ML19295F973
| ML19295F973 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/30/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 8012180009 | |
| Download: ML19295F973 (1) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION c
REGION 11
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,f 101 MARIETTA ST., N.W.. sulTE 3100 o,
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ATLANTA, GEORGIA 3o3o3 OCT 3 01950 In Reply Refer To:
RII:JP0 C509 95 )
South Carolina Electric and Gas Company ATTN:
T. C. Nichols, Jr., Vice President Power Production and Systems Operations P. O. Box 764 Columbia, SC 29218 Gentlemen:
This Information Notice is forwarded to provide a notification c.f a potential source of degradation that might occur in a safety-related component over long-term operation. No specific action or written response to this Information Notice is required at this time.
If you have any questions related to this matter, please contact this office.
Sincerely, s
~.
James P. O'Rei y Director
Enclosures:
1.
IE Information Notice No. 80-38 w/ Enclosure 2.
List of Recently Issued IE Information Notices cc w/ enc 1:
A. A. Smith, Site QA Coordinator J. B. Knotts
- 0. S. Bradham, Manager Nuclear Operations s o 3 e 1.s 0009
SSINS No.-
6835 Accession No.
UNITED STATES 8008220180 NUCI. EAR REGULATORY C0!e!ISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 October 30, 1980 IE Infomation Notice No. 80-38: CRACKING IN CHARGING PUMP CASING CLADDING Description of Circumstances:
In January 1980 Ccmmonwealth Edison Company (CECO) reported to the NRC that a radiographic examination had revealed crack indications in the cladding on the suction end plate of the 1A charging pump at Zion Unit 1.
This cen-trifugal charging pump 1A is one of two pumps installed in Zion Unit I for high head safety injection of borated water to the reactor loops. These pumps are additionally utilized as charging pumps during normal operation. ASME Section XI inservice inspection rules referenced in the plant technical specification requires pump examination only once during the 10 year service interval and this pump had been in service about 7 years.
The pumps are 2-1/2 inch, 11 stage, Type IJ manufactured by the Pacific Pumps Division of Dresser Industries. The pump casing end assembly in the area of interest, Figure 1, consists of a suction end plate of A515 grade 60 carbon steel plate welded to the casing barrel forging of A266 class I carbon steel using an Inconel weldment. The entire inner surface is clad with type 308 stainless steel applied by submerged arc welding.
An in-situ ultrasonic examination conducted in late April confirmed clad cracking indications at the barrel case to er.d plate inner radius for approximately 330 degrees around the circumference and that the cracking possibly extended into the pump base material in the bottom 180 degrees of the assembly. A review of the original radiographs revealed crack like indications in the clad overlay, however, not to the extent observed during this examination.
Subsequently, the entire suction end of the pump was removed and cross sections metallographically examined to further evaluate the nature and extent of the cracking.
It was determined that initiation and propagation of the clad cracks probably resulted from stress concentration and dilution effects in the initial corner bead pass due to the difficult access and bead sequencing required by the fairly sharp corner geometry. Extension of the cracks at the base metal-clad interface ranged to a depth of 1/16 inch maximum in the 1-1/2 inch thick base material.
These crack tip areas were well blunted and slightly cavitated from corrosion effects due lengthy exposure to the localized boric acid attack.
Examination of the crack morphology revealed that the clad cracking essentially arrested at the base metal-clad interface and that base metal corrosion progres-sed at a relatively slow rate.
The 1A charging pump was replaced with a new pump provided with a casing con-structed entirely of stainless steel. The licensee improved NDE procedures for examin next refueling outage. Further, t developing repair procedures in th DUPLICATE DOCUMENT Entire document Previously entered into system under.
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