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

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


COMMISSION
NUCLEAR REGULATORY COMMISSION


OFFICE OF INSPECTION
OFFICE OF INSPECTION AND ENFORCEMENT


===AND ENFORCEMENT===
WASHINGTON, D.C. 20555 July 31, 1985 IE INFORMATION NOTICE NO. 85-65:  CRACK GROWTH IN STEAM GENERATOR
WASHINGTON, D.C. 20555 July 31, 1985 IE INFORMATION


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


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


==Purpose==
==Purpose==
: This information
:
This information notice is provided to alert recipients of a potentially


notice is provided to alert recipients
significant problem pertaining to the growth in indications in steam generator


of a potentially
circumferential welds. Ultrasonic examination had determined previously that


significant
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.


problem pertaining
The NRC is continuing to evaluate pertinent information. An additional notifi- cation will be made if specific actions are determined to be required.


to the growth in indications
==Description of Circumstances==
:
In 1982 Indian Point Station Unit 3 had a leak at weld No. 6 on one of their


in steam generator circumferential
steam generators (see Information Notice 82-37). Weld No. 6 is a full- penetration circumferential weld located in the transition zone between


welds. Ultrasonic
the tube bundle and steam dryer areas, below the feedwater nozzles, and


examination
subject to thermal cycling. The crack was started by corrosion and operating


had determined
temperature fluctuations caused it to grow through the wall because of low-cycle


previously
fatigue. The repair method reduced the defects to an acceptable level.


that the welds were acceptable.
Ultrasonic examinations have been performed during outages since 1982 and in


It is suggested
the summer of 1985. Previously known indications that appear to have grown in


that recipients
size are being evaluated.


review the informa-tion for applicability
In 1983 Surry Power Station Unit 2 performed ultrasonic examinations of the


to their facilities
No. 6 welds. The original construction weld at Unit 2 is 6 inches above the


and consider actions, if appropri-ate, to preclude a similar problem occurring
weld that attached the lower portion of all three replacement steam generators


at their facilities.
in 1980 (see attached sketch). The examination showed widespread indications


However, suggestions
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


contained
8507290456


in this information
IN 85-65 July 31, 1985 decided that they were surface blemishes of reflections from weld geometry. In


notice do not constitute
March 1985, an ultrasonic reexamination was performed on the original construc- tion weld at Surry and larger, but acceptable, discontinuities were found in


NRC require-ments; therefore, no specific action or written response is required.The NRC is continuing
the same locations. The inside surface of the weld in generator A was


to evaluate pertinent
visually examined, but no defects were seen. However, when magnetic particle


information.
testing was performed at the request of the NRC, closely spaced linear cracks


An additional
were found over a large portion of the circumference. The appearance of these


notifi-cation will be made if specific actions are determined
cracks was similar to those at Indian Point. The safety significance is that


to be required.Description
substantial loss of secondary coolant could occur without warning if cracking


of Circumstances:
degradation continued undetected.
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
The cracks in generator A were in a narrow band at the upper edge of the weld


circumferential
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


weld located in the transition
examination. Generators B and C had numerous, smaller, circumferential cracks


zone between the tube bundle and steam dryer areas, below the feedwater
in the same location. To complicate matters, there were 10 unacceptable


nozzles, and subject to thermal cycling. The crack was started by corrosion
subsurface indications in generator B, based on the requirements of ASME


and operating temperature
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


fluctuations
three generators were removed by grinding; repair welding was not necessary.


caused it to grow through the wall because of low-cycle fatigue. The repair method reduced the defects to an acceptable
Weld No. 6 was made on-site and had high residual stresses as a result of the


level.Ultrasonic
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


examinations
ions. In addition to internal pressure, this portion of the steam generator


have been performed
has a change in cross-section and undergoes thermal cycling. Heat treatment of


during outages since 1982 and in the summer of 1985. Previously
the nearby replacement weld in 1980 reduced the residual stresses, but could


known indications
not undo any existing damage to the original construction weld. The cracks ran


that appear to have grown in size are being evaluated.
from pit to pit and grew to an unacceptable size in less than one inspection


In 1983 Surry Power Station Unit 2 performed
period.


ultrasonic
At the next outage, the No. 6 welds in all three steam generators at Surry Unit


examinations
2 will be partially examined by magnetic particle testing. The subsurface


of the No. 6 welds. The original construction
indications in generator B also will be examined by ultrasonic methods. Slow


weld at Unit 2 is 6 inches above the weld that attached the lower portion of all three replacement
growing corrosion cracks are irregular in length and depth. When the cracks


steam generators
are located in the fusion line between the weld and the base metal, evaluation


in 1980 (see attached sketch). The examination
is very difficult by ultrasonic methods alone. Magnetic particle testing is


showed widespread
more sensitive than visual examination and supplements ultrasonic examinations


indications
where there is a possibility of surface defects. ASME Section XI specifies the


of discontinuities
maximum allowable planar indications and the methods of examination, but these


on the inside surface of this weld in the "A" steam genera-tor. None of the indications
methods may not be sufficient to identify indications and defects in all cases.


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


of reflections
smaller ultrasonic probes may result in a better understanding of the ultrason- ic indications.


from weld geometry.
IN 85-65 July 31, 1985 No specific action or written response is required by this information notice.


In March 1985, an ultrasonic
If you have any questions about this matter, please contact the Regional


reexamination
Administrator of the appropriate regional office or this office.


was performed
ar L. Jordan Director


on the original construc-tion weld at Surry and larger, but acceptable, discontinuities
Division of Eme gency Preparedness


were found in the same locations.
and Engineering Response


The inside surface of the weld in generator
Office of Inspection and Enforcement


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


at the request of the NRC, closely spaced linear cracks were found over a large portion of the circumference.
===P. Cortland, IE===
                    (301) 492-4175 Attachments:
1. Sketch of Steam Generator


The appearance
2. List of Recently Issued IE Information Notices


of these cracks was similar to those at Indian Point. The safety significance
Attachment 1 IN 85-65 July 31, 1985 Sketch Showing Steam Generator A


is that substantial
ORIGINAL


loss of secondary
CONSTRUCTION


coolant could occur without warning if cracking degradation
_-              WELD N006
                              / 9980 WELD


continued
6 N.                      THAT ATTACHED


undetected.
THE REPLACEMENT


The cracks in generator
STEAM GENERATORS


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


The cracks were as deep as 1/2 inch and were covered by the surface oxide, which obscured detection
Attachment 2 IN 85-65 July 31, 1985 LIST OF RECENTLY ISSUED


by visual examination.
IE INFORMATION NOTICES


Generators
===Information                                  Date of===
Notice No.    Subject                      Issue    Issued to


B and C had numerous, smaller, circumferential
85-64          BBC Brown Boveri Low-Voltage 7/26/85  All power reactor


cracks in the same location.
K-Line Circuit Breakers, With          facilities holding


To complicate
Deficient Overcurrent Trip            an OL or CP
 
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
Devices Models OD-4 and 5
85-63          Potential for Common-Mode    7/25/85  All power reactor


2 IN 85-65 July 31, 1985 LIST OF RECENTLY ISSUED IE INFORMATION
Failure of Standby Gas Treat-         facilities holding


NOTICES Information
ment System on Loss of Off-            an OL or CP


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


K-Line Circuit Breakers, With Deficient
85-62          Backup Telephone Numbers to  7/23/85  All power reactor


Overcurrent
the NRC Operations Center              facilities holding


Trip Devices Models OD-4 and 5 Potential
an OL and certain


for Common-Mode
fuel facilities


Failure of Standby Gas Treat-ment System on Loss of Off-Site Power Backup Telephone
85-61          Misadministrations to Patients 7/22/85 All power reactor


Numbers to the NRC Operations
Undergoing Thyroid Scans              facilities holding


Center 7/26/85 7/25/85 7/23/85 85-62 85-61 85-60 Misadministrations
an OL and certain


to Patients 7/22/85 Undergoing
fuel facilities


Thyroid Scans Defective
85-60          Defective Negative Pressure  7/17/85  All power reactor


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


Valve Stem Corrosion
Respirators                            an OL or CP


Failures 7/17/85 Failure Of A General Electric 7/17/85 Type AK-2-25 Reactor Trip Breaker All power reactor facilities
85-59          Valve Stem Corrosion Failures 7/17/85 All power reactor


holding an OL or CP All power reactor facilities
facilities holding


holding an OL or CP All power reactor facilities
an OL or CP


holding an OL and certain fuel facilities
85-58          Failure Of A General Electric 7/17/85  All power reactor


All power reactor facilities
Type AK-2-25 Reactor Trip              facilities designed


holding an OL and certain fuel facilities
Breaker                                by B&W and CE holding


All power reactor facilities
an OL or CP


holding an OL or CP All power reactor facilities
85-57          Lost Iridium-192 Source      7/16/85  All power reactor


holding an OL or CP All power reactor facilities
Resulting In The Death Of              facilities holding


designed by B&W and CE holding an OL or CP All power reactor facilities
Eight Persons In Morocco              an OL or CP; fuel


holding an OL or CP; fuel facilities;  
facilities; and
and material licensees All power reactor facilities


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


In The Death Of Eight Persons In Morocco Inadequate
85-56          Inadequate Environment        7/15/85  All power reactor


Environment
Control For Components And            facilities holding


Control For Components
Systems In Extended Storage            an OL or CP


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


License CP = Construction
OL = Operating License


Permit}}
CP = Construction Permit}}


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

Latest revision as of 03:39, 24 November 2019

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
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

_- WELD N006

/ 9980 WELD

6 N. THAT ATTACHED

THE REPLACEMENT

STEAM GENERATORS

V,

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 BBC Brown Boveri Low-Voltage 7/26/85 All power reactor

K-Line Circuit Breakers, With facilities holding

Deficient Overcurrent Trip an OL or CP

Devices Models OD-4 and 5

85-63 Potential for Common-Mode 7/25/85 All power reactor

Failure of Standby Gas Treat- facilities holding

ment System on Loss of Off- an OL or CP

Site Power

85-62 Backup Telephone Numbers to 7/23/85 All power reactor

the NRC Operations Center facilities holding

an OL and certain

fuel facilities

85-61 Misadministrations to Patients 7/22/85 All power reactor

Undergoing Thyroid Scans facilities holding

an OL and certain

fuel facilities

85-60 Defective Negative Pressure 7/17/85 All power reactor

Air-Purifying, Fuel Facepiece facilities holding

Respirators an OL or CP

85-59 Valve Stem Corrosion Failures 7/17/85 All power reactor

facilities holding

an OL or CP

85-58 Failure Of A General Electric 7/17/85 All power reactor

Type AK-2-25 Reactor Trip facilities designed

Breaker by B&W and CE holding

an OL or CP

85-57 Lost Iridium-192 Source 7/16/85 All power reactor

Resulting In The Death Of facilities holding

Eight Persons In Morocco an OL or CP; fuel

facilities; and

material licensees

85-56 Inadequate Environment 7/15/85 All power reactor

Control For Components And facilities holding

Systems In Extended Storage an OL or CP

Or Layup

OL = Operating License

CP = Construction Permit


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