Original sentence: However, the totally different form of moderation makes it physically impossible for them to duplicate the circumstances of the accident at Chernobyl.The reactor at Chernobyl used a pressure suppression containment similar to half of the US's reactors designed by General Electric and Westinghouse
Edited sentence: However, changes were made in both the reactors themselves (use of low enriched uranium) and in the control system (prevention of disabling safety systems) to prevent the possibility of a duplicate accident