[en] Titanium is contained in lithium titanate which is a tritium breeding material candidate. In the nuclear design, accurate nuclear data are needed. However, few benchmark experiments had been performed for titanium. We performed a benchmark experiment with a titanium assembly and a DT neutron source at JAEA/FNS. The titanium assembly was covered with Li₂O blocks in order to reduce background neutrons. Dosimetry reaction rates were measured with niobium, indium and gold foils inside the assembly. And fission rates of ²³⁵U were measured by using micro fission chambers. This experiment was analyzed by using the Monte Carlo neutron transport code MCNP5-1.40 with recent nuclear data libraries of ENDF/B-VII.0, ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and JENDL-4.0u1. The calculation results were compared with the measured one in order to validate the nuclear data libraries of titanium. The calculated results with ENDF/B-VII.1 agreed with the measured one the best because the (n,2n) and (n,n′_cont) reaction cross section data and resonance parameters were improved

[en] Highlights: •We have benchmarked FENDL-3.0 with integral experiments with DT neutron sources in Japan. •The FENDL-3.0 is as accurate as FENDL-2.1 and JENDL-4.0 or more. •Some data in FENDL-3.0 may have some problems. -- Abstract: The IAEA supports and promotes the gathering of the best data from evaluated nuclear data libraries for each nucleus involved in fusion reactor applications and compiles these data as FENDL. In 2012, the IAEA released a major update to FENDL, FENDL-3.0, which extends the neutron energy range from 20 MeV to greater than 60 MeV for 180 nuclei. We have benchmarked FENDL-3.0 versus in situ and TOF experiments using the DT neutron source at FNS at the JAEA and TOF experiments using the DT neutron source at OKTAVIAN at Osaka University in Japan. The Monte Carlo code MCNP-5 and the ACE file of FENDL-3.0 supplied from the IAEA were used for the calculations. The results were compared with measured ones and those obtained using the previous version, FENDL-2.1, and the latest version, JENDL-4.0. It is concluded that FENDL-3.0 is as accurate as or more so than FENDL-2.1 and JENDL-4.0, although some data in FENDL-3.0 may be problematic

[en] JENDL-4.0, the latest version of Japanese Evaluated Nuclear Data Library (JENDL), was released in May 2010. In order to validate JENDL-4.0, we have analyzed TOF experiments at Osaka University OKTAVIAN with JENDL-4.0 and the Monte Carlo N-Particle transport code MCNP5. And for comparison, older version JENDL-3.3 and other recent nuclear data libraries ENDF/B-VII.0 and JEFF-3.1 have also been used. As a result, the followings have been found out: (1) Si, As, Se, Mo, W: Calculation results with JENDL-4.0 agreed with the experimental ones better than those with JENDL-3.3. (2) Cr, Mn, Nb: Calculation results with JENDL-4.0 were partially better and partially worse than those with JENDL-3.3. (author)

[en] In order to assure the safe d-t operation of ITER tokamak, a design of neutron shields is important. Since the vacuum vessel of ITER tokamak has many ports, gaps and cavities, neutron streaming through them causes radioactivation of reactor equipments and gives a threat to safety environment. In the present paper, results of the neutron streaming test done at FNS (Fusion Neutronics Source) and progress in the development of computer codes for calculating neutron streaming are given. (T.I.)

[en] We have already pointed out that the background cross sections and weighting flux are not adequate in the multigroup library VITAMIN-B6. Here we examine whether the latest multigroup libraries, VITENEA-J, VITJEFF31.BOLIB, MATJEFF31.BOLIB, V7-200N47G in SCALE6, MATXS file in ADS-2.0, HILO2k and MATXSLIB-J33, have the same problems or not. The followings are found out from simple benchmark calculations with ANISN; 1) MATXSLIB-J33 has no problem, 2) VITENEA-J, VITJEFF31.BOLIB, V7-200N47G in SCALE6 and HILO2k are produced by using an inadequate weighting flux, 3) VITJEFF31.BOLIB, MATJEFF31.BOLIB and MATXS file in ADS-2.0 have insufficient background cross section data. It is noted that the self-shielding correction in VITENEA-J, VITJEFF31.BOLIB, MATJEFF31.BOLIB, V7-200N47G in SCALE6, MATXS file in ADS-2.0 and HILO2k is not always adequate, which can lead to unexpected results. (author)

[en] A new collimator is designed and optimized to produce a new DT neutron beam with a small target at the first target room of the Fusion Neutronics Source facility in Japan Atomic Energy Agency. The characteristics of the collimator are calculated with the DORT code and the FENDL/MG-2.1 multi-group cross section library. It is concluded that the calculated neutron fluence above 14 MeV at the exit of the collimator is 180 times as large as that at the 10 cm offset position from the beam axis (author)

[en] JENDL-4.0, the major revised version of Japanese Evaluated Nuclear Data Library (JENDL), was released in May 2010. In order to validate JENDL-4.0, we analyzed TOF experiments with DT neutrons at OKTAVIAN in Osaka University with JENDL-4.0 and MCNP5.14. For comparison, the older version JENDL-3.3 and other recent nuclear data libraries ENDF/B-VII.0 and JEFF-3.1 were also used. As a result, the followings were found out: (1) Si, As, Se, Mo and W : the calculation results with JENDL-4.0 agreed with the measured ones better than those with JENDL-3.3, (2) Cr, Mn and Nb : the calculation results with JENDL-4.0 were partially better and partially worse than those with JENDL-3.3. (author)

[en] We measured neutron spectra in beryllium and an ITER-TBM simulating assemblies by means of a Multi-Foil Activation Method (MFAM) at the FNS facility of JAEA to confirm applicability of MFAM. An unfolding code, NEUPAC, was used to determine neutron flux spectra. Initial guessed neutron spectra were calculated with the Monte Carlo code MCNP4C and a nuclear data library FENDL-2.1. JENDL Dosimetry File 99 was adopted as response data for reaction rates. We deduced neutron flux spectra in the simulated assemblies with the MFAM. From the experiments, it was found out that MFAM gave appropriate results, which indicated that MFAM was a prospect to the application of neutron spectrum measurement in ITER-TBM. However, it was also pointed out that some improvements for measurement of slow neutron below 10 eV were necessary (author)

[en] In 2007 we pointed out that most of the unresolved resonance data in JENDL-3.3 had a problem related to self-shielding effect. Here through comparison of calculated neutron spectra from simple sphere assemblies and the TOF experiment for a manganese sphere at OKTAVIAN we investigate whether the latest JENDL, JENDL-4.0, is improved for the problem or not. The results for the spherical assemblies indicate that the unresolved resonance data in JENDL-4.0 are improved, but the data of the manganese TOF experiment at OKTAVIAN suggest that the unresolved resonance data in JENDL-4.0 still have some problems from the view of the self-shielding effect. New benchmark experiments such as deep penetration experiments are strongly recommended in order to validate the unresolved resonance data in JENDL-4.0. (author)

[en] At International Conference on Nuclear Data for Science and Technology in 2007 we pointed out that most of unresolved resonance data in JENDL-3.3 have a problem related to self-shielding correction. Here with a simple calculation model we have investigated whether the latest JENDL, JENDL-4.0, was improved for the problem or not. The results suggest that unresolved resonance data in JENDL-4.0 have no problem, but it seems that self-shielding effects for the unresolved resonance data in JENDL-4.0 are too large. New benchmark experiments for unresolved resonance data are strongly recommended in order to verify unresolved resonance data. (author)