ML20086Q500

Interim Significant Deficiency Rept SDR 5 Re High Pressure Svc Water Valve Weld Failure.Caused by Insufficient Fillet Weld Throat Dimension.Valves Reworked to Eliminate Shims & Mounting Plates Rewelded

ML20086Q500
Person / Time
Site:	Peach Bottom
Issue date:	06/28/1973
From:	Boyer V PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Kreusi F US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086Q469	List: ML20086Q500
References
SDR-5, NUDOCS 8402270577
Download: ML20086Q500 (4)

Text

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PHIL ELPHIA ELECTRIC COM NY 2301 MARKET STREET PHILADELPHI A. PA.19101 V.S.BOYER vfCE-PRESIDENT June 28, 1973 Pr. F. Kreusi, Director Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D.C. 20$h5

SUBJECT:

Significant Deficiency Interim Report High Pressure Service Water Valve Weld Failure Peach Bottcm Atomic Power Station Units No. 2 and 3 AEC Construction Permit Nos. CPPR-37 and CPPR-38 File: QUAL 2-10-2 SLR No. 5

Dear Sir:

In ecnpliance with 10 CFR 50 55 paragraph (e), we are hereby transmitting the attached Significant Deficiency Interim Report concerning the weld failure on a valve in the High Pressure Service Water System.

The AEC, DRO I organization was notified of this item by telephone by our Mr. H.B. Winitsky to Pr. J. Allentuck on June 1, 1973 Sincerely,

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j TOV:lew Attachment Copy to J.P. O'Reilly, USAEC 8402270577 731026 PDR ADOCK 05000277 S pg

' SignificQDeficiency Interim Report-SDRO. s High PresMre Service Water Valve Weld Failure Peach Bottom Atomic Power Station-Units 2 & 3 AEC Construction Fermit Nos. CPPR-37 and CPPR-38 DESCRIPTION OF DEFICIENCY A 12" - 300// motor operated globe valve in the High Fressure Service Water line on the discharge side of one FER heat exchanger on Unit 2 has experienced a weld failure of the weld between the valve yoke and the motor operater mounting plate. The reason for the failure has been identi-fied as insufficient fillet veld throat dimension caused by the installa-tion of unauthorized shins between the ycke legs and the mounting plate which reduced the effective size of the fillet weld.

CORREETIVE ACTICN 1.

There are a total of eight valves (four on Unit 2 and four on Unit 3) including the subject valve, which are essentially identical. All of these valves were inspected and a second valve of this group was identified to have shims. In view of the failure of the subject valve it was decided that all eight valves would be reworked to assure that a ccmparable failure could not occur. The rework will involve elinination of the shims and rewelding the mountir.g plate to the yoke legs with a full penetration weld.

2. The investigation of similar valves, elsewhere in the plant has begun.

A total of 10h valves (including the above mentioned eight) have been identified thus far as having yoke construction similar to the failed valve . The manufacturer's weld stress analysis calculation for one i

of these valves will be reviewed as representative of the design. A l field inspection progran has been instituted for these valves to detemine the acceptability of the welds as they exist.

l l SAFETY IMPLICATICNS l

Potential safety implicatiens resulting from this failure are being reviewed. -

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COMPIETE SIGNIFICANT DEFICIENCY REPORT It is anticipated that the report will be completed on or about l August 15, 1973 l

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHIA, PA.19101 f 215) 841 4 5o0 vies-enssIDsNT June 28, 1973 Mr. F. Kreusi, Director Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D.C. 205h5

SUBJECT:

Significant Deficiency Interhn Report High Pressure Service Water Valve Weld Failure Peach Bottom Atomic Power Station Units No. 2 and 3 AEC Construction Permit Nos. CPPR-37 and CPPR-38 File: QUAL 2-10-2 SDR No. 5

Dear Sir:

In ocupliance with 10 CFR 50 55 paragraph (e), we are hereby transmitting the attached Significant Deficiency Interim Report concerning the weld failure on a valve in the High Pressure Service Water System.

The AEC, DRO I organization was notified of this item by telephone by our Mr. H.B. Winitsky to Mr. J. Allentuck on June 1, 1973 Sincerely,

. . c TOV:lew Attachment Copy to J.P. O'Reilly, USAEC

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. o .. O Significant Deficiency Interim Report-SDR No. 5 High Pressure Service Water Valve Weld Failure Peach Bottom Atomic Power Station-Units 2 & 3 AEC Construction Permit Nos. CPPR-37 and CPPR-38 4

DESCRIPTION OF DEFICIENCY i

A 12" - 300# motor operated globe valve in the High Pressure Service Water line on the discharge side of one RHR heat exchanger on Unit 2 has experienced a weld failure of the weld between the valve yoke and the '

motor operater mounting plate. The reason for the failure has been identi-fied as insufficient fillet weld throat dimension caused by the installa-tion of unauthorized shims between the yoke legs and the mounting plate which reduced the effective size of the fillet weld.

, CORRECTIVE ACTION

1. There are a total of eight valves (four on Unit 2 and four on Unit 3) including the subject valve, which are essentially identical. All of these valves were inspected and a second valve of this group was identified to have shims. In view of the fad. lure of the subject valve it was decide.1 that all eight valves would be reworked to assure that a comparable failure could not occur. The rework will involve elimination of the shims and rewelding the mounting plate to the yoke legs with a full penetration weld.

2. The investigation of similar valves, elsewhere in the plant has begun.

A total of 10h valves (including the above mentioned eight) have been identified thus far as having yoke construction similar to the failed valve. The manufacturer's weld stress analysis calculation for one of these valves will be reviewed as representative of the design. A field inspection program has been instituted for these valves to detemine the acceptability of the welds as they exist.

SAFErY IMPLICATIONS Potential safety implications resulting from this failure are being reviewed.

COMPIETE SIGNIFICANT DEFICIENCY REPORT It is anticipated that the report will be completed on or about August 15,1973

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