Flow diagram of the BN-600 N-200M SG APS: 1 – evaporator; 2 –superheater; 3 – intermedi- ate superheater; 4 – buffer tank; 5 – safety diaphragm; 6 – reaction product discharge line; 7 – stage I and II separa- tors; 8 – safety valve; 9 – fast-acting valves; 10 – emergency water discharge line; 11 – expansion tank; 12 – sodium valves; 13 – hydrogen-in-sodium detector; 14 – hydrogen-in-gas detector; 15 – gas pressure sensor; 16 – detector of hydrogen bubbles in sodium; 17 – small sodium leakage line; 18 – sodium flow meter; 19 – emergency water (steam) discharge safety valve.