Influence of chloride ions on the pitting corrosion of candidate HLW overpack materials in synthetic oxidized boom clay water

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20002568

Druyts, F; Kursten, B

The corrosion behavior under repository conditions is an important issue in the selection of a container material for the deep-geological disposal of high-level nuclear waste. In considering corrosion resistant materials for the containers, attention has to be focused on localized corrosion. Therefore, cyclic potentiodynamic polarization measurements were used to investigate the pitting behavior of a number of candidate materials, including stainless steels AISI 316L, AISI 316L hMo, AISI 316Ti, higher alloyed stainless steels UNS N08904 and UNS N08926, nickel alloy UNS N96455, and titanium alloy UNS R52400. The environment considered was synthetic oxidized Boom clay water at a temperature of 90 C and with varying chloride content. UNS N96455 and UNS R52400 did not show any pitting corrosion at chloride concentrations up to 10,000 ppm. UNS N08926 was resistant to pitting at 100 and 1,000 ppm Cl{sup {minus}}. The other alloys suffered minor or no pitting attack in the reference solution containing 100 ppm chloride, but were attacked at elevated chloride concentrations. A SEM study of the pit morphology on AISI 316L hMo and UHB 904 revealed large central pits surrounded by minor satellite pits, resulting in a rose shape. This morphology probably resulted from subsurface pit growth, where the pit was covered by a thin layer of metal.

• Research Organization: Belgian Nuclear Research Center, Mel (BE)
• OSTI ID: 20002568
• Report Number(s): CONF-990401--
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
CHLORIDES
CONTAINERS
CORROSION RESISTANT ALLOYS
HIGH-LEVEL RADIOACTIVE WASTES
NICKEL BASE ALLOYS
PITTING CORROSION
RADIOACTIVE WASTE DISPOSAL
STAINLESS STEEL-316
STAINLESS STEEL-316L
STAINLESS STEELS
TITANIUM ALLOYS