Original sentence: Fission is thus necessary to start fusion, helps to sustain fusion, and captures and multiplies the energy released in fusion neutrons.Fusion produces neutrons which dissipate energy from the reaction.Using the heat and pressure of fission, hydrogen-2, or deuterium ( 2D), fuses with hydrogen-3, or tritium ( 3T), to form helium-4 ( 4He) plus one neutron (n) and energy:
Edited sentence: Attempting to achieve a large fraction of a weapons yeild from solely Fusion reactions leads to the inherent problem that Fusion reactions are unlikely to be self-sustaining because they do not, on their own, produce the necessary heat and pressure necessary for more fusion, as each fusion event produces neutrons which run away with most of the liberated energy.Even modern pure fission weapons include neutron generators that generate neutrons from Fusion reactions from accelerated deuterium ions, these neutrons are generated to increase the probability of, and jump start, the fission  supercriticality event in the Fissile material.. Older fission weapon designs utilized fission initiators of the Polonium-210 Beryllium 'Urchin' type.However as Po-210 has a very short half-life of only 140 days, these inititiators proved impractical to use as the shelf life of any weapon is directly related to the half-lives of the materials that make up the weapon.In Weapons Fission is thus, at the moment, necessary to start fusion, helps to sustain fusion, and captures and multiplies the energy released in fusion neutrons.Interestingly, every modern Nuclear weapon makes some use of fusion reactions.Therefore Modern neutron emitters utilize a small-scale linear fusion accelerator, or "neutron tube," which have a much longer shelf life and the added benefit of being able to control the neutron emission rate.Using the heat and pressure supplied by fission, hydrogen-2, or deuterium ( 2D), fuses with hydrogen-3, or tritium ( 3T), to form helium-4 ( 4He) plus one neutron (n) and energy: