Abstract: Disclosed is a method of searching for positions to place control rods with crack in a boiling water reactor core. When a control rod is broken in a nuclear reactor core, it is determined whether the smallest cold shut-down margin meets the regulations of the laws. Positions meeting the regulations of the laws are found to place control rods that might be broken but are still in operation in the reactor core. After the cold shut-down margins are confirmed, the critical safety is determined to avoid the risk of not being able to shut down the reactor core when urgent shut-down is needed.

Abstract: A nuclear fuel arrangement in fuel pools for nuclear power plant is disclosed, which comprises: a plurality of nuclear fuel bundles, being arranged in a tight formation; a pool partition framework, formed with a plurality of grids for storing the plural nuclear fuel bundles; wherein the partition frame has a plurality of blocks of different heights disposed at the bottoms of their corresponding grids to be used for enabling any neighboring nuclear fuel bundles in the tight formation to be ruggedly arranged with different heights.

Abstract: A dry storage of nuclear fuel is disclosed, which comprises: a plurality of nuclear fuel bundles, being arranged in a tight formation; a dry storage canister, formed with a cavity inside to be used for storing the plural nuclear fuel bundles; wherein the cavity is formed with a plurality of blocks of different heights at the top and bottom thereof that each of the blocks on the top and bottom are provided for one of the plural nuclear fuel bundles to mounted fixedly thereon for enabling any neighboring nuclear fuel bundles in the tight formation to be ruggedly arranged with different heights.

Abstract: Usually an analysis of fuel displacement accident is required before operating a reactor. In the present invention, fuel displacement accident is analyzed by linearly combining calculation results of single displacement layouts and a calculation result of a default placement layout. In this way, a number of displacement combinations to be analyzed can be reduced. And, thus, time for the analysis is saved and safety of the reactor core can be affirmed.