"R" In the numeric designation signifies that the 2004 standard was reaffirmed (recertified) as an American National Standard in 2009. No changes can be made to a standard during reaffirmation.
This standard is for those involved in the design, operation, and review of fast pulse reactors. It has been formulated in general terms to be applicable to all current fast pulse reactors. This standard does not apply to periodically pulsed reactors or booster assemblies.