Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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
