Information Notice 1988-06, Foreign Objects in Steam Generators

Foreign Objects in Steam Generators
	ML031150625
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	02/29/1988
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-88-006, NUDOCS 8802230035
	Download: ML031150625 (6)
	v • d • e

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 February 29, 1988 INFORMATION NOTICE NO. 88-06: FOREIGN OBJECTS IN STEAM GENERATORS

Addressees

All holders of operating licenses or construction permits for pressurized

water reactors (PWRs).

Purpose

This information notice is being provided to alert addressees to a potentially

generic problem with foreign objects on the secondary side of steam generators

in PWRs and the potential for failure of steam generator tubes as a result of

fretting. It is expected that recipients will review the information for ap- plicability to their facilities and consider actions, as appropriate, to pre- clude similar problems from occurring at their facilities. However, suggestions

contained in this information notice do not constitute NRC requirements; there- fore, no specific action or written response is required.

Description of Circumstances

On February 3, 1988, during the first refueling outage at Catawba 2, the licensee

submitted a report to the NRC, as required under 10 CFR 50.72, indicating that

foreign metal objects in two of four steam generators had caused loss of 50% of

the wall thickness for one tube in each of these steam generators. One of the

objects was a steel block 1-1/2 inches x 2 inches x 3 inches and the other was

a steel sliver approximately 1/4 inch x 3/8 inch x 8 inches. Both objects were

located on the tube sheet. On the basis of a subsequent evaluation, the licensee

concluded that it was unlikely that these obJects had caused damage. However, the licensee found three jacking studs 2 to 3 inches long by 2-1/4 inches in

diameter on the tube sheet in one of the other two steam generators. One of

these studs did cause significant damage to a tube in that steam generator.

The licensee also found small gauge wire, a nail, a 6 inch piece of welding

rod, and welding slag in the steam generators. The licensee was able to remove.

all of the foreign objects and debris except for the piece of welding rod. The

licensee did eddy current testing of 100% of the peripheral tubes in all of the

steam generators for Catawba 2 and found that plugging of seven tubes was neces- sary. Of the seven tubes plugged, two had visible damage to the exterior surface

near the tube sheet. The maximum defect indicated by eddy current testing was 77%.

The licensee's records indicate that all of the steam generators were carefully

inspected for foreign objects after fabrication of the steam generators was com- pleted and prior to operation of the reactor at power. Nothing of significance

IN 88-06 February 29, 1988 was found at that time. The foreign objects and debris found recently in the

steam generators may have accumulated in the top works of the steam generators

and may have been washed down to the tube sheet after preservice inspections.

Discussion:

As described in NUREG/CR-0718, 'Steam Generator Tube Integrity Program Phase I

Report," tests for certain steam generators Indicate that tube failure can be

expected during normal operation if the tube wall thickness is reduced by 85%

to 90% and if the defect is 1-inch long or longer. Likewise, during a steam

line break accident, failure can be expected if wall thickness is reduced by

75% to 80%.

Information Notice 83-24, "Loose Parts in the Secondary Side of Steam Generators

at Pressurized Water Reactors," addressed events involving foreign objects and

loose parts on the secondary side of steam generators at PWRs, including the

events at Ginna and Prairie Island I where tube ruptures were related to the

presence of loose parts.

Generic Letter 85-02, "Staff Recommended Actions Stemming from NRC Integrated

Program for Resolution of Unresolved Safety Issues Regarding Steam Generator

Tube Integrity," requested that PWR licensees perform visual inspections on

steam generator secondary sides in the vicinity of the tube sheet along the

entire periphery of the tube bundle and the tube lane to identify any foreign

objects-and-damage-to-the external surfaces of tubes. For licensees with

operating licenses, these inspections were to be performae durIng the next--

planned outage for eddy current testing and after any secondary side repairs

or modifications to steam generator internals were completed. For applicants

for operating licenses, these inspections were to be performed as part of the

preservice Inspection program. The licensee for Catawba 2 complied with this

request as an applicant for an operating license. The preservice inspections

would not detect foreign objects in the top works of the steam generators that

could be washed down to the tube sheets during the first fuel cycle.

No specific action or written response is required by this information notice.

If you have questions about this matter, please contact the technical contact

listed below or the Regional Administrator of the appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Roger Woodruff, NRR

(301) 492-1180

Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 88-06 February 29, 1988 Page I of i

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

88-05 Fire in Annunciator Control 2/11/88 All holders of OLs

Cabinets or CPs for nuclear

power reactors.

88-04 Inadequate Qualification '2/5/88 All holders of OLs

and Documentation of Fire or CPs for nuclear

Barrier Penetration Seals power reactors.

88-03 Cracks in Shroud Support 2/2/88 All holders of OLs

Access Hole Cover Welds or. CPs for BWRs.

88-02 Lost or Stolen Gauges 2/2/88 All NRC licensees

authorized to possess

gauges under a

specific or general

license.

88-01 SafetyInjection Pipe 1/27/88 --

All holders of OLs

- ~~Fa iT-Ore -' or CPs for nuclear

power reactors.

86-81, Broken External Closure 1/11/88 All holders of OLs

Supp. 1 Springs on Atwood & Morrill or CPs for nuclear

Main Steam Isolation Valves power reactors.

87-67 Lessons Learned from 12/31/87 All holders of OLs

Regional Inspections of or CPs for nuclear

Licensee Actions in Response power reactors.

to IE Bulletin 80-11

87-66 Inappropriate Application 12/31/87 All holders of OLs

of Commercial-Grade or CPs for nuclear

Components power reactors.

87-28, Air Systems Problems at 12/28/87 All holders of OLs

Supp. 1 U.S. Light Water Reactors or CPs for nuclear

power reactors.

87-65 Plant Operation Beyond 12/23/87 All holders of OLs

Analyzed Conditions or CPs for nuclear

power reactors.

OL = Operating License

CP F Construction Permit

-

IN 88-06 February 29, 1988 was found at that time. The foreign objects and debris found recently in the

steam generators may have accumulated in the top works of the steam generators

and may have been washed down to the tube sheet after preservice inspections.

Discussion:

As described in NUREG/CR-0718, "Steam Generator Tube Integrity Program Phase I

Report," tests for certain steam generators indicate that tube failure can be

expected during normal operation if the tube wall thickness is reduced by 85%

to 90% and if the defect is 1-inch long or longer. Likewise, during a steam

line break accident, failure can be expected if wall thickness is reduced by

75% to 80%.

Information Notice 83-24, 'Loose Parts in the Secondary Side of Steam Generators

at Pressurized Water Reactors," addressed events involving foreign objects and

loose parts on the secondary side of steam generators at PWRs, including the

events at Ginna and Prairie Island 1 where tube ruptures were related to the

presence of loose parts.

Generic Letter 85-02, "Staff Recommended Actions Stemming from NRC Integrated

Program for Resolution of Unresolved Safety Issues Regarding Steam Generator

Tube Integrity," requested that PWR licensees perform visual inspections on

steam generator secondary sides in the vicinity of the tube sheet along the

entire periphery of the tube bundle and the tube lane to identify any foreign

objects and damage to the external surfaces of tubes. For licensees with

operating licenses, these inspections were to be performed during the next

planned outage for eddy current testing and after any secondary side repairs

or modifications to steam generator internals were completed. For applicants

for operating licenses, these inspections were to be performed as part of the

preservice inspection program. The licensee for Catawba 2 complied with this

request as an applicant for an operating license. The preservice inspections

would not detect foreign objects in the top works of the steam generators that

could be washed down to the tube sheets during the first fuel cycle.

No specific action or written response is required by this information notice.

If you have questions about this matter, please contact the technical contact

listed below or the Regional Administrator of the appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Roger Woodruff, NRR

(301) 492-1180

Attachment: List of Recently Issued NRC Information Notices

see previous concurrence

EAB:NRR* EAB:NRR* C:EAB:NRR* C:GCB:NRR* Tech Ed* AD:RGN II*

RWoodruff:db RLobel Wianning CBerlinger AThomas GLainas

2/18/88 2/19/88 2/19/88 2/22/88 2/18/88 2/19/88

IN 88- February xx, 1988 was found at that time. The foreign objects and debris found recently in the

steam generators may have accumulated in the top works of the steam generators

and may have been washed down to the tube sheet after preservice inspections.

Discussion:

As described in NUREG/CR-0718, "Steam Generator Tube Integrity Program Phase I

Report," tests for certain steam generators indicate that tube failure can be ex- pected during normal operation if the tube wall thickness is reduced by 85% to 90%

and If the defect is 1-inch long or longer. Likewise, during a steam line break

accident, failure can be expected if wall thickness is reduced by 75% to 80%.