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Yamamoto, Akio*; Chiba, Go*; Kirimura, Kazuki*; Miki, Yosuke*; Yokoyama, Kenji
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(4), p.241 - 245, 2018/04
no abstracts in English
Suyama, Kenya
Kaku Deta Nyusu (Internet), (117), p.5 - 14, 2017/06
The benchmark calculation is one of the main activities of the Nuclear Science Committee under the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (OECD/NEA/NSC). The international benchmark relatively frequently means the benchmark activity carried out by the NEA. In this manuscript, the author discusses the significance of the international benchmark by describing (i) the current status of the benchmark in the field of the reactor physics conducted by the OECD/NEA/NSC, (ii) revision of the neutronics calculation code system to reflect the results of the benchmark, (iii) the benchmark calculation as the asset for the future research and development, (iv) examples of the benchmark calculation based on the experimental data, and (v) how to propose the benchmark in the OECD/NEA/NSC.
Kitano, Akihiro; Takegoshi, Atsushi*; Hazama, Taira
Journal of Nuclear Science and Technology, 53(7), p.992 - 1008, 2016/07
Times Cited Count:8 Percentile:60.26(Nuclear Science & Technology)A feedback reactivity measurement technique was developed based on a reactivity model featuring components that depend on the reactivity coefficients, denoted as reactor power (K) and reactor vessel inlet temperature (K). This technique was applied to the feedback reactivity experiment conducted in the Monju system start-up test in May 2010. A thorough evaluation considering all possible biases and uncertainties revealed that the reactivity coefficients can be evaluated with a measurement uncertainty smaller than 3%. The evaluated reactivity coefficients were simulated considering the temperature distribution in the core. The C/E value of K showed good agreement between calculated and measured values within the established uncertainty, and the value of K was consistent with that reported in a previous isothermal temperature coefficient experiment. The measured and calculated fuel subassembly outlet temperatures also agreed well within 0.2C.
; Numata, Kazuyuki*; ; *; Oigawa, Hiroyuki*
JNC TY9400 2000-006, 162 Pages, 2000/04
no abstracts in English
Wada, Hiroaki
JNC TN8400 2000-015, 37 Pages, 2000/03
This report describes the study done within the period of time when I was postdoctoral research worker at Japan Nuclear Cycle Development Institute. The report includes two parts as follows. (1) Exact Solution of Electric Transitions for High Energy photons. Technologies for creating high-energy beams have been rapidly developed. These advancements make the research using high-energy -rays more important. The electric transition rates for high-energy -rays were formulated. The electric multipole fields were treated strictly in the process of calculating the electric transition rates and the nuclear states were taken as the harmonic oscillator wave functions. (2) Production of the isomeric state of Cs in the thermal neutron capture reaction Cs(n, )Cs. In order to obtain precise data of the neutron capture cross section of the reaction Cs(n, )Cs, the production probability of isomer state Cs was measured in this work. The 1436 keV -ray emitted from both of Cs and Cs was measured. A production ratio of Cs to (Cs and Cs) was deduced from time dependence of peak counts of 1436keV -ray. The probability of the production of CS was obtained as 0.750.18 and this value revised the effective cross section upwards 92%. The effective cross section and the thermal neutron capture cross section were obtained as =0.290.02 b and =0.270.03 b with taking into account the production of Cs.
Dietze, K.
JNC TN9400 99-089, 20 Pages, 1999/11
The integral experiments performed at the Rossendorf fast-thermal coupled reactor RRR/SEG have been reanalyzed using the JNC route for reactor calculation JENDL3.2/SLAROM / CITATION / JOINT / PERKY. The Rossendorf experiments comprise sample reactivity measurements with pure fission products and structural material in five configurations with different neutron and adjoint spectra. The shapes of the adjoint spectra have been designed to get high sensitivities to neutron capture or the scattering effect. The calculated neutron and adjoint spectra are in good agreement with former results obtained with the European route JEF2.2/ECCO/ERANOS. The C/E-values of the central reactivity worths of samples under investigation are given. Deviations in the results of both routes are due to the different libraries, codes, and self-shielding treatments used in the calculations. Results outside of the error are discussed.
Mizuta, Shunji; ;
JNC TN9400 99-082, 60 Pages, 1999/10
The density measurement of the internal creep specimens irradiated in FFTF/MOTA (Fast Flux Test Facility / Material open Test Assembly) was conducted MMF (Materia1 Monitoring Facility) and accurate separation of swelling strain from total strain leaded in the derivation of the irradiation creep coefficients. Irradiation creep coefficients for PNC 316, 15Cr-20Ni base S.S. and 14Cr-25Ni base S.S. were systematically expressed, while thermal creep coefficients K, under irradiation were separately expressed for above three steels. The results obtained are follows, (1)The effect of stress induced swelling was recognized in the temperature range from 405 to 605C. The swelling in high stress specimens have a tendency to increasing swelling. (2)The irradiation creep coefficients derived from PNC316 and l5Cr-20Ni are similar to that of derived from 20%CW316S.S., CW316Ti and CW15-15Ti which were reported by other authors. (3)The irradiation creep coefficient derived from gas pressurized tube irradiation using FFTF/MOTA expressed appropriately irradiation creep strain from fuel pins using FFTF/MFA-2(15Cr-2ONi base S.S.).
; Toyama, Shinichi; Nomura, Masahiro; Hirano, Koichiro; Yamazaki, Yoshio; Sato, Isamu
JNC TN9400 99-073, 18 Pages, 1999/08
A short traveling wave accelerator with a traveling wave resonant ring is proposed for high beam current accelerators (including the linear accelerator, circular accelerator and storage ring). It is a normal conducting accelerator. The CW beam current can be as high as 10A. Such kind of accelerator unit has large beam holes for damping all of the cavity high order modes in order to avoid the resonant buildup of the fields that would cause multibunch instabilities at high currents. It has high efficiency, high power input capability and low K. It is called "single mode" type. Even though beams are accelerated off the crest for phase stability in circular accelerator, the cavities do not need detuning.
; Aoto, Kazumi;
JNC TN9400 99-061, 32 Pages, 1999/07
In this report, reconstruction of magnetic charges induced by mechanical damages in a test piece of SUS304 stainless steel is performed as a part of eforts to establish a passive nondestructive testing method on the basis of the inspection of leakage magnetic field. The approach for solving this typical ill-posed inverse problem is selected as a way in the least square method category. Concerning the ill-poseness of the system of equations, an iteration algorithm is adopted to its solving in which the designations of initial profile, the weight coefficients and the total number of iterations are taken as means of reqularization. From examples using simulated input data, it is verified that the approach gives good reconstruction results in case of signals with a relative high S/N ratio. For improving the robustness of the proposed method, a Galerkin procedure with base functions chosen as the Daubechies' wavelet is also introduced for discretizing the governing equation. By comparing the reconstruction results of the least square method and those using wavelet discretization, it is found that the wavelet used approach is more feasible in the inversion of noise polluted signals. Reconstruction of 1-D and 2-D magnetic charges with the least square strategy and reconstruction of an 1-D problem with the wavelet used method are carried out from both simulated and measured magnetic field signals which are used as the validation of the proposed inversion strategy.
Hunter
JNC TN9400 99-049, 74 Pages, 1999/04
This document describes a series of calculations that were carried out to model various measurements from the BFS-58-1-I1 experiment. BFS-58-1-I1 was a mock-up of a uranium-free, Pu burning core at BFS-2, a Russian critical assembly operated by IPPE. The experiment measured values of keff, Na void reactivity worth, material sample reactivity worths and reaction rate ratios. The experiments were modelled using a number of different methods. Basic nuclear data was taken from JENDL-3.2, in either 70 or 18 groups. Cross-section data for the various material regions of the assembly were calculated by either SLAROM or CASUP; the heterogeneous structure of the core regions was modelled in these calculations, with 3 different options considered for representing the (essentially 2d) geometry of the assembly components in a 1D cell model. Whole reactor calculations of flux and keff were done using both a diffusion model (CITATION) and a transport model (TWOTRAN2), both using an RZ geometry. Reactivity worths were calculated both directly from differences in keff values and by using the exact perturbation calculations of PERKY and SN-PERT (for CITATION and TWOTRAN2, respectively). Initial calculations included a number of inaccuracies in the assembly representation, a result of communication difficulties between JNC and IPPE; these errors were removed for the final calculations that are presented. Calculations for the experiments have also been carried out in Russia (IPPE) and France (CEA) as part of an international comparison exercise, some of those results are also presented here. The calculated value of keff was 1.1%k/k higher than the measured value, Na void worth C/E values were 1.06; these results were considered to be reasonable. (Discrepancies in certain Na void values were probably due to experimental causes, though the efect should be investigated in any future experiments.) several sample worth values were small compared with calculational uncertaint
Saito, Hioraki*; Iriya, Yoshikazu*
JNC TJ8440 99-003, 156 Pages, 1999/03
no abstracts in English
Kasahara, Naoto; Yacumpai, A.*; Takasho, Hideki*
JNC TN9400 99-019, 34 Pages, 1999/02
At incomplete mixing area of high temperature and low temperature fluids near the surface of structures, temperature fluctuation of fluid gives thermal fatigue damage to wall structures. This thermohydraulic and thermomechanical coupled phenomenon is called thermal striping, which has so complex mechanism and sometimes causes crack initiation on the structural surfaces that rational evaluation methods are required for screening rules in design codes. In this study, frequency response characteristics of structures and its mechanism were investigated by both numerical and theoretical methods. Based on above investigation, a structural response diagram was derived, which can predict stress amplitude of structures from temperature amplitude and frequency of fluids. Furthermore, this diagram was generalized to be the Non-dimensional structural response diagram by introducing non-dimensional parameters such as Biot number, non-dimensional frequency, and non-dimensional stress. The use of the Non-dimensional structural response diagram appears to evaluate thermal stress caused by thermal striping, rapidly without structural analysis, and rationally with considering attenuation by non-stationary heat transfer and thermal unloading. This diagram can also give such useful information as sensitive frequency range to adjust coupled thermohydraulic and thermomechanical analysis models taking account of four kinds of attenuation factors: turbulent mixing, molecular diffusion, non-stationaly heat transfer, and thermal unloading.
Yang Jin An*;
JNC TN9400 99-013, 89 Pages, 1998/12
This report presents a variance reduction technique to estimate the reliability and availability of highly complex systems during phased mission time using the Monte Carlo simulation. In this study, we introduced the variance reduction technique with a concept of distance between the present system state and the cut set configurations. Using this technique, it becomes possible to bias the tansition from the operating states to the failed states of components towards the closest cut set. Therefore a component failure can drive the system towards a cut set configuration more effectively. JNC developed the PHAMMON (Phased Mission Analysis Program with Monte Carlo Method) code which involved the two kinds of variance reduction techniques : (1) forced transition, and (2)failure biasing. However, these techniques did not guarantee an effective reduction in variance. For further improvement, a variance reduction technique incorporating the distance concept was introduced to the PHAMMON code and the numerical calculation was carried out for the different design cases of decay heat removal system in a large fast breeder reactor. Our results indicate that the technique addition of this incorporating distance concept is an effective means of further reducing the variance.
Hunter
PNC TN9410 98-015, 81 Pages, 1998/02
The study was carried out within the framework of the PNC-CEA collaboration agreement. Data were provided, by CEA, for an experimental loading of a start-up core in Super-Phenix. This data was used at PNC to produce core flux snapshot calculations. CEA undertook a comparison of the PNC results with the equivalent calculations carried out by CEA, and also with experimental measurements from SPX. The resu1ts revealed a systematic radial flux tilt between the calculations and the reactor measurements, with the PNC tilts only 30-401 of those from CEA. CEA carried out an analysis of the component causes of the radial tilt. It was concluded that a major cause of radia1 tilt differences between the PNC and CEA calculations lay in the nuclear datasets used: JENDL-3.2 and CARNAVAL IV. For the final stage of the study, PNC undertook a sensitivity analysis, to examine the detailed differences between the two sets of nuclear data. The PNC flux calculations modelled SPX in both 2D (RZ) and 3D (hex-Z) geometries, using the diffusion programs CITATION and MOSES. The sensitivity analysis of the differences between the JENDL-3.2 and CARNAVAL IV nuclear datasets used the SAGEP calculational route. Both datasets were condensed to a single, non-standard, set of energy group boundaries. There were some incompatibilities in the cross-section formats of the two datasets. The sensitivity analysis showed that a relatively small number of nuclear data items contributed the bulk of the radial tilt difference between calculations with JENDL-3.2 and with CARNAVAL IV. A direct comparison between JENDL-3.2 and CARNAVAL IV data revealed the following. The Nu values showed little difference (<5|%). The only large fission cross-section differences were at low energy (<30% otherwise, with <10% typical). Although down-scattering reactions showed some large fractional differences, absolute differences were negligible compared with in-group scattering; for in-group scattering fractional ...
*; *; *; Horiki, Oichiro*; Suzaki, Takenori
JAERI-Review 97-014, 43 Pages, 1997/10
no abstracts in English
Fletcher, J. K.
PNC TN9410 97-065, 25 Pages, 1997/07
None
Bottcher, J. T.
PNC TN9440 97-011, 215 Pages, 1997/06
J.H.Bottcher started his intemational Fellow position at PNC on March 25, 1996.During his 15 months in PNC he worked in the Irradiation Section of the Experimental Reactor Division. There he worked on conceptual design reviews and related the US irradiations methodology to the members. His work extended to other Divisions at OEC and Tokai Works, mainly related to fuel development and irradiation performance. In these efforts he published two papers, wrote a desip review document, and presented six lectures on irradiated fuels and materials. In addition he participated in coordinating a new four year PNC/DOE collaborative program on irradiated steels characterization.
Suzaki, Takenori
Nihon Genshiryoku Gakkai-Shi, 39(6), p.480 - 481, 1997/06
no abstracts in English
Shiotsu, Masahiro*; Hata, Koichi*; *; Shirai, Yasuyuki*; *; Sakai, Takaaki
PNC TY9604 97-002, 15 Pages, 1997/03
no abstracts in English