Thin walled channel

A fuel assembly comprising a plurality of fuel rods positioned in a spaced array by upper and lower tie-plates, an open ended flow channel surrounding said array for conducting coolant upward about said fuel rods, said open ended channel having a polygon shaped cross section with flat side sections connected between corner sections;

• with other means connecting said upper and lower tie-plates together and maintaining said fuel rods in spaced array independent of said flow channel, the improvement in said flow channel comprising:
• four corners having a first thickness;
• four sides having a second and reduced thickness from said corner section;
• said sides defining corrugations formed therein extending at least partially the span of said flat side sections for reinforcing said flat sections to resist pressures from the inside of said channel to and toward the outside of said channel.

A fuel assembly comprising a plurality of fuel rods positioned in spaced array by upper and lower tie-plates, an open ended flow channel surrounding said array for conducting coolant upward about said fuel rod, said open ended channel having a polygon shaped cross section with flat side sections connected between corner sections;

• with other means connecting said upper and lower tie-plates together and maintaining said fuel rods in spaced array independent of said flow channel, the improvement in said flow channel comprising:
• four corners having a first thickness;
• and,
• four sides having a second and reduced thickness from said corner section, said sides fastened to said corner section to provide support of said side sections in the vicinity of said corner sections;
• each said side defining transverse grooves on the exterior of said channels.

A fuel assembly comprising a fuel assembly comprising a plurality of fuel rods positioned in a spaced array by upper and lower tie-plates, an open ended flow channel surrounding said array for conducting coolant upward about said fuel rods, said open ended channel having a polygon shaped cross section with flat side sections connected between said corner sections;

• means separate from said channel connecting said upper and lower tie-plates together and maintaining said fuel rods in spaced array independent of said flow channel improvement in said flow channel comprising:
• four corners having a first thickness;
• four sides having a second and reduced thickness from said corner section, said sides welded to said corner sections to provide support to said sides;
• each said side having longitudinal grooves on the external surface of the channel.

A fuel assembly comprising a fuel assembly comprising a plurality of fuel rods positioned in a spaced array by upper and lower tie-plates, an open ended flow channel surrounding said array for conducting coolant upward about said fuel rods, said open ended channel having a polygon shaped cross section with flat side sections connected between said corner sections;

• means separate from said channel connecting said upper and lower tie-plates together and maintaining said fuel rods in spaced array independent of said flow channel improvement in said flow channel comprising:
• four corners having a first thickness;
• four sides having a second and reduced thickness from said corner section, said sides welded to said corner sections to provide support to said sides;
• each said side having longitudinal grooves on the internal surface of the channel.

A fuel assembly comprising a fuel assembly comprising a plurality of fuel rods positioned in a spaced array by upper and lower tie-plates, an open ended flow channel surrounding said array for conducting coolant upward about said fuel rods, said open ended channel having a polygon shaped cross section with flat side sections connected between said corner sections;

• means separate from said channel connecting said upper and lower tie-plates together and maintaining said fuel rods in spaced array independent of said flow channel improvement in said flow channel comprising:
• four corners having a first thickness;
• four sides having a second a reduced thickness from said corner section, said sides welded to said corner sections to provide support to said sides;
• each said side having longitudinal grooves on the external surface of the channel in the lower one-half (1/2) to three-quarter (3/4) of the channel height and longitudinal grooves on the internal surface of the channel in the upper three-quarters (3/4) to one-half (1/2) of the channel height.