Highly stressed Alloy 600 is susceptible to intergranular stress corrosion cracking (IGSCC) in high purity water at nuclear steam generator (NSG) operating temperatures. Two regions in recirculating steam generators (RSG) are particularly prone to primary side initiated SCC: tube expansion transitions of the tube in the tubesheet and tight radii tube bends. One remedial measure to ameliorate IGSCC in these regions is to heat the tubes and thus relieve the residual stresses which contribute significantly to the cracking problem. This paper describes a corrosion test program using the accelerated SCC environments of sodium tetrathionate and sodium hydroxide to qualify an in situ stress relief process for the most SCC susceptible U-bends in an RSG.

Subject
Test methods, Intergranular stress corrosion cracking, Heaters, Tubes, Steam generators, Stress cracking, Thermal stress, Stress, Tubing, U bends, Sodium, Alloys, Stress corrosion cracking
© 1988 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1988
Association for Materials Protection and Performance (AMPP)
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