Japan Atomic Energy Research Institute

Power Reactor and Nuclear Fuel Development Corporation

Japan Atomic Energy Res. Institute

Hajime Nakajima

Tatsuo Kondo

Susumu Isobe

Masami Shindo

Ryohei Tanaka

Hirokazu Tsuji

Sadao Ohta

Rikizo Watanabe

Taiki Kobayashi

Takeshi Okada

Watanabe Rikizo

Susumi Isobe

Yasukazu Ishida

Katsutoshi Watanabe

The improved superalloy that possesses all the characteristics required of the high-temperature structural material of high-temperature gas-cooled reactors (i.e., high-temperature strength, corrosion resistance, good producibility, good hot workability and resistance to embrittlement due to thermal aging) consists essentially of 16-28% Cr, 15-24% W (provided that Cr+W=39-44%), 0.01-0.1% Zr, 0.001-0.015% Y, 0.0005-0.01% B, up to 0.05% C, up to 0.1% Si, up to 0.1% Mn (provided that Si+Mn.ltoreq.0.1%), up to 0.1% Ti, up to 0.1% Al and up to 0.1% Nb (provided that Ti+Al.ltoreq.0.1% and Ti+Al+Nb.ltoreq.0.15%), with the balance being Ni and inevitable impurities and all percentages being on a weight basis.

Nickel-chromium-tungsten base superalloy

The improved superalloy that possesses all the characteristics required of the high-temperature structural material of high-temperature gas-cooled reactors (i.e., high-temperature strength, corrosion resistance, good productibility, good hot workability and resistance to embrittlement due to thermal aging) consists essentially of 16-28% Cr. 15-24% W (provided that Cr+W=39-44%), 0.01-0.1% Zr, 0.001-0.015% Y, 0.0005-0.01% B, up to 0.05% C, up to 0.1% Si, up to 0.1% Mn (provided that Si+Mn.gtoreq.0.1%), up to 0.1% Ti, up to 0.1% Al and up to 0.1% Nb (provided that Ti+Al.gtoreq.0.1% and Ti+Al+Nb.gtoreq.0.15%), with the balance being Ni and inevitable impurities and all percentages being on a weight basis.

A solid solution strengthened iron-base austenitic alloy is suitable for use in nuclear reactors having low oxidizing environment. It has a composition of 8 up to but not including 16.0% by weight of Cr, 14-35% by weight of Ni, 5-15% by weight of Mo plus 0.522 W, up to 1.0% by weight of Ti, up to 2% by weight of Mn, up to 1% by weight of Si, up to 0.1% by weight of C and the balance iron and unavoidable impurities.

Solid solution strengthened iron-base austenitic alloy

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Ibaraki, Japan

Hajime Nakajima