Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
pumps are located in CPS 3 and 4. The emergency makeup of the spray pools is provided from 6
shaft pump station (ShPS) in the valley of Danube River.
On the other hand, at loss of group A service water supply system reactor fuel cooling can
be ensured by use of alternative system for SG makeup, and SFP fuel cooling can be ensured by
SFP flooding system.
The Shaft Pump Stations 1¸6 are powered from BPS by cable-overhead lines 6kV with
process name ShPS-A and ShPS-B. ShPS-A is powered from the V 6kV section of BPS. ShPS-B is
powered from the IX 6kV section “Uninterruptible power supply”. Procedure for temporary power
supply of ShPS-А outlet to ShPS of diesel-generator of BPS.
2.5.3.4 Other indirect impacts caused by fires or explosions
2.5.3.4.1 Internal floodings due to seismic causes – at the site or in the buildings
In this review existing analyses of hazards from internal floodings as well as seismic
qualification status of the site and buildings pipelines has been assessed.
Measures are provided to prevent from adverse effects on the plant safety from internal
flooding resulting from rupture of non-seismically qualified pipelines in the site of the buildings.
2.5.3.4.1.1 Analyses of consequences of internal floodings in reactor building outside the
containment turbine hall
Under the modernization programme analyses of consequences of internal flooding were
performed, [86]. Individual analyses of flooding of rooms for all respective fluid systems located in
the reactor building outside the containment, Appendices 5 to 24 [86], for turbine hall, Appendices
25 [86] were developed. Appendix 26 [86] specified the differences for unit 5 as the study is
performed based on unit 6. For each room conclusions are provided depending on the influence of
the flooding on the safety system equipment and on the civil structures.
2.5.3.4.2 Measures to cope with fires
According to item 3.3.14 of [7],[8] the fire extinguishing system is built in accordance with
the following requirements:
[7],[8]:
· To reduce fire risk;
· To ensure physical separation of the systems required for the plant safety.
The fire safety system of units 5 and 6 consists of the following subsystems, item 7.6.1
· External fire ring - Units 5, 6;
· Reactor building and DGS fire alarm and fire extinguishing systems;
· Containment fire alarm and automatic fire extinguishing system;
· Gas fire fighting system in the electric equipment rooms;
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