The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 06, 1990
Filed:
Aug. 24, 1988
Shunsuke Ogiya, Yokohama, JP;
Mamoru Nagano, Yokohama, JP;
Kouji Hiraiwa, Zushi, JP;
Hisao Suzuki, Kawasaki, JP;
Shouichi Watanabe, Ibaraki, JP;
Makoto Ueda, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A fuel assembly for a nuclear reactor includes a number of fuel rods filled with a fuel material. A water rod having a cross sectional area larger than that of each fuel rod is disposed at substantially the central portion of the fuel assembly. The fuel rods include first fuel rods having a whole effective fuel zone filled with a fuel material throughout the entire length thereof and second fuel rods each having an interposed zone in which enrichment of a fissile nuclide is significantly reduced or the fissile nuclide does not exist at all. The second fuel rods are arranged so as to surround the water rod so that the interposed zones are positioned on an axial level including a portion at which subcriticality is made small at a period in which maintenance of reactor shut-down margine is made difficult during the reactor operation period. The water rod may be provided with a lower portion having a cross sectional area smaller than that of an upper portion and short fuel rods are disposed so as to surround the lower portion of the water rod.