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A spacer grid for dual-cooling nuclear fuel rods arranged at a narrow interval. The spacer grid solves the problem in which, since the dual-cooling nuclear fuel rods are used to improve the cooling performance and stability of nuclear fuel and obtain high burnup and output, the outer diameter of eac

A spacer grid for dual-cooling nuclear fuel rods arranged at a narrow interval. The spacer grid solves the problem in which, since the dual-cooling nuclear fuel rods are used to improve the cooling performance and stability of nuclear fuel and obtain high burnup and output, the outer diameter of each dual-cooling nuclear fuel rod is increased, and thus the gap between each dual-cooling nuclear fuel rod and the grid strap is decreased. The spacer grid includes first grid straps and second grid straps, which are crossed and arranged in transverse and longitudinal directions at regular intervals and have the shape of a flat strip, and support structures, which are fitted into the first and second grid straps around intersections of the first and second grid straps so as to support the dual-cooling nuclear fuel rods.

대표청구항 ▼

1. A spacer grid for dual-cooling nuclear fuel rods using intersectional support structures, the spacer grid comprising: first grid straps and second grid straps, which are crossed and arranged in transverse and longitudinal directions at regular intervals and have a shape of a flat strip; andsuppor

1. A spacer grid for dual-cooling nuclear fuel rods using intersectional support structures, the spacer grid comprising: first grid straps and second grid straps, which are crossed and arranged in transverse and longitudinal directions at regular intervals and have a shape of a flat strip; andsupport structures, each of which is fitted into the first and second grid straps around a respective intersection of the first and second grid straps, the support structures being configured to support the dual-cooling nuclear fuel rods,wherein the first grid straps each include first grid slits spaced apart from each other at regular intervals at an upper portion thereof, and first fastening slits formed on opposite sides of the respective first grid slits at an upper portion of each of the first grid straps; andthe second grid straps each include second grid slits spaced apart from each other at regular intervals at a lower portion thereof, and second fastening slits formed on opposite sides of the respective second grid slits at an upper portion of each of the second grid straps,wherein each support structure comprises: a prism having a quadrilateral cross section; andslits at each corner of the prism coupled with corresponding first fastening slits and second fastening slits. 2. The spacer grid of claim 1, wherein each support structure comprises: supports configured to support the dual-cooling nuclear fuel rods, the supports comprising faces configured to support the dual-cooling nuclear fuel rods. 3. The spacer grid of claim 1, wherein each support comprises: a contact portion, which protrudes from a prism face of the support structure and is configured to contact with an outer circumference of a dual-cooling nuclear fuel rod after the dual-cooling nuclear fuel rod is charged; andconnector portions, which extend from upper and lower ends of the contact portion in a curved shape and connect the contact portion to the prism face. 4. The spacer grid as set forth in claim 3, wherein each support structure additionally includes dimples in upper and lower portions of each support. 5. The spacer grid as set forth in claim 1, wherein each support structure includes supports having one of concave, convex and planar shapes in a longitudinal direction on faces thereof so as to be configured to contact outer circumferences of the dual-cooling nuclear fuel rods. 6. The spacer grid as set forth in claim 5, wherein the support having the concave shape has a curvature equal to that of the outer circumference of each dual-cooling nuclear fuel rod after each dual-cooling nuclear fuel rod is charged. 7. The spacer grid as set forth in one of claims 2 through 6, wherein each support structure is formed by bending a rectangular sheet at a right angle. 8. The spacer grid as set forth in claim 1, wherein each support structure includes four slits in a circumference of a cylinder having a circular cross section at right angles so as to be coupled with the first fastening slits and the second fastening slits, and supports supporting the dual-cooling nuclear fuel rods between the four slits. 9. The spacer grid as set forth in claim 8, wherein each support includes a contact portion, which comes into contact with an outer circumference of each dual-cooling nuclear fuel rod after each dual-cooling nuclear fuel rod is charged, and connector portions, which extend from upper and lower ends of the contact portion in a curved shape. 10. The spacer grid as set forth in claim 9, wherein each support structure additionally includes dimples in upper and lower portions of each support. 11. The spacer grid as set forth in claim 4 or 10, wherein each dimple includes a contact face having one of concave, convex and planar shapes so as to be in contact with the outer circumference of each dual-cooling nuclear fuel rod. 12. The spacer grid as set forth in claim 3 or 9, wherein the contact portion has a concave shape so as to have a curvature equal to that of the outer circumference of each dual-cooling nuclear fuel rod after each dual-cooling nuclear fuel rod is charged. 13. The spacer grid as set forth in claim 3 or 9, wherein the contact portion has a convex shape protruding toward a space where each dual-cooling nuclear fuel rod is to be mounted. 14. The spacer grid as set forth in claim 3 or 9, wherein the contact portion has a planar shape. 15. The spacer grid as set forth in claim 8, wherein each support structure is formed by rolling a rectangular sheet into a cylindrical shape. 16. The spacer grid as set forth in claim 1, wherein each support structure includes four slits in a circumference of a cylindrical tube at right angles so as to be coupled with the first fastening slits and the second fastening slits, and each dual-cooling nuclear fuel rod is supported by directly contacting an outer circumference of each support structure. 17. The spacer grid as set forth in claim 1, wherein the first grid straps, the second grid straps, and the support structures are welded to each other. 18. A spacer grid for dual-cooling nuclear fuel rods using intersectional support structures, the spacer grid comprising: first grid straps and second grid straps, which are crossed and arranged in transverse and longitudinal directions at regular intervals and have a shape of a flat strip; andsupport structures, each of which is fitted into the first and second grid straps around a respective intersection of the first and second grid straps, the support structures being configured to support the dual-cooling nuclear fuel rods,wherein the first grid straps each include first grid slits spaced apart from each other at regular intervals at a lower portion thereof, and first fastening slits formed on opposite sides of the respective first grid slits at the lower portion of each of the first grid straps; andthe second grid straps each include second grid slits spaced apart from each other at regular intervals at an upper portion thereof, and second fastening slits formed on opposite sides of the respective second grid slits at a lower portion of each of the second grid straps,wherein each support structure comprises: a prism having a quadrilateral cross section; andslits at each corner of the prism coupled with corresponding first fastening slits and second fastening slits. 19. The spacer grid of claim 18, wherein each support structure comprises: supports configured to support the dual-cooling nuclear fuel rods, the supports comprising faces configured to support the dual-cooling nuclear fuel rods. 20. The spacer grid of claim 18, wherein each support comprises: a contact portion, which protrudes from a prism face of the support structure and is configured to contact with an outer circumference of a dual-cooling nuclear fuel rod after the dual-cooling nuclear fuel rod is charged; andconnector portions, which extend from upper and lower ends of the contact portion in a curved shape and connect the contact portion to the prism face.