Review of LOFW

1. Review of LOFW

2. LOFW category • In VVER-1200 designs these PIEs are design basis conditions of Category 2 (anticipated operational occurrences, frequency 0.01 per year or more). • Comment: acceptable but need details as the following

4. Acceptance criteria • Pressure of the primary coolant and SG steam lines will be less than 115 %of design value of design value; • DNB is not reached DNB is not reached with a probability of 95% for the most hot fuel rod (minimum DNBR in the core is more than (minimum DNBR in the core is more than 1.0); - Acceptable • Fuel pellets do not melt even locally (temperature is lower than 2540°С for “burnout” fuel and less than 2840°С for fresh fuel); - Inconsistent with graph (1818 °С ??) and not stated in calculation result • Radially-averaged fuel enthalpy does not exceed 586 J/g along the J/g along the axis of any fuel rod – Prove??

5. Computer Codes • The LOFW calculation is made with the use of computer code DINAMIKA-97 included into the computer code package TRAP-97 described in section 15.3. The code package TRAP-97 is validated against large scope of domestic and international experimental data and certified by Russian regulatory body. • Comment: Acceptable

6. Thank you