Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
beyond design basis accidents in SFS, internal and external events) their seismic qualification status
shall be confirmed due to lack of a referent qualification document.
The following safety related systems equipment, valves and pipelines are qualified:
· compartment cooldown system;
· spent fuel storage pool.
During the period from 1994 to 1998 the following projects related with equipment seismic
qualification (mechanical-process, handling equipment) have been implemented:
· Seismic strengthening of the SFS civil structure. Recovery of process and electrical
installations.
· Seismic strengthening of railways of cranes with lifting capacity Q=160/32/8t and
Q=16t in SFS
· seismic qualification and seismic strengthening of mechanical-process equipment of
SFS performing safety functions,
During the period from 2001 to 2004 a programme and detailed design was developed for
seismic qualification of the equipment in SFS and a part of equipment was replaced where needed.
In 2005 technical solution for SFS equipment, pipelines and valves reinforcement and
replacement was implemented [104].
2.6.3 Assessment of indirect effects of the earthquake
2.6.3.1 Assessment of potential failures to SSCs, not seismically qualified that may
compromise heat removal to the ultimate heat sink, by mechanical interaction or by
internal floodings
SFS Building is located on Kozloduy NPP site, to the south of Auxiliary Building 2. On 36
m of the north-east corner of SFS ventilation pipe (chimney) of AB-2 is located.
The ventilation - 2 has the required seismic safety and at RLE damage to SSCs (SFS
building, emergency DG building) or hindered access to them is not anticipated.
2.6.3.2 Potential loss of off-site power due to destruction of the main site infrastructure
At analysis of accident with DBE loss of off-site power supply shall be considered first of
all. SSCs (emergency DG of SFS and mobile DG of NPP) are provided to ensure power supply to
the SFS loads from autonomous sources of category I and II power supply.
To ensure reliable functioning of the systems in conditions of loss of off-site power
according to [45] the required inventories of fuel and oil for SFS are maintained:
2.6.3.3 Other indirect impacts caused by fires or explosions
Active and passive measures have been taken to ensure SFS fire safety to the extent possible
(section 12.6.3 [25]).
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