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Home My WebLink About851188.tiff SSINS No. : 6835 IN 85-69V(Ip COUNTY Cn�tt^Prnrrap UNITED STATES � ^ NUCLEAR REGULATORY COMMISSION ('fr OFFICE INSPECTION ENFORCEMENT C AUU 1 WASHINGTON, D.C. 20555 3 198s 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 851188 1,r1 m-cq Afiaix5 IN 85-65 July 31, 1985 Page 2 of 3 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 Page 3 of 3 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. dward 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 Page 1 of 1 Sketch Showing Steam Generator A ORIGINAL CONSTRUCTION WELD N006 1980 WELD THAT ATTACHED 6i "' 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 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 pr .,i,SS•\�1"�E'�S "'='11 ct SSINS No. : 6835 IN 85-62 t 205 ESA�$ _ UNITED - NUCLEAR REGULATORYTCOMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 July 23, 1985 IE INFORMATION NOTICE NO. :85-62: BACKUP TELEPHONE NUMBERS TO THE NRC OPERATIONS CENTER Addressees: All nuclear power reactor facilities holding an operating license and certain fuel facilities. Purpose: This notice is being issued to inform licensees of commercial telephone numbers for the NRC Operations Center which are to be used as backup to the Emergency Notification System and the Health Physics Network. It is expected that recipients will review the information and forward to cognizant individuals for review and appropriate use. Suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: The following commercial telephone numbers for the NRC Operations Center are available for event and emergency notification whenever the Emergency Notifica- tion System or the Health Physics Network is inoperable. 301-951-0550* 301-427-4056 301-427-4259 301-492-8893 * Reported previously as area code 202; however, either area code can be used at the present time. To ensure that the backup telephone numbers are made available when needed, telephone stickers with the backup telephone numbers have been provided for your convenience to attach to the telephones for Emergency Notification System and Health Physics Network. 8507220280 Li nn 7 u ghY�85 IN 85-62 July 23, 1985 Page 2 of 2 No specific action or written response is required by this information notice. If you have any questions regarding this matter, please contact the Regional Administrator of the appropriate NRC regional office or the NRC Headquarters incident response contacts listed in this notice. /�G�ar� Jordan, Director Divisio f Emergency Preparedness and E ineering Response Office of Inspection and Enforcement Technical Contacts: Don Marksberry, IE (301) 492-4156 Ray Priebe, IE (301) 492-4333 Attachment: List of Recently Issued Information Notices Attachment IN 85-62 July 23, 1985 LIST OF RECENTLY ISSUED IE INFORMATION NOTICES Information Date of Notice No. Subject Issue Issued to 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 85-55 Revised Emergency Exercise 7/15/85 All power reactor Frequency Rule facilities holding an OL or CP 85-54 Teletheraphy Unit Malfunction 7/15/85 All NRC licensees authorized to use teletheraphy units 85-53 Performance Of NRC-Licensed 7/12/85 All power reactor Individuals While On Duty facilities holding an OL or CP OL = Operating License CP = Construction Permit Hello