The goal of NNSA’s scientific efforts is to develop, support and improve science and technology across the entire nuclear weapons complex so that NNSA can better assess the safety, reliability, and performance of nuclear weapons without further underground testing.  In addition to improving NNSA’s weapon assessment technologies, these efforts help retain the readiness to conduct underground nuclear testing if directed by the President and for developing the essential scientific capabilities and infrastructure across the nuclear weapons complex.

As the U.S. stockpile ages and NNSA transforms itself to meet future challenges, NNSA will increasingly rely on its ability to assess a weapon’s performance without underground testing by using highly sophisticated, scientific predictive capabilities that are developed and validated by NNSA’s experts.  NNSA will rely on its supercomputers and other laboratory facilities to simulate and predict a weapon’s performance, instead of physically exploding weapons underground to see how they perform.

This work provides capabilities that support NNSA’s assessment and certification of its life extension program designs.  It is focused on improving the response time for resolving difficulties, and for certifying warhead replacement components.

For instance, in 2007 NNSA reacquired its ability to manufacture plutonium pits, which are the trigger of a nuclear weapon, for the W88 warhead.  Through its scientific efforts, NNSA was able to confirm the nuclear performance of a W88 warhead with a manufactured pit and established certification processes for future replacement pits.

In order to transform and modernize the nuclear weapons complex and stockpile for the future, NNSA will need to rely heavily on its science and technology people and facilities, especially in the absence of underground testing.  With a strong base of science and technology, NNSA will continue to be able to address and reduce uncertainties within the stockpile and be able to provide an objective quantitative measure of confidence in the stockpile.

NNSA’s goal is to improve its predictions of weapons performance by developing and maintaining an agile workforce that has the proper tools and is knowledgeable enough to avoid technological surprises, and able to quickly understand and respond to problems.  This will only be possible through NNSA’s continued support of nuclear weapons science.

Assessment Technologies
One of the main goals of NNSA’s science efforts is to develop improved capabilities to better assess the safety, reliability and performance of the “nuclear package,” or primary and secondary explosive components, portion of U.S. nuclear weapons without further underground testing.

In order to do its assessments, NNSA is principally responsible for the development of quantification of margins and uncertainties, or QMU, which is the principal technique for assessing and certifying the safety and reliability of the nuclear stockpile.  Developed by Los Alamos and Lawrence Livermore National Laboratories, QMU is a specific methodology that NNSA uses to create and facilitate analysis, and thus communicate confidence in an assessment or certification of a weapon.  QMU focuses on creating a list of factors that are the most critical to the operation and performance of a nuclear weapon and then tries to quantify how likely it is that each of these critical factors will fail to perform as designed.

NNSA also has additional experimental capabilities to support the development of other analytic tools and methodologies required to assess the nuclear safety and performance of current, as well as any aged or rebuilt, primary (or nuclear trigger) without nuclear testing.

In addition, to improve and validate the computer simulations codes that NNSA uses in its Advanced Simulation and Computing program, NNSA uses modern interpretive models, codes and methods to further analyze historical underground nuclear test data and develops of an archive of information that has been an invaluable source of information.

Test Readiness
NNSA is also responsible for retaining the “readiness,” or ability as required by federal law, to conduct underground nuclear testing should NNSA be directed by the President to do so.  In 1992, the United States voluntarily stopped testing its nuclear weapons underground.  However, NNSA is required by federal law to maintain the ability to test a weapon underground at the Nevada Test Site should the President deem it necessary.

NNSA ensures the readiness to conduct underground nuclear testing by fielding experiments and diagnostics tests, maintaining the proper test-specific equipment, tools infrastructure, and ensuring that the critical personnel are properly trained.  These assets are maintained so that if necessary, they could prepare and execute an underground nuclear test on a timescale that is established by national policy.