Pipe Crack Study Group - Enclosing NUREG-0531 & Notice (Generic Letter 79-14)

GL79014 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

                              March 15, 1979 

ALL POWER REACTOR LICENSEES 

Gentlemen: 

On September 14, 1978, the Nuclear Regulatory Commission established a new 
Pipe Crack Study Group which was to evaluate recent pipe and safe end 
cracking experience relative to previous staff conclusions and 
recommendations. The bases for establishing the new Study Group were (1) the
discovery of cracks in the inner surface of large-diameter austenitic 
stainless steel piping (recirculation lines) in a BWR and (2) questions 
concerning the capability of ultrasonic detection methods to detect small 
cracks. 

The new PCSG reviewed existing information that either was contained in 
written records or had been collected through meetings in this country and 
in foreign countries. The review was in the context of changes occurring 
since the preparation by the original Pipe Cracking Study Group of NUREG-
75/067 "Technical Report -- Investigation and Evaluation of Cracking in 
Austenitic Stainless Steel Piping of Boiling Water Reactor Plants". the 
conclusions and recommendations of the new Pipe Crack Study Group are 
presented in the enclosed "Investigation and Evaluation of Stress Corrosion 
Cracking in Piping of Light Water Reactor Plants", NUREG-0531. This report 
is for your information and comment. Also enclosed is a copy of a related 
Federal Register Notice. 

The NRC staff will review the Study Group report and its 
conclusions/recommendations and any comments received about the report. 
Following this review, the staff will decide what further actions, if any, 
are required for the licensing and operation of reactors. 

                                        Sincerely, 



                                        Brian K. Grimes, Assistant Director 
                                          for Engineering and Projects 
                                        Division of Operating Reactors 

Enclosures:
1.   NUREG-0531
2.   Notice