Sleipner A was installed in 1992/93. The seawater piping was made in 6Mo stainless steel with some 25Cr duplex valves. The piping system contained chlorinated seawater. After approx. 18 months in service several leaks were observed in the firewater system due to crevice corrosion in valve components, flange sealing areas and threaded components.

To avoid more leaks it was decided to install internal cathodic protection in both the firewater and seawater systems. In 1996 Resistor controlled Cathodic Protection - RCP was installed using available flanges and fitting access points. This was one of the pilots in the early phase of the Resistor controlled Cathodic Protection system designs. The design gave a range of anode lifetimes from 5 to 30 years. The paper will review 10 years of operational experiences from the Sleipner A & T platforms, from solving some initial problems with the CP system, through historical monitoring data with comparisons between monitoring data and design values and change out of anodes after ended lifetime.

Subject
Voltage drops, Piping, Anode potential, Piping systems, Cathodic protection, Zinc anodes, Flanges, Seawater, Anode resistance, Resistors, Anodic current, Stainless steel, Anodes
Keywords:
Resistor controlled Cathodic Protection, 6Mo stainless steel, chlorinated seawater piping
© 2008 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).
2008
Association for Materials Protection and Performance (AMPP)
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