The accounting methods currently applied for pyrochemical experiments are conventional destructive analyses such as ICP-AES, ICP-MS and у spectroscopy for concentration analyses, and weight measurements for bulk analyses. Because destructive analyses usually require a long time to prepare the liquid solution from salt or metal samples, it is important to develop a method for on-line monitoring of the concentrations of elements in molten salt. It might be difficult to measure the weights of materials in a large vessel; thus, a method of measuring bulk amounts using level probes and density equations to calculate weights from volumes must be developed. It is also important to develop sampling technology to decrease sampling errors in pyrochemistry. In this section, the development of monitoring techniques specific to pyrochemistry is summarized.