In addition to controlling the intergranular stress corrosion cracking (IGSCC) of the recirculation piping of a boiling water reactor (BWR), hydrogen water chemistry (HWC) has been shown to offer protection of IGSCC-susceptible reactor internals and vessel attachments in selected regions. The Monticello BWR Nuclear Generating Plant of the Northern States Power Company recently began measuring the degree of protection provided by HWC to those components in the lower plenum region of their reactor vessel. To this end, during Monticello’s spring 1991 refueling outage, an electrochemical potential (ECP) monitoring apparatus was installed in the vessel’s bottom head drain line.

IGSCC preventative actions at Monticello are summarized and the chronology of HWC is reviewed. Ongoing efforts to resolve measurement difficulties experienced with the monitoring system’s reference electrodes are discussed. HWC effects on the ECP of the reactor lower plenum region materials and on shutdown radiation dose rates are presented.

Subject
Water, Boiling water reactors, Hydrogen concentration, Recirculation, Reactors, Hydrogen peroxide, Reference electrodes, Water chemistry, Platinum, Stainless steel, Electrodes, Electrode potential, Hydrogen
© 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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