Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
6.3.3.4 I&C, required for monitoring of condition of fuel in SFP and for accident
management
I&C, required for monitoring of condition of fuel in SFP, are located at the MCR. At level
reduction in the pools up to the controlled margin sound and light alarm actuates.
6.3.3.5 Accessibility and habitability of the MCR
Accessibility and habitability of the MCR are not limited at accident.
6.3.4 Accident management after uncoverage of the upper part of fuel in the SFS pool
6.3.4.1 Control of hydrogen
According to the assessment performed for complete loss of off-site power supply and loss
of emergency power supply, hydrogen accumulation is possible due to switching off of the
ventilation systems, but minimum air flowrate of 17,5 m 3 /h is sufficient to ensure concentration of
hydrogen above the surface of the pools does not exceed 0,4 % volumetric [25].
6.3.4.2 Ensuring of adequate protection against radiation
Executing of protection measures, envisioned in the emergency response plan, see
par.6.1.3.1.4. of [28], ensures adequate protection against radiation.
6.3.4.3 Limitation of releases after significant fuel damage SFS pool
At emptying of fuel storage compartment, releases of aerosols and radioactive noble gases
may not be localized, as in order to prevent damage of the fuel elements conditions are created for
efficient natural air circulation through the compartment [25], [113].
6.3.4.4 I&C, required for monitoring of condition of fuel SFS pool and for accident
management
SFS has available with the following systems:
· Monitoring system for radiation background above fuel storage compartments and
SFS building.
· Monitoring system for temperature and water level in compartments.
· Leakage monitoring system.
6.3.4.5 Accessibility and habitability of the control room
[25].
At complete drainage of the SFP compartments, control room in the SFS is not accessible
6.3.5 Radioactive releases from dry spent fuel storage
Beyond design basis accidents such as earthquake and flooding do not result in release of
the radioactive materials or to reduction of protective shielding provided by the containers in the
DSFS [33].
6.3.6 Measures which may be envisioned to improve possibility for localization of
radioactive substances releases
6.3.6.1 Measures for Units 3 and 4
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