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Corrosion of SG Tube Alloys in Typical Secondary Side Local Chemistries Derived from Operating Experience

  • Ian de CurieresEmail author
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

In spite of strong industry improvements (new alloys, more stringent chemistry control…), Outer Diameter Stress Corrosion Cracking (ODSCC) still occurs in modern SG alloys, although at a lesser extent than it used to affect 600MA tubes . Currently, alloy 600TT, and even 800NG, do indeed suffer from ODSCC. Since the chemistry of the secondary side of PWR NPPs improved, past tests do not enable to assess simply the risks for modern alloys (too extreme pH for instance). Thus, IRSN reviewed what typical chemical conditions could be met in actual steam generators. Based on this review, IRSN performed corrosion tests in these conditions to assess the potential risks for alloys 600TT and 690TT in “typical” top-of-tubesheet environments. This paper will present the safety, technical and industrial frames of these tests, as well as the first results. An emphasis will also be put on the scientific implications of these results.

Keywords

Steam generators Tubes Corrosion Secondary side Lead Sulphur 

Acronyms

ODSCC

Outer diameter stress corrosion cracking

SCC

Stress corrosion cracking

IGA

Inter granular attack

SG

Steam generator

MA

Mill-annealed

SN

Sensitized

TT

Thermally treated

AVT

All volatile treatment

RUB

Reversed U-bend

FIB

Focused ion beam

HOR

Hide-out-return

pHT

High temperature pH

GC

Generalized corrosion

LME

Liquid metal embrittlement

Notes

Acknowledgements

IRSN would like to thank the AREVA Technical Center in le Creusot who performed the tests and analyses.

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Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  1. 1.IRSNFontenay-aux-RosesFrance

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