"R" in the numeric designation signifies that the 1999 standard was reaffirmed (recertified) as an American National Standard in 2009. No changes can be made to a standard during reaffirmation. The "W" indicates that this standard is considered withdrawn and is no longer a current American National Standard. This standard was superseded by ANSI/ANS-6.1.2-2013.
This standard specifies neutron and gamma-ray cross sections and related group-averaged or derived data for the energy range and materials of importance in nuclear radiation protection and shielding calculations for nuclear power plants.