1. Approaches and measures aimed at ensuring safety, preventing severe accidents in new RF NPP designs
Gutsalov N.A.
10/03/2016

2. NEW RF NPP DESIGNS
- VVER.1200
- VVER.TOI

3. An analysis of the events happened at the Fukushima-1 NPP
An analysis of the events happened at the Fukushima-1 NPP shows that the accident was caused by a combination of extreme external influences. The main initiating events and subsequent failures were as follows:
seismic impact with intensity above 8 points on the MSK scale;
loss of normal and emergency (diesel generator) power supply (blackout);
tsunami and, therefore, the ultimate heat sink failure (sea water);
hydrogen generation due to zirconium-steam reaction, release of hydrogen in the reactor plant building volume and damage to the building due to hydrogen explosion;
damage to the foundation of the reactor plant building and release of radioactivity into the environment;
inability to recover the safety features for a long time.

4. protection against external hazards
20/400

5. passive safety systems
The list of passive safety systems incorporated in the design includes the following ones:
- a passive core flooding system from the ECCS hydro accumulators and from the system of second and third (low-pressure) stage hydro accumulators (HA-2,3);
- a passive heat removal system (PHRS) from the steam generators with air-cooled heat exchangers-condensers located on the outer containment’s surface;
- a system of passive hydrogen recombiners located in the containment volume.
Autonomy (absence of core damage) is determined by the water inventory in the 2nd&3rd stage hydro accumulators and makes at least 24(72) h in case of the reactor coolant leak with break of the maximum diameter (DN=850) pipeline.

6. passive safety systems
Passive heat removal system

7. additional (alternative) Safety systems
For the case of NPP blackout and loss of all water ultimate heat sinks for more than 24(72) h, additional (alternative) systems are incorporated in the design.
These additional systems include the following ones:
- an alternative component cooling circuit.
- an alternative diesel generator with air cooling;

8. additional (alternative) Safety systems

9. diesel-generator unit
The diesel generator electric power output is 2 MW at 0.4 kV. The diesel-generator unit (DGU) is made in a container design that allows its outdoor storage and operation. The fuel inventory will in this case be sufficient to supply the DGU with fuel for about 20 days.

10. THANK YOU