Information Notice No. 82-37: Cracking in the Upper Shell to Transition Cone Girth Weld of a Steam Generator at anOperating Pressurized Water Reactor

                                                            SSINS No.: 6835 
                                                            IN 82-37 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                          WASHINGTON, D. C. 20555 

                             September 16, 1982 

Information Notice No. 82-37:   CRACKING IN THE UPPER SHELL TO TRANSITION
                                   CONE GIRTH WELD OF A STEAM GENERATOR AT 
                                   AN  OPERATING PRESSURIZED WATER REACTOR 

Addressees: 

All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP). 

Purpose: 

This information notice provides early notification of a potentially 
significant problem with the upper shell to transition cone girth welds in 
the steam generator at an operating pressurized water reactor (PWR). The 
potential safety significance of this problem is still under review by the 
Nuclear Regulatory Commission (NRC) staff. If NRC evaluation so indicates, 
further licensee action may be requested. In the interim, the staff expects 
licensees to review the information herein for applicability to their 
facilities. No specific action or response is required at this time. 

Description of Circumstances: 

The Power Authority of the State of New York (PASNY) reported that, while 
Indian Point 3 was shut down for refueling in the spring of 1982, a leak was
observed in the upper shell to transition cone girth weld of steam generator
#32. Subsequent ultrasonic examinations of these welds on all four steam 
generators revealed that each generator had extensive indications of 
cracking. There was an average of 170 indications per steam generator, 
typically 3/4-inches deep by 4 to 6 inches long. One through-wall 
penetration was observed in steam generator #32. PASNY examined selected 
sections of other steam generator welds in accordance with inservice 
inspection requirements and found no other reportable indications. 

The upper shell to transition cone weld is a difficult final closure weld. 
It had a local post weld heat treatment rather than a furnace post weld heat
treatment. It is located just below the feedwater ring in the normal 
operating water level zone where it may be subjected to thermal cycling. 
This condition may be generic to all Westinghouse plants. The cracks have no
apparent geometrical correlation with the configuration of the feedwater 
ring. Although there is a slight tendency for cracks to cluster near large 
weld repairs, most cracks do not occur at weld repairs. Nearly 40% of the 
cracks are reported to, occur in weld metal. This weld was made by the 
submerged arc welding (SAW) process from the outside with the root 
backgouged and welded with the shielded metal arc welding (SMAW) process 
using 8018-C3 electrodes. No reportable indications were found in a 1978 
ultrasonic inspection of 3 feet of this weld. 

8208190220  
.

                                                      IN 82-37  
                                                      September 16, 1982  
                                                      Page 2 of 2 

A preliminary metallurgical evaluation of boat samples containing cracks 
from steam generator #32 has tentatively established certain elements of the
cracking to be characteristic of corrosion-fatigue. A full cross-section of 
the shell containing the leaking crack is currently being examined to 
further determine other possible causes that may have contributed to the 
cracking. 

The Indian Point Unit 3 steam generators have experienced both fabrication 
and operational problems that may have accelerated the initiation and 
propagation of cracks. In regard to fabrication, the affected welds were 
subject to numerous weld repairs, after which a post weld heat treatment was
performed locally rather than being given a furnace heat treatment to 
achieve the desired tempering and stress relief. In regard to operation, a 
long history of condenser events resulted in poor oxygen control. In January 
1981, a turbine blade failed and fragments entered the condenser causing a 
massive intrusion of chlorides reaching 325 ppm. To date, the synergistic 
conditions that were primarily responsible for the cracking remain to be 
firmly established. 

If you have any questions regarding this matter, please contact the 
Administrator of the appropriate Regional Office, or this office. 



                              Edward Jordan, Director 
                              Division of Engineering and 
                                Quality Assurance 
                              Office of Inspection and Enforcement 

Technical Contact:  M. S. Wegner 
                    301-492-4511 

Attachment: 
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