ML20210B001
| ML20210B001 | |
| Person / Time | |
|---|---|
| Issue date: | 02/04/1987 |
| From: | Baker E, Jeffrey Jacobson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| Shared Package | |
| ML20210A899 | List: |
| References | |
| REF-QA-99900835 NUDOCS 8702090055 | |
| Download: ML20210B001 (7) | |
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ORGANIZATION: BBC BROWN B0 VERI, INCORPORATED WEST COLUMBIA, SOUTH CAROLINA REPORT INSPECTION INSPECTION N0.: 99900835/86-01 DATES: 12/02-05/26 ON-SITE HOURS: 24 CORRESPONDENCE ADDRESS: BBC Brown Boveri, Incorporated ATTN: F. M. D' Antonio General Manager 167 Overland Drive Post Office Box 4659
} West Columbia, South Carolina 29171 4659 ORGANIZATIONAL CONTACT: Ed Rhoads TELEPHONE NUMBER: 215-822-4274 NUCLEAR INDUSTRY ACTIVITY: BBC Brown Boveri, Incorporated manufactures medium and low voltage circuit breakers which have been supplied to various nuclear power plants.
ASSIGNED INSPECTOR: -(- 4DN .4
. h J. B. Jacobson, Re tive Inspection Section (RIS) 2 4 ST Date OTHER INSPECTOR (S): J. C. Harper, RIS APPROVED BY: \-_ 6\A4v% h '4-87 E rd T. Baker, : ting Chief, RIS, Vendor Program Branch Date INSPECTION BASES AND SCOPE:
A. BASES: 10 CFR Part 21 and Appendix B to 10 CFR Part 50.
B. SCOPE: This inspection was conducted to discuss the failure and proposed testing of 7.5 HK circuit breakers supplied to Cemanche Peak steam electric station. Additionally, an audit of the quality assurance program in effect at this facility was conducted.
PLANT SITE APPLICABILITY: All Nuclear Power Plants.
8702090055 870205 PDR GA999 ENVBBC 99900835 PDR
o ORGANIZATION: BBC BROWN B0 VERI, INCORPORATED WEST COLUMBIA, SOUTH CAROLINA REPORT INSPECTION RESULTS: PAGE 2 of 5 N0.: 99900835/86-01 A. VIOLATIONS:
None.
B. NONCONFORMANCES:
- 1. Contrary to Criterion VII of Appendix B to 10 CFR Part 50, BBC has not established controls necessary to ensure charging motors purchased from subvendors conform to BBC drawings. (86-01-01)
- 2. Contrary to Criterion III of Appendix B to 10 CFR Part 50, BBC has not established controls necessary to ensure environ;nental qualifi-cation when similar parts are substituted for those originally installed in qualified circuit breakers. (86-01-02)
C. UNRESOLVED ITEMS:
None.
D. STATUS OF PREVIOUS INSPECTION FINDINGS:
None.
I E. OTHER FINDINGS OR COMMENTS:
- 1. Jackshaft weld failure at Corecche Peak On October 20, 1986, the NRC received a 10 CFR 50.55(e) report from l Texas Utilities Generating Company (TV) which concerned the failure of a jackshaft weld in a Class 1E 7.5kv BBC circuit breaker installed at their Comanche Peak facility. Subsecuent inspection of some 30 similar 7.5kv HK breakers at Comanche Peak revealed numerous cases of jackshaft/ closing arm fillet welds having poor workmanship, voiding, incomplete fusion, and undersized fillets.
TU has sent two jackshafts representative of the worst case of the jackshaft welds to BBC for testing where they will undergo a 10,000 cycle fatigue test. The jackshafts were examined by the NRC inspec-tor who determined that both exhibited undersized welds, excessive l
convex weld beads, and incomplete fusion.
A 10,000 cycle life criteria is the current industry standard (see ANSI /IEEE C37.09-1979 for the breakers in question). Should the l
fatigue test be ccmpleted without failure, the remaining welds in service will be considered satisfactory for their intended service life.
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l ORGANIZATION: BBC BROWN B0 VERI, INCORPORATED WEST COLUMBIA, SOUTH CAROLINA REPORT INSPECTION N0.: 99900835/86-01 RESULTS: PAGE 3 of 5 l
The failed jackshaft (after 600 cycles) was also sent back to BBC from TU for analysis. Upon examination of the failed jackshaft '
closing arm, it was apparent that the weld was undersized and 3 exhibited incomplete fus. ion. Approximately one eighth (1/8) of the circumference of the single fillet had failed in the shaft base metal, and the remainer had failed as a result of incomplete fusion.
The initiation cf the failere is believed to be a result of cyclic loading combined with incomplete fusion.
According to BBC, the failed jackshaft and the other jackshafts supplied to TU were manufactured and welded during the 1976-1979 time frame at the BBC Philadelphia plant. The fillet welds were performed by an automated weld process at the Philadelphia plant which was closed in hte 1979. Production was then moved to a plant in Florance, SC where welding of these jackshafts is currently being performed manually. The NRC inspector visited the Florance, SC plant where the welding area and the welding inspection area were observed.
The welding supervisor explained that prior to welding, joint prepar-ation is done to remove any rust, grease, oil, dirt or moisture and every jackshaft weld is examined following welding. The welders use the manufacturing process procedure #3331-070.4, dated May 30, 1986, for welding the jackshafts. Following the completion of the welds, each jackshaft closing arm is hammer tested in order to assure adequate impact properties. One lot of jackshafts was available for examination and all the welds examined exhibited acceptable weld quality. It is BBC standard practice for final inspection to inspect one jackshaft per lot per operation.
- 2. Review of Subvendor Control The NRC inspector reviewed Purchase Order PAV28461 from Georgia Power Company to BBC for the supply of 15 HK 750 circuit breakers and parts. The purchase order specified 10 CFR Part 21 and 10 CFR 50, Appendix B were applicable. BBC provided certification for those breakers to 10 CFR 50, Appendix B; ANSI 45.2-1971 and 1977; IEEE 323; and IEEE 344 All Brown Boveri circuit breakers are manufactured in accordance with the same cuality assurance program. Nuclear circuit breakers are identical to non-nuclear circuit breakers except for the wire ard trip devices installed.
a ORGANIZATION: BBC BROWN B0 VERI, INCORPORATED WEST COLUMBIA, SOUTH CAROLINA REPORT INSPECTION N0.: 99900835/86-01 RESULTS: PAGE 4 of 5 BBC was questioned concerning their source of charging motors for these breakers. Three sources for charging motors were determined to be in use (Von Weise Gear Company, Black and Decker, and Lamb 0 Motors). None of these verdors appeared on the BBC approved vendors list. These motors are used interchangably although appear somewhat different in construction.
BBC bases its circuit breaker environmental qualification on type testing which was performed on a sample breaker. BBC could not provide information pertaining to which charging motor was in the breaker that was qualified and has not performed an analysis for similiarly between the three types of motors. Until this is done qualification of these circuit breakers could be in question.
Furthernore, BBC does not have controls in place to ensure design changes made by the motor manufacturers will not affect qualifica-tion of the circuit breaker in which they will ultimatly be installed. ;
BBC also does not have measures necessary to ensure the charging motors supplied meet BBC drawing specifications. Nonconformances 86-01-01 and 86-01-02 of this report were written as a result.
- 3. Desian Control The inspector reviewed two design changes made to the LK 1600 circuit breaker line. The first change concerned the addition of booster springs onto the existing opening springs of the LK 1600 breaker. This change was prompted by the failure of twe LK 1600 breakers which failed to open at the Shearon Harris Nuclear Pcwer Plant. The failures were attributed to a previous design change which roved the breaker pushred-to-bridge blade pivot point and resulted in an additional 48 lb. force necessary to open the breaker main contacts. The second change involved the addition of a contact alignment check which is performed during the manufacturing process.
Both changes were found to have been reviewed, implemented, and documented as required.
- 4. 10 CFR Part 21 Program BBC's Part (1 QA procedure 15.2, " Reporting of Product Defects," was l reviewed and1.found to address all recessary requirements. Implemen-totion of ths; procedure was ensured by reviewing recent BBC Part 21 reports to the NRC.
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ORGANIZATION: BBC BROWN B0 VERI, INCORPORATED WEST COLUMBIA, SOUTH CAROLINA REPORT INSPECTION RESULTS: PAGE 5 of 5 N0.: 99900835/86-01
- 5. Testing BBC uses specific procedures for each type of circuit breaker to be tested with data being recorded on objective evidence records keyed to the specific procedure being used. The inspector reviewed the procedures and the implementation of testing for K-line breakers currently under productinn. No deficiencies were noted.
- 6. Calibration System The NRC inspector conducted an overview of the BSC calibration system. A BBC tensile machine, micrometers, and dial calipers were checked and found to be in current calibration.
The BBC master gage was current in calibration and the certification was by Mitutoyo Mfg. Co. Ltd., Code #516-901 for set # bel-81-1, traceable to NBS #731/237607. Hand crimping sets 050-049 and 050-0023 were both calibrated according to procedure 458-505 and current in calibration.
- 7. Audits Auidts are conducted at the Columbia, SC facility by Quality Assurance Personnel from corporate headquarters in Pennsylvania. The most recent audit conducted June 10-11, 1986, had addressed a number of findings which had been corrected and closed out accordingly.
I
! F. PERSONS CONTACTED:
- F. J. Wazzardo, Product Engineer
- F. M. D' Antonio, General Manager, Columbia, SC
- Attended exit meeting.
BBC Brown Boveri, Incorporated 3- February 5, 1987
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