Numerical simulations of forest fire propagation and smoke transport as an external hazard assessment methodology development for a nuclear power plant

Okano, Yasushi; Yamano, Hidemasa   

A new method has been developed to assess potential challenges by forest fire smoke on a cooling function of a decay heat removal system (DHRS) of a sodium-cooled fast reactor. Combinational numerical simulations of a forest fire propagation and a smoke transport were performed by FARSITE and ALOFT-FT to evaluate a cumulative amount of smoke captured on air filters of the DHRS. The evaluated time-dependent changes of spatial particle matter (PM) density were utilized to calculate a cumulative amount of PM captured on the air filters of the DHRS. Sensitivity analysis was performed on prevailing wind speed to which both the fireline intensity and the smoke transport behavior are sensitive. The total amount of PM on the air filters was conservatively estimated around several hundred grams per m which is well below the utilization limit.