ML20003A618

Forwards Interim Deficiency Rept Re Fractured Valve Body on Jacket Water Thermostatic Valve,Initially Reported 800626. Cause Under Investigation.Final Rept by 810520

ML20003A618
Person / Time
Site:	Grand Gulf
Issue date:	01/29/1981
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, AECM-81-55, NUDOCS 8102040409
Download: ML20003A618 (3)

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Emahhdemans MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi P. O. BOX 164O. J ACK SON mis SIS SIP Pi 39 205

1. 1. 7, $rTfs%Ye*ajR January 29, 1981 Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Region II 101 Mariatta Street, N.W.

Suite 3100 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Director

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15225/15526 PRD-80/35, Interim Report #3, Standby Diesel Generator Jacket Water Cooler Thermo-static Valve Fracture AECM-81/55

References:

1) AECM-80/166, 7/23/80

2) AECM-80/281,11/10/80 On June 26, 1980, Mississippi Power & Light Company notified Mr. M. Hunt, of your office, of a Potentially Reportable Defi-ciency (PRD) concerning the Standby Diesel Generator. The de-ficiency was a fractured valve body on the Jacket Water Thermo-static Valve.

We have determined this deficiency to be reportable within the meaning of 10CFR50.55(e). The condition is not reportable under 10CFR21 because the components have not been offered to MP&L for acceptance. Attached is our interim report.

We expect to submit a final report by May 20, 1981.

Yours truly, S

Y l7l J. P. McGaughy, Jr.

ATR:mt Attachment ictor Stello, Director Mr. G. B. Taylor ec: Mr. N. L. Stampley I.

Mr. R. B. McGehee Div. of Insp. & Enforcement South Miss. Electric gy020 40 Mr. T. B. Conner U. S. Nuclear Reg. Comm. Power Association Washington, D.C. 20555 P. O. Box 1589 f Hattiesburg, MS 39401 Member Middle South Utilities System

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INTERIM REPORT No. 3 FOR PRD-80/35

1. Description of Deficiency The Unit 1 "B" Standby Diesel Generator Jacket Water Thermostatic Control Valve (P75 System) failed during a pneumatic pressure test.

The test was being conducted to verify the integrity of the drain connections on the jacket water cooler. The control valve was within the pressure boundary of the test. The valve suffered catastrophic failure (cracked) at the flange connection. The pressure at the moment of failure was less than the valve design pressure.

The Standby Diesel Generator supplies emergency power to the Division I and II ESF 4.16 busses upon loss of normal off-site power. The failure of the Thernostatic Control Valve could have led to a loss of coolant water and subsequent failure of the Standby Diesel Generator. The failure of the Diesel Generator could have adversely affected the safety of plant operations in that the power would not be supplied to systems that are required to shutdown and cooldown the reactor and to maintain the reactor in this condition.during a loss of off-site power. ,

II. Approach to Reso'ution of the Problem A. The cause may be attributed to one or a combination of the following:

1. Installation of mismated flanges on the valve and adjacent piping.

2. Jacking of the attached pipe for a pneumatic pressure test.

3. Applied pressure during.a pneumatic pressure test.

4. Shipping and handling of the valve with attached piping.

5. A material defect in the valve or error in the manufacturing process.

B. The remaining Unit i valve, on the "A" Standby Diesel Generator, was subjected to magnetic particle excmination. The valve was found to have a hairline linear indication. It was determined that the valve had been subjected to similar conditions as the Unit i "B" valve.

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Interim Report No. 3 for PRD-80/35 Page 2 C. Both Unit 2 valves were subjected to magnetic particle examination and determined to be satisfactory. The Unit 2 valves will be used to replace the defective Unit i valves and new valves will be purchased for Unit 2.

D. The pneumatic pressure test alone would not have caused the valves to fail. The test was conducted within the pressure test rating of the valves. The pressure test may have contributed to the failure only by amplifying a defect which had been initiated by other causes.

E. The jocking of the attached pipe for pneumatic pressure test and the shipping and handling of the valve with the pipe attached will be procedurally controlled by issuance of a generic Work Plan / Procedure (WP/P).

F. The architect / engineer will coordinate directly with the vendor to determine the applicability of =aterial defect or manufacturing process of the value as a cause of the defect.

G. The raised face flanges on Unit 1 pipe are being replaced with flat face flanges. Unit 2 flanges are to be examined for mismatched flanges and replaced if necessary.

III. Status of Proposed Resolution A. The generic WP/P noted in item II.E. is being prepared and is scheduled for issue by March 15, 1981.

B. The Unit i flanges have been replaced to eliminate the mismatch.

The Unit 2 tlanges on the piping / valve interface have been examined and it was determined a mismatch does not exist for Unit 2.

C. The architect / engineer is coordinating with the vendor to obtain the data necessary to determine the applicability of material defects /

manufacturing process as a cause of the condition.

IV. Reason Why A Final Report Will Be Delayed Sufficient information has not been obtained from the vendor to effect a complete determination of _ necessary corrective actions.

V. Date When Final Report Will Be Submitted A' final report is expected to be submitted by May-20, 1981 1

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