Original sentence: Because of this lower density (of mass, and consequently of atom nuclei able to absorb neutron), light water's capability of absorbing neutrons would practically disappear,  allowing more neutrons to fission more U-235 nuclei and thereby increasing the reactor power,  which leads to higher temperatures that boil even more water ...
Edited sentence: Because of this lower density (of mass, and consequently of atom nuclei able to absorb neutron), light water's capability of absorbing neutrons would practically disappear,  allowing more neutrons to fission more U-235 nuclei and thereby increasing the reactor power,  which leads to higher temperatures that boil even more water, creating a thermal feedback loop