ML19340C778

Forwards IE Info Notice 80-38, Cracking in Charging Pump Casing Cladding. No Written Response Required

ML19340C778
Person / Time
Site:	Rancho Seco
Issue date:	10/30/1980
From:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
NUDOCS 8012170414
Download: ML19340C778 (1)

Text

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UNITED STATES

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! %.,g('.i NUCLEAR REGULATORY COMMISSION 3. Cd/

4 REGION V 0, - bhd

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1990 N. CALIFORNIA LIOULEVARD U, *, ',, ' *,[

SulTE 202. WALNUT CRE E K PLAZA s +

WALNUT CR E E K, CAllFORNI A 94596 October 30, 1980 Docket t!o. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95313 Attention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:

This Information liotice is forwarded to provide a notliication of a potential source of degradation that might occur in a safety related component over long tem operacion. iio specific action or written response to this Information flotice is required at this time.

If you have any questions related to this matter, please contact this office.

Sincerely, i: D.",' - v,. L ( 2 -

R. II. Engelken Director

Enclosures:

1.

IE Informatior. I:otice

!!o. 80-33 P

List of Recently Issued i

IE Information flotices cc w/ enclosures:

R. J. Rodriguez, SMUD L. G. Schwieger, SMUD 8012170Vf Q

SSIt!S flo. : 6835 Accession t'o. :

UtlITED STATES 8008220180 fUCLEAR REGULATORY COMMISSI0fl If t-80-38 0FFICE OF If;SPECTIC!! AtlD EllFORCEMErlT UASHINGTON, D.C.

20555 October 30, 1980 IE Inforration i:otice No. 80-39:

CPACKING IN CHARGING PUMP CASIt!G CLADDING Descriction of Circunstances:

In 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 charaina punp 1A is one of two purns installed in Zion Unit 1 for high head safety injection of borated water to the reactor loops.

These pumps are additionally utilized as charcina punos durina normal operation.

ASME Section XI inservice insoection rules referenced in the plant technical specification recuires pump examination only once during the 10 year service interval and this pump had been in service about 7 years.

The cumos 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.

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 circumference and that the cracking possibly extended into the cump base material in the botton 130 degrees of the assembly. A review of the cricinal radiographs revealed crack like indications in the clad overlay, however, not to the extent observed daring this examination.

Subsecuently, the entire suction end of the rumo was removed and cross sections metallographically examined to further evaluate the nature and extent of the cracking.

!t 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 ceometry.

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 raterial. 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 retal-clad interface and that base metal corrosion progres-sed at a relatively slow rate.

The 1A charqino pumn was 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 i

next refueling outage.

Further, the licensee and pump manufacturer are l

develooing repair procedures in the event cracks are discovered in the remaining pumps.

L

IN-80-33 October 30, 1980 Pace 2 of 2 A corrosion evaluation orovided CECO by Westinobouse indicates the corrosion rate of carnsn steel subject to environrental conditions typical of tha installed punos is on *he order of 2-1/2 to 4 nils per conth.

Addi tionally, ' stress analysis of the eurs casirn by the ranufacturer usino ASME Eection Ili, Subsec-tien NC rules, indicates that at desian conditions a flaw with death of U.'63 inches could be tolerated.

Based on the available inforration no irmediate safety concern is indicated.

However, the observed conditions reveal a potential sourc3 of pump degradation over long tern coerations. Therefore, to assure maximum availability, it aopcars prudent to cerforn a nondestructive exanination of this pump type at the earliest cractical time durino the first code reouired in-service inspection interval and if crackino is confirned, take approoriate corrective actions per the. rules of AS"E Section XI SP&V Code.

This Information Notice is provideo as a notificaton of a potential source of decradation of a safety related component Inat is still under review by the NR' staff.

It is expectea tnat recipients will review the information for possible applicability to their facility.

No specific action or response is reauested ".c this time.

If you have any auestions regarding this matter, please contact the Director of the appropriate dRC Regional Office.

Enclosure:

Figure 1 l

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FIGURE

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- SUCTION END PLATE j

(ASIS GP. 60 )

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CASING BARPEL

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W g Nh I!! EC-38 RW October 30, 1980 CECE::TLY ISSUED 9

IE 17CMT!0:1 ':0TICES Infornation Bte of tiotice :'o.

Subiect

ssue Issued to 80-37 Containment cooler leaks 10/24/80 All nuclear cower and reacter cavity facilities holdinn f'eceir.o at Indian Point power reactor OLs Unit 2 or cps 80-36 Failure of Steam 10/10/80 All nuclear power Gererator Succort Poltino reactor facilities holdina cower reactor OLs or cps 80-35 Leakinn and dislodced 10/10/80 All cateoories G and Icdine 124 innlant seeds G1 nedical licensees 80-3a Boren dilution of reactor 9/26/80 All pressurized water coolant during stean reactor facilities l

renerator decontamination holding pcwer reactor OLs CO-33 Deternination of teletherapy 9/15/80 All teletherapy tirer accuracy (G3) licensees 80-32 Clarification of certain G/12/00 All ::RC and agreenent recuirenents for Exclu-state licensees cive-use snip.ents of radicactive materiais 80-31

'aloneration of acuic-3/27/30 All light water reactor Brown Boveri Tyce 430 facilities holding OLs vol t t"pe K-COOS and or cps T-00" 6003 circuit breakers 80-30 Potential fcr unaccept-8/19/80 All twiling water reactor able interaction between facilities holding power 9e control rod drive scran reactor OLs or cps.

fonction and non-essential control air at certain GE B'.!R facilities 30-29 Droken studs on Terry 3/7/80 All light water reactor turbine stean inlet facilities holding flange power reactor OLs or cps *

• Operating Licenses or Construction Pernits