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Journal Articles

Problems of DPA cross-sections above 20 MeV in FENDL-3.1d found in A-FNS neutronics analysis

Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Kasugai, Atsushi*

Journal of Nuclear Science and Technology, 57(3), p.344 - 351, 2020/03

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

We found out that there was a questionable iron DPA value just above 20 MeV neutron energy in neutronics analyses of A-FNS using FENDL-3.1d. Our detailed investigation on the iron data in FENDL-3.1d figured out that residual nucleus production yield data of $$^{56}$$Fe just above 20 MeV had a problem, which caused a sharp spike just above 20 MeV in the DPA cross section of $$^{56}$$Fe. Thus we modified the yield data of $$^{56}$$Fe and verified that the questionable DPA value disappeared using the modified data. We also examined DPA cross sections of other nuclei in FENDL-3.1d. It was found out that DPA cross sections of more than 70% of nuclei in FENDL-3.1d have similar problems as that of $$^{56}$$Fe.

Journal Articles

IRDFF-II; A New neutron metrology library

Trkov, A.*; Griffin, P. J.*; Simakov, S. P.*; Greenwood, L. R.*; Zolotarev, K. I.*; Capote, R.*; Aldama, D. L.*; Chechev, V.*; Destouches, C.*; Kahler, A. C.*; et al.

Nuclear Data Sheets, 163, p.1 - 108, 2020/01

 Times Cited Count:2 Percentile:10.18(Physics, Nuclear)

The version II of the International Reactor Dosimetry and Fusion File (IRDFF-II) has been released as a consistent set of nuclear data for fission and fusion neutron metrology applications up to 60 MeV neutron energy. The library is intended to support: (a) applications in research reactors; (b) safety and regulatory applications in the nuclear power generation in commercial fission reactors; and c) material damage studies in support of the research and development of advanced fusion concepts. The paper describes the contents of the library, documents the thorough verification process used in its preparation, and provides an extensive set of validation data gathered from a wide range of neutron benchmark fields. The new library is expected to become the international reference in neutron metrology for multiple applications.

Journal Articles

TENDL-2017 benchmark test with iron shielding experiment at QST/TIARA

Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Ochiai, Kentaro*; Sato, Satoshi*; Kasugai, Atsushi*

Fusion Engineering and Design, 144, p.209 - 214, 2019/07

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

We performed a TENDL-2017 benchmark test with iron shielding experiments by using 40 and 65 MeV neutrons, in order to verify a nuclear data library above 20 MeV for neutronics analyses of A-FNS. We found out that the calculated neutron spectra with TENDL-2017 unnaturally increased near 30 MeV. We figured out that incorrect secondary neutron spectrum data in $$^{54}$$Fe, $$^{56}$$Fe and $$^{58}$$Fe at 30 MeV caused the increase of the neutron flux. Similar problems occurred in a lot of nuclei of TENDL-2017, TENDL-2015 and FENDL-3.1d from TENDL-2010 and TENDL-2011.

Journal Articles

FENDL-3.1b test

Konno, Chikara; Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*

JAEA-Conf 2017-001, p.117 - 122, 2018/01

The revised version of FENDL-3, FENDL-3.1b was released in October, 2015. Thus we have tested FENDL-3.1b neutron sub-library for the problems we reported to IAEA before. Most of the MATXS files above 20 MeV had no scattering matrix data of non-elastic scattering, but this problem was fixed by re-processing FENDL-3 with NJOY2012.50. As for the problem on KERMA factors and DPA data, IAEA revised the wrong Q value of the capture reaction in $$^{15}$$N and re-calculated KERMA factors and DPA data with NJOY2012.50. It was confirmed that most of the KERMA factors and DPA data were revised correctly except for huge gas production cross-section data. However a new problem on NJOY processing of gas production data was found out. It was pointed out that this problem was due to a bug of NJOY. Additionally we investigated a trouble on $$^{116}$$Sn and $$^{117}$$Sn NJOY processing at IAEA and specified that one of NJOY patches caused this trouble.

Journal Articles

ENDF/B-VIII$$beta$$2 benchmark test with shielding experiments at QST/TIARA

Kwon, Saerom*; Konno, Chikara; Ota, Masayuki*; Sato, Satoshi*; Ochiai, Kentaro*

JAEA-Conf 2017-001, p.123 - 128, 2018/01

The $$beta$$-version of ENDF/B-VIII, ENDF/B-VIII$$beta$$2, was released in August, 2016. Thus we studied whether the overestimation problems due to the $$^{16}$$O and $$^{56}$$Fe data of ENDF/B-VII.1 were corrected in the iron and concrete shielding experiments with 40 and 65 MeV neutrons at TIARA. We produced the ACE files of ENDF/B-VIII$$beta$$2 with the NJOY2012.50 code and used the MCNP-5 code for this analysis. The nuclear data libraries, ENDF/B-VII.1, FENDL-3.1b and JENDL-4.0/HE, were also used for comparison. The following results were obtained; (1) the drastic overestimation of around 40 MeV due to the 5$$^{56}$$Fe data was improved, (2) the overestimation for around 65 MeV due to the $$^{56}$$Fe data was also slightly improved, though it was worse than that with FENDL-3.1b, (3) the drastic overestimation due to the $$^{16}$$O data was not improved. The final version of ENDF/B-VIII should also be modified based on these results.

Journal Articles

Benchmark experiment on copper with graphite by using DT neutrons at JAEA/FNS

Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*; Konno, Chikara; Ochiai, Kentaro*

Fusion Engineering and Design, 124, p.1161 - 1164, 2017/11

 Times Cited Count:1 Percentile:79.18(Nuclear Science & Technology)

Copper is used as a material for superconducting coil in magnetic confinement fusion reactor and for accelerator-driven neutron source such as IFMIF. In our previous copper benchmark experiment, we had pointed out that the elastic scattering and capture reaction data of the copper had included some problems in the resonance region, which had caused a large underestimation of reaction rates of non-threshold reactions. In order to corroborate this issue, we carried out a new benchmark experiment on copper with graphite in the neutron field with more low energy neutrons. We measured reaction rates using the activation foils. We analyzed the experiment with MCNP code and the latest nuclear data libraries. As a result, the calculated reaction rates related to low energy neutrons, still excessively underestimated the measured ones as in the previous benchmark experiment. We also tested the nuclear data of copper modified in the previous study, where the elastic scattering and capture reaction cross section of copper. Then the calculated reaction rates with the modified copper nuclear data reproduced the measured ones well. It was revealed that the modification of the specific cross sections had been sufficient in the neutron field with more low energy neutrons.

Journal Articles

Lead benchmark experiment with DT neutrons at JAEA/FNS

Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*; Konno, Chikara; Ochiai, Kentaro*

Fusion Science and Technology, 72(3), p.362 - 367, 2017/10

 Times Cited Count:1 Percentile:79.18(Nuclear Science & Technology)

Lead is a candidate material as a neutron multiplier, a tritium breeder and a coolant in nuclear fusion reactor system, and a $$gamma$$ ray shielding for beam dump or shielding of components in accelerator-driven neutron source such as IFMIF. A benchmark experiment on lead with DT neutrons had been performed at JAEA/FNS seven, where the reaction rates related to neutrons below a few keV had included background neutrons scattered in concrete walls of the experiment room. Thus, we designed and carried out a new benchmark experiment with a lead assembly covered with Li$$_{2}$$O blocks absorbing background neutrons. We successfully measured reaction rates of the non-threshold reactions with the activation foil method. The experiment was analyzed with MCNP code and the latest nuclear data libraries. All the calculated reaction rates (C) tended to underestimate the experimental ones (E) with the depth of the lead assembly. Although reasons of the underestimation have not been specified yet, we discovered that there are remarkable different tendencies of C/Es each reaction rate among the nuclear data libraries.

Journal Articles

Important comments on KERMA factors and DPA cross-section data in ACE files of JENDL-4.0, JEFF-3.2 and ENDF/B-VII.1

Konno, Chikara; Tada, Kenichi; Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*

EPJ Web of Conferences, 146, p.02040_1 - 02040_4, 2017/09

 Times Cited Count:0 Percentile:100

So far we pointed out that KERMA factors and DPA cross-section data of a lot of nuclei in the official ACE file were different among nuclear data libraries for the following reasons; (1) incorrect nuclear data, (2) NJOY bugs, (3) huge helium production cross section data, (4) mf6 mt102 data, (5) no secondary particle data (energy-angular distribution data). Now we compare the KERMA factors and DPA cross section data included in the official ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 in more detail. As a result, we find out new reasons of differences among the KERMA factors and DPA cross section data in the three nuclear data libraries. The reasons are categorized to no secondary charged particle data, no secondary $$gamma$$ data, wrong secondary $$gamma$$ spectra, wrong production yields and mf12-15 mt3 data for the capture reaction, some of which seem to be unsupported with NJOY. The ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 with these problems should be revised based on this study.

Journal Articles

JENDL-4.0/HE benchmark test with concrete and iron shielding experiments at JAEA/TIARA

Konno, Chikara; Matsuda, Norihiro; Kwon, Saerom*; Ota, Masayuki*; Sato, Satoshi*

EPJ Web of Conferences, 153, p.01024_1 - 01024_6, 2017/09

 Times Cited Count:2 Percentile:9.06

As a benchmark test of JENDL-4.0/HE released in 2015, we have analyzed concrete and iron shielding experiments with the 40 and 65 MeV neutron sources at TIARA in JAEA by using MCNP5 and ACE files processed from JENDL-4.0/HE with NJOY2012. As a result, it was found out that the calculation results with JENDL-4.0/HE agreed with the measured ones in the concrete experiment well, while they underestimated the measured ones in the iron experiment more for the thicker assemblies. We examined JENDL-4.0/HE in detail and it was considered that the larger non-elastic scattering cross sections of $$^{56}$$Fe caused the underestimation in the calculation with JENDL-4.0/HE for the iron experiment.

Journal Articles

Benchmark experiment on molybdenum with graphite by using DT neutrons at JAEA/FNS

Ota, Masayuki*; Kwon, Saerom*; Sato, Satoshi*; Konno, Chikara; Ochiai, Kentaro*

Fusion Engineering and Design, 114, p.127 - 130, 2017/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

A new fusion neutron source is now under consideration in Japan. Type 316L stainless steel (SUS316L) which is a structural material of the target-system contains a few percent of molybdenum. In our previous benchmark experiment on molybdenum at JAEA/FNS, we found problems of the cross section data above a few hundred eV in Mo. We perform a new benchmark experiment on Mo with graphite in order to validate the Mo data in the lower energy region. Several dosimetry reaction rates and fission rates are measured in the assembly and compared with the calculated values with the Monte-Carlo transport code MCNP5-1.40 and the recent nuclear data libraries. It is suggested that the (n,$$gamma$$) cross section of $$^{95}$$Mo is underestimated in the tail region below the large resonance at 45 eV in the recent nuclear data libraries.

Journal Articles

New remarks on KERMA factors and DPA cross section data in ACE files

Konno, Chikara; Sato, Satoshi; Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro

Fusion Engineering and Design, 109-111(Part B), p.1649 - 1652, 2016/11

 Times Cited Count:1 Percentile:82.51(Nuclear Science & Technology)

Recently we have examined KERMA factors and DPA cross section data in the latest official ACE files of JENDL-4.0, ENDF/B-VII.1, JEFF-3.2 and FENDL-3.0 in more detail and we found out the following new problems on the KERMA factors and DPA cross section data. (1) NJOY bugs and incorrect nuclear data generated KERMA factors and DPA cross section data of no increase with decreasing neutron energy in low neutron energy. (2) Huge helium production data caused drastically large KERMA factors and DPA cross section data in low neutron energy. (3) It seemed that NJOY could not adequately process capture cross section data in File 6, not File 12-15. (4) KERMA factors with the kinematics method are not correct for nuclear data libraries without detailed secondary particle data (energy-angular distribution data). These problems should be resolved based on our study.

Journal Articles

Beam commissioning of the linac for iBNCT

Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11

The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.

Journal Articles

New integral experiments for a variety of fusion reactor materials with DT neutron source at JAEA/FNS

Sato, Satoshi*; Kwon, Saerom*; Ota, Masayuki*; Ochiai, Kentaro*; Konno, Chikara

Proceedings of 26th IAEA Fusion Energy Conference (FEC 2016) (CD-ROM), 8 Pages, 2016/10

In the integral experiments on tungsten, vanadium and copper performed with the DT neutron source at JAEA/FNS over 20 years ago, the calculated results had largely underestimated the measured ones sensitive to low energy neutrons in the experiments. Since background neutrons scattered in the concrete wall of the experimental room were considered to cause these underestimations, in this study we performed new integral experiments with these materials covered with Li$$_{2}$$O blocks absorbing background neutrons. We also performed similar integral experiments on molybdenum and titanium. We analyzed these experiments by using MCNP5-1.40 with ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0. The large underestimations observed in the previous tungsten and vanadium experiments disappeared in the present experiments, which led that the nuclear data of tungsten and vanadium had no problem. On the other hand, the underestimation was not improved so much in the copper experiment, and the calculation results also did not show good agreements with the measured ones in the molybdenum and titanium experiments. Detailed analyses with partly modified nuclear data clarified the problems of the nuclear data libraries on copper, molybdenum and titanium.

Journal Articles

Some comments on KERMA factors and DPA cross-section data in ACE and MATXS files of JENDL-4.0

Konno, Chikara; Kwon, Saerom; Ota, Masayuki; Sato, Satoshi

JAEA-Conf 2016-004, p.233 - 238, 2016/09

We compared the KERMA factors and DPA cross section data included in the official ACE and MATXS files of JENDL-4.0 with those of ENDF/B-VII.1 and JEFF-3.2. As a result, they were different from those of ENDF/B-VII.1 and JEFF-3.2 in a lot of nuclei, which was considered to be caused by the following new problems; (1) NJOY bugs, (2) huge helium production cross section data, (3) $$gamma$$ production data format in the nuclear data, (4) no detailed secondary particle data (energy-angular distribution data). The ACE and MATXS files of JENDL-4.0 with these problems should be revised based on this study.

Journal Articles

A Simple method for modification of capture reaction and elastic scattering nuclear data in analyses of nuclear data benchmark experiments

Konno, Chikara; Kwon, Saerom; Ota, Masayuki; Sato, Satoshi

JAEA-Conf 2016-004, p.239 - 242, 2016/09

In order to specify reasons of the discrepancy between the calculated and measured results in analyses of benchmark experiments, some parts of some isotope data in nuclear data files are often modified and the modifies nuclear data files are processed with the NJOY code and the new ACE or MATXS files are used. However it is not easy to modify capture and elastic scattering data below 1 MeV with resonance data. Thus we devised a simple method to use capture and elastic scattering cross section data generated from resonance data with the NJOY code. This method was applied to detailed analyses of copper and molybdenum benchmark experiments at JAEA/FNS and it was demonstrated that this method was a very powerful tool.

Journal Articles

Problems on FENDL-3.0

Konno, Chikara; Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro; Sato, Satoshi

JAEA-Conf 2015-003, p.131 - 136, 2016/03

We carried out the benchmark tests of the general-purpose data library for neutron-induced reactions in FENDL-3.0 with the integral experiments at JAEA/FNS, JAEA/TIARA and Osaka Univ./OKTAVIAN. We also tested the MATXS files of FENDL-3.0 with a simple calculation model and compared KERMA and DPA data included in the ACE and MATXS files of FENDL-3.0 with those in other nuclear data libraries. In this symposium we present the following problems in FENDL-3.0 found out in our study; (1) The $$^{16}$$O data above 20 MeV in FENDL-3.0 should be revised. (2) The most MATXS files in FENDL-3.0 have no energy-angular distribution data for the non-elastic scattering reaction. (3) Some of KERMA and DPA data included in the ACE and MATXS files of FENDL-3.0 should be revised.

Journal Articles

JENDL/HE-2007 benchmark test with iron shielding experiment at JAEA/TIARA

Konno, Chikara; Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro; Sato, Satoshi

JAEA-Conf 2015-003, p.125 - 130, 2016/03

At the last nuclear data symposium we presented the detailed analyses of the iron and concrete shielding experiments with 40 and 65 MeV neutrons at TIARA in JAEA in order to validate FENDL-3.0 and JENDL/HE-2007 and pointed out that calculation results with JENDL/HE-2007 underestimated the measured neutron spectra and calculated ones with FENDL-3.0 in the iron experiment with 65 MeV neutrons. Thus we studied reasons of this underestimation in detail. As a result, we specified that the larger non-elastic scattering cross section data of $$^{56}$$Fe in JENDL/HE-2007 caused the underestimation. The non-elastic scattering data of $$^{56}$$Fe in JENDL/HE-2007 should be revised.

Journal Articles

New nuclear data group constant sets for fusion reactor nuclear analyses based on FENDL-2.1

Konno, Chikara; Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro; Sato, Satoshi

JAEA-Conf 2015-003, p.137 - 141, 2016/03

For fusion reactor nuclear analyses we produce new nuclear group constant sets, FUSION-F21.175 (neutron: 175 groups, $$gamma$$: 42 groups, P5 approximation) and FUSION-F21.42 (neutron: 42 groups, $$gamma$$: 21 groups, P5 approximation), similar with FUSION-J3 and FUSION-40 from FENDL-2.1 with the TRANSX code. The materials in these sets are H-1, H-2, He-3, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-12, N-14, O-16, F-19, Na-23, Mg, Al-27, Si, P-31, S, K, Ca, Ti, V-51, Cr, Mn-55, Fe, Co, Ni, Cu, Zr, Nb-93, Mo, Cd, W, Pb, Bi-209, Cl, Ta-181, Sn and Ga. It should be noted that the self-shielding effect is not corrected in these libraries. KERMA, DPA and gas production libraries are also prepared from the MATXS files with TRANSX. Several test calculations are carried out in order to validate these nuclear group constant sets. They suggest that these group constant sets have no problem.

Journal Articles

Effect of neutron energy and fluence on deuterium retention behaviour in neutron irradiated tungsten

Fujita, Hiroe*; Yuyama, Kenta*; Li, X.*; Hatano, Yuji*; Toyama, Takeshi*; Ota, Masayuki; Ochiai, Kentaro; Yoshida, Naoaki*; Chikada, Takumi*; Oya, Yasuhisa*

Physica Scripta, 2016(T167), p.014068_1 - 014068_5, 2016/02

 Times Cited Count:21 Percentile:15.06(Physics, Multidisciplinary)

The irradiation defects were introduced by Fe$$^{2+}$$ irradiation, fission neutron irradiation and D-T neutron irradiation. After the irradiation, the deuterium ions (D$$_{2}^{+}$$) implantation was performed and the D retention behavior was evaluated by thermal desorption spectroscopy. The experimental results indicated that dense vacancies and voids within the shallow region near the surface were introduced by Fe$$^{2+}$$ irradiation. The trapping state of D by vacancies and void were clearly controlled by the damage concentration and the voids would become the most stable D trapping site. For fission neutron irradiated W, most of the D was adsorbed on the surface and/or trapped by dislocation loops and no vacancies and voids for D trapping due to its lower damage concentration. D trapping by vacancies were found in the bulk of D-T neutron irradiated W, indicating that the neutron energy distribution could make a large impact on irradiation defect formation and the D retention behavior.

Journal Articles

Integral test of international reactor dosimetry and fusion file on graphite assembly with DT neutron at JAEA/FNS

Ota, Masayuki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara

Fusion Engineering and Design, 98-99, p.1847 - 1850, 2015/10

 Times Cited Count:2 Percentile:73.66(Nuclear Science & Technology)

International Reactor Dosimetry and Fusion File release 1.0 (IRDFF 1.0), has been released from the International Atomic Energy Agency (IAEA) recently. In order to validate and test IRDFF 1.0, IAEA has initiated a new Co-ordinated Research Project (CRP). Under this CRP, we have performed an integral experiment on a graphite pseudo-cylindrical slab assembly with DT neutron source at JAEA/FNS. The graphite assembly of 31.4 cm in equivalent radius and 61 cm in thickness is placed at a distance of about 20 cm from the DT neutron source. A lot of foils for the dosimetry reactions in IRDFF1.0 are inserted into the small spaces between the graphite blocks along the center axis of the assembly. After DT neutron irradiation, reaction rates for the dosimetry reactions are measured by the foil activation technique. This experiment is analyzed by using Monte Carlo neutron transport code MCNP5-1.40 with recent nuclear data libraries of ENDF/B-VII.1, JEFF-3.2, and JENDL-4.0. The experimental assembly and DT neutron source are modeled precisely in the MCNP calculation. The reaction rates calculated with IRDFF 1.0 as the response functions for the dosimetry reactions are compared with the experimental values. Also the calculations with JENDL Dosimetry File 99 (JENDL/D-99) are performed for comparison. The results calculated with IRDFF 1.0 show good agreement with the experimental results.

161 (Records 1-20 displayed on this page)