Ceramic Breeder Test Blanket Module Research Articles

Development of TSACO and application to Chinese HCCB TBM cooling system

In this study, a thermal-hydraulic and safety analysis code (TSACO) for helium cooling system has been developed using Fortran 90 language, and the simulation has been performed for the cooling system of the Chinese helium cooled ceramic breeder test blanket module (CH HCCB TBM). The semi-implicit finite difference technique was adopted for the solution of the dynamic behavior of helium cooling system. Furthermore, a detailed illustration of the numerical solution for heat structures and critical model was presented. The code was verified by the comparison of RELAP5 code with the same initial condition, boundary condition, heat transfer and flow friction models. The TBM inlet/outlet temperatures and pressure drop were obtained and the results simulated by TSACO were shown in good agreement with those by RELAP5. Thereafter, the design basis accident in-vessel loss of coolant accident (LOCA), was investigated for the CH HCCB TBM cooling system. The critical flow model was also verified by comparing with RELAP5 code. The results indicated that the TBM can be cooled down effectively. The vacuum vessel (VV) pressure and the mass of helium spilled into the VV maintained below the design limits with a large margin.

Development of the Water Cooled Ceramic Breeder Test Blanket Module in Japan

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. In Japan, fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90mm, was confirmed toward the fabrication of the real scale back wall by F82H. Important key technologies are almost clarified for the fabrication of the real scale TBM module mockup. From the view point of testing and evaluation, development of the technology of the blanket tritium recovery, development of advanced breeder and multiplier pebbles and the development of the blanket neutronics measurement technology are also performed. Also, tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been started as the verification test of tritium production performance. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.

Overview of Russian Federation activity on the LLCB TBM design and analysis

According to the Technical program of cooperation between the leading research institutes of India and Russian Federation the joint development of lead-lithium ceramic breeder (LLCB) test blanket module (TBM) is one of preferential directions in this program. The concept of LLCB TBM and corresponding DEMO blanket has been proposed by Indian TBM Team and India is a “Leader” in this concept. Russian Federation takes part in the design, analysis and R&D activities on LLCB TBM concept on the rights of “Partner”. In particular the joint efforts are focused now on the development of LLCB TBM in the electromagnetic option (so-called EM-TBM).In the framework of the design and analysis for LLCB TBM several design options have been considered by RF specialists during 2010–2011 period. The main directions of design and analysis works are as follows:-the designing of TBM load-bearing casing including the reliable cooling layout;-the development of tritium breeding zone (TBZ) basing upon the minimizing of MHD-pressure drops for liquid metal circulation, increasing of eutectic outlet temperature (up to 500°C) and tritium production rate;-to create the TBM attachment system that will be able to withstand the loads for all the ITER operation modes;-thermal hydraulic analyses for TBM helium cooling system and eutectic circuit (taking into account the magnetic field conditions);Brief results of this activity and consequent proposals on the design improvements are presented in this paper.The critical issues and further plans on the development of LLCB TBM in Russian Federation are also discussed and analyzed in this article.

Progress on design and R&D for helium-cooled ceramic breeder TBM in China

The helium-cooled ceramic breeder (HCCB) test blanket module (TBM) is the primary option of the Chinese TBM program. Current progress on the design and R&D for Chinese helium-cooled ceramic breeder TBM (CN HCCB TBM) in China is presented. The main updated design and related R&D of CN HCCB TBM are introduced briefly. The mock-up fabrication and component tests for Chinese test blanket module are being carried out. Recent status of the components and fabrication technology development is also reported. The neutron multiplier Be pebbles, tritium breeder Li4SiO4 pebbles, and structure material CFL-1 are being prepared in the laboratory scale. The fabrication of 1/3 sized mock-up and construction of a He test loop are being carried out. The key technology development is proceeding to the large scale mock-up fabrication and demonstration tests toward on ITER testing.

Analysis of the reference accidental sequence for safety assessment of LLCB TBM system

Abstract Safety analysis of the reference accidental sequence has been carried out for Lead Lithium cooled Ceramic Breeder (LLCB) Test Blanket Module (TBM) system; India's prototype of DEMO blanket concept for testing in International Thermonuclear Experimental Reactor (ITER). The accidental event analyzed starts with a Postulated Initiating Event (PIE) of ex-vessel loss of first wall helium coolant due to guillotine rupture of coolant pipe with simultaneous assumed failure of plasma shutdown system. Three different variants of the sequences analyzed include simultaneous additional failures of TBM and ITER first wall, failure of TBM box resulting in to spilling of lead lithium liquid metal in to vacuum vessel and reactor trip on Loss of Coolant Accident (LOCA) signal from TBM system. The analysis address specific reactor safety concerns, such as pressurization of confinement buildings, vacuum vessel pressurization, release of activated products and tritium during these accidental events and hydrogen production from chemical reactions between lead–lithium liquid metal and beryllium with water. An in-house customized computer code is developed and through these deterministic safety analyses the prescribed safety limits are shown to be well within limits for Indian LLCB-TBM design and it also meets overall safety goal for ITER. This paper reports transient analysis results of the safety assessment.

Evaluations on reduction of the ITER TFC ripple generated by CN HCCB-TBM

Reduced Activation Ferritic/Martensitic (RAFM) steel has been chosen as structural material for China Helium-Cooled Ceramic Breeder Test Blanket Module (CN HCCB-TBM). The magnetization of RAFM definitely increases the toroidal field perturbation (called TF ripple) in international thermonuclear experimental reactor (ITER). The TF ripple could cause ripple loss of high-energy particles and result in a large localized heat load on the first wall of TBMs. Thus some positive measures to reduce the TF ripple generated by TBMs have been evaluated by finite element models (FEM) in this paper. It has been shown that under the intervention of ferromagnetic inserts (FIs) the TF ripple could be reduced to the acceptable level of ITER (namely, TF ripple ∼0.7% at R = 8.2 m of plasma edge near the equatorial plane) while fully considering several actual combinations (mass-reduction and recess) of HCCB-TBM and introduction of correction coils.

Recent status of fabrication technology development of water cooled ceramic breeder test blanket module in Japan

As the primary candidate of ITER test blanket module (TBM) of Japan, development of water cooled ceramic breeder (WCCB) TBM is being performed. For installation of the TBMs in ITER, it is required to certify the quality of the TBMs. To certify the quality, it is necessary to show verifications of fabrication technique, fabrication capability and the integrity of prototypical size mockup in corresponding operation condition before the delivery of the TBM to ITER. This paper overviews the recent achievements of the fabrication technology development of the WCCB TBM in Japan.

Conceptual and preliminary engineering design of experimental helium loop for China HCCB TBM components test

Chinese Helium Cooled Ceramic Breeder Test Blanket Module (CN HCCB TBM) had been confirmed to be one of the leader concepts, which will be tested in half of ITER equatorial port. It is responsible for each TBM does not jeopardize ITER operation. In order to ensure the future CN HCCB TBM safely and effectively operating in ITER, components and even full scale of TBM should be tested before delivery to ITER site. Therefore, a new high temperature and high pressure experimental helium loop will be constructed to validate the thermal-hydraulic and thermal-mechanical capability of those components. In this article, a rational conceptual design of the experimental helium loop was presented. At the same time, preliminary engineering design includes thermal-hydraulics assessment of equipments, thermal stress of pipes in the loop were performed. The assessment results show that technical issues of helium loop construction are expected to be solved successfully. Finally, possible test strategies have been presented to fulfill the TBM thermo-hydraulics campaigns.

Investigation of alternative configurations of the LLCB TBM to increase neutronic and thermo-hydraulics performances

Lead lithium ceramic breeder (LLCB) test blanket module (TBM) was proposed by Indian TBM team for ITER tests. It uses lead lithium eutectic alloy for tritium production and cooling, and ceramic breeder to enhance the tritium production rate (TPR). The TBM first wall and outer structural elements are cooled with helium. Preliminary analysis of RF DEMO-S blanket shows some advantage of Indian concept modification. Alternative variants of TBM, corresponding to the proposed modification, are investigated in this paper from thermo-hydraulics and TPR point of view.

Assessment of the activation, decay heat, and waste disposal of the US helium-cooled ceramic breeder test blanket module in ITER

The radioactivity inventory and decay heat in the US helium-cooled ceramic breeder (HCCB) test blanket module (TBM) have been assessed at shutdown and for several times thereafter. The sub-module will have its own FW and structural container box that houses the breeder and beryllium pebble bed units, arranged in an edge-on-configuration. Low activation ferritic steel (F82H) is used as the structure and helium is used as a coolant. The breeder beds are made of Li 2TiO 3 pebbles in which lithium has been enriched up to 75% in Li-6. Pulsed operation mode is assumed. During operation in the D-T phase, the total heating rate in the TBM is ∼263 kW. The total amount of tritium generated in the breeder and the beryllium multiplier is ∼9 g and 0.07 g, respectively, after reaching the 0.3 MWa/m 2 fluence limit. At shutdown, the total radioactivity and decay heat levels are ∼0.89 MCi and ∼0.002 MW, respectively. These values drop sharply after 1 min to ∼0.098 MCi and ∼0.0006 MW. The contribution from the F82H structure is the dominant one up to ∼10 years following shutdown. After ∼10 years, the contribution to the total activation and decay heat from the breeder material is the dominant one due to the generated tritium. The WDR of various components are far below unity and thus are well within ITER regulatory guidelines.