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Kinoshita, Hidetaka; Kaminaga, Masanori; Haga, Katsuhiro; Hino, Ryutaro
JAERI-Tech 2002-052, 28 Pages, 2002/06
JAERI-Tech-2002-052.pdf:7.59MB
Since the Neutron Scattering Facility will be using mercury as the target material and contain radioactive products, it is necessary to estimate reliability of instruments in a system. The system would be damaged by erosion. An erosion test section and coupons were installed in the mercury loop, and their thickness was measured. As a result, the erosion is about 3
m in 1000 hours under 0.7m/s condition. The wall thickness decrease during facility lifetime of 30 years is estimated to be less than 0.5mm. Therfore, the effect of erosion on component strength is extremely small. Moreover, a measurement of residual mercury on the piping surface was carried out. As a result, 19g/m
was obtained. Thus, estimation of residual mercury for 150A-sch80 piping is 8.5g/m, and for the mercury target is about 40g. As for the target, radioactivity of the residual mercury is 1.2
10
Bq, which is extremely lower than that in the target casing of 1.010
Bq. Then, there is no influence for maintenance and storage of the spent mercury target.
Kaminaga, Masanori; Kinoshita, Hidetaka; Haga, Katsuhiro; Hino, Ryutaro
JAERI-Tech 2002-002, 22 Pages, 2002/02
JAERI-Tech-2002-002.pdf:5.37MB
The Neutron Scattering Facility will be utilized for advanced fields of Material and Life science using high intensity neutron generated by spallation reaction of 1MW pulsed proton beam and mercury target. Design of spallation mercury target system is in progress to obtain high neutron performance with high reliability and safety. The target system is using mercury and contains large amount of radioactive spallation products, therefore to establish the safety of the target system, transient behaviors of the system during anticipated events should be well understood. The safety protection system and an instrumentation system for detecting abnormal conditions must be designed based on the transient behaviors in order to terminate the transient events safely. Transient behaviors of the mercury system have been analyzed by using RELAP5 code. This report presents a test plan of mercury system transient phenomena during abnormal events using a mercury experimental loop and modification of the mercury experimental loop for abnormal transient simulation tests.