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In order to complete the tritium production of irradiated tritium breeder in the solid tritium breeder reactor of fusion reactor, in addition to the conventional ionization chamber, a high-precision gas chromatography on-line detection and analysis method of neon carrier gas was established in this work. The tritium production in the system was verified by measuring the helium production in the tritium production circuit. Thus, a new tritium production rate measurement and verification method was provided for the irradiation tritium production performance of tritium producing cladding solid breeder materials in fusion reactor. It’s necessary to establish the method of analyzing trace 4He, H2 and impurity components in Ne, in order to complete the test of real-time online detection of the system, developing three detectors and five chromatographic columns. The results show that the developed chromatographic analysis system can realize the detection and analysis of 4He, H2 and impurity components in high-purity Ne, the detection limits of H2 and 4He can reach 1.0×10-6 and 5.9×10-6 respectively, the relative standard deviation(sr) of each component content and peak area are less than 5.0%(n=6), and the linear correlation coefficient r2 is greater than 0.99, indicating that the detection method has good repeatability. According to the on-line test of multicomponent gas in Ne, the measurement repeatability in single period and multi period is good, which can provide an analytical means for the verification of tritium production rate in the irradiation tritium production assessment system, and then provide technical support for the formal entry into the reactor to obtain irradiation data and tritium balance.

As one of CFETR’s candidate blankets, water cooled ceramic breeder (WCCB) blanket undertakes important nuclear-related functions such as tritium breeding, nuclear heat extraction, and neutron shielding. The reliability of neutronics design directly affects the realization of CFETR tritium self-sustaining goal. In order to verify the reliability of the neutronics design tool, i.e. MCNP and FNEDL databases, in the WCCB blanket neutronics design, the WCCB scaling-down mock up was developed to carry out the neutronics experiment in the DT neutron environment, including two layers of lithium titanate, two layers of beryllium, three layers of cooling plate, and one layer of tungsten armor. The neutronics performance of the mock up are similar with the real blanket module. The mock up neutronics experiments were carried out using DT neutron generator, the simulated value (C) and experimental value (E) of neutronics parameters represented by tritium production rate (TPR) were analyzed. For TPR validation, two independent detection technologies were used, including the Li2TiO3 pellets as off-line TPR detectors, and the developed lithium glass detectors as on-line TPR detectors. The TPR validation was complemented by evaluating the predicted neutron-induced reaction rates of the Au, Zr foils. The experiments on the mock up were analyzed by MCNP-4C code and FENDL-3.0 nuclear data libraries, and the source term for Monte Carlo simulation was built using the custom-developed model based on depth profiling of tritium in the tritide target. The analysis results show that the C/E of TPR in the axis of two lithium titanate layers is 0.97 and 1.08 respectively, while there is a large deviation between the calculated and experimental values of TPR in the edge region of the mock up. According to the experimental results from Li2TiO3 pellets, the C/E of TPR at the edge of two lithium titanate layers is 0.65 and 0.82, respectively. The TPR is obviously underestimated by simulation at the edge of lithium titanate layers, confirmed by the C/E results of 197Au(n, γ)198Au reaction rate at the edge of lithium titanate layers, which are 0.72 and 0.90, respectively. It is indicated that there are unexpected scattered neutrons in the edge region of the mock up, resulting in the higher TPR than expected. The further experiments are needed to verify the influence of the scattered neutron on the TPR at the edge region of the mock up. To investigate the TPR gap between simulation and the experimental results from lithium glass detectors, the contribution of the fast neutrons on the 6Li(n, t)4He should be further studied. Also the other suggestions are provided for further experimental research, refering to the radiation protections and nuclear measurements.

Study of spatial spectra and tritium breeding ratio (TBR) in a lithium blanket play a crucial role for the successful operation of a Fusion reactor. In this paper, we have reported the results for the space-dependent fast neutron spectra and tritium production rate (TPR) in cylindrical assemblies of Li2O. The multigroup diffusion equation has been solved using eigenfunction expansion method. The obtained results for scalar spectra, total flux and TPR in Li2O are compared with corresponding values for natural Li. The space dependent scalar spectrum in Li2O has been compared for different configurations (slab, sphere and cylindrical). We find that the shapes of the curves are almost similar, though the neutron flux is found to be highest in the case of cylindrical assembly. This suggests a larger value of total TBR for a cylindrical geometry. Further, the study of space variation of total flux for Li2O and natural Li shows that there is not much change in the shapes and numerical values, however, it falls sharply near the boundary end surface of the assembly for Li2O as compared to natural Li. Similarly, the fall in the TPR curves becomes more rapid for the case of Li2O as compared to natural Li near the boundary end. The calculated results of spatial distributions of TPR for 6Li (n,?)t and 7Li (n,n'a)t reactions are compared with experimentally obtained results for cylindrical slab assemblies. and it is found that agreement is fairly good, both in the case of 7Li and 6Li. [ABSTRACT FROM AUTHOR]

BackgroundChina Dual Functional Lithium-Lead (DFLL) blanket is designed by the Institute of Nuclear Energy Safety Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences for fusion reactor. Since the designs of fusion reactor tritium breeding blankets are highly depended on neutronics calculation, nuclear data and simulation software used for DFLL cladding design is needed to be verified.PurposeThis study aims to evaluate the feasibility of nuclear data and code in DFLL cladding design by neutronics experiments.MethodsFirst of all, a DFLL mock-up was built and a series of neutronics experiments were performed on the D-T Fusion Neutron Generator. Then, a combination of Nb activated foil with reaction channel 93Nb(n,2n)92mNb and 238U fission chamber was chosen in this experiment for neutron yield measurement and relative neutron source intensity monitoring respectively. The Li2CO3 pellets and activation foils were used to measure the tritium production rates (TPR) and the multi-threshold reaction rates at different depths in the DFLL mock-up respectively. Finally, the measured TPR and reaction rates of the activation foils were compared with Monte Carlo simulation results coupled with JEFF3.2 nuclear data library.ResultsThe comparison results show that measurement uncertainty of neutron source intensity is within 4.2%, and the ratios of calculation results to experimental data (C/E) are 1.0~1.07 on TPRs and 0.77~1.1 on reaction rates.ConclusionsThe obtained results indicate that the tritium breeding ratio in neutronics design can be accurately evaluated.

• Diamond detector covered with 6LiF (LiDia) to be used for Tritium production rate at JET. • LiDia calibrated in a reference thermal flux to determine the 6Li mass. • Benchmark experiment performed at the FNG facility using 14 MeV neutrons. • LiDia located in a polyethylene phantom, irradiated and Tritium production measured. • Experimental results compared to MCNP5 simulation, good agreement between experiment and simulation (< ±4%) found. One relevant experiment selected for the DT phase at JET is the irradiation of the HCPB-TBM mock-up of ITER which will be located in front of the horizontal port of Octant-8. The neutronics performances of the HCPB-TBM will be studied through independent measurement techniques and the experimental quantities compared to the results of Monte Carlo simulation. Of paramount importance is the measurement of the tritium production rate (TPR) to be performed by using a single crystal diamond detector covered with a thin layer of 6LiF (LiDia detector). This requires the knowledge of the 6Li mass. In this work the 6Li mass calibration of the selected LiDia detector was first performed in a well characterized thermal neutron flux spectrum. Furthermore, a performance test of the detector was carried out by locating it inside a polyethylene phantom irradiated with 14 MeV neutrons at the Frascati Neutron generator. The experimental set-up was accurately simulated by using the MCNP5 code and the TPR compared to the measured one. The goal was to point out and assess the issues with the measurement method. [ABSTRACT FROM AUTHOR]

Highlights • Four blanket benchmark mockups of a fusion–fission hybrid reactor have been established. • Distribution of TPR in the mockups was obtained by lithium glass detector method. • Distribution of TPR was assessed by using MCNP5 program and ENDF/B-VII database. • Difference between calculations and experiments in lithium hydride may be caused by lack of S(α,β) thermal neutron data. Abstract As an important parameter of neutronics integral experiment, tritium production rate could not only be used for validation of programs and evaluation database, but was also related to tritium self-consistency after the activation of the sub-critical reactor. This parameter was a key component of the sub-critical reactor design. Four blanket benchmark mockups of a fusion-fission hybrid reactor were established utilizing lithium materials, which consisted of depleted uranium/lithium hydride, uranium/lithium hydride/polyethylene, uranium/lithium hydride/graphite/iron, and uranium/Li-Pb alloy/polyethylene. Based on the Cockcroft–Walton neutron generator, the distribution of tritium production rate by D–T neutrons in the four mockups was evaluated by two pairs of different sizes lithium glass detectors. The distribution was then quantitatively assessed using MCNP5 program and ENDF/B-VII database. The tritium production rates of the mockups with lithium hydride significantly deviated from the experimental results; whereas those of the mockup with lithium-lead alloy were agree well with the experimental results. [ABSTRACT FROM AUTHOR]

Experiments were conducted with breeding blanket mock-up consisting of two layers of breeder material lithium titanate pebbles and three layers of pure lead as neutron multiplier. The radial dimensions of breeder, neutron multiplier and structural material layers are similar to the current design of the Indian Lead–Lithium cooled Ceramic Breeder (LLCB) blanket. The mock-up assembly was irradiated with 14 MeV neutrons from DT neutron generator. The local tritium production rates (TPR) from 6 Li and 7 Li in breeder layers were measured with the help of two different compositions of Li isotopes (60.69% 6 Li and 7.54% 6 Li) in Li 2 CO 3 . Tritium production in the multiplication layers were also measured with above mentioned two types of pellets to compare the experimental tritium production with calculations. TPR from 6 Li at one location in the breeder layer was also measured by direct online measurement of tritons from 6 Li(n, t) 4 He reaction using silicon surface barrier detector and 6 Li to triton converter. Additional verification of neutron spectra ( E n > 0.35 MeV) in the mock-up zones were obtained by measuring 115 In(n, n′) 115m In reaction rate and comparing it with calculated values in all five layers of mock-up. All the measured nuclear responses were compared with transport calculations using code MCNP with FENDL2.1 and FENDL3.0 cross-section libraries. The average C/E ratio for tritium production in enriched Li 2 CO 3 pellets was 1.11 in first breeder zone and 1.09 in second breeder zone with uncertainty 8.3% at 1 σ level. The experimental details and results are discussed in this paper. [ABSTRACT FROM AUTHOR]

Test blanket modules (TBMs) will be installed in the ITER with the aim to investigate the nuclear performance of different breeding blanket designs for fusion power reactors. Here, we present an overview of our ongoing work on three types of neutron flux monitors under development at Karlsruhe Institute of Technology (KIT) for the TBMs. A foil activation system with pneumatic sample transport was constructed by KIT utilizing the intense DT neutron generator of Technical University of Dresden. It is used as a test bench for the development of a neutron activation system for the TBMs. Self-powered neutron detectors (SPNDs) are widely applied in fission reactor monitoring, and the commercially available SPNDs are sensitive to thermal neutrons. We are investigating novel materials for SPND which would be sensitive also to the fast neutron flux expected in the TBMs. Within the I_SMART project, funded by KIC InnoEnergy, KIT is developing an online detector based on silicon carbide electronics for the TBMs. [ABSTRACT FROM PUBLISHER]

Abstract: India is developing lead lithium cooled ceramic breeder (LLCB) TBM to be tested in ITER. Liquid lead lithium along with lithium titanate has been adopted as basic material in Indian TBM for neutron multiplication and tritium breeding. RAFMS is used as the structural material and the first wall is cooled by helium. Li-6 enrichment is taken as 60 and 90% in lithium titanate and lead lithium, respectively. The LLCB TBM design is under progress and two design variants are being considered viz. plate design and tube design. In plate design the lead lithium and lithium titanate zones are arranged alternatively and are parallel to the first wall of TBM. In tube design circular tubes of RAFMS are assumed parallel to first wall and lead lithium flows inside the tubes or outside the tubes and lithium titanate is placed accordingly. For the neutronic design of the LLCB TBM, a detailed 3D neutronic model with “look alike” LLCB TBM in equatorial port in ITER has been constructed. A 3D neutron source has been used for the D-T neutrons emitted by plasma. Neutronic study is carried out using Monte Carlo transport code with FENDL-2.1 library with the following objectives: (1) to examine the profiles of heating and tritium production rates in the LLCB TBM, both in the radial and toroidal direction, in order to identify locations where neutronics measurements can be best performed with least perturbation from the surroundings, (2) to provide both local and integrated values for nuclear heating rates required for subsequent thermo-mechanical analysis, and (3) to compare the tritium production capabilities of two variants of the geometries. This paper will present the main findings from this neutronic study. [Copyright &y& Elsevier]

Abstract: A neutronics experiment was performed to measure the tritium production rate (TPR) profile in the breeder assembly with LiAlO2 as breeder and high density polyethylene (HDPE) as neutron reflector. The breeder assembly was irradiated with 14MeV neutrons from DT neutron generator at IPR Neutronics Laboratory. The objective of the experiment was to validate the tritium production prediction capability of the Monte-Carlo code MCNP and FENDL 2.1 data library. The tritium production rate profile in the breeding assembly was measured by irradiating Li2CO3 pellets kept at various locations and then tritium counting liquid scintillation technique. Experiment was analyzed with 3D Monte-Carlo code MCNP with FENDL 2.1 cross-section data library. The calculation results were found to agree with the measured tritium production rates except one point near to the source. This experiment is a starting experiment in the series of benchmark experiments for the Indian Demo breeding blanket. [Copyright &y& Elsevier]

Abstract: In the neutronics experiment for the ITER test blanket module with a 6Li-enriched Li2TiO3 layer and a beryllium layer conducted at the FNS facility of Japan Atomic Energy Agency, the calculated tritium production rate (TPR) was approximately 10% larger than the measured value only when a neutron source reflector composed of SS316 was attached. On the other hand, the influence of the reflector on the TPR prediction accuracy was not seen in the recent blanket experiment with a natural Li2TiO3 layer, beryllium layers and the reflector. We investigated the former experiment in detail, and found an unphysical tendency in the measured TPR distribution. In order to clarify whether the deterioration of the TPR prediction accuracy originates from the reflector or not, we have conducted the same experiment as the previous experiment again. In the present experiment, the measured TPR distribution inside the 6Li-enriched Li2TiO3 layer agreed well with the calculated value within an estimated experimental error of 6%. We conclude that the overestimation of TPR observed in the previous experiment would be due to some experimental faults and that the TPR prediction accuracy is good even in the case with the reflector. [Copyright &y& Elsevier]

Abstract: Within the European Fusion Technology Programme dedicated computational methods, tools and data have been developed and validated for sensitivity and uncertainty analyses of fusion neutronics experiments. The present paper is devoted to this kind of analyses on the recent neutronics experiment on a mock-up of the Helium-Cooled Lithium Lead Test Blanket Module for ITER at the Frascati neutron generator. They comprise both probabilistic and deterministic methodologies for the assessment of uncertainties of nuclear responses due to nuclear data uncertainties and their sensitivities to the involved reaction cross-section data. We have used MCNP and MCSEN codes in the Monte Carlo approach and DORT and SUSD3D in the deterministic approach for transport and sensitivity calculations, respectively. In both cases JEFF-3.1 and FENDL-2.1 libraries for the transport data and mainly ENDF/B-VI.8 and SCALE6.0 libraries for the relevant covariance data have been used. With a few exceptions, the two different methodological approaches were shown to provide consistent results. A total nuclear data related uncertainty in the range of 1–2% (1σ confidence level) was assessed for the tritium production in the HCLL mock-up experiment. [ABSTRACT FROM AUTHOR]

Abstract: In support of the breeder blanket development program, the EU is conducting a dedicated neutronics R&D effort to provide the basis for the design of nuclear tests to be performed in ITER on the Test Blanket Modules (TBMs). It includes the development of computational tools comprising both Monte-Carlo and deterministic transport, sensitivity and uncertainty codes, the generation of high quality neutron cross-section and covariance data libraries. These are validated experimentally in view of their application in the ITER TBM and the DEMO design. To this purpose, two neutronics experiments have been carried out on mock-ups of both the Helium Cooled Pebble Bed (HCPB) and the Helium Cooled Lithium Lead (HCLL) variants of ITER TBMs, at 14-MeV neutron sources. Redundant experimental techniques have been used to measure the resulting tritium production rate and the neutron and gamma ray spectra which are needed to predict the blanket shielding performance, nuclear power production and all nuclear loads. The comparison of experiment and corresponding calculation is obtained with the associated uncertainty margin based on experimental as well as calculational uncertainties. At the same time, suitable nuclear measuring techniques for TBMs in ITER, in particular for the tritium production, are being developed, optimised, and tested in the mock-up experiments. In particular, the present paper summarizes the preliminary results of the latest of such experiments, i.e. the one conducted on a mock-up of the HCLL blanket. It describes also the dedicated neutronics R&D activities, including the efforts to specify the neutronics tests and objectives in TBMs in ITER, considering the various design concepts. [ABSTRACT FROM AUTHOR]

Abstract: In the previous blanket neutronics experiments conducted at the FNS facility of Japan Atomic Energy Agency, the following disagreements between experiments and analyses have been pointed out: (1) in the experiment with a 6Li-enriched Li2TiO3 layer and a beryllium layer, the calculation was found to overestimate the tritium production rate (TPR) by approximately 10% when a neutron source reflector composed of SS316 was attached. (2) In the experiment with natural Li2O pebbles sandwiched by beryllium layers, TPR near the rear beryllium layer was overestimated by up to 10%. In order to identify the cause of the above problems clearly, a new blanket neutronics experiment with DT neutrons using natural Li2TiO3 layer and beryllium layers was conducted at FNS. TPR distributions inside the natural Li2TiO3 layer in assemblies with and without the source reflector were measured with Li2CO3 pellets. The measured TPR agreed well with the calculations within 6% in both assemblies. The influence of the reflector and beryllium on TPR prediction accuracy was not seen in the present experiment. [ABSTRACT FROM AUTHOR]

The high-flux test module (HFTM) of the International Fusion Materials Irradiation Facility (IFMIF) will be exposed to an intense flux of fast neutrons with energy values of up to approximately 55 MeV. The threshold of tritium-producing reactions in the HFTM and the specimen materials is typically between 10 and 20 MeV: therefore, the assessment of the tritium inventory becomes important for the handling of the specimen cells and specimens after the irradiation cycle. In this paper, we calculate the tritium production in the specimen cells by neutrons with the McDeLicious code and activation nuclear data from the libraries EAF-2007 and IEAF-2001. The results differ by roughly a factor of two. We discuss ambiguities in the relevant activation data and conclude that better experimental verification of cross sections of isotopes most important for the tritium production in the test cells is desirable. [ABSTRACT FROM AUTHOR]

Abstract: Irradiation experiments with a LiAlPb assembly have been performed using the DT neutron generator of Technical University of Dresden. The main goal was to qualify LiF thermoluminescence detectors (TLDs) for tritium breeding experiments and to test a recently improved NE-213 spectrometer, both for application in a neutronics mock-up experiment of the European HCLL-TBM at ENEA Frascati and Technical University of Dresden (TUD) planned for 2008. The LiF-TLD were set up inside the LiAlPb assembly and irradiated with the DT neutron generator of TUD in continuous mode. A good agreement with TPR calculated with MCNP was found. Fast neutron spectra inside the assembly have been obtained with the NE-213 detector. The flux of the thermal and epithermal neutrons inside the assembly, which is important for the tritium production rate from , was measured with a counter and the DT neutron generator operated in pulsed mode. [Copyright &y& Elsevier]

Abstract: A series of breeding blanket neutronics experiments were carried out with DT neutrons in the Japanese ITER test blanket module at JAEA Fusion Neutronics Source (FNS), and tritium production rates (TPRs) inside different blanket mock-ups were measured in detail. Most of calculations made using FENDL-2.1 and MCNP agreed well with the measured TPRs. On the other hand, there were overestimations of the calculation for the TPR in the experiment with a reflector and the TPR around the boundary between the rear part of the breeder layer and the beryllium in the pebble bed mock-up experiment. In this study, we investigated the possibility of improvement of the calculation by modifying the part of angular distributions in backward directions in FENDL-2.1. By uniformly decreasing the backward elastic scattering cross-sections of 56Fe by 20% below the original data for incoming neutrons in the energy range from 0.5234MeV up to 15.0MeV, the overestimation of the calculations for the TPR in the enriched breeding blanket experiment with a reflector was reduced. Also, by uniformly decreasing the backward elastic scattering cross-sections of 9Be by 20% and 30% below the original data for the incoming neutrons in the energy range from 0.93MeV up to 14.94MeV, and by 20% for those from 0.62MeV up to 14.94MeV, the overestimation of the calculations for the TPR around the boundary between the rear part of the breeder layer and the beryllium was lessened. [Copyright &y& Elsevier]

Abstract: A neutronics experiment performed at the Frascati Neutron Generator (FNG) on a mock-up of the Helium-Cooled Pebble Bed (HCPB) breeder test blanket module (TBM) has been analysed on the basis of neutron transport, sensitivity and uncertainty calculations using both deterministic and probabilistic computational methods. The calculations revealed a slight but systematic underestimation of the measured tritium activities by 5 to 10% on average, independent of the nuclear data used that were taken from the EFF-3 and FENDL-2.0, -2.1 data files. The uncertainty assessments showed data related uncertainties of the calculated tritium production rates at a level of 4% (2σ confidence level). The beryllium cross-section data were shown to be the main source of these uncertainties. The total uncertainties of the tritium production prediction including the data uncertainties, the statistical uncertainties of the Monte Carlo calculation and the experimental uncertainties are in the order of 8 to 10% (2σ). The observed underestimation of the measured tritium production is at the lower bound of the assessed uncertainty margin. The obtained results indicate that design calculations for the tritium breeding ratio (TBR) of fusion power reactors employing a HCPB type breeder blanket are conservative. Thus, an additional TBR margin is provided which allows compensation for potential other uncertainties. [Copyright &y& Elsevier]

Abstract: A clean benchmark experiment on beryllium was performed with D-T neutrons at the FNS facility of the Japan Atomic Energy Agency. The main objective was to verify the integral data related to the tritium production on lithium isotopes. Tritium production rates, as well as activation reaction rates were measured inside the beryllium assembly that was shaped as a pseudo-cylindrical slab with an area-equivalent diameter of 628mm and a thickness of 355mm. Experimental results were analyzed with a three-dimensional Monte Carlo transport code MCNP-4C and FENDL/MC-2.0, JENDL-3.2/3.3 neutron transport libraries. Evaluation of reaction rates was based on the cross section data taken from the JENDL Dosimetry File and ENDF B-VI data libraries. Analysis shows that all calculation combinations (transport and activation cross section libraries) used for evaluation of reaction rates give data that is agreeable with measured values within 10%. [Copyright &y& Elsevier]

Abstract: The neutronics study in support of the DEMO blanket concept has been performed using the DT neutrons at the FNS facility in JAERI on blanket mockups and a bulk beryllium assembly. From the results obtained in the blanket mockups, it has been clarified that the C/Es of the integrated tritium production are 1.01–1.04 and 1.11–1.13 in the experiments without and with the neutron reflector, respectively. The tritium production can be very accurately predicted in the experiment without the reflector. In the mockups with the 12.6 and 25.2mm thick tungsten armors, the integrated tritium productions are reduced by 3 and 6% relative to the case without the armor, respectively. Based on analysis of the integral experiment on the beryllium assembly, it is possible to conclude that the calculation uncertainty of the reaction rates in beryllium provides an acceptable agreement with the experimental data related to tritium breeding. Tritium techniques used for TPR measurements have been tested in the international benchmark experiment. There is a very good agreement within the estimated uncertainties between results obtained at JAERI and at TUD, though the results obtained at ENEA show an underestimation (about 15–20%) in comparison with FNS and TUD results. [Copyright &y& Elsevier]

Abstract: Experiments have been conducted with breeding blanket mock-ups consisting of layers of candidate materials for JAERI’s pebble bed blanket design: lithium titanate, beryllium and reduced activation ferritic steel F82H. The mock-ups were irradiated with 14 MeV neutrons from the DT neutron source at FNS. The lithium titanate was enriched to 40 and 95% in . The local tritium production rate in the 12 mm thick breeding layers was measured by means of pellet detectors of lithium titanate, Li2CO3 and liquid scintillation counting techniques. Additional verification of the neutron spectrum was obtained from material activation such as activation foils. The results were analyzed with the Monte Carlo neutron transport code MCNP-4C and several transport cross section libraries such as FENDL/MC-2.0. The calculation/experiment ratio was found to be within the combined error estimate of calculation and experiment but in some cases, the calculations showed an overestimation tendency. [Copyright &y& Elsevier]

• A multi-layer mockup with uranium alloy disks and breeder pebble bed which represents real engineering design of HTBB has been setup. • Several neutronic responses such as fission reaction rate, plutonium producction rate, activation reaction rate and tritium production rate have been measured. • The C/E results show that calculations generally agree with experiments within 4% for tritium production rate. • The experiment has provided validation to the HTBB design, calculation code and nuclear data used in the simulations. A neutronic experiment has been performed using DT neutrons on a blanket mockup of the hybrid tritium breeding blanket (HTBB) at CAEP. As a backup blanket configuration for CFETR, HTBB design which uses uranium alloy, water coolant and ceramic breeder pebble bed has been proposed to obtain high tritium breeding ratio. The experiment has provided validation not only to the preliminary design of HTBB, but also to calculation code and nuclear data used in the simulations. Various neutron responses such as fission reaction rate, plutonium production rate, activation reaction rate and tritium production rate (TPR) have been measured. Numerical analyses were carried out with MCNP-4C code using ENDF/B-VII.1, TENDL-2017, IRDFF-v1.05 and FENDL3.1 nuclear data libraries. The comparisons between the calculation and experimental results show an agreement within about 10% for most of the measured quantities. The ratios of calculated to measured results (C/E) of tritium production rate are in 0.98–1.04 range which shows good agreement. [ABSTRACT FROM AUTHOR]

• Investigation of the D–T neutron deep penetration experiment FNG-Cu using the TRIPOLI-4 Monte Carlo radiation transport code. • Calculation of the neutron reaction rates for various activation foils (Nb, Al, Ni, In, Au, W) versus penetration depth in the FNG copper block. • Simulation of the D–T neutron slowing down and thermalization in polyethylene moderator by TRIPOLI-4 for the FNG lithium diamond detector. • Verification of the tritium production rate in LiDia detector for ITER-TBM experiment using different TRIPOLI-4 models of FNG experiment. For the future ITER (International Thermonuclear Experimental Reactor) operation needs, several D–T fusion neutron experiments have been conducted at FNG (Frascati Neutron Generator) facility. These FNG experimental results are useful to validate neutron transport codes and nuclear data libraries. The TRIPOLI-4 Monte-Carlo radiation transport code has been widely used on radiation shielding, criticality safety and fission reactor physics fields to support nuclear energy research and industrial applications. With the growing interest in using the TRIPOLI-4 code for ITER applications, a key issue that arises is whether or not the released TRIPOLI-4 code and its associated nuclear data libraries are verified and validated for the 14 MeV fusion neutronics calculations. Copper is a key material used in different components of ITER tokamak machine and the FNG copper benchmark experiment funded by F4E (Fusion for Energy) was recently introduced into the OECD/NEA SINBAD database. In the first part of this work, TRIPOLI-4 calculations were performed to simulate the D–T fusion neutron transport in a pure copper block of FNG-Cu experiments. The reaction rates were evaluated for various activation foils (93Nb(n,2n), 27Al(n,α), 58Ni(n,p), 115In(n,n'), 197Au(n,2n), 186W(n,γ), and 197Au(n,γ)) versus penetration depth in the Cu block. To study the measurement tool of tritium production for the future ITER Test Blanket Module (TBM), the second FNG experiment analyzed in this work arranged a thin layer of 6LiF (LiDia detector) placed inside a polyethylene cylinder and irradiated with FNG 14 MeV neutrons. TRIPOLI-4 simulation models were run to evaluate the tritium production in the LiDia detector. The purpose of this study is to investigate the TRIPOLI-4 calculations against the FNG experimental ones. TRIPOLI-4 calculation methods and results are reported. [ABSTRACT FROM AUTHOR]

• Nuclear responses of WCCB TBM with container design change were evaluated. • The nuclear responses were assessed by using MCNP5.1.60 and FENDL-2.1. • Tritium production rate increased by about 2times with the container design change. • The container design change led to a decrease in total nuclear heating of the TBM. • Nuclear heating and TBR could be improved by changing blanket arrangements. In test blanket module (TBM) program blanket major functions, which are tritium production, heat extraction for electric power production, and neutron shielding, will be demonstrated under fusion reactor environments in ITER. National Institutes for Quantum and Radiological Science and Technology (QST) has performed developments of water cooled ceramic breeder (WCCB) TBM as a primary concept in Japan. The container design of WCCB TBM was changed from the Box-shaped to a cylindrical structure to increase tritium breeding capability while maintaining pressure resistance under In-Box LOCA caused by water ingress into the container. The nuclear responses related to the blanket major functions would be changed with the container design change. The nuclear responses of WCCB TBM with the container design change were evaluated and the effects of the changed nuclear responses were described in this study. Tritium production rate increased by about 2 times with the container design changes. In contrast neutron shielding performance decreased due to the container design change. Degradation of neutron shielding in the cylindrical TBM led to an increase in nuclear heating of the TBM frame as well as an average of neuron flux behind TBM-set. [ABSTRACT FROM AUTHOR]

• Li glass detectors for measuring the tritium production rate (TPR) of fusion blankets. • Discrepancies have been found in TPRs measured by the Li glass method and the pellet method. • Neutron responses of Li glass detectors were calculated to study the discrepancies. • Corrections for the Li glass method were evaluated by the calculated neutron responses. • Corrected TPRs of the Li glass method agree well with TPRs of the pellet method. Lithium (Li) glass scintillation detectors were utilized by the neutron response of a 7Li glass subtracted from the neutron response of a 6Li glass to evaluate the tritium production rate (TPR) in the fusion blanket neutronics experiments, which is a so called Li glass method. TPRs in the Li 2 O blanket and the Li/V-alloy blanket were measured by a 6Li 2 O and a 6Li 2 CO 3 pellet method, and by the Li glass method in the benchmark neutronics experiment with D-T neutrons at the Fusion Neutronics facility (FNS) of JAERI. TPRs measured by the Li glass method are lower than TPRs measured by the pellet method. The neutron responses of Li glass detectors have been calculated to study the discrepancies of two different methods by using the PHITS code. In the blanket, the neutron spectra change to harder from the backside to the front side of blanket. The reaction rate of several reactions, such as 6Li(n, n'α)D, 7Li(n, n'α)T, 7Li(n, 2n)6Li, and the elastic scattering of 6Li and 7Li increase with the neutron energy. The low-energy neutron peak was considered only for the calculation of TPR from Li glass, which loses the information of the 6Li(n, α)T reaction from high-energy neutron range. In addition, the reaction rate of this peak evaluated by the Li glass method is lower than real TPR of this peak for 6Li glass caused by weakened effect from other reactions. Therefore, the ratios of this peak reaction rate from the Li glass method against the total TPR of 6Li glass were evaluated to be a correction factor to correct Li glass method. After the correction, TPRs measured by Li glass method agree well with TPRs measured by pellet method. [ABSTRACT FROM AUTHOR]