The National Interest:
While Ukraine renounced its own possession of nuclear weaponsin 1994, many scientists and design bureaus in the country still have the know-how required to manufacture important components of strategic weapons. China has often been particularly keen of this knowledge, acquiring Ukrainian help in designing their first phased-array radar system.
Chinese poaching of Ukrainian aerospace, tank and naval engineers is also a common phenomenon, most notably Valerii Babich, designer of the Varyag aircraft carrier. There are even rumors of “Ukrainetowns” in some Chinese cities founded by the large number of expats hired by Chinese firms. Ukrainian and Russian businessmen even sold Kh-55 nuclear cruise missiles (without the warheads) from Ukrainian stockpiles to China in the 2000s.
As China continues to modernize their ICBM fleet, it begs the question: how much help is Ukraine providing, willingly and unwillingly?