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:
Jan. 08, 2002
Filed:
Sep. 06, 2000
Masao Chaki, Hitachi, JP;
Koji Nishida, Hitachiohta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In each of a number of fuel assemblies loaded in a core of a boiling water reactor, a fuel holding portion of a lower tie plate holds lower end portions a plurality of fuel rods and at least one water rod. The water rod includes a rising pipe opened to a space in the lower tie plate below the fuel holding portion and introducing upward a coolant introduced to the rising pipe, and a falling pipe communicated with the rising pipe and introducing downward the coolant introduced through the rising pipe. The falling pipe has a coolant outlet opened to a second coolant passage defined between the fuel rods above the fuel holding portion. The rising passage is filled with the coolant during a period of rated power operation of the reactor, and a surface of the coolant is formed in the rising pipe during a period of non-rated power operation in which a flow rate of the coolant supplied to the fuel assemblies is lower than that during the period of rated power operation. As a result, influences of a transient event during the rated power operation can be suppressed, and the nuclear thermal-hydraulic stability of the core during the non-rated power operation can be improved.