Summary Report for Conduct of Kozloduy NPP Stress Tests

“Kozloduy NPP” PLC
SUMMARY REPORT
for Conduct of Kozloduy NPP
Stress Tests
In accordance with 4.2.1.1. of [45], the operational (inviolable) fuel inventory in Dieselgenerator
station – 2 is totally 136,2 m 3 (22,7 m 3 per one diesel-generator) which according to item
4.2.1.2 of [45] ensures continuous operation of each of the diesel-generators for at least 7 days.
In accordance with item 4.2.1.5 of [45], the operational oil inventory is 2,7 m 3 , stored in oil
tank of each cell in Diesel-generator station - 2 or total of 16,2 m 3 . This oil inventory according to
item 4.2.1.6. of [45] ensures operation of the 6 diesel-generators in Diesel-generator station - 2 for
at least 10 days. Considering also the non-operational inventory additional operation of all Dieselgenerators
for at least 7 days can be provided for fuel, in accordance with item 4.2.1.4 and 20 days
for oil in accordance with item 4.2.1.7 of [45].
3.2.1.2 Units 5 and 6s of Kozloduy NPP
3.2.1.2.1 Major SSCs
The list of SSCs of safety systems and safety related systems includes equipment failure to
which may lead to deterioration of or failure to perform the following functions:
· Reactor safe shutdown and maintaining in safe critical condition during and after
accident;
· Core decay heat removal after reactor shutdown during and after accident;
· SFP decay heat removal during and after accident;
· Limiting radioactive releases into the environment.
Based on Level 1 PSA results [36] major SSCs for individual systems have been defined.
3.2.1.2.2 Protective measures to maintain cooling water supply
The design of conventional components service water supply system does not provide for
specific measures for maintaining of cooling water supply besides those provided for performance
of the system function. The cooling water is provided from pumps taking water from the advance
chamber of cold channel. The system is not a part of the safety system and belongs to normal
operation systems.
The essential components service water supply system is a part of the safety system. The
design incorporates all principles of building safety system: redundancy, physical separation and
independence of the trains. The system trains operate by a closed circuit with cooling of water in
spray pools. Each train includes per two spray pools. Each of them is designed to remove the entire
quantity of heat generated in unit accident mode and to ensure essential components service water
inlet temperature within the range of +4°С +33°С.
With this dimensions of the spray pool, the level change by 1.5 m ensures operation of
essential component service water without pools filling at wind speed up to 2 m/s for 30 hours.
Spray pools operating and emergency makeup with water is ensured.
108/202