ML19209B521

Forwards Final Response to IE Bulletin 79-15, Deep Draft Pump Deficiencies. Summary of Startup,Testing & Maint, Operational Problems & Major Repair Efforts Encl

ML19209B521
Person / Time
Site:	Sequoyah
Issue date:	09/24/1979
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
79092A, NUDOCS 7910100056
Download: ML19209B521 (5)

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TENNESSEE VALLEY AUTHQF31JY-- -,..

d CHATTANOOGA. TENN ESSEE 40$ Nd 400 Chestnut Street Tower II "3 S; P Pc a!C : 4 0 September 24, 1979 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Cormission Region II - Suite 3100 101 Marietta Street Atlanta, Georgia 30303

Dear Mr. O'Reilly:

OFFIC/. OF INSPECTION AND ENFORCEMENT BULLETIN 79 RII:JPO 50-327, -328 - SEQUOYAH NUCLEAR PIANT A partial response for the Sequoyah Nurlear Plant was submitted on September 10, 1979, in the initial response to OIE Bulletin 79-15.

Enclosed is the final response to the subject bulletin for the Sequoyah Nuclear Plant. If you have any questions regarding this.

matter, please call Tish Jenkins at FTS 854-2014.

Very truly yours, TENNESSEE VALLEY AUTHORITY k

L. M. Mills, Mana' ger Nuclear Regulation and Safety Enclocare cc (Enclosure):

Mr. Victor Stello, Director Of fice of Inspection and Enforcemen';

U.S. Nuclear Regulatory Commission Washington, DC 20555 Director of the Division of Operating Reactors Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission

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OFFICIAL COPY An Equal Opportunity Employer

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_ _ _ _.. _ _ _ _. 7 ENCLOSURE RESP 0hSiiO'NRC-IEBULLETIN79-15 DEEP DRAFT PUMP DEFICIENCIES Item 4.

Summary of startup, testing, and routine maintenance for each type pump.

(a)

Essential Raw Cooling Water (ERCW) Pumps (New).

Pumps,are presently being installed by the Division of Construction and no startup, test, or history information is available.

(b)

Essential Raw Cooling Water (ERCW) Screen Wash Pumps (New)

Pumps are presently being installed by the Division of Construction and no startup, test, or history information is available.

(c)

Essential Raw Cooling Water Pumps (Old)

Preoperational testing was performed March 20 through May 24, 1978, including vibration, header flow, header pressure, motor current, and bearing temperature.

Performance of pumps is presently checked a minimum of each 31 days. Routine maintenance includes annual change of motor bearing oil.

(d)

High-Pressure Fire Pumps (HPFP)

First pumps were put into service in April 1974, and the last in February 1977.

Performance is checked annually and compared with manufacturers' design performance curve.

A routine maintenance schedule has not been established at this time.

(c)

Auxiliary Fssential Raw Cooling Water (AERCW) Pumps Preoperational pump tests were performed on May 20, 1978, in which header. flow, pump discharge pressure, motor current, bearing temperature, and vibration were measured..

One pump experienced high vibration due to loose iron in the motor.

It was retested satisfactorily on February 7, 1979.

Pump perfor=ance is checked a minimum of every 31 days. The routine maintenance schedule includes annual change of motor bearing oil.

(f)

Auxiliary Essential Raw Cooling Water (AERCW) Screen Wash Pumps Preoperational tests were performec on May 2 and 8, 1978, in which header flow, pump discharte pressure, and vibration were measured. The routine maintenance schedule includes t

lubrication (grease) of motor bearings.

L goSSH.

.ti Item 5.

. operational Problems and Major Repair Ef forts (a)

ERCW Screen Wash Pumps (New)

No major problems!

(b) ERCW Pumps (New)

No major problems.

(c) ERCW Pumps (Old)

No major problems.

(d) HPFP Between March 1977 and March 1978, five pump failures were experienced: one each with 1AA (November 1977), 7AA (March 1977), and 2BB (November 1977) and two wit's 1BB (January and Mar N 1978).

In each case, the pumps were dismantled and t.2 iupellers found loose on the shaft. The method of impeller attachment to tht shaft was with a tapered locking collet which was to accept the thrust load of each impeller; however, investigation of the impeller collet design revealed that a pressure differential across the impeller thrusts the impeller away from the locking collet. After consultation with the Division of Engineering Design and Johnston Pump, the decision was made to attach the impellers to the shaft via a split ring with the retainer bolted to the impeller huS. Refer to Figure 1 (enclosed) for a typical drawing of this thrust ring construction. This modification was made to all four pumps between September 1978 and January 1979. No pump failures have been experienced since this modification.

(e) AERCW Pump No major repairs have been made to pump A-A.

High vibration in pump B-B was found during Preoperational Test TVA-19 May 10, 1978. Several attempts were made in July and August 1978 to balance the pump / motor, but with no success.

On July 28, 1978, the pump was dismantled for inspection o.f possible vibration sources (shaft or impeller runout, etc.); however, no problems were fcund. The vibration source was traced to loose iron in the motor. The motor was repaired by Johnston Pump under warranty.

(f) AERCW Screen Wash Pumps No major repairs.

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Item 6.

The folicaing table is a listing of the longest interval that each puap has been available 'ar operation without major maintenance:

I

_ Pump Interval (Months)

HPFP 1AA 43 HPFP IBB 45 HPFP 2AA 35 HPFP 2BB 9

ERCW A-A*

22 ERCW C-B*

22 ERCW F-B*

22 ERCW H-A*

22 AERCW A-A*

19 AERCW B-B 7

AERCW SW A-A*

19 AERCW SW B-B*

19

• Available since tent tive transfer a

Due to the demands for equipment operation during the tentative transfer phase and preoperational test program at Sequoyah, the number of cycles of operation during the longest available interval, cycle duration and operating modes, and longest continuous operation at rated flow conditions are not available.

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