Iran’s nuclear chief said Sunday that the country has launched “preliminary activities for designing” a new process to enrich uranium for its 50-year-old research reactor in Tehran, according to the Associated Press. Ali Akbar Salehi’s announcement further undermines that already shaky nuclear 2015 deal, from which President Trump withdrew in May. Under the imperiled accord, Iran is permitted to enrich uranium up to 3.67 percent. But Salehi said on Iranian state-run television that “preliminary activities for designing modern 20 percent (enriched uranium) fuel have begun.”Salehi said this “modern fuel” will boost efficiency in the research reactor.“We are at the verge” he also said. Low-level uranium enrichment can be used in a civilian reactor, whereas a weapon would require 90 percent enrichment required for a nuclear weapon, per the AP.