An Iranian nuclear official on Tuesday denied a report that technicians had removed the core of the country’s only heavy-water reactor and poured concrete into the cavity, a final step toward the completion of the historic nuclear agreement in July and the lifting of sanctions on Iran. The official, Ali Asghar Zarean, Iran’s deputy nuclear chief, told state television that a report about the Arak reactor by the semiofficial Fars News Agency on Monday was baseless. He added that Iran planned to sign an agreement next week with China to modify the reactor, which is capable of producing the plutonium needed to build an atomic weapon. Analysts cautioned that the denial did not necessarily mean that the actions, which are required by the nuclear deal reached in Vienna, will not be taken. In November, there were similarly conflicting reports about the disassembling of thousands of enrichment centrifuges, […]