An oxidizing biocide and an organic biodispersant-penetrant were simultaneously injected into the safe-shutdown cooling systems at the Clinton Nuclear Power Station to mitigate microbiologically influenced corrosion (MIC) of system piping and heat exchangers. The residual oxidizing power remaining as the treated water left the station was removed by the injection of a reducing agent prior to discharge of the cooling waters to the environment. A visual inspection and microbiological culturing of post-treatment samples from the pipe surfaces indicated that the chemical treatment was successful. Follow-up treatment using the same chemicals six to nine months later proved less successful as a residual oxidant was not detected in some systems due to oxidant demand. Within one month of the second treatment, tubes in four emergency diesel generator heat exchangers failed after only fourteen months in service. The suspected contributing factors to the failure of the tubes in these heat exchangers are microbioligally influenced corrosion, biofouling and underdeposit corrosion.

Subject
Acids, Water, Piping, Tubes, Tubercles, Engines, Oxidants, Heat exchangers, Sodium, Treatment chemicals, Generators, Microbiologically influenced corrosion, Samples
Keywords:
biofouling, MIC, biocide, biodispersant, penetrant, pitting, heat exchanger 90-10 copper/nickel
© 1992 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).
1992
Association for Materials Protection and Performance (AMPP)
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