Release That Witch
Cheng Yan travels through time, only to end up becoming an honorable prince in the Middle Ages of Europe. Yet this world was not quite as simple as he thought. Witches with magical powers abound, and fearsome wars between churches and kingdoms rage throughout the land. Roland, a prince regarded as hopeless by his own father and assigned to the worst fief, spends his time developing a poor and backward town into a strong and modern city, while fighting against his siblings for the throne and absolute control over the kingdom. Join Roland as he befriends and allies with witches and, through fighting and even farming, pushes back invaders from the realm of evil.
A Wind Chaser
Editor: Transn
Neutron sources, which could be classified as catalyst, provided extra neutrons that could sustain the chain reaction even when Uranium-235 was under its critical mass.
Technically, both polonium and radium separated from natural uranium could form compounds with beryllium to serve as neutron sources. Roland did not foresee any technical difficulties, for polonium could release a large number of neutrons when colliding with alpha particles. All of the three elements were existing in nature, which saved them a lot of time to create elements artificially.
Roland preferred polonium to radium purely out of safety concerns. Although polonium-210 had a short half-life, it released very few photons upon a decay, which meant it was no more dangerous than inactive uranium. However, radium, which released radon and photons upon activation, posed a potential safety hazard. As such, polonium was a better candidate to provide neutrons.