The "Clean" Mk-21C which was tested in the Redwing Navajo shot did not interest the US Air Force, or AEC.
As the decision not to pursue the "clean" Mk-21 closely coincided with the decision to terminate development of the Mk-26 in April 1957, it is possible that Mk-26 was the designation for the clean version of the Mk-21.
This article related to nuclear weaponry is a stub.
You can help Wikipedia by expanding it.This article relating to the history of the United States is a stub.
You can help Wikipedia by expanding it.This United States military article is a stub.