Current Status on the Development of Sodium Boiling Detection System in Japan

H.Araki*; T.Komab*; Sato, Kazujiro*; Y.Ozaki*; H.Inuzi*; K.Koday*; Y.Shino*

PNC TN941 81-114, 11 Pages, 1981/06

PNC-TN941-81-114.pdf:1.12MB

Some studies for confirmation of the usefulness of the measurements of boiling sound and fluctuations of sodium temperature, flowrate and neutron flux for detection of sodium boiling have been curried out in Japan. For the development of acoustic detection system, acoustic transmission decay and velocity change by fuel pins, gas plenum and neutron shield were measured. Acoustic transmission from the reactor core to the detectors which were installed in the upper core structure and the upper flange of reactor vessel were studied theoretically and experimentally using the reactor vessel mockup. Sodium boiling acoustic spectra which were dependent of detector positions were obtained in the out-of-pile experimental facility. Acoustic background caused by flow and electric noise were measured in the Experimental Fast Reactor. On the other hand, coolant temperature and flowrate fluctuations caused by the sodium boiling were measured by the Temp/Flow detector which were mounted on the outlet of fuel subassembly. Simulation tests by computer on the correlation method between neutronic and acoustic signals were carried out. Current status and future plans about these studies in Japan are summarized briefly in this paper.