Rooppur Unit 1 begins Stage C power start-up, grid link pending

Unit 1 does not send power to customers yet. It uses the thermal power it generates for internal operations while turbine checks and other tests continue, NPCBL said.

Grid connection would add a new source of electricity to Bangladesh and make the country the world's 33rd nuclear power producer. The first tranche is expected to be about 300MW, a quarter of Unit 1's 1,200MW capacity, so the immediate relief for the grid is limited.

Stage C approval and what it covers

BAERA approved Power Start-Up Stage C on 29 October, and NPCBL said Stage C activities formally began at Unit 1 after the approval.

Stage C raises reactor power in steps so the reactor, turbine-generator and safety systems can be tested together. One of its main objectives is to synchronise Unit 1's generator with the national grid once the required tests are done, in phases and subject to regulatory and commissioning requirements.

The approval followed the B-2 sub-stage authorisation BAERA issued on 8 October, which cleared the start of a controlled nuclear reaction. First criticality, a self-sustaining chain reaction at minimal power, began at around 3:34pm on 11 October, Science and Technology Secretary Md Anwar Hossain told The Daily Star.

What 300MW means, and what it does not

The ramp is gradual by design. The unit will initially run at about 3% of capacity, with output rising to 20-30% before electricity could be supplied to the grid.

Project authorities said it could take 15 to 20 days to reach the next stage and begin trial supply to the grid. Project officials told The Business Standard that trial electricity could reach the national grid by the end of December. Neither amounts to a scheduled date. Once generation reaches 300MW, another inspection follows, and the project will seek permission to supply the grid if the results are satisfactory, BAERA chairman Mahmudul Hasan said.

Unit 1 has a rated capacity of 1,200MW, and the two units at Rooppur have a combined design capacity of 2,400MW. A 300MW trial is therefore a quarter of the finished plant, and the first grid electrons will not close Bangladesh's supply gap on their own.

The safety sequence behind the schedule

The B-2 approval had been delayed by complications with Unit 1's automatic pressure relief safety valves. A Russian team of specialists resolved the problem and the system passed several tests, project officials said.

Physical start-up, including first criticality, was expected to take about 30 to 40 days. Stage C tests cover the reactor, primary and secondary systems, the turbine-generator, electrical systems, instrumentation and control, and reactor protection and safety systems. The project runs designated tests and assessments at each power increase, with particular attention to turbine control and protection systems and to the generator and associated electrical equipment.

Under the B-2 authorisation, heat output rises gradually, and the project can move towards power generation once the reactor reaches about 37% of its prescribed thermal power. Hasan said turbine checks were underway and would continue as output rises.

Cost and financing

The money is largely Russian. The Business Standard reported an initial project cost of Tk113,093 crore, with a proposal under way to raise it by Tk26,181.26 crore, or 23.15%, after exchange rate adjustments. Rosatom's Engineering Division is the general designer and general contractor.

The plant uses two Russian-designed Generation III+ VVER-1200 reactors.

What happens next

The next gate is Certification D, which Unit 1 must obtain before it supplies first nuclear power to the national grid. BAERA has said further stages, C and D, follow the B-2 authorisation, each with its own clearance.

Trial generation may continue for seven to eight months after production begins, before commercial production starts.