This paper summarizes the structural materials used in light water reactors (LWRs), their historical degradation evolution vs. time, improvements and subsequent vulnerabilities discovered, and possible future degradation phenomena over long-term operation. Little was known about high temperature water environments 50+ years ago, and reasonable but inadequate judgments were made on structural materials based partly on simple, short term tests and partly on intuition of low temperature corrosion phenomena. A steady evolution and improvement in structural materials occurred, especially over the first twenty years of LWR experience. Degradation continues and is managed by a combination of inspection, mitigation and replacement, although concerns for surprises remains because of declining expertise, funding and historical conservatism. Materials of higher resistance undoubtedly exist, and some examples are discussed. New forms of degradation and aging synergies that accelerate the kinetics of known degradation phenomena are considered.

Subject
Crack growth, Water, Materials, Stainless alloys, Boiling water reactors, Nickel based alloys, Stress cracking, Stainless steel, Alloys, Immunity, Weld metal, Stress corrosion cracking, Residual stress
Keywords:
Stress corrosion cracking, light water reactors, structural materials, welds, water chemistry, extended plant life
© 2012 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).
2012
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.