Information Notice 1985-65, Crack Growth in Steam Generator Girth Welds: Difference between revisions

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{{#Wiki_filter:SSINS No.: 6835IN 85-65UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555July 31, 1985IE INFORMATION NOTICE NO. 85-65: CRACK GROWTH IN STEAM GENERATORGIRTH WELDS
{{#Wiki_filter:SSINS No.: 6835 IN 85-65 UNITED STATES NUCLEAR REGULATORY
 
COMMISSION
 
OFFICE OF INSPECTION
 
===AND ENFORCEMENT===
WASHINGTON, D.C. 20555 July 31, 1985 IE INFORMATION
 
NOTICE NO. 85-65: CRACK GROWTH IN STEAM GENERATOR GIRTH WELDS


==Addressees==
==Addressees==
:All nuclear power pressurized water reactor (PWR) facilities holding an operat-ing license (OL) or a construction permit (CP).
:
All nuclear power pressurized
 
water reactor (PWR) facilities
 
holding an operat-ing license (OL) or a construction
 
permit (CP).


==Purpose==
==Purpose==
:This information notice is provided to alert recipients of a potentiallysignificant problem pertaining to the growth in indications in steam generatorcircumferential welds. Ultrasonic examination had determined previously thatthe welds were acceptable. It is suggested that recipients review the informa-tion for applicability to their facilities and consider actions, if appropri-ate, to preclude a similar problem occurring at their facilities. However,suggestions contained in this information notice do not constitute NRC require-ments; therefore, no specific action or written response is required.The NRC is continuing to evaluate pertinent information. An additional notifi-cation will be made if specific actions are determined to be required.
: This information
 
notice is provided to alert recipients
 
of a potentially
 
significant
 
problem pertaining
 
to the growth in indications
 
in steam generator circumferential
 
welds. Ultrasonic
 
examination
 
had determined
 
previously
 
that the welds were acceptable.
 
It is suggested
 
that recipients
 
review the informa-tion for applicability
 
to their facilities
 
and consider actions, if appropri-ate, to preclude a similar problem occurring
 
at their facilities.
 
However, suggestions
 
contained
 
in this information
 
notice do not constitute
 
NRC require-ments; therefore, no specific action or written response is required.The NRC is continuing
 
to evaluate pertinent
 
information.
 
An additional
 
notifi-cation will be made if specific actions are determined
 
to be required.Description
 
of Circumstances:
In 1982 Indian Point Station Unit 3 had a leak at weld No. 6 on one of their steam generators (see Information
 
Notice 82-37). Weld No. 6 is a full-penetration
 
circumferential
 
weld located in the transition
 
zone between the tube bundle and steam dryer areas, below the feedwater
 
nozzles, and subject to thermal cycling. The crack was started by corrosion
 
and operating temperature
 
fluctuations
 
caused it to grow through the wall because of low-cycle fatigue. The repair method reduced the defects to an acceptable
 
level.Ultrasonic
 
examinations
 
have been performed
 
during outages since 1982 and in the summer of 1985. Previously
 
known indications
 
that appear to have grown in size are being evaluated.
 
In 1983 Surry Power Station Unit 2 performed
 
ultrasonic
 
examinations
 
of the No. 6 welds. The original construction
 
weld at Unit 2 is 6 inches above the weld that attached the lower portion of all three replacement
 
steam generators
 
in 1980 (see attached sketch). The examination
 
showed widespread
 
indications
 
of discontinuities
 
on the inside surface of this weld in the "A" steam genera-tor. None of the indications
 
seemed large enough to be rejected and it was 8507290456 IN 85-65 July 31, 1985 decided that they were surface blemishes
 
of reflections
 
from weld geometry.
 
In March 1985, an ultrasonic
 
reexamination
 
was performed
 
on the original construc-tion weld at Surry and larger, but acceptable, discontinuities
 
were found in the same locations.
 
The inside surface of the weld in generator
 
A was visually examined, but no defects were seen. However, when magnetic particle testing was performed
 
at the request of the NRC, closely spaced linear cracks were found over a large portion of the circumference.
 
The appearance
 
of these cracks was similar to those at Indian Point. The safety significance
 
is that substantial
 
loss of secondary
 
coolant could occur without warning if cracking degradation
 
continued
 
undetected.
 
The cracks in generator
 
A were in a narrow band at the upper edge of the weld and covered almost the entire inside diameter.
 
The cracks were as deep as 1/2 inch and were covered by the surface oxide, which obscured detection
 
by visual examination.
 
Generators
 
B and C had numerous, smaller, circumferential
 
cracks in the same location.
 
To complicate
 
matters, there were 10 unacceptable
 
subsurface
 
indications
 
in generator
 
B, based on the requirements
 
of ASME Section XI, IWB-3511.
 
After a fracture and fatigue evaluation, these subsur-face indications
 
were accepted by ASME IWB-3600.
 
The surface cracks in all three generators
 
were removed by grinding;
repair welding was not necessary.
 
Weld No. 6 was made on-site and had high residual stresses as a result of the low preheat and postweld heat treatment
 
temperatures.
 
The steel in the vicini-ty of the weld pitted when the secondary
 
water contained
 
high oxygen concen-trations (higher than 25 ppb) and contaminants
 
such as chlorides
 
and copper ions. In addition to internal pressure, this portion of the steam generator has a change in cross-section
 
and undergoes
 
thermal cycling. Heat treatment
 
of the nearby replacement
 
weld in 1980 reduced the residual stresses, but could not undo any existing damage to the original construction
 
weld. The cracks ran from pit to pit and grew to an unacceptable
 
size in less than one inspection
 
period.At the next outage, the No. 6 welds in all three steam generators
 
at Surry Unit 2 will be partially
 
examined by magnetic particle testing. The subsurface
 
indications
 
in generator
 
B also will be examined by ultrasonic
 
methods. Slow growing corrosion
 
cracks are irregular
 
in length and depth. When the cracks are located in the fusion line between the weld and the base metal, evaluation
 
is very difficult
 
by ultrasonic
 
methods alone. Magnetic particle testing is more sensitive
 
than visual examination
 
and supplements
 
ultrasonic
 
examinations
 
where there is a possibility
 
of surface defects. ASME Section XI specifies
 
the maximum allowable
 
planar indications
 
and the methods of examination, but these methods may not be sufficient
 
to identify indications
 
and defects in all cases.Additional
 
surface preparation, calibration
 
notches, personnel
 
training, and smaller ultrasonic
 
probes may result in a better understanding
 
of the ultrason-ic indications.
 
IN 85-65 July 31, 1985 No specific action or written response is required by this information
 
notice.If you have any questions
 
about this matter, please contact the Regional Administrator
 
of the appropriate
 
regional office or this office.ar L. Jordan Director Division of Eme gency Preparedness
 
and Engineering
 
Response Office of Inspection
 
and Enforcement
 
Technical
 
Contact: P. Cortland, IE (301) 492-4175 Attachments:
1. Sketch of Steam Generator 2. List of Recently Issued IE Information
 
Notices
 
Attachment
 
1 IN 85-65 July 31, 1985 Sketch Showing Steam Generator
 
===A ORIGINAL CONSTRUCTION===
6 N._- WELD N0 0 6/ 9980 WELD THAT ATTACHED THE REPLACEMENT
 
STEAM GENERATORS
 
Attachment
 
2 IN 85-65 July 31, 1985 LIST OF RECENTLY ISSUED IE INFORMATION
 
NOTICES Information
 
Date of Notice No. Subject Issue Issued to 85-64 85-63 BBC Brown Boveri Low-Voltage
 
K-Line Circuit Breakers, With Deficient
 
Overcurrent
 
Trip Devices Models OD-4 and 5 Potential
 
for Common-Mode
 
Failure of Standby Gas Treat-ment System on Loss of Off-Site Power Backup Telephone
 
Numbers to the NRC Operations
 
Center 7/26/85 7/25/85 7/23/85 85-62 85-61 85-60 Misadministrations
 
to Patients 7/22/85 Undergoing
 
Thyroid Scans Defective
 
Negative Pressure 7/17/85 Air-Purifying, Fuel Facepiece Respirators
 
Valve Stem Corrosion
 
Failures 7/17/85 Failure Of A General Electric 7/17/85 Type AK-2-25 Reactor Trip Breaker All power reactor facilities
 
holding an OL or CP All power reactor facilities
 
holding an OL or CP All power reactor facilities
 
holding an OL and certain fuel facilities
 
All power reactor facilities
 
holding an OL and certain fuel facilities
 
All power reactor facilities
 
holding an OL or CP All power reactor facilities
 
holding an OL or CP All power reactor facilities
 
designed by B&W and CE holding an OL or CP All power reactor facilities
 
holding an OL or CP; fuel facilities;
and material licensees All power reactor facilities
 
holding an OL or CP 85-59 85-58 85-57 Lost Iridium-192 Source Resulting


==Description of Circumstances==
In The Death Of Eight Persons In Morocco Inadequate
:In 1982 Indian Point Station Unit 3 had a leak at weld No. 6 on one of theirsteam generators (see Information Notice 82-37). Weld No. 6 is a full-penetration circumferential weld located in the transition zone betweenthe tube bundle and steam dryer areas, below the feedwater nozzles, andsubject to thermal cycling. The crack was started by corrosion and operatingtemperature fluctuations caused it to grow through the wall because of low-cyclefatigue. The repair method reduced the defects to an acceptable level.Ultrasonic examinations have been performed during outages since 1982 and inthe summer of 1985. Previously known indications that appear to have grown insize are being evaluated.In 1983 Surry Power Station Unit 2 performed ultrasonic examinations of theNo. 6 welds. The original construction weld at Unit 2 is 6 inches above theweld that attached the lower portion of all three replacement steam generatorsin 1980 (see attached sketch). The examination showed widespread indicationsof discontinuities on the inside surface of this weld in the "A" steam genera-tor. None of the indications seemed large enough to be rejected and it was8507290456 IN 85-65July 31, 1985 decided that they were surface blemishes of reflections from weld geometry. InMarch 1985, an ultrasonic reexamination was performed on the original construc-tion weld at Surry and larger, but acceptable, discontinuities were found inthe same locations. The inside surface of the weld in generator A wasvisually examined, but no defects were seen. However, when magnetic particletesting was performed at the request of the NRC, closely spaced linear crackswere found over a large portion of the circumference. The appearance of thesecracks was similar to those at Indian Point. The safety significance is thatsubstantial loss of secondary coolant could occur without warning if crackingdegradation continued undetected.The cracks in generator A were in a narrow band at the upper edge of the weldand covered almost the entire inside diameter. The cracks were as deep as 1/2inch and were covered by the surface oxide, which obscured detection by visualexamination. Generators B and C had numerous, smaller, circumferential cracksin the same location. To complicate matters, there were 10 unacceptablesubsurface indications in generator B, based on the requirements of ASMESection XI, IWB-3511. After a fracture and fatigue evaluation, these subsur-face indications were accepted by ASME IWB-3600. The surface cracks in allthree generators were removed by grinding; repair welding was not necessary.Weld No. 6 was made on-site and had high residual stresses as a result of thelow preheat and postweld heat treatment temperatures. The steel in the vicini-ty of the weld pitted when the secondary water contained high oxygen concen-trations (higher than 25 ppb) and contaminants such as chlorides and copperions. In addition to internal pressure, this portion of the steam generatorhas a change in cross-section and undergoes thermal cycling. Heat treatment ofthe nearby replacement weld in 1980 reduced the residual stresses, but couldnot undo any existing damage to the original construction weld. The cracks ranfrom pit to pit and grew to an unacceptable size in less than one inspectionperiod.At the next outage, the No. 6 welds in all three steam generators at Surry Unit2 will be partially examined by magnetic particle testing. The subsurfaceindications in generator B also will be examined by ultrasonic methods. Slowgrowing corrosion cracks are irregular in length and depth. When the cracksare located in the fusion line between the weld and the base metal, evaluationis very difficult by ultrasonic methods alone. Magnetic particle testing ismore sensitive than visual examination and supplements ultrasonic examinationswhere there is a possibility of surface defects. ASME Section XI specifies themaximum allowable planar indications and the methods of examination, but thesemethods may not be sufficient to identify indications and defects in all cases.Additional surface preparation, calibration notches, personnel training, andsmaller ultrasonic probes may result in a better understanding of the ultrason-ic indications.


IN 85-65July 31, 1985 No specific action or written response is required by this information notice.If you have any questions about this matter, please contact the RegionalAdministrator of the appropriate regional office or this office.ar L. Jordan DirectorDivision of Eme gency Preparednessand Engineering ResponseOffice of Inspection and Enforcement
Environment


===Technical Contact:===
Control For Components
P. Cortland, IE(301) 492-4175Attachments:1. Sketch of Steam Generator2. List of Recently Issued IE Information Notices


Attachment 1IN 85-65July 31, 1985 Sketch Showing Steam Generator AORIGINALCONSTRUCTION6 N._- WELDN006/ 9980WELDTHAT ATTACHEDTHE REPLACEMENTSTEAM GENERATORS
And Systems In Extended Storage Or Layup 7/16/85 7/15/85 85-56 OL = Operating


Attachment 2IN 85-65July 31, 1985LIST OF RECENTLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to85-6485-63BBC Brown Boveri Low-VoltageK-Line Circuit Breakers, WithDeficient Overcurrent TripDevices Models OD-4 and 5Potential for Common-ModeFailure of Standby Gas Treat-ment System on Loss of Off-Site PowerBackup Telephone Numbers tothe NRC Operations Center7/26/857/25/857/23/8585-6285-6185-60Misadministrations to Patients 7/22/85Undergoing Thyroid ScansDefective Negative Pressure 7/17/85Air-Purifying, Fuel FacepieceRespiratorsValve Stem Corrosion Failures 7/17/85Failure Of A General Electric 7/17/85Type AK-2-25 Reactor TripBreakerAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL and certainfuel facilitiesAll power reactorfacilities holdingan OL and certainfuel facilitiesAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities designedby B&W and CE holdingan OL or CPAll power reactorfacilities holdingan OL or CP; fuelfacilities; andmaterial licenseesAll power reactorfacilities holdingan OL or CP85-5985-5885-57Lost Iridium-192 SourceResulting In The Death OfEight Persons In MoroccoInadequate EnvironmentControl For Components AndSystems In Extended StorageOr Layup7/16/857/15/8585-56OL = Operating LicenseCP = Construction Permit
License CP = Construction


}}
Permit}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Revision as of 13:21, 31 August 2018

Crack Growth in Steam Generator Girth Welds
ML031180225
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, 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, 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, Skagit, Marble Hill
Issue date: 07/31/1985
From: Jordan E L
NRC/IE
To:
References
IN-85-065, NUDOCS 8507290456
Download: ML031180225 (5)
v • d • e


SSINS No.: 6835 IN 85-65 UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF INSPECTION

AND ENFORCEMENT

WASHINGTON, D.C. 20555 July 31, 1985 IE INFORMATION

NOTICE NO. 85-65: CRACK GROWTH IN STEAM GENERATOR GIRTH WELDS

Addressees

All nuclear power pressurized

water reactor (PWR) facilities

holding an operat-ing license (OL) or a construction

permit (CP).

Purpose

This information

notice is provided to alert recipients

of a potentially

significant

problem pertaining

to the growth in indications

in steam generator circumferential

welds. Ultrasonic

examination

had determined

previously

that the welds were acceptable.

It is suggested

that recipients

review the informa-tion for applicability

to their facilities

and consider actions, if appropri-ate, to preclude a similar problem occurring

at their facilities.

However, suggestions

contained

in this information

notice do not constitute

NRC require-ments; therefore, no specific action or written response is required.The NRC is continuing

to evaluate pertinent

information.

An additional

notifi-cation will be made if specific actions are determined

to be required.Description

of Circumstances:

In 1982 Indian Point Station Unit 3 had a leak at weld No. 6 on one of their steam generators (see Information

Notice 82-37). Weld No. 6 is a full-penetration

circumferential

weld located in the transition

zone between the tube bundle and steam dryer areas, below the feedwater

nozzles, and subject to thermal cycling. The crack was started by corrosion

and operating temperature

fluctuations

caused it to grow through the wall because of low-cycle fatigue. The repair method reduced the defects to an acceptable

level.Ultrasonic

examinations

have been performed

during outages since 1982 and in the summer of 1985. Previously

known indications

that appear to have grown in size are being evaluated.

In 1983 Surry Power Station Unit 2 performed

ultrasonic

examinations

of the No. 6 welds. The original construction

weld at Unit 2 is 6 inches above the weld that attached the lower portion of all three replacement

steam generators

in 1980 (see attached sketch). The examination

showed widespread

indications

of discontinuities

on the inside surface of this weld in the "A" steam genera-tor. None of the indications

seemed large enough to be rejected and it was 8507290456 IN 85-65 July 31, 1985 decided that they were surface blemishes

of reflections

from weld geometry.

In March 1985, an ultrasonic

reexamination

was performed

on the original construc-tion weld at Surry and larger, but acceptable, discontinuities

were found in the same locations.

The inside surface of the weld in generator

A was visually examined, but no defects were seen. However, when magnetic particle testing was performed

at the request of the NRC, closely spaced linear cracks were found over a large portion of the circumference.

The appearance

of these cracks was similar to those at Indian Point. The safety significance

is that substantial

loss of secondary

coolant could occur without warning if cracking degradation

continued

undetected.

The cracks in generator

A were in a narrow band at the upper edge of the weld and covered almost the entire inside diameter.

The cracks were as deep as 1/2 inch and were covered by the surface oxide, which obscured detection

by visual examination.

Generators

B and C had numerous, smaller, circumferential

cracks in the same location.

To complicate

matters, there were 10 unacceptable

subsurface

indications

in generator

B, based on the requirements

of ASME Section XI, IWB-3511.

After a fracture and fatigue evaluation, these subsur-face indications

were accepted by ASME IWB-3600.

The surface cracks in all three generators

were removed by grinding;

repair welding was not necessary.

Weld No. 6 was made on-site and had high residual stresses as a result of the low preheat and postweld heat treatment

temperatures.

The steel in the vicini-ty of the weld pitted when the secondary

water contained

high oxygen concen-trations (higher than 25 ppb) and contaminants

such as chlorides

and copper ions. In addition to internal pressure, this portion of the steam generator has a change in cross-section

and undergoes

thermal cycling. Heat treatment

of the nearby replacement

weld in 1980 reduced the residual stresses, but could not undo any existing damage to the original construction

weld. The cracks ran from pit to pit and grew to an unacceptable

size in less than one inspection

period.At the next outage, the No. 6 welds in all three steam generators

at Surry Unit 2 will be partially

examined by magnetic particle testing. The subsurface

indications

in generator

B also will be examined by ultrasonic

methods. Slow growing corrosion

cracks are irregular

in length and depth. When the cracks are located in the fusion line between the weld and the base metal, evaluation

is very difficult

by ultrasonic

methods alone. Magnetic particle testing is more sensitive

than visual examination

and supplements

ultrasonic

examinations

where there is a possibility

of surface defects. ASME Section XI specifies

the maximum allowable

planar indications

and the methods of examination, but these methods may not be sufficient

to identify indications

and defects in all cases.Additional

surface preparation, calibration

notches, personnel

training, and smaller ultrasonic

probes may result in a better understanding

of the ultrason-ic indications.

IN 85-65 July 31, 1985 No specific action or written response is required by this information

notice.If you have any questions

about this matter, please contact the Regional Administrator

of the appropriate

regional office or this office.ar L. Jordan Director Division of Eme gency Preparedness

and Engineering

Response Office of Inspection

and Enforcement

Technical

Contact: P. Cortland, IE (301) 492-4175 Attachments:

1. Sketch of Steam Generator 2. List of Recently Issued IE Information

Notices

Attachment

1 IN 85-65 July 31, 1985 Sketch Showing Steam Generator

A ORIGINAL CONSTRUCTION

6 N._- WELD N0 0 6/ 9980 WELD THAT ATTACHED THE REPLACEMENT

STEAM GENERATORS

Attachment

2 IN 85-65 July 31, 1985 LIST OF RECENTLY ISSUED IE INFORMATION

NOTICES Information

Date of Notice No. Subject Issue Issued to 85-64 85-63 BBC Brown Boveri Low-Voltage

K-Line Circuit Breakers, With Deficient

Overcurrent

Trip Devices Models OD-4 and 5 Potential

for Common-Mode

Failure of Standby Gas Treat-ment System on Loss of Off-Site Power Backup Telephone

Numbers to the NRC Operations

Center 7/26/85 7/25/85 7/23/85 85-62 85-61 85-60 Misadministrations

to Patients 7/22/85 Undergoing

Thyroid Scans Defective

Negative Pressure 7/17/85 Air-Purifying, Fuel Facepiece Respirators

Valve Stem Corrosion

Failures 7/17/85 Failure Of A General Electric 7/17/85 Type AK-2-25 Reactor Trip Breaker All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL and certain fuel facilities

All power reactor facilities

holding an OL and certain fuel facilities

All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

designed by B&W and CE holding an OL or CP All power reactor facilities

holding an OL or CP; fuel facilities;

and material licensees All power reactor facilities

holding an OL or CP 85-59 85-58 85-57 Lost Iridium-192 Source Resulting

In The Death Of Eight Persons In Morocco Inadequate

Environment

Control For Components

And Systems In Extended Storage Or Layup 7/16/85 7/15/85 85-56 OL = Operating

License CP = Construction

Permit


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