Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
Having fulfilled its purpose, service water returns to the river by so called hot channel. It has
a length of 6930 m, trapezoidal cross-section with bottom width 12 m, at the beginning and 15 m in
the rest. The conductivity of the hot channel is180 m 3 /s and depends on the elevation of the spillway
after the low pressure channels and water level in Danube River.
Emergency pump station is located immediately before BPS- 2 and 3. It is fitted with three
emergency pump units, which in case of need supply water to the emergency inventory of "cold"
channel and, thus, ensure emergency service water supply. Loss of water from emergency inventory
is prevented both from barrier in the beginning of the hot channel and from hot water recirculation
facility before the CPS-1.
If needed, alternative service water supply can be implemented from lake "Shishmanov
shaft" from which water, gravitationally, passes by an open channel and by water intake from it by a
pipeline falls into the emergency inventory of "cold" channel.
1.6.2.3 BPS power supply
Off-site power supply to BPS is performed by switchyard 220 kV, with transmission lines
"Atom" and "Neutron" and line "Harlets" 110 kV. The voltage is transformed from 220 kV or 110
kV to 6 kV and is supplied to the pump sets of the BPS.
At loss of power supply by the three transmission lines, through uninterruptible power
supply system essential components related with the nuclear and fire safety systems, as well with
the auxiliary systems are powered.
In the BPS diesel generator station is equipped, consisting of two diesel generators constant
available and having active power 1600 kW each. The diesel generators supply power to the
emergency pump station which provides the emergency service water inventory in the cold channel.
The water supplied can be used by all circulating pump stations [7], [8].
In the BPS two batteries are installed. They ensure continuous power supply to the
following loads:
· DC power supply to control, protection and alarm systems;
· Process measurements and instrumentation;
· Operational voltage for 6kV and 0.4кV circuit breakers;
· Operational voltage for DG automation logics;
· Emergency lighting.
On the BPS numerous upgrades have been done – implementation of automatic system for
Danube River level control, replacement of circuit breakers, replacement of measurement
transformers, replacement of electrical and process protections of DG, etc. With this upgrades
maintenance of the facilities has been improved to ensure reliable and effective operation of the
BPS.
1.6.3 Connections of units 3 and 4 with units 5 and 6 and connections between the twin units
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