PLA-1762, Interim Deficiency Rept Re Scram Discharge Vol Vent,Drain Valve & Water Hammer Loads.Initially Reported on 830628. Performance of Analysis to Determine Load & Impact Underway. Also Reported Per Part 21
| ML20077H932 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 07/28/1983 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, PLA-1762, NUDOCS 8308120067 | |
| Download: ML20077H932 (3) | |
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@ Pennsylvania Power & Light Company Two North Ninth Street
- Allentown, PA 18101
- 215 / 770 5151 Norman W. Curtis Vice President-Engineering & Construction-Nuclest 215/770-7501 July 28, 1983 Dr. Thomas Murley Regional Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 SUSQUEHANNA STEAM ELECTRIC STATION INTERIM REPORT OF A DEFICIENCY INVOLVING SDV VENT & DRAIN VALVE WATERHAMMER ERs 100450/100508 FILE 821-10 PLA-1762
Dear Dr. Murley:
l This letter serves to provide the Commission with an interim report on a deficiency involving SDV Vent and Drain Valve and Waterhammer Loads.
This deficiency was originally reported by telephone to Mr. G. Rhoades at NRC Region I on June 28, 1983 by Mr. J. Saranga of PP&L as potentially reportable under the provisions of 10CFR50.55(e) for Unit II.
It is anticipated a final report will be submitted in November, 1983.
The attachment to this letter contains a description of the deficiency, its cause, an analysis of safety implications and the corrective action taken and planned. This information is furnished pursuant to the provisions of 10CFR50.55 (e).
Since the details of this report provide information relevant to the reporting requirements of 10CFR21, this correspondence is considered to alco discharge any formal responsibility PP&L may have in compliance thereto.
We trust the Commission will find this report to be satisfactory.
Very truly yours, O
1 4
W N. W. Curtis Vice President-Engineering & Construction-Nuclear JBW:sab B300120067 830728
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// gig PDR ADDCK 05000388 S
PDR Attachment
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July 28,1983 SSES PLA-1762 ERs 100450/100508 File 821-10 cc:
Mr. Richard C. DeYoung (15)
Director-Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. Mcdonald, Director Office of Management Information & Program Control U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Gary Rhoads U.S. Nuclear Regulatory Commission P.O. Box 52 shickshinny, PA 18655 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, GE 30339 l
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Attachm nt to PLA-1762 SSES PLA-1762 ERs 100450/100508 File 821-10 INTERIM REPORT ON SDV VENT & DRAIN VALVE WATERHAMMER PROBLEM:
General Electr!c SIL-331, Supplement 4 indicated that a waterhanner load in the Scram Discharge Volume (SDV) Vent and Drain lines, due to the opening of the SDV vent and drain valves on scram reset, should be incorporated in the SDV system design. A review of the stress report for the SDV indicates that this load was not considered.
i CAUSE:
In October of 1980, General Electric issued SIL-331, l
Supplement 4, which addresses concerns regarding the design of the SDV and its associated instrumentation, piping, and 1
valves. This was the result of an incident at the Hatch Nuclear Plant where floats in level instrumentation were crushed. It was later determined that the damage was due to a waterhammer in the SDV vent and drain lines caused by the opening of the vent and drain valves during scram reset.
Consequently, GE made reconmendations for design modifications to the level instrumentation, and indicated the " transient load" should be evaluated in the design of vent and drain lines. An investigation of the Stress Report for the piping at Susquehanna indicated that this load was not considered for Unit I or II.
I EXTENT:
The SDV vent and drain valve waterhammer phenomena is limited to the SDV system piping. However, the full impact of the load on the SDV system is not known at this time. This information will be provided.following testing to determine the load.
1 SAFETY IMPLICATIONS:
If it is determined that the SDV Vent and Drain Valve Waterhammer load exceeds the allowable design stress for the pipe, then the failure of this pipe could result in a leak l
outside of containment. This would be similar to the accident l
postualted in NUREG-0803; however, it is anticipated that it would be less severe since the crack size would be smaller.
Furthermore, should this break occur it would be mitigated in
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the same manner as NUREG-0803; for which PP&L has demonstrated adequate mitigation capability (please see PLA-1292, PLA-ll32, PLA-987).
CORRECTIVE ACTION: PP&L is evaluating various vendors to perform the necessary testing and analysis to determine the load and its impact.
Additional corrective action will be determined when the results of this analysis are available.
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