"R" in the numeric designation signifies that the 1996 standard was reaffirmed (recertified) as an American National Standard in 2002 & 2007. No changes can be made to a standard during reaffirmation.
This standard provides guidance for the use of borosilicate-glass Raschig rings as a neutron absorber for criticality control in ring-packed vessels containing solutions of 235U, 239Pu, or 233U. The chemical and physical environment, properties of the rings and packed vessels, maintenance inspection procedures, and operating guidelines are specified.
