Resistance pressure weld for nuclear reactor fuel rod tube end plug

A fuel rod for a nuclear reactor, comprising:

• a cladding tube having a first end with an annular end face, a second end with an annular end face, and a cylindrical body portion extending therebetween;
• and
• a first tube end plug including a front portion, an annular lip with an annular end face, and a substantially straight cylindrical body portion extending therebetween, the annular lip and a fuel seat of the first tube end plug being formed and separated by an annular undercut defined in the first tube end plug, the annular undercut having a bottom wall that is axially positioned between the annular lip and the front portion of the first tube end plug;
• and
• the annular end face of the first end of the cladding tube and the annular end face of the annular lip of the first tube end plug are connected by a resistance pressure weld,
• wherein the bottom wall of the annular undercut defines a constant radius of curvature in cross section.

A fuel rod for a nuclear reactor, comprising:

• a cladding tube having a first end with an annular end face, a second end with an annular end face, and a cylindrical body portion extending therebetween;
• and
• a first tube end plug including a front portion, an annular lip with an annular end face, and a substantially straight cylindrical body portion extending therebetween, the annular lip and a fuel seat of the first tube end plug being formed and separated by an annular undercut defined in the first tube end plug, the annular undercut having a bottom wall that is axially positioned between the annular lip and the front portion of the first tube end plug;
• and
• the annular end face of the first end of the cladding tube and the annular end face of the annular lip of the first tube end plug are connected by a resistance pressure weld,
• wherein the annular undercut has a cylindrical first inner wall and a cylindrical second inner wall that are connected by the bottom wall,
• wherein the bottom wall of the annular undercut defines a continuous curve between the cylindrical first inner wall and the cylindrical second inner wall.

A fuel rod for a nuclear reactor, comprising:

• a cladding tube having a first end with an annular end face, a second end with an annular end face, and a cylindrical body portion extending therebetween;
• and
• a first tube end plug including a front portion, an annular lip with an annular end face, and a substantially straight cylindrical body portion extending therebetween, the annular lip end face and a fuel seat of the first tube end plug being formed and separated by an annular undercut defined in the first tube end plug extending from a first annular location at the annular end face of the annular lip to a second annular location defining an outer circumference of the fuel seat, the first annular location being radially outward of the second annular location, the annular undercut having a bottom wall that is axially positioned between the annular lip and the front portion of the first tube end plug;
• and
• the annular end face of the first end of the cladding tube and the annular end face of the annular lip of the first tube end plug are connected by a weld.