Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex

Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.

Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12

https://doi.org/10.1103/PhysRevSTAB.17.120101

We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.

Study on fluid mixing in a fuel subassembly of a fast reactor; Mixing phenomena with cross flow and applicability of subchannel analysis

Kawamata, Nobuhiro; Miyakoshi, Hiroyuki; Kamide, Hideki

JNC TN9400 2004-047, 99 Pages, 2004/08

JNC-TN9400-2004-047.pdf:8.02MB

Sodium experiments were carried out for mixing phenomena in a subassembly of fast reactor. A blockage was installed in a wire wrapped 37-pin subassembly in order to form cross flow around the blockage. Temperature distributions in the subassembly were measured under a condition that only one pin was heated. Investigation on mixing phenomena with the cross flow is useful to predict thermohydraulics in a deformed pin bundle of high burnup core. The subchannel analysis code, ASFRE, was applied to the experimental analyses. The ASFRE solves momentum equations in multi dimensions and has the distributed resistance model for a wire spacer.Following remarks were obtained:1).Measured axial temperature distributions showed that the sodium temperature decreased due to the core flow coming from the cold blockage side. Local peaks were found at the subchannels which have the wire spacer. 2).ASFRE simulated the temperature decreases due to the cross flow and axial temperature profiles were in good agreement with the measured data.3).The local peaks at wire positions were also simulated by ASFRE, however, the peak value was underestimated. ASFRE has high applicability to the mixing phenomena in a wire wrapped subassembly where the cross flow has significant role due to the change of flow area.4).Experimental database for the mixing phenomena with the cross flow were obtained for a subassembly of sodium cooled fast reactor.

Study on natural convection in core barrel; Experimental and numerical results for band type spacer pads

Hayashi, Kenji; Kawamata, Nobuhiro; Kamide, Hideki

JNC TN9400 2003-043, 64 Pages, 2003/03

JNC-TN9400-2003-043.pdf:2.67MB

In a fast reactor an lnter-Wrapper Flow (IWF)is one of significant phenomena for decay heat removal under natural circulation condition, when a direct reactor auxiliary cooling system (DRACS)is adopted for decay heat removal system. Cold coolant provided by dipped heat exchangers (DHX) of DRACS can penetrate into the core barrel (region between the subassemblies)and it makes natural convection in the core barrel. Such IWF will depend on a spacer pad geometry of subassemblies. Water experiment, TRIF(Test Rig for inter-wrapper Flow),was carried out for IWF in a reactor core. The test section modeled a 1/12th sector of the core and upper plenum of reactor vesse1. Experimental parameters were the spacer pad geometry and flow path geometries connecting the upper plenum and core barrel. Numerical simulation using AQUA code was also performed to confirm applicability of a simulation method. An experimental series using a button type spacer pad had been carried out. Here a band type spacer pad was examined. Temperatures at subassembly wall were measured with parameter of the flow path geometries; one was a connection pipe between the upper plenum and core barrel and the other was flow hole in core former plates between the outermost subassemblies and the core barrel. It was found that these flow paths were effective to remove heat in the core in case of the band type spacer pad. A general purpose three dimensional analysis code, AQUA,was applied to the experimental analysis. Each subassembly and inter wrapper gap region were modeled by slab mesh geometry. Pressure loss coefficient at the spacer pad was set based on the geometry. The numerical simulation results were in good agreement with measured temperature profiles in the core.