U.S. Department of Energy Secretary Chris Wright provided an important clarification following Donald Trump’s directive to resume nuclear-weapons testing, by noting on Sunday that any planned tests will not involve nuclear detonations. (AP News +2 Reuters).
Instead, the tests are being described as non-critical experiments that aim to verify components of weapons rather than cause full-scale nuclear explosions, according to Al Jazeera +1.
Here’s how U.S. officials predict these tests will work — and how they plan to avoid explosions while maintaining weapons readiness.

What the U.S. means by “limited” or “noncritical” testing

Wright noted the tests will focus on testing non-nuclear components of weapons – detonators, high explosives used to propel implosion of warheads, electrical and mechanical components — but will avoid setting off chain reactions of fission or fusion. Al Jazeera+1 reported on Wright:
“These explosions do not involve nuclear detonations; instead they’re known as non-critical explosions.
Al Jazeera
In practice, the U.S. plans to conduct nuclear explosion tests without actually detonating them; rather, their goal is to validate that components still function reliably despite ageing warheads and evolving threats. For more information about this subject visit Reuters –
Why This Matters
Since 1992 and the end of the Cold War, no full nuclear-detonation tests have taken place within U.S. territory due to a moratorium governing such tests imposed by Congress and adhered to by President George H.W. Bush (AP News, February 10, 2013).
Resuming full detonations would represent a break with this longstanding practice and have serious diplomatic, environmental, and security implications. By forgoing actual explosions, the U.S. hopes to strike a balance: meeting reliability concerns with its nuclear stockpile while simultaneously mitigating fallout–both literally and politically.

Secretary Wright noted that modern computational modeling and high-performance simulation allow the United States to predict much of what a nuclear detonation would reveal — meaning full yield tests are less necessary now than earlier decades. Reuters How explosions are avoided in practice.

There are multiple strategies the U.S. appears to be employing:

Sub-critical or zero-yield experiments: These are experiments in which a nuclear core is never brought to criticality; its chain reaction never reaches self-sustaining fission, permitting testing of high explosives and implosion geometry without yielding nuclear radioactivity.

Component Tests: Verifying detonators, conventional explosives, arming/firing mechanisms, instrumentation and electronics to ensure all the “other parts of a nuclear weapon” operate as intended.
Advanced Simulations and Modelling: Utilizing data from past tests as well as experimental inputs, advanced simulations and modeling allow scientists to accurately simulate what will happen during a nuclear explosion before it ever actually happens. As reported by AP News: “Through our science and computation power, we are able to simulate nuclear explosions incredibly accurately.”
Controlled environments and non-nuclear physics experiments: Programs like Scorpius previously attempted to understand plutonium behavior under conditions resembling implosion without detonation. AP News What are the risks and controversies involved?

Analysts warn this approach still contains significant risks; without full yield tests, uncertainties about any untested changes to warhead design, material aging or unexpected failures remain.
CSIS Nuclear tests also carry diplomatic consequences: Even tests without detonation can raise concerns among other nuclear-armed states, cause arms race dynamics to emerge or alter treaty norms.

Critics contend that non-explosive tests can cross into what many consider nuclear-testing territory, undermining international efforts like the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As wired.com reported.
What’s Next
According to Wright, the U.S. plans on conducting system-level tests within the near term. Verification agencies and other countries will closely observe to ensure no explosion occurs and that tests remain within their intended parameters. Meanwhile, larger issues concerning stockpile reliability, modernisation, and global nuclear policy remain at the core of debate.

As Wright noted, these tests aim to “ensure all other parts of a nuclear weapon are operating as expected” — before stopping short of any explosion. For its part, The WaPo reported: these trials serve as “an assurance test against any sudden detonations”.