At 3:34 PM on October 11, 2026, Unit 1 of the Rooppur Nuclear Power Plant initiated its first controlled nuclear chain reaction. The reactor reached initial criticality — the milestone at which fission becomes self-sustaining and stable. For Bangladesh, it marks a historic turning point, unprecedented in the country’s energy history.
The plant is located in Ishwardi, in the Pabna district, on the banks of the Padma River, approximately 160 kilometers northwest of Dhaka. It consists of two units equipped with VVER-1200 pressurized water reactors, a technology supplied by Rosatom, with a combined capacity of 2,400 megawatts. Unit 1 alone accounts for 1,200 megawatts. Russian specialists and Bangladeshi engineers were present in the control room during startup, monitoring reactor parameters in real time. All readings remained within design limits throughout the process.
The green light for criticality had come just days earlier, on October 8, when the Bangladesh Atomic Energy Regulatory Authority (BAERA) issued a B-2 type commissioning license. The authorization had been held up by technical issues involving the pilot-operated relief and safety valves — PORV/POSV — which had delayed previous phases. A team of Russian technicians had intervened in the preceding weeks to carry out the required inspections, including testing in both the main control room and the emergency control room. BAERA granted its approval only after all tests had been successfully completed.
The physical startup phase — which includes the first criticality — will require between 30 and 40 days of continuous monitoring. Once that period is complete, reactor power will be gradually increased. Before the unit can be connected to the national grid, two additional regulatory licenses will be required: C and D. According to project officials, trial power generation at around 300 megawatts could begin by December, with commercial operations not expected before 2027. At full capacity, a single unit is projected to generate savings of approximately one billion dollars per year in fossil fuel imports.
Bangladesh has now joined the select group of countries with active nuclear capability. Rooppur was conceived more than a decade ago, with the first nuclear agreement between Dhaka and Moscow signed in 2011. Nuclear fuel arrived at the site in October 2023, granting the facility official nuclear status. Since then, commissioning phases have advanced steadily. The path to the national grid is still a long one — turbine testing, grid synchronization, final safety checks — but first criticality is the threshold that separates a plant under construction from a live reactor. Rooppur has crossed it.
