Strong Link Weak Link
A Strong link/weak link and Exclusion zone nuclear detonation mechanism is a type of safety mechanism employed in the arming and firing mechanisms of modern nuclear weapons. It is a form of automatic safety interlock.
The safety mechanism starts by enclosing the electronics and mechanical components used to arm and fire the nuclear weapon with a mechanical and electrical isolation barrier, forming the Exclusion zone. This is insulated from mechanical, thermal, and electrical disruptions (such as static electricity, lightning, fire).
Between the exclusion zone and the actual detonators, a normally disconnected link mechanism is used, such as a switch which has a built in motor to activate it. The arming system has to activate the switch in order to connect the firing circuits to the detonators in the weapon. This disconnection, which requires the arming mechanism to operate, is called the strong link
It is possible for an accident (rocket explosion, airplane crash, accident while weapon is being moved) to disrupt the weapon and break the integrity of the exclusion zone. As a safety mechanism, a weak link is also built into the system. This is a set of components designed to fail at lower stresses (thermal, mechanical, and electrical) than will cause failure of the strong link mechanisms. The weak link acts to break the connection to the detonators before the strong link could be disrupted and fail by the stress of an accident.
These mechanisms do not prevent misuse of the weapon, which is restricted by Permissive Action Link code systems, or an accident from physically causing initiation of the explosives or detonators directly from extremely high temperatures, impact forces, or electrical disturbance such as lightning. The risk of accidental direct detonation is significantly reduced by using insensitive high explosives such as TATB, which is extremely unlikely to detonate due to fire or impact or electricity. While TATB may decompose or burn in a fire, it is extremely unlikely to detonate as a result of that decomposition or burning.
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Famous quotes containing the words strong, link and/or weak:
“The only rule is, do what you really, impulsively, wish to do. But always act on your own responsibility, sincerely. And have the courage of your own strong emotion.”
—D.H. (David Herbert)
“This sand seemed to us the connecting link between land and water. It was a kind of water on which you could walk, and you could see the ripple-marks on its surface, produced by the winds, precisely like those at the bottom of a brook or lake. We had read that Mussulmans are permitted by the Koran to perform their ablutions in sand when they cannot get water, a necessary indulgence in Arabia, and we now understand the propriety of this provision.”
—Henry David Thoreau (1817–1862)
“Power corrupts ... when the weak band together in order to ruin the strong, but not before. The will to power ... far from being a characteristic of the strong, is, like envy and greed, among the vices of the weak, and possibly even their most dangerous one.”
—Hannah Arendt (1906–1975)