CEFDA03-1067 Task Title: TW3-TVM-MDB: RULES FOR · PDF file- 23 - EFDA Technology / Vessel-In Vessel ... RULES FOR DESIGN, FABRICATION AND INSPECTION Establishment and Operation of

- 23 - EFDA Technology / Vessel-In Vessel / Vessel-Blanket and Materials

CEFDA03-1067 Task Title: TW3-TVM-MDB: RULES FOR DESIGN, FABRICATION AND

INSPECTION Establishment and Operation of a Material Database

INTRODUCTION Material research represents a significant part of the European and Worldwide efforts on Fusion research. The properties of new and existing materials need to be known in detail by Designers, by Licensing Authorities and not the least by Material Scientists. The present requirement for a materials Database comes firstly from a need by ITER to establish the status of Fusion materials data for licensing purposes and secondly to consolidate the data so that it is easily available to material researchers in the future, to identify holes in our existing knowledge base and to help establish directions for future material research. The data that are subject of this proposal are those that have been measured and collected as part of the European Fusion program in support of NET and ITER over the past two decades. The database constructed shall in the first instance, concentrate on the mechanical properties and thermal properties of both structural and plasma facing materials collected as part of the Next Step activities. For this purpose UKAEA has been granted a contract as leading Association, with CEA and HAS (Hungarian Academy of Sciences) as supporting associations. The final task report is expected to describe the following aspects of the work done: - A description of the database and its structure. - A list of procedures generated during the database

activity. - A list of users of the database. - A list of contributors to the database and their

contribution. - A list of reports referred to by the database. As one of the supporting associations, CEA will advise the leading Association, UKAEA, throughout the project on the following issues: - The definition of the detailed database structure and

format of the information. - The collection of data. - Checking of data. - Maintenance of database. - Installation, running of database and development of

criteria to access and use the database.

2003-2004 ACTIVITIES Two meetings were held in 2003 and one in 2004, where the progress of work was examined. During the first meeting CEA was asked to help UKAEA with examples of the database format files. These were sent to EFDA and UKAEA and included format files for data collection (product, chemical compositions, tension, impact, impact plots, fracture, creep, fatigue), all with definitions of fields in the databases. Also CEA supplied UKAEA with an example of the Internet server used at CEA for consulting materials properties databases. It was emphasized that in this Intranet system all actions are performed on the server side and the user only needs a simple browser for consulting the databases, extracting data and plotting the figures. Furthermore, the databases can be on local and remote stations. The server in response to a user’s request will instantly fetch data from local or remote servers and presents them on the screen. Since then, UKAEA has presented the latest status of their database, data entry and searching, data templates and administrative tools. They have now extended these by proposals for data qualification and implementation, as well as, future work (short term and long term). CEA has provided extended comments to all parties and two short assessment reports analyzing the work done at UKAEA. It is noted that the progress of the work so far has been satisfactory and promising. The fact that the database uses free and open access software is in particular appreciated. Also the fact that the database can be consulted and maintained via a browser satisfies another main objective of this task. However, there are still some concerns, particularly when new and lesser-known materials are added to database. Most of these will be resolved as the work proceeds and more experience is gained. For this reason the flexibility of the database is important. To ensure perennially of the database it has been proposed and accepted by UKAEA, that the actual data should be independent of the database structure and should permit downloading with all links in a way to be picked up by another database system. Also, a working server configuration should be installed on another server outside the actual UKAEA or JET servers, e.g. at EFDA. With regards to the proposed future work, these are welcomed but should not be at the expense of data collection and verification.


CONCLUSIONS The establishment and operation of a materials database for ITER is proceeding satisfactorily. The database has incorporated most of the initial recommendations and in its final form is expected to cover the rest. REPORTS AND PUBLICATIONS F. Tavassoli, CEA / France, Report on the TW3-TVM-MDB Meeting, September 9, 2003, Place: UKAEA Fusion, Culham Science Centre, Abingdon, England, EU Materials properties Database / Data analysis meeting, EFDA Garching, 24-25 June 2004. A. T. Peacock, V. Barabash, F. Gillemot, P. Karditsas, G Lloyd, J-W Rensman, A-A. F. Tavassoli and M. Walters, EU contributions to the ITER Materials Properties Data Assessment, SOFT, Venice, 20-24 September 2004.

TASK LEADER Farhad TAVASSOLI DEN/DMN CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 60 21 Fax : 33 1 69 08 80 70 E-mail : [email protected]


CEFDA03-1091 Task Title: TW4-TVM-LIP: RULES FOR DESIGN, FABRICATION AND

INSPECTION Modification of ITER materials documents and assessment of material data for licensing TBM’s design rules

INTRODUCTION The properties of materials used in fusion components need to be known in detail by designers, by licensing authorities and the materials specialists. ITER Materials Properties Handbook is a document that provides such information in an internationally accepted format. The main objective of this task is to update and expand the existing ITER MPH files and as a first step this is done for materials used in the vacuum vessel. CEA’s contribution in this task consists of: - Assist ITER International Team (ITER-IT) and EFDA

CSU in revising the ITER materials properties Handbook files.

- Participate in ITER materials working groups for

defining the materials to be assessed. - Participate in ITER materials database groups for

defining the materials data to be put in a European database.

2004 ACTIVITIES DESCRIPTION OF THE WORK PERFORMED IN 2003 AND 2004 a) The first work performed was updating of the existing

ITER materials documentation. This documentation, notably the Materials Properties Handbook (MPH), needed to be updated to include the results of recent R&D activities, references to the correct codes and standards and the inclusion of material properties, which are not well covered at the present time, for example fracture toughness.

CEA’s contribution mainly covered results on the stainless steel type 316LN-IG. At the request of the ITER-IT also the existing fusion weld metal references were also described. An example of CEA contribution to a ITER Question and updating of MPH files on 316LN-IG steel for vacuum vessel is done hereafter.

ITER Question: Data and equation given for Rm in

RCC-MR edition 2002 for 316LN under subsection Z, A3.1S.31 do not match.

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Figure 1 : Plot of Rp versus temperature for steel Type 316LN


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Figure 2 : Plot of Rm versus temperature for steel Type 316LN CEA Contribution was :

- To show that the CEA database is compatible with

those used in RCC-MR edition 2002. Figure 1 below shows the source data used to obtain average and minimum Rp recommended curves. The results obtained are the same as those used in RCC-MR.

- Next, to extend the analysis to Rm, for which data

are not presented in the same manner, see figure 2. Here the values deducted from the min curve also correspond to the RCC-MR, except at room temperature and at temperatures above 650°C. The reason for this is that the room temperature Rm value is a code specified value for this type of steel (must take preference over data in the plot). At temperatures above 650°C, the fitted equation does not cover the data scatter, hence use of lower values as shown by red arrow.

b) The second work performed involved the preparation of

new component specific documents. Specifically these documents would summarize all the material property recommendations needed for the design of specific components. CEA’s main contribution was towards a document prepared by ITER-IT on the vacuum vessel.

c) The third work performed was to support both the

above-mentioned activities by reviewing the data available within the database to ensure that it has been produced with the correct standards and the necessary data trace-ability.

It is possible in the future that this task will provide the

model for which In-vessel materials will be reviewed. This, however, will depend on the experience gained (see also TW3-TVM-MDB ).

d) Future work proposed is on Type 316LN-IG joints.

Such information need to be combined with those available at ITER and presented as MPH files.

CONCLUSIONS ITER Materials Properties Handbook for vacuum vessel materials in general and type 316LN-IG in particular has been updated. Extension of the work to type 316 steel joint as well as substantiation of the documents on other materials are in progress or envisaged for the next phase of the activities. REPORTS AND PUBLICATIONS F. Tavassoli, CEA / France, Report on the TW3-TVM-MDB Meeting, September 9, 2003, Place: UKAEA Fusion, Culham Science Centre, Abingdon, England. EU Materials properties Database / Data analysis meeting, EFDA Garching, 24-25 June 2004. A. T. Peacock, V. Barabash, F. Gillemot, P. Karditsas, G Lloyd, J-W Rensman, A-A. F. Tavassoli and M. Walters, EU contributions to the ITER Materials Properties Data Assessment, SOFT, Venice, 20-24 September 2004. TASK LEADER Farhad TAVASSOLI DEN/DMN CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 60 21 Fax : 33 1 69 08 80 70 E-mail : [email protected]

Not available on line



















TW4-TVV-OSWELD Task Title: QUALIFICATION OF MULTIPLE PHASED ARRAY UT FOR ONE

SIDED WELDS DURING VV MANUFACTURE INTRODUCTION The objective of the 2004 activity deals with qualification studies of non destructive testing methods for the one sided welds during VV manufacture. This work is connected with previous tasks performed between 2001 and 2003. Initial studies were performed to investigate ultrasonic techniques relevant for defect detection in different kind of welds (EB weld or TIG weld). New techniques were needed to improve the whole inspection coverage of the weld thickness. Two mock-ups were manufactured: an EB Weld mock-up and a TIG weld mock-up (weld roots were machined to obtain a smooth state of surface around the weld). These specimens contain surface breaking and embedded notches, as well as side-drilled holes for calibration purposes. Main objectives of task achieved in 2002 were to design phased arrays probes using simulation and to carry out experiments, for most relevant configurations studied in 2001. Techniques evaluated in these works showed a potential interest but needed some optimizations, particularly for TIG weld inspection. That is why new phased array probes were designed and manufactured in 2003. These transducers were carried out using dynamical inspection techniques based on angular scanning associated with beam focusing. 2004 ACTIVITIES GEOMETRICAL CONSTRAINTS All studied methods take into account the geometrical constraints. These constraints are the following: - Just one side access is available to the probes and

instrumentation device (which means that X-ray inspection, for instance, would not be possible for this assembly).

- The presence of the poloidal ribs on the upper surface of

the shell limits the distance for probes scanning over the welds. Therefore, even if two inspections may be performed from both sides (left and right) of the weld, the scanning displacement may be limited to 80 mm from the weld axis.

Apart from their improved flexibility and adaptability to perform different UT techniques, phased arrays here again provide a way to overcome such limited access thanks to beam-steering. It also has to be recalled that the weld type, as well as the final geometry of the component and limits quotations are not known yet, so that the suggested techniques presented in this report should still be modified in case of new requirement from the weld or assembly design.

DESCRIPTION OF NON DESTRUCTIVE TESTING METHODS Further experimental trials have been carried out on both mock-ups to ensure the respect of the maximal available area of 80 mm from the weld centre axis. Electron-Beam Weld inspection Description of the inspection technique The inspection technique consists in an angular scan associated with a focusing along the weld axis. A 5 MHz linear phased array is used in pulse echo mode to generate ultrasonic beams from 40° to 80° respectively focused at 60 and 5 mm depth. This technique offers the possibility to cover a large depth of inspection with only one transducer and without any mechanical displacement. For that case, the geometrical requirement related to the maximal available area is respected, that is to say 80 mm from the weld center axis. Following sketch illustrates the configuration of inspection.

Figure 1 : Illustration of the EB weld inspection Experimental results Acquisitions were carried out on a mock-up including an EB weld. This mock-up contains inner surface breaking and embedded notches.

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All inner surface-breaking notches (from 1 to 10 mm high) were detected and located. Depth sizing was possible with a good accuracy on the higher notches (10 and 4 mm). Both 10 and 4 mm high notches embedded into the weld were correctly detected, located and sized.

Figure 2 : Example of angular scan carried out on the EB weld mock-up

TIG Weld inspection Description of the inspection technique The most difficult area to inspect concerns the inner part of the weld. For this reason, the inspection technique studied in the framework of this work concerns the thickness of the weld from 20 mm in depth to 60 mm. The first 20 mm in depth will be subsequently studied. The inspection technique consists in an angular scan associated with a focusing along a constant radius of curvature. Two linear phased arrays are configured as a dual-element transducer. Delay laws are calculated to generate longitudinal waves from 25° to 60° focused along a 75 mm radius of curvature. Low signal to noise ratio obtained with previous transducers (2 and 5 MHz in pulse echo mode) [2] lead to define a specific transducer for the TIG weld inspection. This probe is composed of two linear arrays of 32 elements (1.2x20 mm² for each element) with a 2 MHz frequency. Dual element configuration is efficient to reduce back-scattering noise in coarse-grained material as in TIG weld. The probe wedge allows to naturally generate 45° longitudinal waves focused at 60 mm depth. For all acquisitions carried out in the framework of this study, the probe has been fixed at the limit of the maximal available area, that is to say 80 mm. Acquisitions have been performed from both sides (left and right) of the weld. As for the previous study on EB weld mock-up, the angular scan offers the possibility to cover a large depth of inspection without any mechanical displacement. Following sketches (figure 3) illustrates the configuration implemented on the TIG weld mock-up. Experimental results The TIG weld mock-up contains inner surface breaking and embedded notches. Experimental results showed that embedded and surface breaking notch greater than 2 mm are detected and sized before the weld.

Figure 3 : Illustration of the TIG weld inspection

Through the weld, inspection performances are altered. Inner surface breaking and embedded notches equal to or greater than 4 mm were detected. 4 and 10 mm high embedded notches can be sized but with lesser accuracy. No inner surface breaking notch is sized. Following figure displays acquisitions carried out on the TIG weld for an area free of defect. We note false calls due to the weld root in both directions. As a consequence the noise level is greater for inner surface breaking defects than for embedded defects.

Following picture illustrates a result obtained on a 4 mm high embedded notch.

Figure 4 : Example of angular scan carried out on the TIG weld mock-up

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QUALIFICATION OF METHOD Among the kind of studied welds, EFDA indicated that the TIG weld seems to provide the best interest. Thus, this part aims to evaluate the validity range of the method previously defined for the TIG weld inspection. This is achieved using simulation software tools of CIVA software. CIVA is an expertise software for NDT developed by the CEA. This software gathers simulation, processing and imaging tools in order to directly compare experimental and computed data. Ultrasonic tools allow to predict the beam propagation from the transmitter to the area being inspected and also to calculate the interaction with acoustic discontinuities within the area (defects or boundaries). Parametric study This study aims to consider a large range of defects that may be expected in such a kind of weld. These defects can vary in terms of size, orientation, position. The effects of these three parameters on the method of inspection performances have been evaluated thanks to the simulation. Defect size influence The first studied parameter concerns the influence of the defect size. Simulations were carried out with flaw sizes equal to 1, 2, 4 and 10 mm high. We note that the corner echo amplitude decreases of 8 dB when the defect size come from 10 to 1 mm. Simulations confirm that only inner surface breaking notches greater than 2 mm can be sized. Following figure corresponds to simulations of inspection on a 1 and a 10 mm high inner surface breaking notches. Corner echoes are detected in both cases, but diffraction echoes are not detected on the 1 mm high notch.

Figure 5 : Simulation of inspection on a 10 mm high inner surface breaking notch

Defect orientation influence This part deals with the influence of the defect orientation. Two different angles are considered: tilt angle, from 0° to 90° around the fusion line, and skew angle from 0° to 10°. If we consider a 10 mm high inner surface breaking notch, when the tilt angle comes from 2° (along the fusion line) to 10°, the corner echo amplitude decreases of 5 dB.

Figure 6 : Simulation of inspection on a 10 mm high inner surface breaking notch with a 10° tilt angle

Effects of skew angles from 0° (along the fusion line) to 10° have been evaluated. Simulation results allow to evaluate the ability of detection considering experimental results obtained in terms of signal to noise ratio.

Figure 7 : Example of a 10 mm high inner surface breaking

notch with a 10° skew angle (Top view) Defect location influence Other simulations have been carried out to appreciate the influence of the defect location on the detection. Defects embedded in the TIG weld mock-up have been taken into account in the simulation. We note that the angular scan from 25° to 60° is not enough. Thus, if the maximal angle is extended to 70°, we observe that the method of inspection is efficient to inspect the weld from 20 mm in depth to the backwall.

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Figure 8 : Inspection from 20 mm in depth to the backwall

Geometrical influence All experimental studies have been carried out on planar mock-ups. The geometry of the final component is not determined yet. Several geometries have been submitted by EFDA. Following image is an example of the possible geometries. In that case, main difficulties of inspection come from permanent geometrical echoes that could hide the presence of a defect along the fusion line.

Figure 9 : Simulation of inspection on a 10 mm high inner surface breaking with a possible geometry

In that example, simulation shows that the defect is too close from the radius of curvature to be correctly detected. The difference between the amplitudes of the corner echo on the defect and the geometrical echo is of 17 dB.

CONCLUSIONS Further experimental trials have been carried out on both mock-ups to ensure the respect of the maximal available area of 80 mm from the weld centre axis. These acquisitions have shown the validity of the methods defined in 2003 on flaws contained into both mock-ups. Since EFDA indicates that the TIG weld seems to provide the best interest, the validity range of the method of inspection defined for this weld has been particularly studied using simulation tools of CIVA. This study aimed to consider a large range of defects that may be expected in such a king of weld. These defects can vary in terms of size, orientation, position. The effects of these three parameters on the method of inspection performances have then been evaluated. The geometry of the final component is not yet defined. Several geometries have been submitted by EFDA and studied by means of simulation. REPORTS AND PUBLICATIONS [1] ‘Development of phased array techniques for the

inspection of one sided welds in ITER vacuum vessel’, SYSSC/04-RT0143/Rev. 0 September 2004.

[2] ‘Development of ultrasonic non destructive testing

method for the vessel inter-sector weld of ITER: development of dynamic phased array techniques’, SISC/03-RT0096/Rev. 0, September 2003.

[3] ‘Development of ultrasonic non destructive testing

method for the vessel inter-sector weld of ITER: simulation of welding process’, DECS/SISC/LMUS/ 02-RT0052, July 2002.

TASK LEADER Philippe BREDIF DRT/DeTECS/SYSSC/LMUS CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 34 68 Fax : 33 1 69 08 75 97 E-mail : [email protected]

Transducer

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R = 10 mm

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Top diffractionzoom

Corner echo

Angular BSCAN

Documents

CEFDA03-1067 Task Title: TW3-TVM-MDB: RULES FOR · PDF file- 23 - EFDA Technology / Vessel-In Vessel ... RULES FOR DESIGN, FABRICATION AND INSPECTION Establishment and Operation of