Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
The structures have the necessary bearing capacity to withstand specific normative and
extreme snow loads.
4.3.4.3 Extreme temperatures
High temperatures, to the maximum measured for the area of Kozloduy NPP do not bear
mechanical loads on the structures of DSFS.
In the given design basis extreme values of temperatures do not lead to failure to the DSFS
safety functions.
In the operational history of the plant there are no events and accident initiated by extremely
low or extremely high temperatures.
4.3.5 Outdoor Switchyard
4.3.5.1 Extreme winds
The structure if OSY building is provided for bearing capacity, robustness and deformability
according to the requirements of the applicable normative documents.
4.3.5.2 Extreme snowfalls
The calculated value of snow load (2,52 kN/m2) is by 50% greater than the normative value
(1.68 kN/m2) and 57% greater than the extreme values of snow loads (1.6 kN/m2).
The structure has reliable stiffness and may withstand normative and extreme snow loads.
4.3.5.3 Extreme temperatures
Extreme temperatures are within the design basis of OSY SSCs.
High temperatures do not apply mechanical loads for the structures and buildings.
4.3.5.4 Freezing
The freezing in the region of Kozloduy is a relatively seldom phenomena.
The current operational experience since 1971 shows that for OSY there is no case of
rupture of power lines for off-site power supply or failure to off-site power supply due to freezing.
Considering the large number of connections in various directions of Kozloduy NPP, breaking of all
lines simultaneously is unlikely.
4.4 CONCLUSION FOR IMPACT OF THE EXTREME EXTERNAL EVENTS
ON THE BUILDINGS AND FACILITIES OF KOZLODUY NPP SITE
Facilities at the site, except ASSGEM, FPS 2 and DSFS, were designed before early 80s of
the 20th century, according to the regulations and standards applicable at the time. Changes in
136/202