A device has been constructed which mimics the geometry and operating conditions of a tube/tube support plate crevice in a pressurized water reactor (PWR) steam generator. This apparatus is instrumented to measure the tube wall temperature in the crevice, the free span and crevice potentials, and the crevice chemistry. Results have been obtained for 280°C NaOH solutions continuously pumped through the autoclave under several crevice temperature and power levels. Changes in tube wall temperature changes after superheat was applied indicated that various depths in the crevice underwent several thermal-hydraulic transitions before reaching equilibrium conditions. The lower third of the crevice was wetted at equilibrium. Sodium hydroxide concentrated at rates near the theoretical limit until equilibrium was reached at concentration factors in the 104 range.

Subject
Water, Salts, Heaters, Tubes, Thermocouples, Autoclaves, Walls, Steam generators, Crevices, Feedwater, Solutions, Heat, Electrochemical potential
Keywords:
heated crevice, steam generator, hideout, alloy 600, PWR, heat transfer, tubesheet crevice, tube support crevice
© 1996 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).
1996
Association for Materials Protection and Performance (AMPP)
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