Robert K. Gjertsen - Monroeville PA
Elmer A. Bassler - North Huntingdon PA
Edgar A. Huckestein - Edgewood PA
Robert B. Salton - Plum Boro. PA
Stephen N. Tower - Washington Township, Westmoreland County PA
Westinghouse Electric Corp. - Pittsburgh PA
A fuel assembly for a pressurized water nuclear reactor incorporating fluid moderator spectral shift control means. During the first part of the fuel cycle when there is excess reactivity, neutron moderation may be decreased by replacing a portion of the water within the core with a less effective moderator such as heavy water. During the life of the fuel, the heavy water is gradually replaced with regular water. The fuel assembly incorporates the necessary means and apparatus to effectuate such control.