This　paper　focuses　on　the　simulation　of　a　fault　arc　in　a　closed　tank　based　on　the　magneto-hydrodynamic　(MHD)　method,　in　which　a　comparative　study　of　three　radiation　models,　including　net　emission　coefficients　(NEC),　semi-empirical　model　based　on　NEC　as　well　as　the　P1　model,　is　developed.　The　pressure　rise　calculated　by　the　three　radiation　models　are　compared　to　the　measured　results.　Particularly　when　the　semi-empirical　model　is　used,　the　effect　of　different　boundary　temperatures　of　the　re-absorption　layer　in　the　semi-empirical　model　on　pressure　rise　is　concentrated　on.　The　results　show　that　the　re-absorption　effect　in　the　low-temperature　region　affects　radiation　transfer　of　fault　arcs　evidently,　and　thus　the　internal　pressure　rise.　Compared　with　the　NEC　model,　P1　and　the　semi-empirical　model　with　0.7　＜　alpha　＜　0.83　are　more　suitable　to　calculate　the　pressure　rise　of　the　fault　arc,　where　is　an　adjusted　parameter　involving　the　boundary　temperature　of　the　re-absorption　region　in　the　semi-empirical　model.