IR 05000413/1993002
| ML20128G747 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 02/03/1993 |
| From: | George Macdonald, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20128G708 | List: |
| References | |
| 50-413-93-02, 50-413-93-2, 50-414-93-02, 50-414-93-2, NUDOCS 9302160095 | |
| Download: ML20128G747 (5) | |
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- UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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101 MARIETTA STREET. N.W.
ATL. ANT A GEORGI A 30323
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FEB 3 1993 Report Nos.:
50-413/93-02 and 50-414/93-02=
Licensee: Duke Power Company 422 South Church Street Charlotte, NC 28242 Docket Nos.:
50-413 and 50-414 License Nos.:
NFF-35 and NPF-52 Facility: Catawba 1 and 2 m
Inspection Conducted: January 4-6, 1993 Inspector: [
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'G. MacDonald Date Signed Accompanying Personnel:
N. Salgado Approved by:
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b Milton B. Shyinlock, Chi 6f Date Signed-
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Plant Systems Section
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Engineering Branch Division of Reactor Safety SUMMARY Scope:
This special announced inspection was conducted to investigate the licensee's identification and analysis of an undetected circuit card component failure in the NSSS Process-Instrumentation and Control-System.
Results:
The component failure was-the result of an incorrectly sized fuse' installed in
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the circuit card by the manufseturer, Westinghouse..The licensee. initiated a-generic review of all plant 7300 series circuit cards, and identified-other-cards with similar deficiencies attributable to manufacturer's error.-
Corrective action to identify and replace improper fuses had been completed on Unit-l. The licensee had not completed their corrective action to' identify and replace all improper fuses on. Unit 2 and warehouse stock. There was no:
apparent-safety challenge resulting from'the presently installed circuit cards on Unit 2.
The inspectors concluded that the licensee's actions,.to date,--
have been appropriate-regarding-this issue. An URI was identified to address-the licensee action resulting from further. inspections.on Unit 2.and warehouse
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stock and for updating _the vendor Bill of Materials _ (BOM).
9302160095 930203
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PDR ADOCK 05000413=
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. REPORT DETAILS
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Persons Contacted Licensee Employees
- B. Finch,-Component Engineer
- J. Forbes, Manager, Engineering Division ~
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- J. Lowery - Regulatory Compliance J. McCart, Design Engineer
- T. Van Deven, Component Engineer Westinghouse T. Puryear, Vendor Representative NRC Employees
- W. Orders, Senior Resident Inspector
- J. Zeiler, Resident Inspector
- Attended Exit Meeting Acronyms and abbreviations used throughout this report are listed in the last paragraph.
2.
Description of Component Failure
.On April' 29, 1992 an I&E technician working in a process control-cabinet-
noted a smoking printed circuit card in_an adjacent cabinet. Me -
i circuit card was identified as._a Westinghouse 7300 Signal Comparator'
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card, part ' number 2837A1301, in control cabinet No. 7-which 'was related to PORVs 2NC-328 and 36B.
Further. inspection of the card indicated.that
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capacitor C21-1 and resistor R424-1.had overheated which enitted the smoke and it was noted that an adjacent MA fuse was charrec, but had.not
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opened.
The MA fuse was sizad to protect,the part of the bircuit.that-had experienced the overheating.
Fuse MA'was found to be incorrectly-sized with a 5 amp rather than a 0.5 amp fuse.
The Westinghouse Process _ Instrumentation and Control System's circuit-cards are designed:to-activate an alarm when a fuse opens.
Because.the fuse did not open, no alarm _was initiated to alert the operators.of the impending process card failure.
The licensee Veplaced the failed circuit card.
3.
Component Failure Analysis
.The circuit card was sent to Westinghouse-for.a detailed failure analysis. Westinghouse concluded.that the capacitor C21-1 failed to a-low resistance value, which-pulled between 2 to 5 amps current through C21 1 and-R424-1. Due to the improperly sized fuse, resistor-R424-1 and capacitor C21-1. experienced high current and smoked after a short period'
of time.
PIR 2-C92-0371 which was issued on this failure concluded that
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Westinghouse had installed the improper fuse.
The.comparator card was replaced, functionally tested prior to installation, and the PORVs;were returned to an operable condition within an hour.
4.
Review of Problem Identification Report The o)erability evaluation part of the PIR concluded that there was no-
opera >ility concern, since the circuits _ within the 7300 Control Cabinets are design to fail in the safe direction upon loss of system power._ The inspector reviewed the operability evaluation and agreed with the licensee's operability determination for this particular circuit card'
component failure.
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5.
Licensee's Generic Corrective Actions
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PIR 2-C92-0371 recommended that 1&E inspect all 7300 series ::ircuit cards in Unit 1, Unit 2, and warehouse stock, to identify an't replace incorrectly sized fuses. The Unit I fus'e inspection had been completed per work request NO. 92031010, " Unit 1 Fuse Inspection" during the Unit 1 RFO. An estimated 1,000 cards were inspected and 56 fuses improperly-sized were identified and replaced.
The inspectors reviewed work request No. 92031013, " Warehouse Fuse inspection," which was near completion.
The inspectors-independently inspected several cards in the warehouse and determined that although the improperly sized fuses had been identified, they had not been replaced.
This was identified to the licensee. The Unit 2 fuse inspection will be conducted during the-upcoming RF0.
This will be reviewed as part of URI 93-02-01.
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6.
Errors in the Bill Of Materials (BOM)
During the licensee fuse inspection and in correspondence with:
Westinghouse it was identified that the BOM CNM 1399.03-252, for the-circuit cards contained errors. The 80M is'a controlled document that'
contains vendor information regarding all 7300 series-printed circuit cards.
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Westinghouse indicated in a. letter to the licensee dated October.22.-
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1992 that they routinely upgrade printed circuit cards returned to them for repair.
The cards -are upgraded to the current revision level at the time of the repair. These upgrades may include replacement of components and fuses with increased amperage ratings. -Although Westinghouse performed these upgrades on some of the cards.. returned to the licensee, the 80M had not been updated to-reflect these changes.
This deficiency was documented in PIR-0-C92-0813.
The inspector reviewed'the BOM and noted that it contained errors-due to its not being updated.
It was' also noted that the BOM sections for.
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particular cards were missing a revision history as it related to the-information in the book.. Design Engineering was. assigned the.
responsibility for updating the BOM, During the inspection it_was noted that no corrections to.the 80M had been accomplishe..
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The scope of mai_ntenance activities being performed on the 7300 series cards by Catawba was limited to just the replacement of fuses. _ They do
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not repair. failed cards.
Resolution of errors between installed cards and the BC!i will be reviewed as part of unresolved item URI 93-02-01.
7.
Review of Incoming Repaired Cards The inspector reviewed several incoming repaired-circuit card packages from Westinghouse.
Each package contained the purchase order, quality release, certificate of conformance (on which the revision level was
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given), and a shipping order.
Upoi arrival at the s'te, the repaired cards were visually inspected.
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The inspector determined that Westinghouse provided documentation d
indicating which circuit card components were replaced and indicated _the new revision level. However, updated circuit card drawing, bulletins.or B0M for the card were not provided. The licensee maintains configuration control over the 7300 circuit cards down to the group level only. The card group reflected design differences such as number of outputs and voltage level for a given card type. The licensee does-not control serial numbers and revision levels for a particular type and group of card.
The vendor maintained control over design revisions and issued certification that circuit card form, fit and function were not affected.
The licensee considered different revisions of a particular-type / group of card to be interchangeable. The inspectors. concluded that updates should be recognized and controlled in a more formal manner.
Without control of revision level it would not be possible to utilize-the correct circuit card drawings for maintenance or troubleshooting
should it be required.
i 8.
Exit Interview The inspection scope'and findings were summarized on January 6,- 1992 with those persons-identified in paragraph 1.
The inspectors described.-
the areas inspected and discussed in detail the inspection finding-listed below. Although reviewed during the inspection, proprietary-information is not contained in this report.
Item Number Description / Reference Paraaraoh-
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93-02-01 URI - Incorrect Fuse Sizing of Westinghouse 7300 Process Control System Cards and Failure to Control Vendor-
,j Manual /BOM.
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Acronyms and Abbreviations Amps Arnperes liOM Bill of Materials 1&E Instrumentation and Electrical NSSS Nuclear Steam System Supplier PIR Problem Identification fleport PORV Power Operated Relief Valves Rf D Refueling Outage URI Unresolved item
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