Development of the FFDL system using resonance ionization mass spectrometry for sodium cooled fast reactors; System design for the JOYO

Harano, Hideki; Nose, Shoichi; not registered 

lmmediate detection of fuel failure and subsequent precise identification of failed fuel assembiies are extremely important and indispensable for fast reactors from the viewpoint of their safety and reliability as well as the improvement of plant availability. ln order to develop the failed fuel detection and location (FFDL) technology, laser resonance ionization spectrometry (RIMS) has been proposed to be applied to the trace analysis of krypton and xenon contained in cover gas, Various promising features have been reported including the results which suggest the feasibility of the method to the on-power real-time monitoring, through the fundamental study using the RIMS device at the nuclear engineering research laboratory (NERL) of the university of Tokyo. Based on the information obtained above, we are developing a new laser FFDL system using RIMS which is planned to be introduced onto the fast experimental reactor JOY0. By the use of the system at the JOY0, isotope analysis can be performed with high sensitivity for not only radioactive but also stable elements in fission product (FP) and tag gas in the cover gas. This permits the improvement of irradiation technology and the immediate identification of failed fuel assemblies. For instance, it is possible to identify burst samples in the breach test of fuel cladding materials during irradiation. From the isotopic composition of the FP nuclides, the burnup of failed fuel can be estimated which allows the preliminary focusing in the FFDL. ln this paper, we review the fundamental study using the RIMS device at NERL and report the basic design of the laser FFDL system for the JOY0.