Doryokuro Kakunenryo Kaihatsu Jigyodan

Kazushige Domoto

Kiyozumi Hayashi

Naoaki Takahashi

Yoshitsugu Mishima

A spacer for supporting a plurality of fuel rods forming a nuclear fuel assembly. The spacer comprises a peripheral band surrounding a bundle of the fuel rods and a plurality of spacer framework units, each holding therein one fuel rod. The spacer framework units are welded or brazed to the peripheral band so as to be arranged inside the peripheral band. Spring members are integrally formed on each of the spacer framework units. The spacer framework units, the spring members and the peripheral band are made of a zirconium alloy containing 5-25% by weight niobium and 0.1-1% by weight chromium and/or iron.

Fuel assembly spacer

A nuclear fuel element is provided which comprises a cladding tube having end plugs for sealing ends of the cladding tube and a multiplicity of fuel pellets stacked within the cladding tube. Each of the fuel pellets has a substantially cylindrical external lateral surface and a plurality of longitudinal recesses having rounded root portions on the external lateral surface, and has a height within the range from 1/2 to 1/3 of the outer diameter thereof. These fuel pellets with the floral petal shape are stacked in such a manner that the recesses of one pellet are not aligned with the recesses of adjacent upper and/or lower pellets.

Growing community of inventors

Yokohama, Japan

Kazushige Domoto