Rooppur NPP: Hydro-accumulators’ testing begins in Russia

Hydraulic testing of half bodies of Passive Core Flooding System (PCFS) Hydro-accumulators begins at Petrozavodsk Branch of AEM-Technologies, Russia.

These are intended for Power Unit - 2 of Rooppur Nuclear Power Plant. Eight PCFS Hydro-accumulators will be installed in each unit.

According to Rosatom, the Russian contractor of the Rooppur NPP, hydraulic test is one of the most important final inspections of the equipment.

PCFS Hydro-accumulator is filled with specially treated thermally enriched water and the pressure in the vessel is raised up to 4.4 MPa and held for 10 min minimum.

After the pressure is released, the outer surface is inspected visually for any leaks and permanent deformations.

Hydro-accumulators each having a capacity of 120 cubic meters are manufactured from stainless steel.

It comprises three shells and two heads. Ladders and maintenance platforms as well as other internals are installed within the body.

PCFS refers to the second level of NPP passive safety systems. It is intended for the removal of the coolant residual heat of the reactor primary circuit.

An aqueous boric acid solution heated to a temperature of approximately 60 degrees is stored in the Hydro-accumulator during operations of the plant.

If for any reason the pressure in the primary circuit falls below a certain level, the fluid is automatically fed into the reactor and the active core is cooled down.

Rooppur NPP is designed and being constructed by the Engineering Division of the Rosatom State Corporation.

AEM-Technologies has been producing main reactor room equipment for both the units of the power plant.

According to Bangladesh Atomic Energy Commission, the implementing authority of the RNPP, the first unit of the power plant was scheduled to start operation in 2022 and second one in 2024.

But recently the first unit's operation was rescheduled to 2024 and second unit to 2025.