U-601113, Part 21 Rept Re Beloit Power Sys HPCS Div III Diesel Generator Rear Bearing & Rotor Shaft Damage.Shaft Repaired & Bearings Replaced

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Part 21 Rept Re Beloit Power Sys HPCS Div III Diesel Generator Rear Bearing & Rotor Shaft Damage.Shaft Repaired & Bearings Replaced
ML20195H114
Person / Time
Site: Clinton Constellation icon.png
Issue date: 01/04/1988
From: Hall D
ILLINOIS POWER CO.
To: Davis A
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-88, REF-PT21-88-006-000 PT21-88-006-000, PT21-88-6, U-601113, NUDOCS 8801150201
Download: ML20195H114 (3)


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U-601113

. L16-8 8(01 - 04)-LP 1A.120 ILLINDIS POWER 00MPANY CLINTON POWER STATION P.O. BOX 678. CLINTON. ILLINOIS 61727 10CFR21.21 January 4, 1988 Docket No. 50-461 Mr. A. B. Davis Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Subj ect : 10CFR21 Defect 21-87-05:

DIVISION III DIESEL GENERATOR DAMAGED BEARING AND SHAFT

Dear Mr. Davis:

On December 3, 1987, Illinois Power Company received a potential 10CFR21 Defect or Noncompliance Referral concerning High Pressure Core Spray (HPCS), Division III, Diesel Generator rear bearing and rotor shaft damage. Based on an evaluation of this matter, Illinois Power Company (IP) is providing the l following information to the Commission in accordance with the requirements of 10CFR, Part 21.21(b)(3).

(1) D. P. Hall, Vice President of Illinois Power Company, is informing the Commission by means of this report.

(ii) The basic component involved in this reportable defect is the HPCS, Division III Diesel Generator.

(iii) The Diesel Generator was built by Beloit Power Systems

(now Louis-Allis).

(iv) The nature of the defect involves the generator rotor shaft and rear bearing. Three small nicks / chias and a gouged area were identified on the shaft and tio bearing was found damaged.

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- U-601113 L16-8 N 01-04 )-LP 1A.120 The nicks / chips were located on the exciter end of the oil seal portion of the shaft. These defects were very small and not uncommon or unexpected, and could have been caused by an object inadvertently striking or hitting the lip of the shaft during machine assembly.

The only concern with respect to the nicks / chips was the oil sealing ability in the area of the defects. Since no oil leak path was visible, and the friction oil seal was more than one and one-half inches from the defects, there was no reason tc believe that a leak would occur at any time.

The gouged area was located approximately one quarter inch away from the friction oil seal and not in a sealing surface or bearing area. The defect was less than one sixty-fourth of an inch deep and was caused by the bearing housing cap rubbing the shaft as a result of the bearing housing cap being installed incorrectly in a cocked position during machine assembly prior to delivery to IP.

Visual inspection of the bearing indicated that the damage was caused by material ground off during the shaft gouging event. This material abraded the bearing cage and allowed the cage to drop onto the inner race of the bearing. This condition produced more debris which allowed the bearing damage to progress to spalling of the rolling elements.

IP has reviewed and evaluated the findings associated with the investigation of the defect / deficiency and has concluded that the matter represents a condition adverse to the safety of operation of the Clinton Power Station.

If this defect / deficiency had gone uncorrected, it could have resulted in failure of the Division III Diesel Generator and loss of the HPCS System during an accident condition. These events could affect the integrity and safe shutdown of the reactor. On this basis, the matter was evaluated to be reportable under the provisions of 10CFR21.

(v) General Electric Company (GE) notified IP of a potential 10CFR21 defect / deficiency on December 3, 1987, during replacement of damaged Division III Diesel Generator exciter leads. The damaged exciter leads were reported to the Commission as 10CFR21 Defect Number 21-87-03.

(vi) The generator for the Division III Diesel Generator is the only generator at the Clinton Power Station built by Beloit Power Systems. The generators for the Division I

& II Diesel Generators were built by Ideal Electric and have a different design.

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U-601113 L16-88 (01 04 ) .Lp 1A.120 (vii) GE evaluated the damage to the bearing and shaft. Field Deviation Disposition Request LHI-4153 was issued by GE to provide the necessary work steps for replacement of the damaged bearing. GE determined that the shaft integrity was not affected by the nicks / chips and the gouging: therefore, the shaft did not require replacement.

The nicks / chips in the shaft required only a cosmetic repair by use of a light emery cloth to dress the affected area. Since the gouged area of the shaft was not in a sealing surface, only a cosmetic repair by use of a light emery cloth was determined necessary to smooth the gouged area to areclude any possible loose metal from entering the luirication system of the bearing.

Repair of the damaged bearing and shaft was performed in conjunction with the exciter lead repair addressed in 10CFR21 Defect Number 21-87-03. The repair of the bearing and shaft commenced on December 6, 1987, and was satisfactorily completed on December 9, 1987.

(viii) This section is not applicable to Illinois Power Company.

Our evaluation of this reportable defect is available for your review at our offices. I trust this letter provides sufficient information for your review and assessment of this reportable defect.

Sincerely yours,

/

. . Hall Vice President RSF/cke cc: USNRC Resident Office, V-690 Director of Inspection and Enforcement (3 copies)

INPO Records Center Illinois Department of Nuclear Safety Energy Systems Division General Electric Company