Hydrogen Evolution From Corrosion of Iron and Steel in Intermediate Level Waste Repositories

Abstract

The production of hydrogen from the anaerobic corrosion of iron or steel is an important issue in low/intermediate level nuclear waste repositories where large quantities of iron and steel (e.g. as drums and reinforcing steel) accompany the waste.Most of the iron in intermediate level repositories is in a cemen-titious environment. A review of the literature on the corrosion of iron and steel at high pH values, in particular in cementitious environments, points to hydrogen evolution rates between 22 and 220 mmol(H2)m−2a−1. There is some indication that the rates might be lower but for normal engineering applications there has been no practical need to demonstrate this, and hence a lower rate cannot be assumed on current evidence.In the present work a volumetric method was used to measure hydrogen evolution rates over several thousand hours under conditions relevant to intermediate level waste repositories. The sensitivity of this method (0.4 mmol(H2)m−2a−1) is sufficient to detect hydrogen evolution rates lower than those predicted for iron and steel in concrete.Hydrogen evolution rates in highly alkaline cement pore water were below 0.4 mmol m−2a−1 and almost 1 mmol m−2a−1 for a pore water representative of an aged cement; no decrease was observed even after 12000 h. In general hydrogen evolution rates in alkaline media were observed to take several thousand hours before approaching a constant rate.

In Vivo Evaluation of Bioabsorbable Fe‐35Mn‐1Ag: First Reports on In Vivo Hydrogen Gas Evolution in Fe‐Based Implants

“…Although in the industry, hydrogen evolution from the corrosion of Fe alloys is well documented. [ 84 ] More importantly, we did not detect any adverse gas‐related complications in the animals.…”

Hydrogen generation by metal corrosion in simulated Waste Isolation Pilot Plant environments. Progress report for the period November 1989 through December 1992

“…Their work clearly demonstrates the profound effect of pH on steel corrosion under anoxic conditions. The low-temperature data of Grauer et al (1991) 4-2 and Simpson and Schenk (1989) Although _hese conclusions are approximate, they provide some guidance in evaluating the potential beneficial effect of additions of alkaline reagents to the WIPP backfill material to decrease the corrosion rate of steel containers.…”

“…The relatively high corrosion rate reported by Braithwaite and Molecke (1980) was apparently due either to the relatively corrosive brine media used in their tests or to the possibility that the test duration used by Simpson and Schenk (1989) was much longer than 28 days, allowing the corrosion rate to decrease to a relatively low level due to the formation of a corrosion product film on the surface of the steel specimens that retarded the corrosion rate. Grauer et al (1991) investigated the corrosion/gas generation of steel under anoxic conditions in aqueous cementitious (alkaline) environments. Their work clearly demonstrates the profound effect of pH on steel corrosion under anoxic conditions.…”

Salt disposal of heat-generating nuclear waste.

“…In the absence of oxygen, water could react with steel or other metallic components of the waste packages and produce hydrogen (H 2 ) gas via anoxic corrosion. Anoxic corrosion is the corrosion of steel or other metals by the oxygen in H 2 O instead of by free molecular O 2 in the aqueous or gaseous phase (Haberman and Frydrych 1988;Simpson and Schenk 1989;Grauer, Knecht, and Simpson 1991).…”