Reports by Ray Kidder 

Reports:

UCRL-53820: Maintaining the US Stockpile of Nuclear Weapons During a Low-Threshold or Comprehensive
LANL report by Ray Kidder "Maintaining the U.S. Stockpile of Nuclear Weapons During a Low-Threshold or Comprehensive Test Ban"  October 1987 

UCRL-LR-107454: Assessment of the Safety of US Nuclear Weapons and Related Nuclear Test Requirements
Report by Ray Kidder on the needed number of tests to update some safety features of the weapons stockpile.
July 26, 1991

UCRL-LR-109503: Assessment of the Safety of US Nuclear Weapons and Related Nuclear Test Requirements
An estimate of the number of tests needed to accomplish a set of specific warhead upgrades, following President George H. W. Bush's Nuclear Weapons Reduction Initiative.  December 19, 1991 

Links:

Nature: Problems with Stockpile Stewardship
US Government proposals for maintaining competence in nuclear weapons while observing a test ban have serious flaws. An approach based on remanufacturing proven weapons when necessary offers significant advantages.
Nature 17 April 1997