Stockpile stewardship by means other than nuclear testing is not a new requirement imposed by the CTBT. It has always been the mainstay of the U.S. approach to maintaining confidence in stockpile safety and reliability. Based on the available evidence, we conclude that the measures outlined in the preceding sections are both necessary and sufficient for maintaining confidence in the continued safety and reliability of the enduring stockpile. These measures are independent of nuclear testing and are therefore unaffected by a CTBT.

An essential requirement is to safeguard the vitality of the DOE nuclear-weapon activities at the three laboratories, the production plants, and collaborating institutions. In the event that quantity replacements of major components of the nuclear subsystem should become necessary, prudence would indicate the desirability of extensive formal peer reviews. Evaluation of the acceptability of age-related changes relative to original specifications and the cumulative effect of individually small modifications of the nuclear subsystem should also be subject to periodic independent review. Such reviews, involving the three weapon laboratories and external reviewers, as appropriate, would evaluate potential adverse effects on system performance and the possible need for nuclear testing.

We judge that the United States has the technical capabilities to maintain confidence in the safety and reliability of its existing nuclear-weapon stockpile under the CTBT, provided adequate resources are made available to the Department of Energy’s (DOE) nuclear-weapon complex and are properly focused on this task. Specific measures to bolster stockpile confidence include intensifying stockpile surveillance, strengthening manufacturing/remanufacturing capabilities, and increasing the performance margins of nuclear-weapon primaries. With no new weapons replacing older weapons, one can anticipate that the average age of weapons in the enduring stockpile will increase over time far beyond past experience. For this reason we regard these measures to be essential with or without nuclear testing or a CTBT. Refining computational understanding of the existing nuclear-test database and stockpile-related hydrodynamic experiments can play a key role in protecting the capability to produce new designs against the possibility that new weapon types were deemed needed in the future and a return to testing mandated to develop and certify them.

Some have asserted, in the CTBT debate, that confidence in the enduring stockpile will inevitably degrade over time in the absence of nuclear testing. Certainly, the aging of the stockpile combined with the lengthening interval since nuclear weapons were last exploded will create a growing challenge, over time, to the mechanisms for maintaining confidence in the stockpile. But we see no reason that the capabilities of those mechanisms—surveillance techniques, diagnostics, analytical and computational tools, science-based understanding, remanufacturing capabilities—cannot grow at least as fast as the challenge they must meet. (Indeed, we believe that the growth of these capabilities—except for remanufacturing of some nuclear components—has more than kept pace with the growth of the need for them since the United States stopped testing in 1992, with the result that confidence in the reliability of the stockpile is better justified technically today than it was then.) It seems to us that the argument to the contrary—that is, the argument that improvements in the capabilities that underpin confidence in the absence of nuclear testing will inevitably lose the race with the growing needs from an aging stockpile—underestimates the current capabilities for stockpile stewardship, underestimates the effects of current and likely future rates of progress in improving these capabilities, and overestimates the role that nuclear testing ever played (or would ever be likely to play) in ensuring stockpile reliability.

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