Mumbai :  Rosatom in July 2013,  successfully performed the passive fast-acting boron injection system (PFBIS) of the operating reactor, at Unit 1 of the Kudankulam Nuclear Power Plant ( NPP).

This system has no analogues both in the national and global practice. Successful tests of PFBIS performed at the Indian VVER reactor, built under the Russian project, have become a new step towards further strengthening of VVER reactors’ safety.

Passive fast-acting boron injection system (PFBIS) is a new development developed by Russian specialists.

It is an additional safety system for controlling beyond-design-basis accidents in case the regular emergency protection system fails to act, for one reason or another.

It is designed to switch the nuclear reactor core to subcritical state by injecting a concentrated solution of boric acid into the primary coolant circuit in the event of failure of the reactorr control and protection system.

The system is comprised of four independent channels, each of which includes a tank containing boric acid and connected to the circulation loop in parallel with main circulating pump (MCP).

When opening fast-acting isolation valves on the pipelines connecting PFBIS tanks to the primary coolant circuit, boron solution is displaced from them by the coolant of the primary circuit due to the MCP head, including the time during their coastdown. Boron solution displaced to the primary coolant circuit of the reactor system flows to the reactor core’s entry, which results in the reduced power of the reactor.

The PFBIS system is installed in the first two units of the Kudankulam NPP. There were suggestions to employ it in the Bulgarian Belene Nuclear Power Plant.  This system in future will be deployed at   Unit 3 and Unit 4 of the Khmelnitsky Nuclear Power Plant

At the first unit of the Kudankulam NPP, tests for PFIBIS were performed prior to the physical start-up of the reactor, while in July, 2013, they were carried out after the physical start-up. The results obtained comply with the design values.

Nether French nor American light water reactors include any analogue of the Russian PFBIS.

Source : Amrita