ML20087F978
| ML20087F978 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 03/12/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-84 NCR-2393, NUDOCS 8403190287 | |
| Download: ML20087F978 (3) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II 34 MAR 15 A 8 : 38 March 12, 1984 BLRD-50-438/83-42 U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNIT 1 - MAltEUP/HIGH PRESSURE INJECTION PUMP VIBRATION -BLRD-50-438/83 THIRD INTERIM 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 Enclosed is our third interim report. We expect to submit our next report by July 23, 1984. 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 l
L. M.' Mills, Manager Nuclear Licensing Enclosure oc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8403190287 840312 PDR ADOCK 05000438 S
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1983-TVA SOTH ANNIVERSARY An Equal Opportunity Employer l
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ENCLOSURE ~
BELLEFONTE NUCLEAR PLANT UNIT 1 i
MAKEUP /HIGH PRESSURE INJECTION PUMP VIBRATION BLRD-50-438/83-42 NCR 2393 10 CFR 50.55(e)
THIRD IlffERIM REPORT A
Description of Deficiency Measured vibration levels on one of the three makeup /high pressure-
-injection l(MU/NPI) pumps provided by Babcock & Wilocx (B&W) for Bellefonte unit 1 are not consistently below the established high level limit of 0.75 mila. 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 temperatum of the pump.
Since the attempt. to balance the rotating assemb3y on site was not successibl, the inner casing and rotating asseebly were removed and shipped to the manufacturer, Bingham-Willamette in Portland, Oregon. The shaft and
' rotating assembly were examined by Bingham and returned to Bellefonte in March 1983. The pump was massembled 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 _or greater than the 0.75 mils limit. The
-pump to date has failed to operate within the vibration limit on a consistent basis and still shows a significant variation of the vibration level with temperature.
Interim Prostress In msponse to NCR 2393, B&W performed 'several tests on the pump to determine if a bowed shaft was causing the high vibration levals or if changes in the resonant-frequency caused by thermal transients msulted in the high vibratio9 levels. The tests consisted of the following:
(1). ' The rotating element was mmoved from' the pump.
-(2) A shaft straightness check was made with the rotating element at room temperature.
-(3) The rotating element was placed in a 1450-1500F water bath and allowed to stabilize.at that temperature.
. (4) The element was mmoved from the bath and a second shaft straightness test was performed.
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(5) The element was allowed to stabilize at ambient conditions and a final shaft straightness test was performed.
(6) A " rap" test on the rotating assembly was performed to determine the resonant frequency at each tneraal condition.
1 In each case, the shaft straightness test detected no bowing in the shaft.
The results did not show any susceptibility to the thermal transient imposed on it.
B&W's conclusion was that a bowed shaft was not producing the vibration pattern observed.
The " rap" test data was obtained using accelerometers mounted on the shaft and resulted from impacts in both the horizontal and vertical directions at two locations. The data indicated that the vertical first msonant fmquency was unchanged from the hot to cold condition. B&W indicated that,'since this is the most m11able test configuration, the absence of frequency changes indicates no shaft stiffness chango. There wene measured changes in the horizontal direction for the first, second, and third resonant frequencies. B&W believes that these dianges were due to the lack of control over the horizontal support beundary conditions and should not be of concern. B&W concluded from the frequency tests that the vibration problem was not the result of a thermally induced rotor characteristic change.
Based on B&W's and Bingham-Willamette's operating experience, the current levels of vibration are not injurious to the pump and can be "used-as-is" after reassembly / balancing is complete.
(Current levels are based on the last 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of pump operation occurring in May 1983 after B&W had balanced the pump rotating assembly. Maximum vibration seen during this time was 0.6 mi/s.). TVA will reassemble and attempt to balance the pump on site by June 1, 1984, and balance weights, where necessary, will be permanently attached and documented during the field balancing. TVA will provide additional information on this item after the balancing is complete.
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