ML19284A891
| ML19284A891 | |
| Person / Time | |
|---|---|
| Site: | Perkins, Cherokee  |
| Issue date: | 02/29/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Dail L DUKE POWER CO. |
| References | |
| NUDOCS 8003180318 | |
| Download: ML19284A891 (2) | |
Text
3
'o UNITED STATES 8
NUCLEAR REGULATORY COMMISSION n
e REGION 11 o
'S E
101 MARIETTA ST., N.W., SUITE 3100 o
ATLANTA, G EORGIA 30303 In Reply Refer To:
RII:JPO FEB 291980 50-491, 50-492 1 12. 5 50-493, QtTr4BBD c50 ' 89,55_0-490; t
Duke Power Company ATTN:
L. C. Dail, Vice President Design Engineering P. O. Box 33189 Charlotte, NC 28242 Gentlemen:
This Information Notice is provided as an early notification of a possible significant matter.
It is expected that recipients will review the informa-tion for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, 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 Fegional Office.
Sincerely,
'Th s
..__ m 4
' James P. O'Reill(y [
Director
Enclosures:
1.
IE Information Notice No. 80-07 2.
Lict of Recently Issued IE Information Notices 8 0 031803rg
N
(( [i 2 $ l9E
Duke Power Company
- cc w/ encl:
J. T. Moore, Project Manager Post Office Box 422 Gaffney, South Carolina 29340
- 4 o
)
M SSINS No.:
6870 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 Octcber 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 that excessive vibration had been experienced prior to detection of the cracks by ultrasonic and visual inspection.
TVA also reported that catastrophic failure had been experienced with a boiler feed pump at their Paradise fossil unit.
The TVA failed pump shaf ts were of type 414 stainless steel. TVA plans to replace the shafts with a type 17-4ph stainless steel.
A number of centrifugal charging / safety injection pump shaf t 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 coolant injection.
These pumps were procured by Westinghouse from the Pacific Pump Division of Dresser Industries.
The pump shaft material was supplied tb 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 shaf t material deficiencies, design and/or abnorm.-l operation of the centrifugal pumps.
s Forty centrifugal charging / safety injection pump shafts fabricated from four heats of A276 type 414 stainless steel bar were air cooled and te2pered at 1000 F.
The above stated heat treating practice resulted in shafts with low toughness (Charpy "V" notch energies - Longitudinal 6-10 f t-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 use of formed cutting tools during fabrication.
M IE Information Notice No. 80-07 February 29, 1980 Page 2 of 2 3.
A review of the operating history of the dual purpose centrifugal pumps indicate abnormal operation to be a potentially significant contributor to the early failure of the pump shaf ts.
Abnormal operation includes any condition that results in partial or complete loss of fluid in the pump or continued operation under high vibration conditions caused by misalign-ment or other installation problems. Westinghouse Nuclear Service Division's Technical Bulletins 77-9, 78-1 Rev. I 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 shaf ts in safety-related pumps and non-safety-related pumps which could af fect safety-related system performance.
Particular attention shob1d be paid to abnormal operating conditions which could induce high stress in the pump shafts, 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 possible significant matter that is still under review by the NRC staff.
It is expected that recipients will review the information for possible applicabil-ity to their facility.
No specific action or response is requested at this time.
If you have any questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
4 IE Information Notice No. 80-07 Enclosure Februa ry 29, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-07 Pump Shaft Fatigue Cracking 2/29/80 A'.1 holders of power reactor OLs and cps 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 Exces7 of Limits power reactor OL or CP 80-03 Main Turbine Electro-1/31/E0 All holders of power Ilydraulic 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 Etress 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 lleat OLs and cps Exchangers 79-33 Improper Closure of 12/21/79 All power reactor facilities 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