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Journal Articles

Great achievements of M. Salvatores for nuclear data adjustment study with use of integral experiments

Yokoyama, Kenji; Ishikawa, Makoto*

Annals of Nuclear Energy, 154, p.108100_1 - 108100_11, 2021/05

 Times Cited Count:1 Percentile:53.73(Nuclear Science & Technology)

In the design of innovative nuclear reactors such as fast reactors, the improvement of the prediction accuracies for neutronics properties is an important task. The nuclear data adjustment is a promising methodology for this issue. The idea of the nuclear data adjustment was first proposed in 1964. Toward its practical application, however, a great deal of study has been conducted over a long time. While it took about 10 years to establish the theoretical formulation, the research and development for its practical application has been conducted for more than half a century. Researches in this field are still active, and the fact suggests that the improvement of the prediction accuracies is indispensable for the development of new types of nuclear reactors. Massimo Salvatores, who passed away in March 2020, was one of the first proposers to develop the nuclear data adjustment technique, as well as one of the great contributors to its practical application. Reviewing his long-time works in this area is almost the same as reviewing the history of the nuclear data adjustment methodology. The authors intend that this review would suggest what should be done in the future toward the next development in this area. The present review consists of two parts: a) the establishment of the nuclear data adjustment methodology and b) the achievements related to practical applications. Furthermore, the former is divided into two aspects: the study on the nuclear data adjustment theory and the numerical solution for sensitivity coefficient that is requisite for the nuclear data adjustment. The latter is separated to three categories: the use of integral experimental data, the uncertainty quantification and design target accuracy evaluation, and the promotion of nuclear data covariance development.

Journal Articles

Criticality configuration design methodology applied to the design of fuel debris experiment in the new STACY

Gunji, Satoshi; Tonoike, Kotaro; Clavel, J.-B.*; Duhamel, I.*

Journal of Nuclear Science and Technology, 58(1), p.51 - 61, 2021/01

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

The new critical assembly STACY will be able to contribute to the validation of criticality calculations related to the fuel debris. The experimental core designs are in progress in the frame of JAEA/IRSN collaboration. This paper presents the method applied to optimize the design of the new STACY core to measure the criticality characteristics of pseudo fuel debris that simulated Molten Core Concrete Interaction (MCCI) of the fuel debris. To ensure that a core configuration is relevant for code validation, it is important to evaluate the reactivity worth of the main isotopes of interest and their k$$_{rm eff}$$ sensitivity to their cross sections. In the case of the fuel debris described in this study, especially for the concrete composition, silicon is the nucleus with the highest k$$_{rm eff}$$ sensitivity to the cross section. For this purpose, some parameters of the core configuration, as for example the lattice pitches or the core dimensions, were adjusted using optimization algorithm to find efficiently the optimal core configurations to obtain high sensitivity of silicon capture cross section. Based on these results, realistic series of experiments for fuel debris in the new STACY could be defined to obtain an interesting feedback for the MCCI. This methodology is useful to design other experimental conditions of the new STACY.

Journal Articles

Pressure resistance thickness of disposal containers for spent fuel direct disposal

Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.121 - 135, 2020/09

A series of structural analysis of disposal containers for direct disposal of spent fuel was carried out to provide preliminary estimates of the required pressure resistance thickness of the disposal container. Disposal containers were designed to contain either 2, 3 or 4 spent fuel assemblies in linear, triangular or square arrangements, respectively. The required pressure resistance thickness was evaluated using separation distance of the housing space for each spent fuel assembly as a key model parameter to obtain the required thickness of the body and then the lid of the disposal container. This work also provides additional analytical technical knowledge, such as the validity of the setting of the stress evaluation line and the effect of the model length on the analysis. These can then be referred to and used again in the future as a basis for conducting similar evaluations under different conditions or proceeding with more detailed evaluations.

Journal Articles

Cross-section-induced uncertainty evaluation of MA sample irradiation test calculations with consideration of dosimeter data

Sugino, Kazuteru; Numata, Kazuyuki*; Ishikawa, Makoto; Takeda, Toshikazu*

Annals of Nuclear Energy, 130, p.118 - 123, 2019/08

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

In MA sample irradiation test data calculations, the neutron fluence during irradiation period is generally scaled by using dosimetry data in order to improve calculation accuracy. In such a case, appropriate correction is required to burnup sensitivity coefficients obtained by the conventional generalized perturbation theory because some cancellations occur in the burnup sensitivity coefficients. Therefore, a new formula for the burnup sensitivity coefficient has been derived with the consideration of the neutron fluence scaling effect (NFS). In addition, the cross-section-induced uncertainty is evaluated by using the obtained burnup sensitivity coefficients and the covariance data based on the JENDL-4.0.

Journal Articles

Sensitivity and uncertainty analysis of $$beta_{rm eff}$$ for MYRRHA using a Monte Carlo technique

Iwamoto, Hiroki; Stankovskiy, A.*; Fiorito, L.*; Van den Eynde, G.*

European Physical Journal; Nuclear Sciences & Technologies (Internet), 4, p.42_1 - 42_7, 2018/11

This paper presents a nuclear data sensitivity and uncertainty analysis of the effective delayed neutron fraction $$beta_{rm eff}$$ for critical and subcritical cores of the MYRRHA reactor using the continuous-energy Monte Carlo transport code MCNP. The $$beta_{rm eff}$$ sensitivities are calculated by the modified $$k$$-ratio method proposed by Chiba. Comparing the $$beta_{rm eff}$$ sensitivities obtained with different scaling factors $$a$$ introduced by Chiba shows that a value of $$a=20$$ is the most suitable for the uncertainty quantification of $$beta_{rm eff}$$. Using the calculated $$beta_{rm eff}$$ sensitivities and the JENDL-4.0u covariance data, the $$beta_{rm eff}$$ uncertainties for the critical and subcritical cores are determined to be 2.2 $$pm$$ 0.2% and 2.0 $$pm$$ 0.2%, respectively, which are dominated by delayed neutron yield of $$^{239}$$Pu and $$^{238}$$U.

Journal Articles

Estimation of sensitivity coefficient based on lasso-type penalized linear regression

Katano, Ryota; Endo, Tomohiro*; Yamamoto, Akio*; Tsujimoto, Kazufumi

Journal of Nuclear Science and Technology, 55(10), p.1099 - 1109, 2018/10

 Times Cited Count:3 Percentile:40.33(Nuclear Science & Technology)

In this study, we propose the penalized regression "adaptive smooth-lasso" for the estimation of sensitivity coefficients of the neutronics parameters. The proposed method estimates the sensitivity coefficients of the neutronics parameters using the variation of the microscopic cross sections and the neutronics parameter obtained by random sampling. The proposed method utilizes only the forward calculations. Thus, the proposed method can be applied for the complex reactor analysis for which the application of the adjoint method is difficult. In this study, we proposed a penalty term considering the characteristics of the sensitivity coefficients of the neutronics parameter to the microscopic multi-group cross sections. Through verification calculation, we show that the proposed method achieves high accuracy with less computational cost compared to the method based on random sampling proposed in the previous studies.

Journal Articles

Sensitivity analysis of source term in the accident of Fukushima Dai-ichi Nuclear Power Station Unit 1 using THALES2/KICHE

Tamaki, Hitoshi; Ishikawa, Jun; Sugiyama, Tomoyuki; Maruyama, Yu

Proceedings of Asian Symposium on Risk Assessment and Management 2018 (ASRAM 2018) (USB Flash Drive), 6 Pages, 2018/10

In the accidents at Fukushima Dai-ichi Nuclear Power Station, Tsunami caused loss of electric power supply and this event led to core melt and failure of Containment vessel. Finally, fission products were released to the environment. Currently, the activities for understanding of accident progressions are carried out based on the measured data during the accident, accident progression analysis using integrated severe accident analysis codes and investigation of inside of reactor buildings and containment vessels. On the other hand, there are some research activities with combination of accident progression analysis and accident consequence analysis. In Japan Atomic Energy Agency (JAEA), the research project of combination of these analyses using the computational simulation codes has been started. The results obtained from the combination analysis are expected to have broad width of uncertainty because of many uncertainty factors in this combined analysis. In order to perform the analysis efficiently, sensitivity analysis for failure location on containment vessel and its failure size were carried out by THALES2/KICHE developed by JAEA at first. This analysis was performed on unit 1, since it was the first plant to release radioactive materials to the environment during the accident and its consequence had no effect from other plants. The authors focused on the failure of containment vessel head flange, penetration seal and vacuum breaker pipe, and possibility of partial open of vent valve based on the investigations of reactor building inside performed by TEPCO. This paper presents the results obtained from this sensitivity analysis.

Journal Articles

Factors affecting the effectiveness of sheltering in reducing internal exposure

Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*; Watanabe, Masatoshi*; Munakata, Masahiro

Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 11 Pages, 2017/11

no abstracts in English

Journal Articles

Sensitivity study on forest fire breakout and propagation conditions for forest fire hazard curve evaluations

Okano, Yasushi; Yamano, Hidemasa

Mechanical Engineering Journal (Internet), 4(3), p.16-00517_1 - 16-00517_10, 2017/06

A sensitivity study on forest fire hazard curves was performed. The probability fluctuation on forest fire breakout time affects the reaction intensity and the fireline intensity around 4% and 14% respectively. The probability fluctuation on forest fire breakout points affects the hazard curve frequency around +70% to -40%. The probability fluctuation due to forest firefighting operation only affects the frequency of the hazard curves, but not the intensity. The hazard curves without the effect of firefighting remarkably increase around 40 to 80 times in frequency in comparison with those with considering the forest firefighting operation effect outside the plant. This study indicated that the most significant factor in the forest fire hazard risk is whether the forest firefighting operation outside the plant is expected before the forest fire arrival at the plant.

Journal Articles

Reliability enhancement of seismic risk assessment of NPP as risk management fundamentals; Quantifying epistemic uncertainty in fragility assessment using expert opinions and sensitivity analysis

Choi, B.; Nishida, Akemi; Itoi, Tatsuya*; Takada, Tsuyoshi*; Furuya, Osamu*; Muta, Hitoshi*; Muramatsu, Ken

Proceedings of 13th Probabilistic Safety Assessment and Management Conference (PSAM-13) (USB Flash Drive), 8 Pages, 2016/10

In this study, we address epistemic uncertainty in structure fragility estimation of nuclear power plants (NPPs). In order to identify and quantify dominant factors in fragility assessment, sensitivity analyses of seismic analysis results are conducted for a target NPP building using a three-dimensional finite element model and a conventional lumped mass model (embedded sway rocking model), and the uncertainty caused by the major factors is then evaluated. The results are used to classify epistemic uncertainty levels in a fragility estimation workflow for NPPs in several stages, and a graded knowledge tree technique, which can be used for future fragility estimations, is proposed.

Journal Articles

An Integrated approach to source term uncertainty and sensitivity analysis for nuclear reactor severe accidents

Zheng, X.; Ito, Hiroto; Tamaki, Hitoshi; Maruyama, Yu

Journal of Nuclear Science and Technology, 53(3), p.333 - 344, 2016/03

AA2014-0796.pdf:0.84MB

 Times Cited Count:9 Percentile:72.4(Nuclear Science & Technology)

Journal Articles

Application of Bayesian nonparametric models to the uncertainty and sensitivity analysis of source term in a BWR severe accident

Zheng, X.; Ito, Hiroto; Kawaguchi, Kenji; Tamaki, Hitoshi; Maruyama, Yu

Reliability Engineering & System Safety, 138, p.253 - 262, 2015/06

 Times Cited Count:8 Percentile:38.26(Engineering, Industrial)

Journal Articles

Investigation of ligand immobilized nano-composite adsorbent for efficient cerium(III) detection and recovery

Awual, M. R.; Hasan, M. M.*; Shahat, A.*; Naushad, M.*; Shiwaku, Hideaki; Yaita, Tsuyoshi

Chemical Engineering Journal, 265, p.210 - 218, 2015/04

 Times Cited Count:195 Percentile:99.29(Engineering, Environmental)

Journal Articles

Dose responses of irradiated fresh papaya recorded on ESR at different temperature

Kikuchi, Masahiro; Ukai, Mitsuko*; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 89, 2015/03

Journal Articles

Organic-inorganic based nano-conjugate adsorbent for selective palladium(II) detection, separation and recovery

Awual, M. R.; Hasan, M. M.*; Znad, H.*

Chemical Engineering Journal, 259, p.611 - 619, 2015/01

 Times Cited Count:183 Percentile:99.16(Engineering, Environmental)

JAEA Reports

Sensitivity analysis on flammable gas dispersion and explosion in HTTR hydrogen production system with fire and explosion analysis code system -P2A- (Contract research)

Inaba, Yoshitomo; Nishihara, Tetsuo

JAERI-Tech 2005-033, 206 Pages, 2005/07

JAERI-Tech-2005-033.pdf:34.71MB

In this report, we investigated the effects of jet for the dispersion and explosion analysis of leaked gas, obstacles, position of an ignition point and cell size for the gas explosion analysis, and atmospheric stability for the dispersion analysis of the leaked gas, with PHOENICS, AutoReaGas, and AUTODYN. Then, we carried out two accident analyses about combustible fluid leakage based on the investigation results of these effects. As a result, it was shown that important buildings related to safety was hardly affected by the explosion of the leaked gas.

Journal Articles

Uncertainty and sensitivity studies with the probabilistic accident consequence assessment code OSCAAR

Homma, Toshimitsu; Tomita, Kenichi*; Hato, Shinji*

Nuclear Engineering and Technology, 37(3), p.245 - 258, 2005/06

This paper addresses two types of uncertainty: stochastic uncertainty and subjective uncertainty in probabilistic accident consequence assessments. The off-site consequence assessment code OSCAAR has been applied to uncertainty and sensitivity analyses on the individual risks of early fatality and latent cancer fatality in the population due to a severe accident. A new stratified meteorological sampling scheme was successfully implemented into the trajectory model for atmospheric dispersion and the statistical variability of the probability distributions of the consequence was examined. A total of 65 uncertain input parameters was considered and 128 runs of OSCAAR were performed in the parameter uncertainty analysis. The study provided the range of uncertainty for the expected values of individual risks of early and latent cancer fatality close to the site. In the sensitivity analyses, the correlation/regression measures were useful for identifying those input parameters whose uncertainty makes an important contribution to the overall uncertainty for the consequence.

Journal Articles

Preliminary evaluation of reduction of prediction error in breeding light water reactor core performance

Kugo, Teruhiko; Kojima, Kensuke; Ando, Masaki; Okajima, Shigeaki; Mori, Takamasa; Takeda, Toshikazu*; Kitada, Takanori*; Matsuoka, Shogo*

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 10 Pages, 2005/05

We have preliminarily evaluated the reduction of prediction errors of the core characteristics of the breeding light water reactor core based on the bias factor method by utilizing the FCA critical experiments carried out for MOX fueled tight lattice light water reactor cores. The prediction uncertainty of k$$_{eff}$$ is reduced from 0.62% to 0.39% by utilizing the FCA-XV-2 (65V) result. As for the reaction rate ratio of $$^{238}$$U capture and $$^{239}$$Pu fission, it is found that the FCA XXII-1 (95V) and XV (95V) results are suitable for the upper core and the upper blanket of the real core and the FCA XXII-1 (65V) and XV-2 (65V) results are suitable for the lower core and the internal blanket.

Journal Articles

Electron beam-induced fries rearrangement of sulfonamide and sulfonate crystals

Kato, Jun*; Maekawa, Yasunari; Yoshida, Masaru

Chemistry Letters, 34(2), p.266 - 267, 2005/02

 Times Cited Count:12 Percentile:43.27(Chemistry, Multidisciplinary)

We have investigated the useful EB induced reactions of sulfonamide and sulfonate derivatives in the crystalline state. In this letter, we found that the EB sensitivity of sulfonic acid derivatives in the crystalline tate was much higher than that of the corresponding carboxylic acid derivatives, which was distinct from the results using other energy sources, to give Fries rearrangement products. It is notable that these reactions are solvent-free and are accompanied by the transformation of amide and ester linkages to hydrophilic aniline and phenol groups; especially, an acidic sulfonamide can be converted to the corresponding basic aniline derivatives. These new EB induced transformations can significantly contribute to designing new materials for EB lithography as well as nanoscopic architectures.

JAEA Reports

Characteristics of 64 $$times$$ 64 channel high-position resolution neutron imaging detector

Sakasai, Kaoru; Katagiri, Masaki; Matsubayashi, Masahito; Rhodes, N.*; Schoonveld, E.*

JAERI-Research 2004-020, 19 Pages, 2004/12

JAERI-Research-2004-020.pdf:4.57MB

no abstracts in English

77 (Records 1-20 displayed on this page)