Helium Cooled Pebble Bed Test Blanket Module Research Articles

Advances in Additive Manufacturing of fusion materials

Recent analysis result in significant impact on the design of the Helium Cooled Pebble Bed (HCPB) Breeding Blanket (BB). Especially the main demanding sub-component of the BB in terms of fabrication, the First Wall (FW) is highly affected. As a matter of fact, the relevance of the developments made for the industrial fabrication of the FW used e.g. in the EU HCPB Test Blanket Module (TBM) for ITER is limited: On one hand in terms of the overall dimensions, but also in terms of geometry and cooling channel configuration. Thus, a fabrication strategy for the FW was proposed as an option in 2018 based on Additive Manufacturing (AM) offering a solution to cover the new aspects. The dedicated fabrication routine is based on Cold Spray (CS) in alternation with machining. In terms of manufacturing of non-plasma facing complex shaped thin- or double wall BB structures (e.g. Fuel Pins proposed for the HCPB BB) the use of AM also provides benefits compared to conventional technologies. Therefore, the AM process of Selective Laser Melting (SLM) is also investigated in terms of applicability for BBs. This paper gives an overview about the advances in different AM options applied for nuclear fusion structural low activation steels. Possibilities for spin-offs to other technological fields are discussed and conclusions are drawn reflecting licensing aspects and technological limits.

Fabrication technologies implemented for the European test blanket modules: Status for HCPB and WCLL

Abstract Within the framework of the European fusion strategy, two tritium Breeder Blankets concepts are developed to be tested in ITER as Test Blanket Modules (TBM): the Water-Cooled Lithium-Lead (WCLL) which uses the liquid Pb-16Li as a breeder, neutron multiplier and tritium carrier, and the Helium-Cooled Pebble-Bed (HCPB) with lithiated ceramic and beryllium pebbles as breeder and neutron multiplier, respectively, and helium purge gas as tritium carrier. Both concepts consider as structural material reduced activation ferritic martensitic steel, the EUROFER97 (X10CrWVTa9-1). Pressurized water (15.5 MPa, 295−328 °C for WCLL) and pressurized helium (8 MPa, 300−500 °C for HCPB) are foreseen for heat removal. The TBM is constituted of a BOX (side caps, first wall), stiffened by stiffening plates (SP) and closed on its back, in the manifold area, with back plates with passing-through elements, like stiffening/tie rods, SP nozzles and inlet/outlet water/He pipes. Internally, breeder units, delimited by SP, are cooled-down by cooling plates for the HCPB and double-wall tubes for the WCLL. This paper describes manufacturing technologies for the TBM and deals with the definition of the preliminary Welding Procedure Specifications (pWPS) and feasibility mock-ups for the manifold area and TBM BOX assembly. The transfer and validation of the pWPS developed for the TBM, from P91 to EUROFER97 steel, is demonstrated. Consolidation of the pWPS for the TBM BOX assembly made with HIP process and development for the HCPB TBM manifold area elements, based on GTAW technique, are discussed. Manufacturing tests are performed using the EUROFER97 steel (RCC-MRx, AFCEN Code rules [ 1 ]). As part of the WCLL conceptual design development activities, an assembly and manufacturing welding sequence is detailed, focusing on design changes and the impact on the selection of manufacturing technologies. The article will present as well the future fabrication developments and the associated design proposals envisaged on TBM.

Preliminary RAMI assessment for HCPB and HCLL ITER test blanket module ancillary systems

A RAMI (Reliability, Availability, Maintainability and Inspectability) assessment performed on the ITER Test Blanket Module (TBM) ancillary systems is presented. The assessment is aimed at evaluating design that may jeopardize the achievement of the overall 75% availability requirements for the TBM plant breakdown structure. The ancillary systems of the European Test Blanket Modules to be operated in ITER that have been analyzed in this assessment are the helium cooling systems (HCSs) of both the Helium Cooled Lithium Lead (HCLL) and Helium Cooled Pebble Bed (HCPB), the lithium-lead loop of the HCLL TBM and the Tritium Extraction System (TES) of the HCPB TBM. RAMI performance was assessed by means of reliability block diagrams (RBDs) over a foreseen mission of 20 years, with operating cycles reflecting ITER schedule. In particular, a set of events leading to unavailability of the systems was initially defined by means of a failure mode and effect analysis. Then RBDs were implemented according to reliability-wise integration of the components included in such systems. Different RBDs were defined depending on the component being judged to impact normal operation or start-up operation mode. Systems analysis was performed exploiting a modular approach in order to elicit the relative contribution to overall availability so to support possible design improvement by highlighting critical sub-systems. In particular the unavailability of cooling, tritium extraction and trapping functions were assessed separately for HCLL and HCPB concepts. Finally the integrated impact of all ancillary systems on overall tokamak operational availability was estimated and the assessed systems, considering the current preliminary level of design development, appear able to meet the expected performance.

Conceptual design of the enhanced coolant purification systems for the European HCLL and HCPB test blanket modules

The Coolant Purification Systems (CPSs) is one of the most relevant ancillary systems of European Helium Cooled Lead Lithium (HCLL) and Helium Cooled Pebble Bed (HCPB) Test Blanket Modules (TBMs) which are currently in the preliminary design phase in view of their installation and operation in ITER.The CPS implements mainly two functions: the extraction and concentration of the tritium permeated from the TBM modules into the primary cooling circuit and the chemistry control of helium primary coolant.During the HCLL and HCPB-TBSs (Test Blanket Systems) Conceptual Design Review (CDR) in 2015 it was recognized the need of reducing the tritium permeation into the Port Cell #16 of ITER. To achieve this and, then, to lower the tritium partial pressure in the Helium Cooling Systems in normal operation, the helium flow-rate treated by each CPS has been increased of almost one order of magnitude.In 2017, to satisfy the CDR outcomes and the new design requirements requested by Fusion for Energy (F4E, the European Domestic Agency for ITER), ENEA performed a preliminary design of the “enhanced” CPSs.This paper presents the current design of the “enhanced” CPSs, focusing on design requirements, assumptions, selection of technologies and preliminary components sizing.

Characterization of the cooling channels of First Wall Mock-up dedicated to the HCPB TBM qualification

The First Wall (FW) of the EU Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) faces the fusion plasma and experiences high heat fluxes; therefore its cooling channels design is a key R&D task for qualifying the HCPB TBM for the fusion reactors ITER and DEMO. Within the manufacturing and qualification activities performed in KIT for the HCPB TBM, a First Wall Mock-up (FWM) was designed and manufactured. The objective of this study is to characterize the hydrodynamic behaviour of the FWM cooling channels by investigating the coolant pressure drop for each channel. The FWM has a shape of rectangular prism (710mm×405mm×45mm) with 10 U-shaped cooling channels which have a square cross section (15mm×15mm) with rounded corners of 4mm radius. The FWM was integrated into a gas loop that has the relevant instruments and piping system for measuring and controlling the air (6bar abs.) flow parameters. This paper presents experimental measurements of the pressure drop across the FWM cooling channels. The present results support the qualification of the HCPB TBM mock-ups which will be tested in the Helium Loop Karlsruhe (HELOKA) facility with fusion-relevant heat flux and helium cooling.

A new HCPB breeding blanket for the EU DEMO: Evolution, rationale and preliminary performances

The Helium Cooled Pebble Bed (HCPB) Breeding Blanket (BB) is one of the 4 BB concepts being investigated in the EU for their possible implementation in DEMO. During 2014 the former “beer-box” BB concept based on the ITER’s HCPB Test Blanket Module suffered several design changes so as to meet the different counteracting nuclear, thermohydraulic and thermomechanical requirements. These studies evidenced that the concept is too rigid to meet the tight TBR requirements imposed for the EU DEMO (i.e. TBR≥1.10). Additionally, the complex manifold system with unbalanced helium mass flow in each of the 2 parallel cooling loops made the concept thermohydraulically complex. However, parametric studies during 2015 revealed that the HCPB concept have potential for a better nuclear performance, as well as margin for a significant simplification of the cooling internals by redefining the cooling plates and the architecture of the blanket, building a symmetric flow scheme.This paper describes the new HCPB concept based on an integrated FW with the breeding zone thermohydraulics and helium manifold systems. The former complex manifold backplates have been compacted and integrated in the cooling plates, releasing ≈300mm of radial space that can be used now to increase breeder zone, the neutron shielding, to reinforce the Back Supporting Structure (BSS) or basically to reduce the reactor size. Detailed neutronic analyses have yielded a TBR of ∼1.20 for the baseline design. Initial analyses show a correct thermohydraulic behavior. Preliminary thermomechanical analyses also indicate that the design can potentially withstand an in-box LOCA at 9 MPa at a level C according to the RCC-MRx code. Future consolidation activities are described, which shall lead to a concept meeting the BB requirements.

Formation and accumulation of radiation-induced defects and radiolysis products in modified lithium orthosilicate pebbles with additions of titanium dioxide

Lithium orthosilicate (Li4SiO4) pebbles with 2.5 wt.% excess of silicon dioxide (SiO2) are the European Union's designated reference tritium breeding ceramics for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). However, the latest irradiation experiments showed that the reference Li4SiO4 pebbles may crack and form fragments under operation conditions as expected in the HCPB TBM. Therefore, it has been suggested to change the chemical composition of the reference Li4SiO4 pebbles and to add titanium dioxide (TiO2), to obtain lithium metatitanate (Li2TiO3) as a second phase. The aim of this research was to investigate the formation and accumulation of radiation-induced defects (RD) and radiolysis products (RP) in the modified Li4SiO4 pebbles with different contents of TiO2 for the first time, in order to estimate and compare radiation stability. The reference and the modified Li4SiO4 pebbles were irradiated with accelerated electrons (E = 5 MeV) up to 5000 MGy absorbed dose at 300–990 K in a dry argon atmosphere. By using electron spin resonance (ESR) spectroscopy it was determined that in the modified Li4SiO4 pebbles, several paramagnetic RD and RP are formed and accumulated, like, E' centres (SiO33−/TiO33−), HC2 centres (SiO43−/TiO3−) etc. On the basis of the obtained results, it is concluded that the modified Li4SiO4 pebbles with TiO2 additions have comparable radiation stability with the reference pebbles.

Creep fatigue assessment for EUROFER components

Creep-fatigue of test blanket module (TBM) components built from EUROFER is evaluated based on the elastic analysis approach in ASME Boiler Pressure Vessel Code (BPVC). The required allowable number of cycles design fatigue curve and stress-to-rupture curve to estimate the creep-fatigue damage are used from the literature. Local stress, strain and temperature inputs for the analysis of creep-fatigue damage are delivered by the finite element code ANSYS utilizing the Mechanical ANSYS Parametric Design Language (MAPDL). A developed external FORTRAN code used as a post processor is coupled with MAPDL. Influences of different pulse durations (hold-times) and irradiation on creep-fatigue damage for the preliminary design of the Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) are discussed for the First Wall component of the TBM box.

Non-linear failure analysis of HCPB blanket for DEMO taking into account high dose irradiation

For the European helium cooled pebble bed (HCPB) blanket of DEMO the reduced activation ferritic martensitic steel EUROFER has been selected as structural material. During operation the HCPB blanket will be subjected to complex thermo-mechanical loadings and high irradiation doses. Taking into account the material and structural behaviour under these conditions is a precondition for a reliable blanket design.For considering high dose irradiation in structural analysis of the DEMO blanket, the coupled deformation damage model, extended recently taking into account the influence of high dose irradiation on the material behaviour of EUROFER and implemented in the finite element code ABAQUS, has been used. Non-linear finite element (FE) simulations of the DEMO HCPB blanket have been performed considering the design of the HCPB Test Blanket Module (TBM) as reference and the thermal and mechanical boundary conditions of previous analyses. The irradiation dose rate required at each position in the structure as an additional loading parameter is estimated by extrapolating the results available for the TBM in ITER scaling the value calculated in neutronics and activation analysis for ITER boundary conditions to the DEMO boundary conditions. The results of the FE simulations are evaluated considering damage at most critical highly loaded areas of the structure and discussed with regard to the impact of high dose irradiation on it.

Experimental layout and thermo-mechanical studies on a Thermo-mechanical Cycle Mock up (TCM) plate

In the frame of the activities of the EU Breeder Blanket Programme, the Karlsruhe Institute of Technology (KIT) is involved in several activities in support of the design and qualification of the Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM). During operation the TBM will be subjected to complex thermo-mechanical loads, especially the plasma facing parts, the so-called First Wall (FW). In the recent years significant effort was dedicated to the FE modeling of the TBM box as a complete assembly: detailed FE models (1 quarter) were developed and thermo-mechanical calculations were performed for the better description of the thermo-mechanical behavior of the HCPB-TBM box under nominal and accidental conditions. In parallel with the numerical studies the manufacturing process for the TBM-FW has progressed. Currently KIT has developed a manufacturing path that will allow the manufacturing of an FW plate, the so-called TCM (Thermo-mechanical Cycle Mock up), with an overall size of 710mm×484mm×30mm. The present paper presents the results of the numerical investigations of a mock up designed to qualify the manufacturing procedure of the TCM. For this the TCM will be subject to the same heat loads as the central part of a TBM-FW operating under TBM characteristic conditions (nominal surface heat flux of 500kW/m2 in pulsed regime). Based on the comparison with the numerical simulations of a full TBM box, a design of the test mock up including the support structure behind the TCM plate will be proposed with the aim of reproducing an equivalent level of stresses in the test object as in a TBM-FW.

Set-up of a pre-test mock-up experiment in preparation for the HCPB Breeder Unit mock-up experimental campaign

The complexity of the experimental set-up for testing a full-scaled Breeder Unit (BU) mock-up for the European Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) has motivated to build a pre-test mock-up experiment (PREMUX) consisting of a slice of the BU in the Li4SiO4 region. This pre-test aims at verifying the feasibility of the methods to be used for the subsequent testing of the full-scaled BU mock-up. Key parameters needed for the modeling of the breeder material is also to be determined by the Hot Wire Method (HWM). The modeling tools for the thermo-mechanics of the pebble beds and for the mock-up structure are to be calibrated and validated as well.This paper presents the setting-up of PREMUX in the L-STAR/LL facility at the Karlsruhe Institute of Technology. A key requirement of the experiments is to mimic the neutronic volumetric heating. A new heater concept is discussed and compared to several conventional heater configurations with respect to the estimated temperature distribution in the pebble beds. The design and integration of the thermocouple system in the heater matrix and pebble beds is also described, as well as other key aspects of the mock-up (dimensions, layout, cooling system, purge gas line, boundary conditions and integration in the test facility). The adequacy of these methods for the full-scaled BU mock-up is discussed and the next steps that follow PREMUX set-up are shown.

Thermo-mechanical analyses and assessment with respect to the design codes and standards of the HCPB-TBM Breeder Unit

The Helium Cooled Pebble Bed-Test Blanket Module (HCPB-TBM) is one of the two breeding blanket concepts currently under development in Europe. Key component of the HCPB-TBM, the Breeder Unit (BU), has entered the detailed engineering design phase. After establishing a base design, thermal and thermo-mechanical analyses have been performed under typical ITER operational conditions: the results are presented and discussed in this paper.A full scaled finite element model of the base design of the HCPB-TBM BU has been built to run thermal analyses of the beryllium and Li4SO4 pebble beds and thermo-mechanical analyses of the BU structure, both in steady state and in a typical transient regime during a pulse of the ITER D–T phase. The temperatures reached in the Li4SO4 and beryllium pebble beds in the BU base design are 930.8°C and 712.9°C, respectively, which are above the recommended values of 920°C for Li4SO4 and 650°C for the beryllium pebbles. The maximum temperature in the structural steel is 548.4°C, which remains under the design limit defined for the TBM studies (550°C). In order to decrease the temperature in the hot spots identified in the pebble beds, a reduction of the Li4SO4 and beryllium bed volumes has been adopted. As for the structural material, the thermo-mechanical analyses have been assessed with respect the RCC-MR design code (completed for irradiation damages with ITER SDC-IC). The results reveal some problematic points in the base design, concentrated in the coolant inlet and outlet pipes and in the connection region of the BU cooling plates with the BU backplate. Submodeling technique has been used to improve the design in these regions. An increase in the thickness of the coolant inlet and outlet pipes and a redesign of the BU backplate have led to a fulfillment of the codes and standards. The design modifications of pebble bed region and structural material have been implemented in the final design of the BU that is presently used as reference for the design and test of a BU mockup in KIT.

Non-linear failure analysis of HCPB Test Blanket Module

For the European Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) the reduced activation ferritic martensitic (RAFM) steel EUROFER 97 is selected as a structural material. During operation the TBM will be subjected to complex thermo-mechanical loadings which yield at certain positions of the structure to stresses beyond the design limits of the structural material. Preliminary structural analyses of the TBM have shown critical behavior in several key points of the structure. An improved design has been proposed and in order to identify and assess the problematic positions in the improved version of the TBM a non-linear failure analysis is performed, for which a coupled deformation damage model developed at KIT for RAFM steels and recently implemented in the finite element code ABAQUS is used. The thermal loads in the form of non-homogeneous temperature fields distributions are obtained from a thermal analysis performed using the finite element code ANSYS on the same structure. Importing the temperature fields into the finite element code ABAQUS and applying the remaining loads – coolant internal pressure and structural boundary conditions – non-linear simulations are conducted taking into account the ITER-typical cyclic nature of the loading. The simulation results are evaluated and discussed considering ratcheting and damage at most critical highly loaded areas of the structure.

HCPB TBM thermo mechanical design: Assessment with respect codes and standards and DEMO relevancy

In the frame of the activities of the European TBM Consortium of Associates the Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) is developed in Karlsruhe Institute of Technology (KIT). After performing detailed thermal and fluid dynamic analyses of the preliminary HCPB TBM design, the thermo mechanical behaviour of the TBM under typical ITER loads has to be assessed. A synthesis of the different design options proposed has been realized building two different assemblies of the HCPB-TBM: these two assemblies and the analyses performed on them are presented in this paper. Finite Element thermo-mechanical analyses of two detailed 1/4 scaled models of the HCPB-TBM assemblies proposed have been performed, with the aim of verifying the accordance of the mechanical behaviour with the criteria of the design codes and standards. The structural design limits specified in the codes and standard are discussed in relation with the EUROFER available data and possible damage modes. Solutions to improve the weak structural points of the present design are identified and the DEMO relevancy of the present thermal and structural design parameters is discussed.

Preliminary thermal design and related DEMO relevancy of the EU-HCPB TBM in vertical arrangement

In the frame of the activities of the European Test Blanket Module Consortium of Associates the Helium-Cooled Pebble-Bed Test Blanket Module (HCPB TBM) is developed in Forschungszentrum Karlsruhe (FZK) to investigate DEMO relevant concepts for blanket modules. A series of four different HCPB TBMs of the EU will be installed into the ITER Vacuum Vessel connected to one dedicated equatorial port. During different test campaigns, the 4 TBMs will test the three main functions of a blanket module (removing heat, breeding tritium and shielding sensitive components from radiation). In 2006–2007 a preliminary version of the HCPB TBM sub-components design has been proposed extrapolating the neutronic analyses performed for the horizontal HCPB TBM. With the input data provided by the preliminary design, together with the ITER 3D 40° toroidal sector model, new nuclear analyses for the vertical HCPB TBM have been performed. Nuclear results are necessary to assess the sub-components design and to validate the design of the HCPB TBM: with this aim thermal analyses of a 1/4 scaled assembly of the vertical HCPB TBM have been performed. As the generation of data in ITER supporting the design of DEMO is very important in the road map to the commercial fusion reactor, the results of nuclear and thermal analyses are fundamental to perform studies concerning the TBM DEMO relevancy.

Neutronics experiments on HCPB and HCLL TBM mock-ups in preparation of nuclear measurements in ITER

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.

Neutronic analysis of the HCPB TBM in ITER utilizing an advanced integral approach

Nuclear design analyses were performed for the new vertical design of the HCPB (Helium Cooled Pebble Bed) Test Blanket Module (TBM) in ITER utilizing an advanced integral approach. The related neutronics calculations were performed with the Monte Carlo code MCNP5 using the latest MCNP geometry model of ITER, named “A-lite”. The TBM model was generated with the geometry conversion tool McCad on the basis of a dedicated CAD model and integrated into one half of the equatorial test blanket port of the A-lite model. The neutronic calculations provided assessments of the total tritium and heat production in the TBM and its components as well as evaluations for the detailed spatial distributions of the neutron flux and the power density. Fine mesh tally calculations were utilized to provide high fidelity results for the distributions that enable identification of crucial issues.

Design Update and Mock-Up Test Strategy for the Validation of the EU-HCPB-TBM Concept

In the frame of the activities of the EU Breeder Blanket Programme and of the Test Blanket Working Group of ITER, the Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) is developed to investigate DEMO relevant concepts for blanket modules. The main functions of a blanket module (heat removal, tritium breeding and sensitive components shielding) will be tested in DEMO relevant conditions during four different test campaigns in ITER. One TBM of the HCPB concept will be installed into the vacuum vessel connected to one equatorial port designed for vertical TBM orientation during each of the four test campaigns. This paper describes the FZK activities in order to verify the design of the HCPB TBM with regard to operational conditions in ITER and to prove the feasibility of the manufacturing techniques proposed.As the studies performed in FZK up to 2006 concerned a horizontal orientation of the HCPB, a review of the design was necessary to match with the new ITER specifications. Even if the general architecture of the horizontal TBM is maintained, nevertheless the change of configuration has significant impact on the design of the TBM sub-components. An overview of the new vertical HCPB design is presented, detailing the strategy adopted to assess the design and the thermal and fluid dynamic analyses performed for the TBM First Wall.In parallel to the TBM design and analysis, a large mock-up programme addresses the main issues of manufacturing and performances for single components and systems. The three medium-size mock-ups foreseen in FZK to validate the fabrication and mounting processes are presented detailing their purposes.

Assessment of EM loads on the EU HCPB TBM during plasma disruption and normal operating scenario including the ferromagnetic effect

Static and transient analyses have been carried out to evaluate Electro Magnetic loads on the European Helium Cooled Pebble Bed Test Blanket Module (HCPB-TBM) during a type II linear disruption (Lorentz forces) and (because of the presence of ferromagnetic structural material) during normal ITER operating scenario (Maxwell forces (MFs)). At last the influence of the toroidal field ripple on the MFs has been investigated.

Monte Carlo based sensitivity and uncertainty analysis of the HCPB Test Blanket Module in ITER

This paper presents the first real test application of the Monte Carlo based sensitivity and uncertainty computational approach to the Test Blanket Module (TBM) in ITER. To this end the standard three-dimensional MCNP model of ITER (20° torus sector) with integrated TBM of the Helium-cooled Pebble Bed (HCPB) type was employed. Sensitivity profiles and integrated sensitivities were calculated for the total tritium production in the HCPB TBM by using the track length estimator approach of MCSEN, a local extension to the Monte Carlo code MCNP. The associated uncertainties of the tritium production due to nuclear data uncertainties were assessed by making use of available co-variance data from different sources. The major contribution to the sensitivities was shown to come from the materials contained in the TBM, in particular the beryllium neutron multiplier and the breeder ceramics constituents 6Li and 16O. With the calculated sensitivity profiles and the available co-variance data, the cross-section induced uncertainties of the tritium production have been assessed at a level of 2.8%.