초록 ▼

A fuel assembly according to the present invention is formed in such a manner that the small diameter portion of an upper end plug of a fuel rod is inserted into a boss of an upper tie-plate. The upper end plug includes a small diameter portion and a large diameter portion which is disposed below th

A fuel assembly according to the present invention is formed in such a manner that the small diameter portion of an upper end plug of a fuel rod is inserted into a boss of an upper tie-plate. The upper end plug includes a small diameter portion and a large diameter portion which is disposed below the former. An expansion spring in disposed in the small diameter portion of the upper end plug. A cover member surrounding this expansion spring is disposed in the large diameter portion of the upper end plug, and extends upwardly. Since the cover member surrounds the expansion spring, pressure loss caused by the expansion spring can be reduced.

대표청구항 ▼

A fuel assembly comprising: an upper tie-plate having a plurality of cylindrical bosses and a plurality of ribs which connect each of said bosses; a plurality of fhel rods having each of top and lower ends which is sealed by a corresponding end plug, which are filled with a plurality of fuel pellets

A fuel assembly comprising: an upper tie-plate having a plurality of cylindrical bosses and a plurality of ribs which connect each of said bosses; a plurality of fhel rods having each of top and lower ends which is sealed by a corresponding end plug, which are filled with a plurality of fuel pellets, and in whcih said upper end plug is supported by said boss; expansion springs secured to said upper end plugs of said fuel rods; and cover means provided for either said fuel rod or said upper tie-plate surrounding said expansion spring and covering at least a part of the axial length of said expansion spring.