Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
· Refuelling handling equipment – refuelling machine and 250 t crane in the
containment central hall.
Seismic category 2:
· Spent nuclear fuel storage system water purification system;
· Fresh fuel compartment.
2.4.2 Key operational measures to maintain SFP 3 and 4 in safe state after the earthquake
According to the updated version of SAR, [16], [17] measures for Units 3 and 4 are
provided and implemented to ensure the required protection against seismic and fire impacts.
Additionally to ensure the safe and secure storage of fuel in SFP seismic qualification of the
systems ensuring its functioning (SFP civil structure; SFP racks [53]; SFP flooding system; SFP
cooldown system; SFP overflow line to emergency makeup tank (EMT); universal slot line the
EMT; universal slot drain line to EMT (AB); SFP emergency flooding system) [54], [55] was
performed. The updated analysis of postulated initiating events for the units in state “E” according
to the regulation for spent fuel control [56] shows adherence to the criteria at different water
density, as well as SFP cooldown and flooding system redundancy [54].
The SFP civil structure performs the design functions, having the required robustness and
carrying capacity at different combinations of load, including emergency temperature and seismic
impacts for DBE. Also, SFP rack robustness at different modes has been proved [57].
Instructions have been developed, as appendices to [58], [59], specifying personnel actions
and performance of improvement measures only by specific programmes (agreed with the NRA) at
achieving safety limits for SFP fuel storage in state Е.
Following the events in Fukushima, according to [60] in the Power Generation 1 a group of
technical and organizational measures was developed aimed at a comprehensive review and
assessment of the current status of the safety related equipment [46]. Special emphasis is focused on
the cases with beyond design basis accidents and adverse external and internal impacts at spent
nuclear fuel storage in the SFP in state “E”.
The following measures have been developed and implemented:
· producing list of beyond design basis accidents scenarios for Units 3 and 4;
· programme for Units 3 and 4 operating personnel training in the beyond design basis
accidents scenarios.
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