ML20084U222

AO 50-265/75-8:on 750218,jet Pump Insp Revealed Discrepancies Including Beam Bolt Retainer Clips & Cap Screws Missing on Jet Pumps 7 & 8 & Restrainer Adjusting Screw on Jet 18 Missing.Caused by Installation Deficiencies

ML20084U222
Person / Time
Site:	Quad Cities
Issue date:	02/28/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J Office of Nuclear Reactor Regulation
Shared Package
ML20084U216	List: ML20084U219 ML20084U222 ML20084U224
References
AO-50-265-75-8, NUDOCS 8306280114
Download: ML20084U222 (9)

Text

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Fe Wuary 28, 1975

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Diredtorate of Licensing Regulation Nuclear Regulatory Comis'sion Washington ,' D. ~ C . 20545 -

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Reference:

Quad-titics Nuct'ese Power Station

'Imeket lio. 50-265. DPR-30

, Appendix A,' Sections 1.0.A.4, 6.6.B.I.a Deir Mr.,0'Ceary: _,.'

Enclosed please find Abnormal Occurrence Report No. 50-265/75-8 for Quad-Citics Huclear Power Station. This occurrence was previously reported to Region 111, Directorate of Regulatory Operst~ ions by telephche 'on February 18, 1975, and to you and Region 11,1, Directorate of Regulatory Operations by telecopy on February 19, 1975. "

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'inis report is submitted to'you in accordance with the requirer,'ents of Technical Specification 6.6.B.I.a. ^-

p-Very truly yours ( -

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C0!$0N'.lEALTil EDICON COMPANY -

QUAD-C(TIES NUCLEAR POWER STATIO!! # '

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H. J. Kdlivianakis '._

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_REPCRT t; UMBER: A 265/75-8 O

REPORT DATE: February 28, 1975 OCCURRENCE DATE: February 18, 1975 IDENTIFICATION OF OCCURRENCE: /-

Jet pump components were discovered missing during a jet purap inspection.

_ CONDITIONS PRIOR TO OCCURRENCE:

The Unit Two reactor fuel assemblies had been removed and inserted into the fuel storage pool to facilitate out-of-core sipping operations and recirculation piping repairs during the refueling outage.

DESCRIPTION OF OCCURRENCE:

With inspectionthe core was void of fuel during refueling operations, a scheduled Jet pump performed. i underwater television camera and video tape unit.This inspection was carried out w are listed below. The various jet pump componentsThe and details of the inspection their physical locations are illustrated on Figures 1 and 2 g (1)

Beam bolt assemblics were observed for movement while applying 300 ft-lbs of torcue to tho haam $ cit 17, both die clockwise and counter-clo<. kwi se di rect ions .

(2)

Beam bolt keepers were Inspected with respect to the following:

(a) Position 4

(b) Evidence of movement (c) Condition of the four tack welds (3) .

The hold-down beams were inspected with respect to the following:

(a) Position (b) Check of beam pocket fits (c) . Evidence of movement (4)

. The lock plates were inspected with respect to the following:

.(a)

Condition of the four flat head screws and their respective tack welds.

(b) Evidence of movement

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Ao 50-265/75-3 February 28, 1975 O O (5) The beam bolt retainers were inspected to determine the condition of the 1/2" cap screw and its tack weld.

(6) The restrainer gate wedges were inspected with respect to the following: .

(a) Position (b) Engagement with the restrainer and belly band of the jet pump .

(c) Evidence of movement (7) The restrainer stops (adjusting screws) were inspected with respect to the following:

(a) Tightness with the belly band of the jet pump.

(b) Evidence of movement (c) Condition of the adjusting screw tack weld.

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(8) The restrainer gates were inspected with respect to the following:

(a) Condition of the two clamp bolts. '

(b) Condition and tightness of the two clamp bolt nuts.

(c) Condition of the two tack welds of.cach clamp bolt keeper.

Upon completion of the tbove inspections on all twenty Jet pumps, the following discrepancies were noted:

(1) The been bolt retainer clips and 1/2" cap screws were found to be missing on jet pumps 7 and 8.

(2) The restrainer adjusting screw on the shroud side of jet pump -

18 was found to be missing.

(3) . Restrainer gate keepers on jet pumps 1, 8, 12, 15, and 18 were found to have their welds in place, but not fused to

'the restrainer gate.

_DESICtlATI0tt OF APPAREL'T CAUSE OF OCCURREtiCE:

Eq'ulpment Failure-The apparent cause of the missing retainer clips, the 1/2" cap screws, and the (adjusting screw is' attributed to equipment failures caused by installation deficiencies. Based on the parts being inadequately installed, the vibrational forces present during nornal operction could cause these components to become dislodged from their normal positions.

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A0 50-265/75-8 .. February 28, 1975 8 O  !

During the jet pump repairs to Unit 2 during 1972, the beam bolts and keepers were the primary components repaired. The repairs necessary to Unit I during its past refueling outage in 1974 revealed that further defective installation existed. It is felt that these present components were originally installed in a deficient nanner and that the possibility of their fallere was not known at the time of the original Unit 2 repairs. 'The discovery of their failure at this time is consistent with the deficienc'es noted during the Unit I outage in 1974 AtlALYSIS OF OCCURRENCE:

The jet pumps are designed to withstand the combined loadings from differential pressure and temperature, dead weight, fluid novement, seismic acceleration, and vibration without failure or loss of integrity. The missing jet pump com-ponents did not lead to jet pump failure or loss of integrity. Particularly, there were no failurcs of any jet pump hold-down components. There were thus no unsafe conditions existing during previous periods of reactor power operation.

Jct pump component f ailures and missing or loose parts have been previously analyzed in the following documents:

(1) Quad-Citics Station, Unit 2, Special Report flo. 2, " Jet Pump O pe rab i l i ty" .

(2) t!E00-10174, May 1970, G. J. Scatena, " Consequences of a Postulated Flow Blockace incident in a Bnilinn Warnr Rene. tor".

(3) Quad-Cities Station, Unit 1, Abnormal Occurrence Report letters of April 25, 1974, May 30, 1974, and July 12, 1974.

The health and safety of the public were not adversely affected by this occurrence.

CORRECTIVE ACT10ti:

The missing beam bolt retainer clips and 1/2" cap screws of Jet pumps 7 and 8 .

will not be replaced. These pieces are important only during the initial construction of the jet pump beam assembly or during their removal. After installation of the beam bolt, the function of these pieces is completed.

A replacement stop (adjusting) screw has been installed and tack welded to its holding clamp on jet pump 18. As an alternative to removal of the jet pump throat, the welding tool used to tack weld the stop screw was modified to per-form its intended function.

Although it has been postulated that the restrainer gate keeper on jet pump 18 was loosened during the repair of the stop screw, the tack welds of all jet pump restrainer gates were reinspected as a precautionary measure. As a result of the faulty tack welds discovered on the jet pump restrainer gate keepers of jet pumps I, 8, 12, 15, and 18, the restrainer gate bolts were retorqued, and new tack welds were placed and verified. A similar inspection of the twenty jet pump beam bolt keepers was performed with satisfactory results.

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A0 50 265/75-8 le- .. February 28, 1975 -

6 a A list of objects, knean to date, which are loose or missing in the unit 2 reactor vessel is attached. Further search for loose or missing parts is being conducted and an attempt will be made to retrieve all these objects before returning the unit to operation. Details of the searches for these parts will be reported in the future.

FAILUP.E DATA:

The problems discovered on this inspection of Unit 2 are similar but were less severe than those discovered following a jet pump failure of Unit 2 in August 1972 At that time, a Jet pump assenbly had become dislodged fro:a its nornal position and rotated in the vessel. Extensive inspections and repairs were perforned on all Unit 2 jet pumps and they have since operated satisfactorily.

An extensive inspection of all Unit 1 Jet pumps during its first refueling outage in April,1974, revealed a large number of Jet pump discrepancies. These included beam bolt torque test failures, sheared restrainer gate bolts and keepers, missing and cracked restrainer gate bolt keeper tack welds, a missing restrainer gate wedge and indications of ucar in the vicinity of the wedge Indicating possible vertical movement of the wedge prior to the inspections.

All of the-Jct pump problems which have occurred at quad-Citics Station have been attributed to faulty craft installation and workmanship during the initial construction of both yunits.

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ORIG 12 L DATE Of DATE GF PART DISCOVERY RETR! EVAL DISPOSITION STAT'{.

!. Lichting Support Sracket From Refuel Bridge Missiro 1/ 9/75 1/17/75 Hung in Unit i Fuct Pool

2. Neutron Desireter Tube Missirn 2/19/75

3. Neutron Dosimeter Mi ss ir g 2/19/75 4 JP 18 Adjusting Stop Screw Miss rq 2/17/75

5. JP 7 1/2" Cap Screw Missja 2/17/75

6. JP 7 Retainer Clin Miss:rq 2/17/75 O . 7JP 8 1/2" Cap Screw 2/17/75 M i s s }r n

8. JP C Retainer Clip Miss rq 2/17/75

9. 3 Pieces of Wire Lcose 2/17/75

10. Piece of Angle I ron Loose 2/17/75

11. Open End Wrench Lcose 2/17/75 12 3 Ficces of Tapc Loose _

2/15/75 2/17/75 Radwas te

13. 1 Piece of Wire Loose 2/15/75 2/17/75 Radwaste

4. Rag Loose _

2/28/75 LOOSE = Observed, but source unknown. '

MISSING = Not in normal location and unaccounted for.

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Distribution w/o incoming: '

A. Giambusso, NRR EDO Files (50-265)

PDR G. Ertter (8974) i w/o enc 1 and ine:

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i EDO Reading w/ incoming:

J. P. Murray, ELD D. F. Knuth, DIE J. G. Davis, IE ,

J. G. Keppler, IE:I R. F. Warnick, IE L. N. Underwood, IE LPDR (50-265)

C S. Files (50-265)

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l Foran ABC.318 (Rev. P 33) AECM 0243 W u. s. soWERNDetNT PRINTleeG O.PtCas1974 33094e

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