ML20100P303
| ML20100P303 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 11/19/1984 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-84 NCR-2393, NUDOCS 8412140116 | |
| Download: ML20100P303 (3) | |
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400 Chestnut' Street Tower II 84 N0%#e=fe) 19 4-
'BLRD-50-438/83-42
.U.S.'Nuolear Regulatory Commiission Region II Attn:' Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear'Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNIT 1 - MkKEUP/HIGH PRESSURE INJECTION PIMP
~ VIBRATION -BLRD-50-438/83 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector Linda Watson on June 22, 1983 in accordance with 10 CFR 50.55(e) as NCR 2393 This was followed by our interim reports dated July 20, and November 30, 1983 and March 12 and July 20, 1984. Enclosed is our final report. We consider 10 CFR Part 21 applicable to this deficiency.
- If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY t
gJ.W.Hufham, Manager Licensing and Regulations Enclosure 00:. W. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Coimaission Washington, D.C.
20555 Records Center (Enclocure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta,' Georgia 30339 DR DO O
wucG_ireasy An Equal Opportunity Employer l
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNIT 1-MAKEUP /HIGH PRESSURE INJECTION PUMP VIBRATION-BLRD-50-438/83-42 NCR 2393 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency Measured vibration levels on one of the three makeup /high pressure injection (MU/HPI) pumps provided by Babcock & Wilcox (B&W) for Bellefonte (BLN) unit 1 are rot consistently below the established high level limit of 0.75 mils.
After the high vibration problem was noted, an attempt by B&W was made to balance the rotating assembly in November 1982. The effort was not successful. It was noted at that time that the vibration level on the pump varied.with the temperature of the pump.
I Since the attempt to balance the rotating assembly on site was not successful, the inner casing and rotating assembly were removed and shipped to the manufacturer, Bingham-Willamette in Portland, Oregon. The shaft and rotating assembly were examined by Bingham and returned to BLN in March 1983 The pump was reassembled and further vibration testing was completed. The initial vibration levels of the reassembled pump were high (2.5 to 3 0 mils displacement). B&W again attempted to balance the pump rotating assembly.
Vibration levels were reduced to a level below the 0.75 mils limit for approximately 70 percent of the measurements, with the remainder of the measurements at ce greater than the 0.75 mils limit.
During October 1983, a shaft straightness check.and a " rap" test (to determine the resonant frequency of the shaf t) were conducted by B&W.
These tests were made under both hot and cold conditions to determine ~
the effect of the thermal transient on the results of the tests. The shaft straightness test detected no bowing of the shaft under both hot and cold conditions. The " rap" test data indicated that the shaft resonant frequencies did not contribute to the vibration problem and did not change as a result of the imposed thermal transient.
Safety Implications Failure of the subject pump due to excessive wear caused by uncorrected high vibration could adversely affect the ability of the MU/HPI system to mLtigate the effects of a loss of coolant accident (LOCA) or safe shutdown earthquake (SSE).
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i Corrective Action During April 16-30,1984,.epresentatives from B&W were at BLN to install a permanent balance ring and perform a final, two plane, balance of the subject pump. The results of B&W's balancing effort were submitted to TVA in B&W report No. 1151454A-00, "TVA Bellefonte Plant Makeup Pump 1B Vibration Investigation.d The report indicated r
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.that1tha vibratirn on th3 pump baaring houIing htd been reduced to ths
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-0.5 to'O.6 mile p-p ranga. B: sed en th:se results, B&W orncluded thtt-future operation of the pump would be satisfactory.
TVA reviewed the ' subject report and had the following coments:
1.
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TVA concurred that the measurements included in B&W's mport indicated that the pump vibration on the bearing housing is now 4
within the 0.75 mils p-p lidt. However, it was noted that the measurements taken by B&W were filtered readings and that during plant operation vibration measurements would be made using unfiltered instruments.- Since the erece margin for unfiltered i
instruments is greater than that for filtered instruments, the 0 75 mils p-p limit may not be appropriate for use with these instruments.
' 2.
TVA noted that B&W had reported only the pump bearing housing i '
_ vibration measurements in their report. The pump was also instrumented to measure shaft vibration levels during the April balancing operation. The shaft vibration data is of interest to TVA due to TVA experience with a pump of sidlar design at the atmospheric fluidized bed combustion (AFBC) demonstration plant in Paducah, Kentucky. The AFBC pump is the same design as the BLN pump except that 'it has 9 stages rather than 11. The AFBC pump also experienced high vibration' levels on the pump bearing housing.
It was found on the AFBC pump that the vibration on the pump bearing housing could be reduced to the 0.2 to 0 3 mils p-p
- range while the pump shaft vibration remained high. Pump shaft vibration levels above 3.0 mils p-p caused failure (destaging) of the pump seals. B&W was mquested to submit the shaft vibration data on the BLN pumps for TVA review.
On September 27, 1984, a meeting was held in Knoxville between TVA and B&W to discuss B&W's mport and resolve the above comments. The meeting msulted in the following agreements:
1.
B&W agreed to myiew the appropriate codes and regulations and consult the pump manufacturer to mcommend a vibration lidt for unfiltered measurements on the pump bearing housing. This limLt
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will be incorporated into the B&W plant lidts and precautions documen t.
2.
B&W submitted the shaft vibration chta to TVA. The data indicates that shaft vibration was in the 1.0 to 1.5 mils p-p range. This was found to be an acceptable vibration level by TVA. It was noted that no lidt has been established for shaft vibration. B&W indicated that they would myiew the matter and make a recommendation for pump shaft vibration limits to be incorporated a
into the plant limLts and precautions document.
In summary, TVA agreed with B&W that the pump can now be "used-as-is".
Nonconformance report (NCR) 2393 has been dispositioned accordingly.
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In order to aid TVA in the long-term operation of the pumps, B&W will establish a vibration limit for unfiltered bearing housing measure-ments and shaft measurements by February 15, 1985.
TVA believes this vibration problem is a unique situation which does not mquire any action to prevent mourrence.
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