage (Section 3).
9401240012 931222-Da ADOCK 05000324 PDR.
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REPORT DETAILS l-1.0 Persons Contacted i
Licensee Employees
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- K. Ahet, Manager, Work Control
- G' Barnes, Operations Manager, Unit 1
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- H. Beane, Manager, Quality Control
- R. Grazio, Mana;er, On-site Nuclear Engineering Department-
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- C. Hinnant, Director, Site Operations
- G. Honma, Manager, licensing
- G. Miller, Manager, Technical Support
- C. Warren, Plant Manager, Unit 2
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- E. Willett, Manager, Project Management Other licensee employees contacted during this inspection included
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engineers, technicians, and administrative personnel.
Other NRC employees:
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- P. Byron, Resident Inspector
- Attended Exit Meeting j
Abbreviations and acronyms used throughout this report are identified in
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the last paragraph.
F-2.0 Unit 1 CP&L Startup Open Item F2, " Neutron Detector Repairs"
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Unit 1 Startup Open Item F2, " Neutron Detector Repairs", consisted of.
several modifications to improve reactor protection system (RPS)
reliability. The modifications consisted of installing new Whittaker hardline coaxial cable from the detectors to the drywell penetrations
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and modifications to auxiliary relays in the reactor protection system and in the startup and intermediate range cabinets. Additionally, ventilation ports and new relay support tracks were. installed _in the source range monitor / intermediate range monitor (SRM/IRM) drive relay'
cabinet, 1-H21-P008.
2.1 RPS and SRM/IRM Auxiliary Relay Modifications
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The installation of metal oxide varistors (MOVs) across the relay coils of RPS reactor automatic scram contactors (C71-14A through H) and reactor scram reset relays (C71-19A through D) per EER 93-203 was inspected.
The MOVs were added across the relay coils for noi.se suppression. This wo*k was documented on individual work requests..The inspector reviewed the work packages and verified by visual' inspection that the MOVs had'been-installed across the Unit I relay coils. This work item was complete.
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The installation of vents and replacement of relay mounting tracks in cabinet 1-H21-P008.per EER 93-0485 was inspected.
The lack of ventilation had caused relay track warpage.. Work was' controlled under WR/JO ATCNI.
The inspector verified that ventilation slots had been added to the cabinet and that the relays had been mounted on new relay track for Unit 1.
This work item was complete.
The installation of zener diodes on auxiliary relays in the source and intermediate range monitor cabinets per EER 93-0334 was inspected.
The zener diodes were added for noise suppression. The inspector verified that the diodes had been installed across the relay coils as required by EER 93-0334 for Unit 1.
This work item was complete.
2.2 Modification 92-049 Installation of Whittaker Hardline Coaxial Cables Unit 1 modification 92-049 installed 124 Whittaker hardline coaxial cables from the ApRM and LPRM neutron detectors to the drywell penetrations.
The hardline cables were silicon dioxide insulated with metal cable jackets. The cable end terminations were hermetically sealed Whittaker QLN connectors. A 0.142 inch diameter cable was. utilized from the drywell penetration to the reactor vessel pedestal where patch panels were utilized for termination of the cable. A 0.09 inch diameter cable was used between the neutron detectors and the patch panels.
The connection between the two cable sections was made in the patch panels with Whittaker QLN connectors.
Field measurements were not utilized to size the individual cable sections.
Existing cable data was used and as a result cable lengths were greater than required.
The cable was supplied with the hermetically sealed QLN connectors attached and could not be spliced in the field. The modification design package incorporated specific instructions for handling, supporting.and storing the excess cable lengths.
The excess 0.09 inch diameter cable was to be coiled on a
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mandrel and stored inside the rear of the patch panel s.
The minimum bend radius for the 0.09 and.0.142 inch diameter hardline cables was 0.3 and.0.5 inches respectively. The mating QLN connectors were located inside the patch panels.
The female QLN connector was supported on a-l metal frame in the patch na-1 and restrained with 2 snap rings.
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The modification post i
- h. ion testing consisted of performing cable / detector current /'
P. curves (I/V curve), performing bridge insulation resistance (1., measurements, and performing time domain
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reflectometry (TDR) traces on the cable / detector circuits. The TDR
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traces were utilized to demonstrate proper circuit connection. The I/V i
curve and IR measurements were utilized to demonstrate that the cable insulation resistance was adequate.
The insulation resistance acceptance criteria was~ a-nominal IXE10 ohms with a minimum of IXE8
ohms.
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During the installation of the hardline cables, the unterminated connectors were exposed to the drywell atmosphere and moisture was absorbed into the connectors.
The moisture absorption caused low cable / connector IR values.
Several of the hardline cables were damaged during installation and required replacement. Vendor support was utilized to resolve the moisture intrusion problem.
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The modification post installation test results were reviewed to determine if the cables met the final acceptance criteria. All the TDR curves indicated correct connections and complete circuits. The I/V
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curve and IR data showed that all cables met the insulation resistance
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acceptance criteria (IR 2: 1XE10 ohms) with the exception of the cables in LPRM group A.
These cables utilized drywell penetration X100G and cabinet QC6.
The penetration IR was reduced. The final testing demonstrated that these cables met the minimum IR acceptance criteria of'
2: 1XE8 ohms for the circuit.
The IR value for the hardline cables without the penetration was 23XE10 ohms. The licensee evaluated the reduced IR values and concluded that the reduced values were acceptable.
GE concurred with the licensee's evaluation.
NRC Inspection Report 50-325/93-33 and 50-324/93-33 provides additional details on the moisture intrusion problem.
The TDR traces performed during post installation testing of the modification were used to demonstrate that a complete circuit existed after connecting the cables. The TDR data was not independently reviewed. The system engineer performed the test and reviewed the results.
The TDR instrument was functionally tested prior to use.
The TDR traces were reviewed and the inspector verified that the data indicated complete circuit connections for all LPRM and APRM detectors.
The inspector verified that Quality Control (QC) checks were performed to ensure that proper cable connections were made.
The inspector concluded that the lack of independent verification of the TDR data was not a concern due to the QC checks.
The inspector performed a walkdown of the modification to determine if the installation complied with the design requirements specified in the modification package.
Two areas were noted where the field configuration was not installed in accordance with the modification design requirements.
The excess 0.09 inch diameter hardline cable at patch panel YZ2 was not coiled on a mandrel and stored inside the patch panels as required by step 8.43.3 of the modification installation procedure. The excess cabling was looped and pressed into the rear of the patch panel.
The concern was that this method of installation could violate the minimum cable bend radius.
The second area of concern was that some Whittaker QLN connectors were installed 'in the patch panels without their' restraining snap rings as required by step 8.45 of the modification installation procedure. The concern was that without the restraint of the snap rings the connector to cable junction could be damaged.
There was no documented evaluation justifying _these deviations i
from the modification design requirements. This has been identified as~
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violation 50-324/93-57-01, Failure to Maintain Unit 1 Modification 92-049 Design Configuration Requirements.
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the licensee initiated.ACR 93B375A and EER 93-0642 was performed _to evaluate the two concerns. The inspector reviewed EER 93-0642 and determined that the evaluation and corrective actions were acceptable.
The EER dispositioned the two concerns as " Acceptable As Is" and
recommended that inspections be performed to ensure correct snap ring installation and acceptable cable bend radius.
Work request WR/JO 93-BEYTl was initiated to inspect the patch panels and to correct identified deficiencies noted with missing snap rings and.
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cable bend radius.
The inspector reviewed the completed work request and noted that the licensee replaced 2 missing, 10 damaged, and reset 5 snap rings.
The inspection did not reveal any deficiencies of cable.
bend radius. TDR traces were performed on the 17 circuits whose snap rings were replaced or reset. All the traces were satisfactory.and indicated complete detector / cable circuits.
The licensee performed a review of eight modifications performed by personnel involved with the installation of Unit 1 modification 92-049 to determine if a generic. workmanship problem was evident.
Modifications87-089, 92-070,92-108, 89-001,92-046, 91-009,86-001, and 92-074 were walked down to evaluate installation workmanship.. The inspector reviewed the walkdown results and concluded that they did not i
demonstrate a generic workmanship problem.
Several minor discrepancies were noted for which the licensee wrote WP/J0s to repair. The
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licensee's corrective action for the identified violation was considered acceptable.
CP&L Unit 1 Startup Open Item F2, " Neutron Detector Repairs" is closed.
3.0 Inspector Followup Item 50-324,325/92-46-01, Transformer Wiring Problems IFI 50-324,325/92-46-01, Transformer Wiring Problems, concerned a wiring failure which occurred on the Unit Auxiliary Transformer on Unit 1 during 1991. The initial wiring inspections performed were not documented.
The licensee was tracking this issue under ACR 92-971. The
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corrective action consisted of performing transformer control-wiring
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inspections to look for embrittled cabling on the unit auxiliary transformers (UAT), station auxiliary transformers (SAT), and main power transformers of both units.
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The corrective action was complete for Unit 1.
Unit 2 corrective action was scheduled for the next refueling outage.
Five individual WR/J0s documented the Unit 1 inspections. WR/J0s 92-BIFP1, 92-BIFQ1, 92-BIFBI, 92-BICY1, and BIFMI were reviewed. One temperature monitoring cable was identified as embrittled on the Unit 1 UAT, and the licensee replaced all 3 temperature monitoring cables on the Unit 1 UAT. The inspector'
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examined all accessible wiring on the Unit 1 UAT, SAT, and main power
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corrective action was acceptable and IFI 50-325/92-46-01 was closed for Unit 1.
IFI 50-324/92-46-01 remains open for Unit 2.
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During the transformer wiring inspection the inspector -identified moisture accumulation within the control cabinets of all Unit 1 main power transformers and within the control cabinet of Unit 2 B phase main power transformer. The licensee initiated WR/J0s to address this
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concern.
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NRC Inspection Report 50-324,325/92-46 indicated that licensee management schedules showed that the system engineer for the 230 KV
.i system would be certified by March 1993.
The inspector verified that the system engineer has not been certified on the 230 Kv system..The scheduled certification date was changed to March,1994, i
4.0 Exit Meeting
The inspection scope and results were summarized on December 3, 1993, with those persons indicated in paragraph 1.
Proprietary information is not included in the report.
There were no dissenting comments received from the licensee.
(0 pen)
Violation 50-325/93-57-01, failure to Maintain Unit 1 Modification 92-049 Design Configuration Requirements.
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(0 pen)
IFI 50-324/92-46-01, Transformer Wiring Problems.
(Closed)
IFI 50-325/92-46-01, Transformer Wiring Problems.
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5.0 Abbreviations and Acronyms ACR Adverse Condition Report
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APRM Average Power Range Monitor CP&L Carolina Power & Light
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EER Engineering Evaluation Report-i GE General Electric
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IFI Inspector FollowupLItem i
IR Insulation Resistance IRM Intermediate Range Monitor kV Kilovolts Alternating Current LPRM Local Power Range Monitor-
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MOV-Metal 0xide Varistor
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NRC Nuclear Regulatory Commission
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QLN type of-coaxial cable connector i
RPS Reactor Protective System SAT Startup Transformer
SRM Source Range Monitor
TDR Time Domain Reflectometry UAT Unit ~ Auxiliary Transformer
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WR/JO Work Request / Job Order
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