Formamide solution of lead(II) iodide (Pbl2) with hexamethylenetetramine (hmta) gave [C6H13N4]2[Pb3I8(C6H12N4)2], while reaction of PbI2 with hmta through intervention of water produced [C6H13N4][PbI3]. From characterization of the crystals by X-ray diffraction, hmta appears to tend to be protonated cations, but one of hmta is coordinated to Pb atom in the former compound.

No abstract

T h e enthalpies of two kinds of simulated radioactive waste glasses have been measured with an ice isothermal calorimeter at temperatures of 424-875 K by means of drop calorimetry. T h e fitting functions for the enthalpies per gram have been determined by the least squares fitting. Specific heat and average molar heat capacity have been obtained. It is likely that heat capacity of waste glass remarkably depends on its composition especially above its glass transition temperature.

In the development of disassembly technologies for the fast reactor fuel assembly, laser cutting was used in tests done in the United Kingdom and the United States due to problems of wear and breakage of cutting-off wheels (CWs); however, the laser can cause thermal damage to fuel pins, melting the part of the fuel pins under the wrapper tube and releasing radioactive materials. Laser cutting conditions to mitigate thermal damage of fuel pins, and development of CWs with appropriate durability to withstand wear and breakage damage were studied. A mock-up machine to be used with a simulated fuel assembly of the fast reactor Monju was designed and manufactured, and the test to confirm the proposed disassembly procedure was conducted. Laser cutting with the reviewed cutting conditions, mechanical cutting with controlled feed speed using CWs, and the disassembly procedure tested with the mock-up machine were confirmed to be workable disassembly technologies.

Japan Atomic Energy Agency (JAEA) has been developing an advanced head-end process based on a disassembly machine using cutting technology as well as a shearing machine with short-stroke shearing for reprocessing fast reactor (FR) fuel assemblies. The FR fuel pins should be removed from the fuel assembly wrapper tube by cutting without damage to reprocess them. In this paper, the applicability of fiber laser cutting as a promising cutting technology for disassembly machines is reported. Toward solving problems such as the welding of wrapper tubes and spacer wires, cutting tests (slit cut and crop cut) using simple test pieces and mock-up tests using a simulated fuel assembly were carried out to determine optimal cutting conditions (e.g., power, cutting speed, focus position, and cutting position (lower plug/knock bar)) and procedure. Under the selected cutting conditions and procedure, damage to the fuel pin and the welding of the spacer wires were reduced, demonstrating that cutting using a fiber laser can be applied to disassemble FR fuel assemblies.