The NaK preparation loop is used for preparing NaK alloy,which is used for cold trap in the primary loop of China Experimental Fast Reactor(CEFR).The loop is reconstructed in test room in F104.The design program on on-line weighting loop of NaK alloy preparation is established by using of the method of pipeline transport based on the working principle of electronic The NaK preparation loop is used for preparing NaK alloy, which is used for cold trap in the primary loop of China Experimental Fast Reactor (CEFR). The loop is reconstructed in test room in F104. The design program on on-line weighting loop of NaK alloy preparation is established by using of the method of pipeline transport based on the working principle of electronic