The invention discloses double-wall-pipe heat exchanging equipment for a liquid metal reactor and a broken-pipe detecting and maintaining method. The heat exchanging equipment comprises a plurality of pipe bundle components which are independent of one another, a shell-side flow guide part, a shell, an inlet header, an outlet header, a gas connecting pipe and a valve, wherein the upper end of each pipe bundle component is connected to the shell and can be taken out of the shell, the inlet connecting pipe of each pipe bundle component is connected with the inlet header, the outlet connecting pipe of each pipe bundle component is connected with the outlet header, the lower portion of each pipe bundle component penetrates the shell-side flow guide part, and the interlayer of each double-wall heat exchanging pipe of each pipe bundle component is filled with low-melting-point alloy and covered with wall-breaking detecting gas. The double-wall-pipe heat exchanging equipment has the advantages that broken pipes are detected timely through gas pressure change, the use safety of the heat exchanging equipment in the liquid metal reactor is increased, the heat exchanging equipment can use the modularized pipe bundle components which can be replaced independently, and the maintenance cost and intensity of the heat exchanging equipment under breaking accidents.