ML20212B373

Part 21 & Revised Final Deficiency Rept Ncr Bln 2393 Re High Vibration Levels Measured for Bingham-Willamette Pumps. Initially Reported on 830622.Cause of Deficiency Unknown. Problem Does Not Represent Problem at Any TVA Facility

ML20212B373
Person / Time
Site:	Bellefonte
Issue date:	07/17/1986
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-86, REF-PT21-86-274-000 NCR-BLN-2393, PT21-86-274, PT21-86-274-000, NUDOCS 8608060309
Download: ML20212B373 (2)

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beb TENNESSEE VALLEY AUTHORITY $-

CHATTANOOGA. TENNESSEE 37401 2 SN 1578 Lookout Place ;3.

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BLRD-50-438/83-42 -

U.S. Nuclear Regulatory Conunission M Region II Attn: Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Dear Dr. Grace:

BELLEFONTE NUCLEAR PLANT UNIT 1 - MAKEUP /HICH PRESSURE INJECTION PUMP VIBRATION - BLRD-50-438/83 REVISED 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.

Our final report was submitted on November 19, 1984. Enclosed is our revised final report. As previously reported, we consider 10 CFR Part 21 applicable to this deficiency.

If you have any questions, please get in touch with D. L. Terrill at FTS 858-2682.

Very truly yours, TENNESSEE VALLEY AUTHORITY t

R. L. Gridley, Director Nuclear Safety and Licensing Enclosure cc: Mr. James Taylor, 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 8608060309 860717 '

PDR ADOCK 05000438 S PDR I

An Equal Opportunity Employer Maf

ENCLOSURE Bellefonte Nuclear Plant Unit 1 Makeup /High Pressure Injection Pump Vibration BLRD-50-438/83-42 NCR BLN 2393 10 CFR 50.55(e)

REVISED FINAL REPORT Description of Deficiency Measured vibration levels on one of the three makeup /high pressure injection (NU/HPI) pumps provided by Babcock and Wilcox (B&W) for Bellefonte Nuclear Plant (BLN) unit 1 are not consistently below the established high level limits of 0.75 mils peak-to-peak (p-p) displacement. 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.

Since the attempt to balance the rotating assembly onsite 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 Bellefonte 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 p-p 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.

During October 1983, a shaf t straightness check and a " rap" test (to determine the resonant frequency of the shaft) 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 shaf t 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. Other tests and inspections did not identify any other factor as being the root cause of the pump vibration. The absolute cause of the deficiency is therefore indeterminate.

This condition does not represent a generic problem at Bellefonte or other TVA nuclear plants.

Safety Implications Failure of the subject pump due to excessive wear caused by uncorrected high vibration could adversely affect the ability of the NU/HPI system to mitigate the effects of a loss of coolant accident (LOCA) or safe shutdown earthquake (SSE).

Corrective Action During April 16-30, 1984, representatives 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. 115145A-00, "TVA Bellefonte plant Makeup Pump 1B Vibration Investigation." The report indicated that the vibration on the pump bearing housing had been reduced to the 0.5 to 0.6 mils p-p range. Based on these results, B&W concluded that future operation of the pump would be satisfactory. TVA reviewed the results of B&W's two-plane pump balance and agreed with their recommendation to use the pump "as-is".

To aid TVA in the long-term operation of the pumps, B&W has established the unfiltered bearing housing vibration limit as 0.75 mils p-p measured at the center of the bearing housing. TVA is working with B&W and Bingham-Willamette to establish an appropriate shaft vibration limit. Once the shaft vibration limit has been established, both limits will be incorporated into the B&W limits and precautions document (document No. 67-1003781-04). This action will be completed by six months before fuel load for unit 1.

TVA considers the problem with the pump to be unique and does not plan to undertake any specific action to prevent recurrence.

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