Influence of pre-hydriding and quench on embrittlement of E110 alloy under LOCA conditions

Conference · Fri Jul 01 04:00:00 EDT 2016

OSTI ID:22750136

Novikov, V. V.; Kuznetsov, V. I.; Fedotov, P. V.; Salatov, A. V. ^[1]; Ignatiev, D. N.; Mokrushin, A. A.; Soldatkin, D. M.; Urusov, A. A. ^[2]

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1. SC A.A. Bochvar High-Technology Research Institute of Inorganic Materials - SC VNIINM, 5a, Rogova st., Moscow, 123098 (Russian Federation)
2. SC Scientific Research Institute Scientific Industry Association 'LUCH' - FSUE SRI SIA 'LUCH', 24, Zheleznodorozhnayast., Podolsk, Moscow region, 142 100 (Russian Federation)

The aims of present work were to investigate the corrosion behavior and residual ductility of pre-hydrided E110 alloy under LOCA conditions including the influence of cooling rate. The fragments of unirradiated and pre-hydrided cladding (9,5*8,33 mm with a 10 mm length) were used as samples. The claddings were made from an E110 sponge based alloy (finish polishing). The hydrogen concentration varied from 5 (as received) to 800 wppm. As a result of pre-hydriding δ- hydrides of zirconium have been formed into cladding material. Corrosion tests were carried out at temperatures 1100 and 1200 C. degrees in a steam (80 mg/s) and argon (25 ml/s) mixture flow. The samples were cooled by 2 regimes: the first one is cooling in the cold zone of test facility with rate about 20 C. degrees/s, the second is cooling in the cold zone of test facility with rate about 20 C. degrees/s from test temperature to 800 C. degrees and quench by dropping in to the water. The change of a sample mass was determined as a difference between initial sample mass and its mass after oxidation. The mechanical tests of oxidized claddings in a diametrical direction were carried out with the use of a universal tension testing machine at a steady deformation rate of 1 mm/min at 135 C. degrees. The investigations have established the following. The initial concentration of hydrogen has no effects on the oxidation kinetics, while the oxidation kinetics are parabolic and the breakaway oxidation is not observed. The oxide films on cladding surfaces are black and shining. There are no cracks, visual spots and peelings. The residual ductility of oxidized samples decreases with the increase of hydrogen concentration. The residual ductility of slow cooled claddings is higher than residual ductility of quenched claddings. The limiting value of ECR (Equivalent Cladding Reacted) corresponding to ductile-brittle transition as function of initial hydrogen content was evaluated. The value of residual ductility 2% was used as a ductile-brittle threshold. The limiting value of ECR for as-received E110 alloy is 18% and it decreases slowly to 15% with hydrogen content rising to 350 wppm. At hydrogen content of about 350 - 400 wppm there is a rapid change of limiting value of ECR from 15% to 8 %. At hydrogen content from 400 to 800 wppm the limiting value of ECR decreases from 8% to 3%. (authors)

• Research Organization: American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 22750136
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
CLADDING
CORROSION
DUCTILE-BRITTLE TRANSITIONS
HYDROGEN
LOSS OF COOLANT
MECHANICAL TESTS
ZIRCONIUM