ML19344D435
| ML19344D435 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/29/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Gerstner W ILLINOIS POWER CO. |
| References | |
| NUDOCS 8003120372 | |
| Download: ML19344D435 (1) | |
Text
[pter 'g NUCLEAR REGULATORY COMMISSION 7 p' d UNITED STATES
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g REGION 111
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a Y. k, 799 RooSEVEL T ROAD oLEN ERYN. lLUNolS 60137
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Docket No. 50-461
((3 2 g 33g Docket No. 50-462 Illinois Power Company ATTN:
Mr. W. C. Gerstner Executive Vice President 500 South 27th Street Decatur, IL 62525 Gentlenen:
This.Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the inform-ation for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluations so in-dicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, y f km _-
,/ James G. Keppler Director
Enclosure:
IE Information Notice No. 80-07 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR
' ocal PDR K31C TIC Mr. Dean Hansell,_ Office of Assistant Attorney General 800312o3} 2_
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SSINS No.:
6870 E
Accession No.:
UNITED STATES 7912190675 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 February 29, 1980 IE Information Notice No. 80-07 PUMP SHAFT FATIGUE CRACKING On October 9,1979, the Tennessee Valley Authority (TVA) reported to NRC that low-stress high-cycle fatigue cracks had been found in two non-safety-related feedwater pumps at their Browns Ferry BWR facility.
One pump had been operated for approximately 20,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> and the other for approximately 28,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />.
TVA. indicated tnat excessive vibration had been experienced prior to detection of the cracks by ultrasonic and visual inspection.
TVA al N reported that catastrophic failure had been experienced with a boiler feed pump at their Paradise fossil unit.
The TVA failed pump shafts were of type 414 stainless steel. TVA plans to replace the shafts with a type 17-4ph stainless steel.
1 A number of centrifugal charging / safety injection pump shaft failures have been reported since 1977.
The pumps of interest are the dual purpose centrifugal pumps which are utilized for a normal charging function and in the safeguard mode are aligned for high pressure borated coolsnt injection.
These pumps were procured by Westinghouse from the Pacific Pump Division of Dresser Industries. The pump shaft material was supplied to Pacific Pump by the Carpenter Technology Corporation.
Westinghouse and Pacific Pump have been conducting an on going investigative program since 1977 to resolve the shaft failure problem.
Results from the program suggested that the causes of the shaft failures could be related to shaft material deficiencies, design and/or abnormal operation of the centrifugal pumps.
Forty centrifugal charging / safety injection pump shafts fabricated from four heats of A276 type 414 stainless steel bar were air cooled and tempered at 1000 F.
The above stated heat treating practice resulted in shafts with low toughness (Charpy "V" notch energies - Longitudinal 6-10 ft-lbs, transverse 2-3 ft-lbs)
Corrective actions taken to reduce the incidence of charging pump / safety injection pump shaft failure have included:
1.
Replacement of the type 414 low toughness stainless steel material.
Replacement material for the charging pump shafts is type 414 stainless steel, oil quenched and tempered at 1150-1200 F.
Some of the air cooled shafts have been re-tempered at 1150 F.
2.
Design modifications to the shaft to reduce stress raisers. The modifica-tions included increasing the fillet radius in the split ring groove, increasing the thread root in the locknut section of the shaft and the f
use of formed cutting tools during fabrication.
IE Information Notice No. 80-07 February 29, 1980 Page 2 of 2 3.
A review of the operating history of tf dual purpose centrifugal pumps indicate aonormal operation to be a potentially significant contributor to the early failure of the pump shafts.
Abnormal operation includes any condition that results in partial or complete loss of fluid in the pump or continued operation under high vibraticr conditions caused by misclign-ment or other installation problems.
Westinghouse Nuclear Service Division's Technical Bulletins 77-9, 78-1 Res. 2 and 79-6 provide guidance for monitoring of and limits for pump vibration as well as guidance for pump operation and maintenance.
Ten additional Safety Injection Pumps manufactured by Pacific Pump were identified as having shafts with the same material and heat treatment as the failed charging / safety injection pump shafts.
These ten additional pumps are of a different design and provide for medium pressure boron injection in the safeguard mode but do not function in normal operation.
Licensees are encouraged to review the materials utilized for and the design of shafts in safety-related pumps and non-safety-related pumps which could affect safety-related system performance.
Particular attention should be paid to abnormal operating conditions which could induce high stress in the pump shaf ts, susceptibility of materials to crack initiation and growth, and the presence of stress raisers.
This Information Notice is provided as an early notification of a possibly significant matter that is still under review by the NRC staff.
It is expected that recipients will review the information for possible applicabi-lity to their facility.
No specific action or response is requested at this time.
If you have any questions regarding this matter, pleasc contact the Director of the appropriate NRC Regional Office.
I IE Information Notice No. 80-07 Enclosure
' February 29,:1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-06 Notification of Significant 2/27/80 All holders of Reactor Events OLs and to near term OL applicants 80-05 Chloride Contamination 2/8/80 All licensees of nuclear of Safety Related Piping power reactor facilities and applicants and holders of nuclear power reactor cps 80-04 BWR Fuel Exposure in 2/4/80 All BWR's holding a Excess of Limits power reactor OL or CP 80-03 Main Turbine Electro-1/31/80 All holders of power Hydraulic Control System reactor OLs and cps 80-02 8X8R Water Rod Lower 1/25/80 All BWR Facilities End Plug Wear holder power reactor OLs or cps 80-01 Fuel Handling Events 1/4/80 All holders of power reactor OLs and cps 79-37 Cracking in Low Pressure 12/28/79 All power reactor OLs Turbine Discs and cps 79-36 Computer Code Defect in 12/31/79 All power reactor OLs Stress Analysis of Piping and cps Elbow 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an OL or CP 79-34 Inadequate Design of 12/27/79 All holders of power reactor Safety-Related Heat OLs and cps Exchangers 79-33 Improper Closure of 12/21/79 All power reactor facilities i
Primary Containment holding OLs and cps Access Hatches 79-32 Separation of Electrical 12/21/79 All power reactor facilities Cables for HPCI and ADS holding OLs and cps