IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fusion Neutronics Studies at Osaka University Isao MURATA Department of Electronic, Information Systems and Energy Engineering, Osaka University September 21, 2004 Workshop on Sub-Task Fusion Neutronics under IEA Implementing Agreement on a Co- operative Programme on the Nuclear Technology of Fusion Reactors Giorgio Cini Foundation, Island of San Giorgio Maggiore, Venice, Italy Title

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fusion neutronics topics of Osaka University Experiment ・ Charged particle emission DDX measurement (already done for several weeks) ・ (n,2n) reaction cross section measurement (to be done in Dec. 2004) Analysis ・ Fusion-Fission hybrid reactor ・ Variance Reduction of Monte Carlo code In addition ・ OKTAVIAN facility will be back

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Measurements of charged particle emission DDX with a pencil-beam DT neutron source Samples: 9 Be[100μm], 27 Al[50μm], 19 F(CF 2 )[50μm] Facility:FNS, pencil-beam DT neutrons φ n =1x10 6 n/sec/cm 2 Beam diameter : 2 cm Method:ΔE-E counter telescope Detector:SSD (ΔE(50 mm 2 x 9.6 μm-t), E(300 mm 2 x 700 μm-t)) Remarks:Spectra have been measured for Be and Al. Preliminary results are described here. For F, preliminary measurement just done. Charged particle DDX

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice D + beam T target Pre-collimator (Fe) Fe polyethylene concrete CdPb sample Vacuum Chamber  E+E silicon detector 2cm  neutron beam 170cm200cm ss Experimental Arrangement

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Measured 2-d energy deposition spectra of ΔE-E detectors for 27 Al(n,charged-particles) reaction at scattering angle of 45 deg. The sample thickness is 50μm. Proton and BG Alpha 27 Al(n,a) 24 Na 27 Al(n,p) 27 Mg

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Measured 2-d energy deposition spectra of ΔE-E detectors for 9 Be(n,charged-particles) reaction at scattering angle of 45 deg. The sample thickness is 100μm. Triton 7 Li (Ground and 1 st excited states) Alpha 6 He (Ground state) 6 He (1 st excited state) 9 Be(n,xa) 9 Be(n,t) 7 Li 9 Be(n,a) 6 He

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Measured 2-d energy deposition spectra of ΔE-E detectors for 19 F(n,charged-particles) reaction at scattering angle of 30 deg. The sample (CF 2 ) thickness is 50 μm. 19 O (ground and 1 st excited states) 19 O (2 nd excited state) 19 O (5-7 th excited states) 18 O (Ground state) 18 O (2 nd excited state) 17 O (Ground state) 17 O (1 st excited state) 19 F(n,n’p) 18 O 19 F(n,p) 19 O 19 F(n,d) 18 O 19 F(n,t) 17 O

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Why can anti-coincidence spectrum be used? ΔEE 9.6μm 600 keV E p <600keV E p >600keV E α <2.5 MeV Hydrogen (p) Helium (α) E α >2.5 MeV Energy loss in ΔE detector (9.6μm) p : ～ 600 keV α: ～ 2.5 MeV 2.5 MeV Energy p + α α only for 0.6 – 2.5 MeV 700μm Background: Sample out < 20 counts / hr Sample in ( neutron scattering at the sample ) φ n (at the detector) < 100 n/sec/cm 2 Correction: Elastic scattering of the sample nuclide → Corrected by the nuclear data Anti Coin Anti Coin Anti

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Aluminum Total cross section of 27 Al(n,α) reaction at 14.1 MeV: This work137±2 mb (Preliminary) JENDL mb ENDF/B-VI130.5 mb

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Beryllium Total cross section of 9 Be(n,xα) reaction at 14.1 MeV: This work546 mb (preliminary, >1.4 MeV) JENDL mb (>1.4 MeV) 483 mb for (n,2n) reaction ENDF/B-VI587 mb (>1.4 MeV) 483 mb for (n,2n) reaction

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice A new charged particle emission DDX spectrometer has been developed with a pencil-beam 14 MeV neutron source and a telescope system with two SSDs of ΔE and E. This spectrometer has good performance of (1) low minimum-measurable- energy below 2 MeV for alpha particle, (2) good energy resolution of around 100 keV and (3) high S/N ratio over 10. From the measurement for aluminum, acceptable agreement with the evaluation was obtained which showed the validity of the spectrometer. For beryllium, highly accurate DDX spectra were so measured that the nuclear reaction mechanism including the branching ratio would be made clear. Measurements for the following light nuclides are planned: Carbon, fluorine(CF2), lithium(LiF) Conclusions and the future work

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice (n,2n) reaction cross section measurement with a beam DT neutron source Samples: 9 Be (2 cm φ x 2 cm long) Facility:FNS, pencil-beam DT neutrons Machine time:4 weeks in Dec and March 2005 Method:Coincidence detection with pulse shape discrimination Detector:NE213 (4 cmφ) x 2 Remarks: Direct measurement of the spectra of two neutrons emitted from (n,2n) reaction. Results: Neutron spectra from 9 Be(n,2n) reaction will be measured. The results is used together with measured DDX data of 9 Be(n,CP) and 9 Be(n,xn) to examine precise reaction mechanism of beryllium induced by high energy neutron. The next target is deuteron. (n,2n)

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice NE213(4cmφ) Collimator (Fe, Pb etc) 200cm 2cm D + beam Routing TiT target sample 10cm ～ 65cm Experimental arrangement 1

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fusion-Fission hybrid reactor Motivation:Fusion reactor: ?, FBR: ?? Energy resource till these final goal Objectives:Considering Japanese circumstances, Energy supply with self sufficiency of tritium Transmutation of nuclear waste and MA Analysis method: MCNP + ORIGEN(burnup) with 3-d ITER model Remarks: ～ 50 %: Breeding, ～ 40 %: Fuel, 10 %: Transmutation Fuel: UO 2 (nat.)+Reprocessed Pu(10 vol. %), i.e., ～ 6% Pu-239. Breeding: Li 2 ZrO 3 (Li-6 30% enriched)+Be(90%) Transmutation: 93 Zr, 99 Tc, 107 Pd, 129 I, 135 Cs Results: TBR ～ 1.2 Energy multiplication ～ 5 k eff ～ 0.7 Power density ～ W/cc FF hybrid

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Poloidal field coil Toroidal field coil Center Solenoid Coil Blanket Diverter Plasma region Horizontal and Vertical Cross Section of Calculation Model (18deg. Sector Model) Vacuum vessel

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Plasma region Transmutation zone 1 st layer 2 nd layer 3 rd layer Blanket model (Poloidal cross section of the blanket in the calculation model.) The blanket model was taken from the ITER test blanket. In the model, the blanket region was divided into 5 sub regions along the toroidal direction, each of which was divided into three layers axially. The total volume is 265 m 3.

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Burnup Loop MCNP input for critical calc. MCNP input for source calc. Input data MCNP(Fixed source) MCNP2ORI ORIGEN2 ORI2MCNP ORIGEN2 cross section lib. ORIGEN2 Composition file MCNP(Criticality) Keff ＜１ Yes ORIGEN2 Input file No Cell Loop Terminate Burnup end? No Yes Calculation flow of hybrid analysis with MCNP and ORIGEN2 codes.

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Plasma parameters Major radius (m)6.2 Minor radius (m)2.1 Plasma volume (m 3 )884 Plasma temperature (keV)*19 Confinement time (s)*1.1 Electron density (m -3 )*4.8 x Fusion power (MW)646 Neutron yield (n/s)2.2 x Neutron wall load (MW/m 2 )0.40 (ave.) Plant factor0.7 Blanket parameters Total thickness (m)0.38 Total volume (m 3 )265 * Taken from JT-60 experiment. Main parameters for calculations based on JT-60 and ITER

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice From the calculation 6 Li enrichment:30 % Breeder material ratio:10 % Multiplier material ratio:90 % Packing fraction:85 %

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fuel is loaded in the first layer. Plasma side Vacuum vessel side Blanket 1 st layer (Fuel) 3 rd layer (Breeder) 2 nd layer (Breeder)

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fuel is loaded in the second layer. Plasma side Vacuum vessel side Blanket 1 st layer (Breeder) 3 rd layer (Breeder) 2 nd layer (Fuel)

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Fuel is loaded in the third layer. Plasma side Vacuum vessel side Blanket 1 st layer (Breeder) 3 rd layer (Fuel) 2 nd layer (Breeder)

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Aiming at near future realization of FF hybrid reactor with the proven technologies, we have analyzed a Japan-oriented hybrid system with (1)reprocessed Pu and natural UO 2, (2)achieved plasma condition of JT-60, and (3)ITER geometrical model, by MCNP-4B and ORIGEN2. As a result, (1) 3-d analysis is very important to estimate reliable k eff. (2) for gas-cooled: difficult to decrease power density to get acceptable results. for water-cooled: significantly difficult to incinerate MA. FP is acceptably incinerated. (3) The present FF-hybrid reactor can be confirmed to operate for at least 5 years with acceptable performance (i.e., energy multiplication ( ～ 10), k eff ( 1.05), power density( < 100W/cc) and acceptable FP transmutation) without fuel exchange or shuffling. (4) The fundamental solution would be employing of Th-U cycle in Japan if considering better MA and FP transmutation. Conclusion

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice New importance estimation method for Weight Window during forward Monte Carlo calculations Objectives:Speed-up, Automatic variance reduction Code:MCNP, MCNPX Technique:Weight Window Method:Point base importance estimation with the point detector based on the adjoint definition Remarks: Point base importance estimation: Every scattering point has an adjoint contribution, which realize precise 3-d importance estimation. Cell base estimation in WWG of MCNP. Results: Better FOM values than WWG because of a statistical advantage of our method. The number of available adjoint data to estimate importance is much larger than WWG. Variance reduction

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Principle of the method × Terminate C1C1 C2C2 C3C3 C4C4 This particle has a total contribution of C 1 + C 2 + C 3 + C 4 to the detector by the point detector. Detector (Point detector) Detector contribution → Importance → WW parameter (C 1 + C 2 + C 3 + C 4 ) (Adjoint)( ～ 1/Imp.) bcause the adjoint definition is “all the contribution, which a particle can affect in the future to the detector, including contribution that his progenies can affect.” Proven by the MC theory

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Difference between WWG and the present method Cell WWGPresent method This particle has an importance contribution. Every scattering point has an importance contribution. Scattering point

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice AccApp’03, June 1-5, 2003, San Diego, California, USA Basic performance test Comparison of figure of merit (FOMs)figure of merit (FOMs) between the present importance estimation method and WWG under the equal condition to examine the variance reduction performance. ● Method and conditions: Code: MCNP-4B Source: 14MeV-n, point and isotropic. No. of histories: Model: Rectangular (2 x 2 x 3 m 3 (or 2 x 2 x 1 m 3 for red material below)) Material: H 2 O, C, liq.-N 2, SiO 2, Al, Ti, Fe, Zr, Mo, W and Pb. WW para.: Estimated by the initial calculation of particles. Basic performance test

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Material Sample Thickness (m) Comparison of the results This workWWG FOMError*Time**FOMError*Time** Water Graphite Liq. Nitrogen SiO Aluminum Titanium Iron Zirconium Molybdenum Tungsten Lead AccApp’03, June 1-5, 2003, San Diego, California, USA Result of the basic performance Results of the basic performance Click below for details * Error of total flux in percentage, ** Computation time in minute. Click below to next

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice OKTAVIAN facility will be back History:Start the operation in 1981 Hanshin-daishinsai Jan. 17, 1995 No budget for maintenance from 2000 Stop the operation since 2001 Problem:Cannot buy tritium targets for DC and Pulse lines Cannot make repairs on Pulse line Countermeasures: Some budget from Laser Fusion community Second hand targets from FNS Plan:DC line with a fixed target of FNS to give ～ n/sec will starts from October, 2004 Pulse line with a repetition frequency of 2 MHz, 2 nsec pulse width and >10 9 n/sec will starts from January 2005 OKTAVIAN

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Present status:Pulse line is under repair DC line is being set up with FNS targets Research plans:Experiments for laser fusion study Fusion-fission hybrid reactor BNCT test irradiation Neutronics Collaboration exp.: Graduate School of DentistryJan Graduate School of Science for Oct Tokai UniversityOct. 2004

IEA Int. WS on Fusion Neutronics Sept. 21, 2004 Venice Summary - Next year plan - CP DDX:F, C and Li-6,7 (n,2n):Be and D FF hybrid:Thorium cycle, DD reactor, Laser fusion reactor