Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
Analyses of the earthquake, flooding, combination of beyond design flooding and the
earthquake, loss of power supply and loss of ultimate heat sink, do not show loss of the SSCs,
including ventilation systems.
6.3.2.3 Limitation of releases after significant fuel damage in the SFP
Analyses of the stress-test on separate positions show that hypothetically only partial,
mechanical failures are possible only not the significant ones of fuel in the SFP.
SFP is located in the central hall, outside the SG box compartment and consequently, at
hypothetic fuel damage in the SFP comparatively hostile consequences may be reached in relation
with radioactive releases. Contact of the central hall (at destruction) with environment is the cause
for the most part of releases of the radioactive substances during the accident occurring with
containment bypassing. This defeats the purpose of strategies for maintaining of underpressure in
the SGBC.
6.3.2.4 I&C, required for monitoring of condition of fuel in SFP and for accident
management
Units 3 and 4 have available the following systems:
· Monitoring system for radiation background above SFP.
· Monitoring system for temperature and water level in SFP.
· Leakage monitoring system.
Accident does not impact I&C.
6.3.2.5 Accessibility and habitability of the MCR
Accessibility and habitability of the MCR are not limited at these accidents.
6.3.3 Accident management after uncoverage of the upper part of fuel in SFP of Units 5 and
6
6.3.3.1 Control of hydrogen
SFP of Units 5 and 6 is located within the containment. Hydrogen which may generate at
possible damage, will spread within the containment and will be recombined by the PAR
6.3.3.2 Ensuring of adequate protection against radiation
Radioactive substances which would release at accident in the SFP, will be maintained
within the containment.
6.3.3.3 Limitation of releases after significant fuel damage in SFP up to controlled margin
Radioactive substances which would release at accident in SFP will be maintained within
the containment, when the unit is in condition of the isolated containment.
In the emergency instruction treating the IEs (initiating events) in the SFP actions are
envisioned for evacuation of the personnel in the containment and isolation of the containment, if
accident occurs in condition of the unit with not isolated containment.
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