Advanced Nuclear Fuels Corporation

Siemens Power Corporation, Inc.

Charles A Brown

John F Patterson

Jack Yates

Rolf Holzer

Peter P King

A boiling water reactor fuel assembly with fuel rods having variable fuel rod pitches.

BWR fuel assembly having fuel rods with variable fuel rod pitches

A fuel assembly for nuclear reactors which comprises the usual upper and lower tie plates and fuel rods extending between them is made debris-resistant by providing a grid spacer in contact, or very nearly so, with the lower tie plate and so positioned as to subdivide the usual openings in the lower tie plate which are provided for the passage of cooling water. This causes debris to be trapped in the openings of the lower tie plate, and keeps it from contacting the fueled portion of the assembly.

Debris-resistant fuel assembly

A marked reduction in the pressure drop of cooling liquid through a grid spacer of a nuclear fuel assembly is attained by convexly contouring the upstream (usually the lower) edges of the grid members. Preferably, they are made streamlined or semicylindrical. This can be done by first beveling and then etching them, by directing a stream of mixture of abrasive and an organic polymer against them, or by traversing an electron or laser beam along them at a power and velocity such as to cause local melting. A lesser improvement is secured by beveling alone. A still further improvement can be obtained by also tapering the downstream (usually upper) edges.

Growing community of inventors

Kennewick, WA, United States of America

Charles A Brown