Sodium-cooled fast reactors use liquid sodium as a coolant, with sodium quantities ranging from several tons to thousands of tons. Metallic sodium is highly reactive, and high-temperature sodium can easily react with oxygen in the air, leading to sodium fires and releasing significant heat. This results in pressure and temperature changes in the leakage area, with non-negligible thermodynamic, chemical, and radiological consequences. Sodium leakage-induced fires are a major risk source for sodium-cooled fast reactors, especially since primary loop sodium is highly radioactive. Combustion of such sodium can generate radioactive aerosols, making it essential to take effective measures to prevent leaks and mitigate consequences promptly after a leakage occurs. SPOOL is a sodium fire accident analysis program developed by the China Institute of Atomic Energy (CIAE), specifically designed for the safety analysis of the China Experimental Fast Reactor (CEFR). Based on the actual processing logic of sodium fire accidents, secondary development and verification of SPOOL have been conducted, enhancing the program's ability to accurately simulate the transient responses during such incidents. The newly developed SPOOL program is utilized to analyze and simulate sodium fire accidents within the primary circuit of the sodium-cooled fast reactor (SFR). The research findings can serve as a valuable reference for detection methods and instrument responses in the primary circuit's process room of sodium-cooled fast reactors.