ML19340C776
| ML19340C776 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/30/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Papay L SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| NUDOCS 8012170411 | |
| Download: ML19340C776 (1) | |
Text
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SulTE 202, V!ALNUT Cf.EE K PLAZA V/AlhUT CREE K. CALIFORNI A 94596 Octocer 30, 1980 Docket tios. 50-205. 50-351 50-362 Southern California Edison Company P. O. Box 800 2244 Walnut Grove Avenue Rosemead, California 91770 Attention: Dr. L. T. Pacay, Vice President Advancaa Enaineering Gentlemen:
This Information Hotice is forwaraea to provide a notification of a potential source of degracation that might occur in a safety related component over long tem operation. do specific action or wricten response to this Infomation flotice is required at this time.
If you have any questions related to this matter, please contact this office.
Sincerely, h 51Cm f._ <
- 1. M. Engelken Director
Enclosures:
1.
IE Infomation Notica fio. 80-33 2.
List of Recently Issued IE Infomation flotices cc w/ enclosures:
J. M. Curran, SCE R. Dietch, SCE o03.%2 ? 08//
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SSI'!S No. : 6835 Accession ?!o. :
UNITED STATES 8008220180 tiUCLEAR REGULATORY COMMISSPJN IN-80-38 0FFICE OF INSPECTION At!D ENF0r. CEMENT UASHINCTON, D.C.
20555 9~,[GD October 30, 1980 i
IE Infornation "otice No. 30-33:
CRyumG IN CHAPGIt!G PUMP CASING CLADDING hscription of Circunstances:
It. January 1980 Commonwealth 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 charoino pumo 1A is one of two cunns installed in Zion Unit 1 for high head safety injection of borated water to the reactor locos.
These pumps are additionally utilized as charaino cunos durino normal ooeration.
ASiiE Section XI inservice inspection rules referenced in the plant technical specification reauires pumo examination only once during the 10 year service interval and this pumo had been in service about 7 years.
The cumps are 2-1/2 inch,11 stage, Type IJ manufactured by the Pacific Pumps Division of Dresser Industries.
The pumo casing end assembly in the area of interest, Figure 1, consists of a suction end plate of ASIS grade 60 carbon steel plate welded to the casing barrel forging of A266 class 1 carbon steel using an Inconel weldaent. 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 end plate inner radius for approximately 330 degrees around the circunference and that the cracking possibly extended into the pump base material in the botton 100 degrees of the assembly. A review of the original radicgraphs 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 cle
. cling essentially arrested at the base metal-clad interface and that base me:..
_orresion progres-sed at a relatively slow rate.
The IA charginq pumn was renlaced with a new pump provided with a casing con-structed entirely of stainless steel. The licensee is currently developing improved NDE procedures for examination of the three remaining pumps at the next refueling outage.
Further, the licensee and pump manufacturer are developing repair procedures in the event cracks are discovered in the remaining pumps.
IN-80-33 October 30, 1980 Page 2 of 2 A corrosion evaluation provided CECO by Westinghouse indicates the corrosion rate of carbon steel subject to environmental conditions typical of the installed pumps is on the order of 2-1/2 to 4 mils per month. Additionally, a stress analysis of the pumo casing by the manufacturer using ASME Sectior: III, Subsec-tion NC rules, indicates that at design conditions a flaw with depth of 0.763 inches could be tolerated.
Based on the available information no immediate safety concern is indicated.
However, the observed conditions reveal a potential source of pump degradation over long tern operations. Therefore, to assure maximum availability, it appears prudent to perform a nondestructive examination of this pump type at the earliest practical time durino the first code recuired in-service inspection interval and if crackinc is confirmed, take approcriate corrective actions per the. rules of ASME Section XI BP&V Code.
This Information Notice is provided as a notificaton of a potential source of dec' Tdation of a safety related comDonent that is still unde; review by the NRC s
It is expected that recipients will review the :nformation for possible appl ~ cability to their facility.
No specific action or response is reouested at this time.
If you have any questions regarding this matter, please contact the Director of the appropriate iiRC Regional Office.
Enclosure:
Figure 1
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IN 80-38 October 30, 1980 RECENTLY ISSUED IE INFORMATION MOTICES Infornation Date of j!otice No.
Subject Issue Issued to 80-37 Containnent cooler leaks 10/24/80 All nuclear power and reactor cavity facilities holdina floodino at Indian Point power reactor OLs Unit 2 or cps 80-36 Failure of Steam 10/10/80 All nuclear power Generator Succort Bolting reactor facilities holdina power reactor OLs or cps 80-35 Leaking and dislodaed 10/10/80 A;I categories G and Iodine-124 implant seeds G1 nedical licensees 80-34 Boron dilution of reactor 9/20/80 All pressurized water coolant during stean reactor facilities generator decontaminatior, holding power reactor OLs 80-33 Determination of teletherapy 9/15/80 Ail teletherapy timer accuracy (G3) licensees 80-32 Clarification of certain 8/12/80 All NRC and agreement reouirenents for Exclu-state licensees sive-use shipments of radioactive materials J0-31 Maloneration of Gould-8/27/80 All light water reactor Brown Boveri Type 480 facilities holding OLs j
volt type K-600S and or cps l
K-00M 6005 circuit breakers 80-30 Potential for unaccept-8/19/80 All boiling water reactor able interaction between facilities holding power the control rod drive scran reactor OLs or cps.
l function and non-essential l
control air at certain GE BWR facilities 80-29 Croken studs on Terry 8/7/80 All light water reactor turbine steam inlet facilities holding l
flange power reactor OLs or cps
- l l
- Operating Licenses or Construction Permits i