PLA-1129, Interim Deficiency Rept Re Emergency Svc Water Sys Water Hammer,Initially Reported on 820505.Condition Being Reviewed & Corrective Action Plan Will Eliminate Problem Associated W/Water Hammer in Emergency Svc Water Sys
| ML20054J373 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 06/18/1982 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, PLA-1129, NUDOCS 8206280550 | |
| Download: ML20054J373 (4) | |
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@ Pennsylvania Power & Light Company Two North Ninth Street
- Alientown, PA 16101 + 2151770LS151
[O-32f Nortnan W. Curtis Vice President-Engineering & Construction-Nucioar 215/ 770-5381 June 18, 1982 Mr. R. C. Ilaynes Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 SUSQUEllANNA STEAM ELECTRIC STATION INTERDi REPORT OF A DEFICIENCY INVOLVING EMERGENCY SERVICE WATER (ESW) SYSTEM WATER llAMMER ERs 100450/100508 FILE 821-10 PLA-1129
Dear Mr. Ilaynes:
This letter serves to provide the Commission with an interim report on the de-ficiency involving the potential for Water Hammer in the ESW System.
This condition yas identified as "Potentially Reportable" to Mr. S. Ebneter of NRC Region I by Mr. A..R.
Sabol of PP&L during a telephone conversation on May 5, 1982.
PP&L now considers this condition to be reportable under the provisions of 10CFR50.55(e).
The attachment to this letter contains a description of the deficiency, its cause, and safety impact. The corrective action is presently being analyzed.
4 As discussed in the attached report, the adverse safety impact of the ESW System Water llammer will exist only af ter initial criticality. The licensing implications of not completing the corrective actions prior to fuel load will be discussed with NRR.
PP&L expects to provide the Commission with a final report one week before initial criticality.
We trust the Commission will find this report to be satisfactory.
Very truly yours, 4
~
fN. W. Curtis i
/ Vice President-Eng eering & Construction-Nuclear
/ BMS:JS:pd Attachment 9206280550 820618 PDR ADOCK 05000387 4
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Mr. R. C. Itaynes SSES PLA-1129 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 Mr. R. Perch Project Manager U.S. Nuclear Regulatory Commission Washington, D.C. 20555 J
s.
SSES PLA-ll29 ERs 100450/100508 -File 821-10 INTERIM REPORT
Subject:
Water hammer in the Emergency Service Water System Description of Deficiency:
During preoperational testing at Susquehanna Steam Electric Station, a water hammer occurred in the ESW System which resulted in damage to three pipe hangers.
An investigation into the cause of the hanger failures revealed that there are certain operating and test conditions under which the ESW System would be sub-jected to water hammer.
The water hammer occurs as a result of the following sequence of events:
(1) ESW System in operation - ESW pumps are on, 36" Motor Operated Bypass Valves to spray pond are open.
(2) Loss of Offsite Power (LOOP) occurs - pumps shut down, 36" MOVs remain open; ESW piping begins to drain to spray pond.
(3) Power supply transfers from offsite to emergency (i.e. diesel generators)
(4) 10 seconds after diesel generator initiation - 36" valves begin to close, drainage to spray pond continues during valve closure.
(Closing time of valves is nominally 30 seconds.)
(5) 55 seconds after diesel generator initiation - ESW pumps restart.
The pump restart causes water to be discharged into the partially emptied ESW piping, thereby resulting in a water hammer. Consequently, the potential exists for the ESW System to be degraded as a result of water hammer loads.
Cause of Deficiency:
FSAR Section 9.2.5 describes the ESW System. This section requires that the ESW System have the capability, during plant power generation, to be tested
~ hrough the full operational sequence that brings the system into operacion t
including the transfer between normal. and emergency power sources.
The existing ESW System design has not considered the LOOP scenario described above. Consequently, the water hammer loads that result from a LOOP, and which may be in excess of other design loads, have not been factored into the final design.
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Safety Impact:
Water hammer may cause degradation of the ESW System.
If the ESW System degrades, the safe shutdown of the plant could be compromised. The safety function of the ESW System is the removal of heat from the ECCS equipment and the diesel generators.
The loss of this heat removal capability will have an adverse affect on plant safety only after initial criticality.
PP6L considers this condition to be reportable under the provisions of 10CFR50.55(e).
Corrective Action:
Corrective action has not yet been established. PP&L and Bechtel are reviewing the condition and developing a corrective action plan which will eliminate the problem associated with water hammer in the ESW System.
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