Rooppur's criticality approval puts grid readiness to the test

The Bangladesh Atomic Energy Regulatory Authority (BAERA) approved the B2 sub-stage of Rooppur Nuclear Power Plant's Unit 1 on 8 October 2026, marking a milestone for Bangladesh's nuclear journey.

The approval allows the reactor to begin physical start-up tests and reach its minimum controllable power level under the Reactor Criticality Programme. This will pave the way for the first sustained nuclear chain reaction at Bangladesh's first nuclear power plant and bring it closer to electricity generation.

The approval confirms that the reactor's design, core and key systems meet safety requirements. BAERA has licensed 52 NPCBL staff and 46 Russian operators for commissioning. The B2 sub-stage is expected to take 15–20 days, during which engineers will conduct low-power tests to check the reactor's performance.

The long climb to full power

If all B2 sub-stage tests are successful, Unit 1 of Rooppur Nuclear Power Plant will enter Stage C (Power Start-up), subject to regulatory approval. The reactor's power will gradually increase towards grid synchronisation.

If tests, safety checks and approvals proceed as planned, with sufficient staff and spare parts available, the unit could supply around 300–350 megawatts of electricity to the national grid in the second half of December 2026.

Initially, reactor power will rise to 1–5% for core and turbine-generator tests. It will then increase gradually to 10–12% and 25–30%. At 30–35% capacity, the unit will connect to the grid after synchronisation checks and maintain a stable load for at least four hours.

First grid synchronisation marks a major milestone for a nuclear power plant, but it does not signal the start of commercial production or uninterrupted electricity supply. Generation may remain intermittent during the subsequent testing phase.

The initial objective is to verify that the turbine-generator can synchronise safely with the national grid. Automatic shutdowns may occur in response to fluctuations, while temporary disconnections allow engineers to conduct mechanical tests, including load rejection and turbine trip tests, and analyse performance data.

The initial supply of around 350 MW from Rooppur NPP should not be considered baseload generation. The national grid must accommodate fluctuations until the plant achieves commercial operation.

Following synchronisation, Unit 1 will gradually increase output to 100% of rated capacity over seven to eight months, subject to Bangladesh Atomic Energy Regulatory Authority (BAERA) licensing and successful safety tests. This process, known as Stage D, comprises two sub-stages.

During D1, output will rise through 45–50%, 70–75%, 85–90% and 100% capacity, with performance tests at each level. During D2, the unit must demonstrate continuous operation at full capacity for at least 15 days.

After completing commissioning tests, meeting contractual requirements and obtaining a commercial operation licence, the unit will be formally taken over by the Bangladesh Atomic Energy Commission (BAEC) and Nuclear Power Plant Company Bangladesh Limited (NPCBL). It will then begin regular baseload supply of around 1,150 MW to the national grid.

Six tests still ahead

Grid synchronisation and maintaining an uninterrupted power supply from Power Unit 1, Rooppur NPP represent complex challenges for Bangladesh. 

1. Nuclear reactors are base-load power units that require rigid operating conditions. Any disruption on the national grid can trigger an automated emergency shutdown of the reactor to protect the core. The primary challenges hindering smooth synchronisation and reliable power evacuation are outlined as: 

Nuclear plants require exceptionally high grid stability, whereas Bangladesh's national grid historically experiences significant voltage and frequency fluctuations.

The power units of the Rooppur NPP demand a strictly controlled 50 Hz frequency. If the grid frequency drops or surges unexpectedly due to failures elsewhere in the network, the reactor's protection systems will automatically isolate the plant from the grid.

Upgrading the system with technologies like Automatic Frequency Control (AFC) and Flexible AC Transmission Systems (FACTS) to withstand sudden faults is critically necessary.

Moreover, evacuating 1,200 MW of power requires robust 400 kV and 230 kV transmission networks that are fully optimised with the necessary redundancy.

2. Moving Rooppur NPP's Unit 1 from power start-up to commissioning requires seamless coordination among the reactor, turbine, generator and safety systems, as well as BPDB, PGCB, emergency response agencies and on-site and off-site nuclear security teams. Establishing this multi-agency coordination is a major challenge.

3. Progressing through criticality, power ascension, grid synchronisation, trial operations and demonstration requires precise equipment and reliable logistics. Previous delays caused by faulty safety valves highlight the need for robust inventory tracking and logistics systems, as even minor errors can halt commissioning.

The Rooppur NPP requires two separate inventories for critical components, strategic spares, and operational consumables:

Commissioning Inventory: Ensures the immediate replacement of any component found damaged or defective during ongoing testing and functional checks.

Reserve Inventory: Acts as a safety buffer for major unexpected mechanical failures, global supply chain disruptions, or the initial days of trial runs and commercial operations.

Safety must not be compromised during Unit 1's first criticality, power start-up or trial operations. Strict quality assurance and quality control protocols for safety valves and other critical components should follow IAEA guidelines and international best practices. Clear procedures are also needed to manage spare parts during the transition from trial operations to commercial operation after provisional takeover.

4. Transitioning Unit 1 from first criticality to provisional takeover requires a strict, sequential testing programme, with thorough data analysis before each sub-stage, alongside site infrastructure readiness for emergency response, radiation monitoring and waste management. It also requires sign-off from ASE, NPCBL/BAEC and regulators, strict hold points, and immediate reporting of non-conformities. 

If any mechanical component fails during transient power-unit checks, it directly impacts the safety and stability of the reactor. In such a situation, verifying complete operational integrity before moving to the next stage is mandatory, in strict alignment with international standards upheld by all Rooppur NPP stakeholders.

5. Operating, Organisational and Competency Development: NPCBL must operate as a licensed organisation and establish its Executive and Corporate Management Framework by filling critical positions with competent personnel. 

It must set up on-site management, an operations department, and a shift structure for Units 1 and 2 at the Rooppur NPP, utilising the Novovoronezh-II reference plant model and IAEA GS-G-1.1 guidelines. 

NPCBL must foster a strong nuclear safety culture built on psychological safety, blameless reporting, and a questioning attitude, while reinforcing leadership integrity, conservative decision-making, ethical governance, workforce pipelines, and long-term supply chain and spare parts strategies. 

6. Addressing technical skill gaps requires stronger management systems, internationally trained inspectors, updated regulatory frameworks and near-site infrastructure at Rooppur to support independent regulatory oversight.

BAERA's near-site facility must have sufficient staff and resources to inspect commissioning and plant operations continuously and monitor radiation and nuclear safety.

Building a nuclear power plant involves much more than visible structures. Behind the reactor buildings, cooling systems and power networks lies a complex framework of preparations essential for long-term safety. These include the 19 infrastructure elements under the IAEA Milestones Approach, regulatory oversight, institutional readiness, safety culture, skilled personnel, quality assurance, operational documentation and safety analysis.

Rooppur NPP's planned 2,400 MW capacity could strengthen Bangladesh's energy security by providing reliable baseload electricity and supporting economic growth and technological development.

Sketch: TBS

Mohammad Shawkat Akbar is the Retired Chairman of the Bangladesh Atomic Energy Commission (BAEC).

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.