Editing Nuclear weapon design (section)

===One-point safety===
While the firing of one detonator out of many will not cause a hollow pit to go critical, especially a low-mass hollow pit that requires boosting, the introduction of two-point implosion systems made that possibility a real concern.{{Citation needed|date=June 2021|reason=utter nonsense. Big citation needed for the claim hollow pits are one-point safe. Also boosting requires significant yield to function. A weapon making 0.1kt of yield from a one point detonation is not safe}}

In a two-point system, if one detonator fires, one entire hemisphere of the pit will implode as designed. The high-explosive charge surrounding the other hemisphere will explode progressively, from the equator toward the opposite pole. Ideally, this will pinch the equator and squeeze the second hemisphere away from the first, like toothpaste in a tube. By the time the explosion envelops it, its implosion will be separated both in time and space from the implosion of the first hemisphere. The resulting dumbbell shape, with each end reaching maximum density at a different time, may not become critical.{{Citation needed|date=June 2021|reason=}}

It is not possible to tell on the drawing board how this will play out. Nor is it possible using a dummy pit of U-238 and high-speed x-ray cameras, although such tests are helpful. For final determination, a test needs to be made with real fissile material. Consequently, starting in 1957, a year after Swan, both labs began one-point safety tests.{{Citation needed|date=June 2021|reason=}}

Out of 25 one-point safety tests conducted in 1957 and 1958, seven had zero or slight nuclear yield (success), three had high yields of 300 t to 500 t (severe failure), and the rest had unacceptable yields between those extremes.{{Citation needed|date=June 2021|reason=}}

Of particular concern was Livermore's [[W47]], which generated unacceptably high yields in one-point testing. To prevent an accidental detonation, Livermore decided to use mechanical safing on the W47. The wire safety scheme described below was the result.{{Citation needed|date=June 2021|reason=wan device, failed massively, would suggest above claims are very wrong}}

When testing resumed in 1961, and continued for three decades, there was sufficient time to make all warhead designs inherently one-point safe, without need for mechanical safing.{{Citation needed|date=June 2021|reason=}}