Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
The power supply of the pump and the I&C is from mobile diesel-generator.
The suction pipeline of the pump is connected through a T-joint to the suction pipeline of the
pump of the first channel of steam generator emergency makeup water system. The pump
connection is provided through one manual valve. The pressure pipeline is connected to the pressure
header of the pump of the first channel of steam generator emergency makeup water system.
Design solutions for systems for heat removal to the ultimate heat sink
Essential components service water system.
The system serves for water supply to the safety system components. It includes spray ponds
that remove heat to the atmosphere, pumps and pipelines to the heat-exchangers. The system is a
part of the safety system.
Low pressure emergency and normal cooldown system.
The low pressure emergency and normal core cooldown system combine the functions of a
protective safety system and a normal operation system (section 12 from [7],[8]) . The system is
designed for:
· reactor core emergency cooldown and continued core heat removal in accidents
conditions associated with primary circuit leakage, including main circulation line break that
ensures supply to the primary circuit of boric acid with concentration over 16 g/kg with flow
rate 250-300 m 3 /h at primary circuit pressure ≤ 2.16 MPa and 700-750 m 3 /h at primary
circuit atmospheric pressure.
· primary circuit normal cooldown during reactor shutdown and core decay heat
removal at maintenance and refuelling.
The system is a part of the safety system and consists of three independent trains with each
train providing for 100% of the system functions.
BRU-A system.
The system of fast acting device for the steam dump to the atmosphere is designed to release
steam from the main steam lines to the atmosphere. The heat is removed from the SGs directly to the
atmosphere at steam cooldown of the primary circuit. BRU-A system is an emergency system and is
used when BRU-K system is not operable. The use requires replenishment of large amount of water
in the SG makeup system. SG makeup at BRU-A operation is through makeup water systems listed
in the preceding paragraph.
Intermediate level emergency boron supply system.
This is a protective system that is a part of the safety systems designed for emergency
primary circuit supply with boric acid solution with initial concentration of 40 g/kg and flow-rate
over 130 m 3 /h, at accident conditions with high pressure (≤ 110 kgf/ m 2 ) maintained in the primary
circuit as well as for replenishment of leakages in modes with the primary circuit depressurized.
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