Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
· passive measures – the main civil structures are built of reinforced concrete, the roof
is filled with 6m fire strips (zones) of non-combustible materials.
· active measures – they include external (ground for the plant) fire ring, internal fire
fighting installation with fire taps in the rooms and dry tube for water extinguishing of
cover.
occurrence.
Fulfilment of the requirements of fire safety ensure the safety of SFS in case of fire
The following possible explosions are discussed:
· explosion of the receiver site of Kozloduy NPP – 1 and 2;
· explosion of the receiver site of Kozloduy NPP – 3.
Thus, the possible events defined do not jeopardize safety of SFS operation.
2.7 MEASURES FOR PROTECTION OF DSFS SEISMIC DESIGN BASES
2.7.1 Systems, structures and components (SSCs) required for DSFS maintaining in safe
state
The analyses are performed based on the NRA approved technical design for construction of
DSFS [38]. As input the latest Interim safety analysis report [39] was used.
Regardless of the fact that the quantity of radioactive material in the DSFS is large at the
end of storage period, in the containers safe leak-tight confinement of this material is always
ensured in pursuance of defence-in-depth principle. The radioactive decay heat is removed in a
passive way.
All safety functions during the storage are maintained in a passive way as there is no need in
active safety systems.
All SSCs of DSFS are classified considering their safety functions in accordance with the
referent documents.
The main SSCs required maintaining operability during and after earthquake are:
· building;
· crane 145 t;
· containers;
The analyzed accident scenarios during and after earthquake are as follows:
· mechanical impact from earthquake;
· container blocked with debris;
· fire impact;
· station blackout.
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