ML17296B135
| ML17296B135 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/30/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 8012170757 | |
| Download: ML17296B135 (10) | |
Text
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W**y4 UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLAZA WALNUTCREEK, CALIFORNIA94696 October 30, 1980 Docket Nos.
50-528, 50-529 50-530 Arizona Public Service Company P. 0.
Box 21666 Phoenix, Arizona 85036 Attention:
t1r. E.
E.
Van Brunt, Jr.
Ilice President, Nuclear Projects Gentlemen:
This Information Notice is forwarded to provide a notification of 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, R. H. Engelken Director
Enclosures:
l.
IE Information Notice No. 80-38 2.
List of Recently Issued IE Information Notices cc w/enclosures:
F.
Ll.. Hartley, APS
UNITED STATES NUCLEAR REGULATORY COMM'ISS ION OFFICE OF INSPECTION AND ENFORCEii1EHT
)JASHIHGTON, D.C.
20555 SSIHS k(o.:
6835 Accession No.:
8008220180 IN-80-38 October 30,- 1980 IE Information Notice Ho. 80-38:
CRACKING IN CHARGING PUf1P CASIflG CLADDING Des cri tion of Ci rcums tances:
In January 1980 Commonwealth Edison Company (CECo) reported to the HRC 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 oump 1A is one of two pumns installed in Zion Unit 1 for high head safety injection of borated water to the reactor loops.
These pumps are additionally utilized as charging numps,during normal operation.
ASiME Sec<ion 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 1 carbon'steel using an Inconel weldment.
Tne 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 az the barrel case to end 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 lA charging pump ias replaced 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.
h
IN-80-38 October 30, 1980 Page 2 of 2 A corrosion evaluation provided CECo by llestinghouse 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 pump casing by the manufacturer using ASME Section 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.
'owever, the observed conditions reveal a potential source of pump degradation'ver long term operations.
Therefore, to assure maximum availability, it appears prudent to perform a nondestructive examination of this pump type at the earliest practical time during the first code required in-service inspection interval and if cracking is confirmed, take appropriate corrective actions per the-rules of ASHE Section XI BP&V Code.'his Information Notice is provided. as a notificaton of a potential source of degradation of a safety related component that is still under review by the NRC staff.
It is expected that recipients will review the information for-possible applicability,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 approoriate NRC Regional Office.
Enclosure:
Figure 1
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(ABlb GR. 60)
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RECENTLY ISSUED IE INFORMATION flOTICES IH 80-38 October 30, 1980 Information Notice Ho.
80-37 80-36 80-35 Sub. ect Containment cooler leaks and reactor cavity flooding at Indian Point Unit 2 Failure of Steam Generator Suooort Bolting Leaking and dislodged Iodine-124 imolant seeds Date of Issue 10/24/80 10/10/80 10/10/80 Issued to All nuclear power facilities holding power reactor OLs or rCPs All nuclear power reactor facilities holding power reactor OLs or CPs All categories G and Gl medical licensees 80-34 80-33 Boron dilution of reactor 9/26/80 coolant during steam generator decontamination Determination of tel etherapy 9/15/80 timer accuracy All pressurized water reactor facilities holding power reactor OLs All teletherapy (G3) licensees 80-32 Clarification of certain reouirements For Exclu-sive-use shipments of radioactive materials 8/12/eo All HRC and agreement state licensees 80-31 80-30 80-29 Haloperation of Gould-Brown Boveri Type 480 volt type Y-60OS and Y,-OOH 600S circuit breakers Potential for unaccept-able interaction between the control rod drive scram function and non-essential control air at certain GE BHR faci1 ities Broken studs on Terry turbine steam inlet flange 8/27/80 8/19/80 8/7/80 All light water reactor facilities holding OLs or CPs All boiling water reactor faci 1 ities holding power reactor OLs or CPs.
All light water reactor facilities holding power reactor OLs or CPs*
- Operating Licenses or Construction Permits