ML19308B792
| ML19308B792 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/14/1975 |
| From: | Kerr W Advisory Committee on Reactor Safeguards |
| To: | Anders W NRC COMMISSION (OCM) |
| Shared Package | |
| ML19308B790 | List: |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001170316 | |
| Download: ML19308B792 (1) | |
Text
mv NUCt. EAR REGLit.ATORY COMMISSION g
WASHINGTON, D. C.,20535 Februcry 14, 1975 l
l l
Honorable Willias A. Anders i
l Chairman U. S. Nuclear Regulatory Commission Washington, D. C.'20555
Subject:
CRACK PROPAGATION RATE IN SENSITIZED STAINLESS STEEL
Dear Mr. Anders:
~~
Your letter of February 12, 1975 requested that tha Advisory Committea cn Reactor Safeguards supplement the description of ~ rapid in the context of crack propagation rate discussed in the ACRS " Report on Cracking in Boiling Water Reactor Piping" of February 8,1975.
The term rapid rate of crack propagation cited in the ACRS letter in used in the context of a total anticipated design life of about 40 years. Failures, such as leaks, which occur in a tima period of 100 to 1000 days after crack initiation in components, such as bypass loops, are considered rapid. At the lou calculated loads in the 4" bypass piping there vill be an additional period of tima for the crack to grow to a size that would result in abrupt failure dua to crack instability. However, this period is difficult to predict quantitatively due to the several variables involved which are not well defined under all conditions.
l Sincerely,
(,,.0J\\p W. Kerr
?'
Chairman l
=
o O
e b
800117,0 3II
.__,,om
< MW, (~Q1#,QUn%J,.
' bef W T4Te iwS W Y "F"" I P D * *' #TN '4'
-+---M--
l
_ _ _ _ _ _ _ - _ _ _.