Index: Status report ENEA tasks (Dec 2005) EFDA Task TW4 TSS SEA slides 2,3,4 EFDA Task TW5 TSS SEA slides 5,6,7,8 EFDA Task TW4 TSS SEA5.5 (CONSEN) slides 9,10 EFDA Task TW5 TSS SEA5.5 (CONSEN) slides 11,12 EFDA Task TW4 TSS SEA2.1A slides 13,14,15 EFDA Task TW4 TSS SEA slides 16,17,18 EFDA Task TW4 TSS SEA slides 19,20,21 EFDA Task TW5 TSS SEA5.5 (ANITA) slides 22,23 EFDA Task TW4-TSW-001 D2-D slides 24,25

EFDA Task TW4 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device It is dedicated to test the active extraction of dusts from the volume used as vacuum vessel. The scope is to demonstrate the possibility to clean the ITER vacuum vessel from the accumulated dusts, generated during the plasma disruption, blowing air inside the volume. The data will be collected also for the validation of the codes simulating the dust transportation in LOVA accidents. Scope of the task

Test matrix and experimental procedure Dust placed in the bottom of the vacuum vessel tank Air inlet at the divertor level Filter weighted before and after the test 1 g of W or C or SS dust in each experiment Air inflow for 10, 30 or 60 minutes VV temperatures: ambient (~ 20 °C) and 50 °C Simulations performed (next slide), experiments on going. EFDA Task TW4 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

The results obtained by means of the ECART simulations suggested that, using an air flow of the order of 0.04 kg/s, as designed in the STARDUST facility, the cleaning interval has to exceed 2000 s. W suspended mass (ECART simulations) In the cold test the dust is pulled out more rapidly, for the reduced turbolence. In about 2000 s the transient is stable. EFDA Task TW4 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

Feasibility study for a closer geometry to ITER (i.e. toroidal), together with the development of a suitable diagnostic on line for dust concentration measurement Scope milestone 1 Scope milestone 2 Further experiments in STARDUST to reduce the uncertainties in dust transport inside and outside the VV: mobilization factor and dust exiting the VV under typical ITER accident conditions (i.e. pressurization rates 10 – 30 Pa/s).Further experiments in STARDUST to reduce the uncertainties in dust transport inside and outside the VV: mobilization factor and dust exiting the VV under typical ITER accident conditions (i.e. pressurization rates 10 – 30 Pa/s). The geometry of the experiment takes into account some characteristics of the ITER VV, like the presence of obstacles (e.g. Divertor) and layer of dusts.The geometry of the experiment takes into account some characteristics of the ITER VV, like the presence of obstacles (e.g. Divertor) and layer of dusts. Experiments with tungsten, stainless steel, carbon and alluminium to simulate beryllium behaviour Experiments with tungsten, stainless steel, carbon and alluminium to simulate beryllium behaviour EFDA Task TW5 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

Feasibility study (on going) 1.The toroidal shape can give precise indication about the reduction of the velocity field (circular section) 2. Scale rule -> 1/10 of ITER major radius : (0.62 m) and minor radius (0.2 m) 3. 4 through windows to allow the visualization and possible measurement of the dust mobilization inside EFDA Task TW5 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

Investigation on Diagnostics (on going) 1. CDD camera for dust visualization, and analysis of the images (up to 8000 images/s) enable the qualitative assessment of the dust concentration. the images (up to 8000 images/s) enable the qualitative assessment of the dust concentration. 2. The light scattering method will be used if the dust concentration is not such to stop the light beam. EFDA Task TW5 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

For 2006 experiments in STARDUST Velocity measurement is a key factor Pressure trasducer will be adopted because hot wires have a reduced range for maximum velocity (maximum 80 m/s) and signal delayed (~500 ms)Pressure trasducer will be adopted because hot wires have a reduced range for maximum velocity (maximum 80 m/s) and signal delayed (~500 ms) The dimension of pressure trasducers does not The dimension of pressure trasducers does not disturb the velocity field Several points of Several points of measurement will be foreseen EFDA Task TW5 TSS SEA5.1 Dust mobilization and transport experiments in the STARDUST device

Scope of the task ValidationCONSEN cryogenic experimentsEVITAValidation of the simulation code CONSEN against the cryogenic experiments carried on in the EVITA facility during pre and post-test calculations11 pre and post-test calculations for steam and water entering the VV with the presence of incondensable gas (helium) water/steamcondensationcryogenic plate inpresence of gasThe objectives of the tests were to determine the water/steam condensation phenomena on a cryogenic plate in presence of gas, to evaluate ice formation kinetics, heat transfer, total condensed water mass, cryogenic surface temperature and dynamic pressure and temperature of the container. EFDA Task TW4 TSS SEA5.5 (CONSEN) Validation of the computer codes and models

Results constant valuesnitrogen heat transfer coefficient The constant values of the nitrogen heat transfer coefficient in the cooling tubes used in the simulations can be the cause of the differences. EFDA Task TW4TSS SEA5.5 (CONSEN) Validation of the computer codes and models ice formation correctly simulated exception 6.51 The ice formation is correctly simulated in all the tests with the exception of the test 6.51, in which more than one calculated output is far from the experimental one. Power extracted satisfactory agreement hot tests discrepancy cold tests. Power extracted from the nitrogen cooling loop is in satisfactory agreement, in general, in the hot tests while a larger discrepancy appears in the cold tests.

Scope of the task ValidationCONSEN cryogenic experimentsEVITAValidation of the simulation code CONSEN against the cryogenic experiments carried on in the EVITA facility during post-test calculations7 post-test calculations for steam and water entering the VV with and without the presence of incondensable gas ice formationThe process of ice formation is the key point of the experimental campaign. Accordingly with the previous experiment the ice formation stops after a couple of minutes while in the CONSEN simulations the ice growth continues until the end of the transients. testssame initial conditionsstopped different timeA series of tests with the same initial conditions stopped at different time have been performed to clarify this point. EFDA Task TW5 TSS SEA5.5 (CONSEN) Validation of the computer codes and models

Results CONSEN correctly ice masslong term short termdifferences 20% The results obtained showed that the CONSEN code simulated correctly the growing of the ice mass on the cryogenic plate on the long term (second EVITA point in the graphs), while in the short term differences of about 20% have been noted. EFDA Task TW5 TSS SEA5.5 (CONSEN) Validation of the computer codes and models

Scope of the task Review and documentation of the past analysis assumptions/parameters and results for 1.Ion Cyclotron Heating and Current Drive System, 2.Electron Cyclotron Heating and Current Drive System, 3.Neutral Beam Heating and Current Drive System, 4.Diagnostics, and 5.Test Blankets Reanalysis of the above systems, on the basis of the current design and operating information. Identification and analysis of potential improvements, for each of the above systems. The results of this sensitivity analysis will be documented to facilitate any future considerations for dose reduction strategies EFDA Task TW5 TSS SEA2.1A Update of ALARA analyses for ITER Occupational Radiation Exposure

Past ORE assessments The contribution of the different sytems are referred to ITER plant limit, that is 500 mSv/y EFDA Task TW5 TSS SEA2.1A Update of ALARA analyses for ITER Occupational Radiation Exposure

Worker dose estimates for NB & LH heating & current drive systems A preliminary ORE assessment of the ITER Neutral Beam and Lower Hybrid heating and current drive system has been performed, as it did not previously exist for these systems. Main assumptions for ORE: -NBI maintained by RH -VTL section in LH maintained in hot cell SystemWork effort (p-h) Dose rate  Sv/h ORE mSv/y NBI&CD LH&CD EFDA Task TW5 TSS SEA2.1A Update of ALARA analyses for ITER Occupational Radiation Exposure

Issues of the task ORE related to remote handling Develop a software tool to assist the safety analysts in evaluating maintenance procedures and ORE values. Assess hands-on activities to be performed in the Equatorial Port number one (Eq#01) in assistance to the RH for maintenance of port plug, i.e.: the clearance of port cell from equipments located in front of the port, the unsealing of port plug and, vice-versa, the sealing of the port plug and the reinstallation of equipments located in port cell. ORE related to waste management Assess maintenance activities on the Waste Treatment System where wastes originated in the ITER plant from the experimental and maintenance activities are collected and treated (such wastes do not include those highly activated and managed inside the Hot Cell Processing System). EFDA Task TW4 TSS SEA2 In-depth assessment of ORE during RH and waste management

A view of the ORE_In_Rooms_Code EFDA Task TW4 TSS SEA2 In-depth assessment of ORE during RH and waste management

Main Results on ORE assessments ORE related to remote handling The total hands-on activities to be performed in assistance to the RH of port plug in Eq#01 require a total work effort of 472 p-h (118 p-h/y) and a collective worker dose of about 30 p-mSv (7.4 p-mSv/y). The highest contribution in terms of collective dose comes from the operations on the port plug flange (main flange unsealing/sealing, cooling pipes cutting/welding), with about 7 p-mSv (~1.8 p-mSv/y). ORE related to waste management The estimated collective annual dose relative to the Waste Treatment System is about 5 p-mSv/y. EFDA Task TW4 TSS SEA2 In-depth assessment of ORE during RH and waste management

Scope of the task It is dedicated to provide activation data in support of ITER safety and design to cover, in due time, the needs arising from design modification and/or optimisation. The analyses have been dedicated: to highlight the impact of the cobalt content into the Vacuum Vessel steels for waste management policy and to characterise the activation of the steel test tubes irradiated in OSIRIS reactor for ITER material release rate tests in CORELE-2 loop and PACTITER code validation EFDA Task TW4 TSS SEA4.1 Activation calculation for ITER

Material clearance index vs. Co content Material contact dose vs. Co content EFDA Task TW4 TSS SEA4.1 Activation calculation for ITER

A neutronic model was set up and used in SCALENEA-1 to simulate the CORELE steel test tubes irradiation in OSIRIS reactor. Once estimated the neutron flux spectra, activation calculation were performed using the ANITA-2000 activation code. The comparison shows a good agreement between measured and calculated isotope activities : therefore the approach is suitable to evaluate the activation data needed by PACTITER code for ACP estimate EFDA Task TW4 TSS SEA4.1 Activation calculation for ITER

Scope of the task Validation of the activation code package ANITA-2000 against experimental vanadium alloys, nickel, copper, lithium orthosilicate, Eurofer-97 steel and tungsten activity data from the Karlsruhe Isocyclotron (KIZ). Validation of the activation code package ANITA-2000 against experimental photon and electron decay heat measurements from Fusion Neutron Generator FNG ENEA-Frascati for Molybdenum and Tantalum. EFDA Task TW5 TSS SEA5.5 (ANITA-2000) Validation of the computer codes and models

Isotope Experimental data (KIZ) ANITA-2000 EAF-2003 Cr E E+08 Mn E E+07 Fe E E+04 Co E E+04 Co E E+05 Co E E+03 W E E+06 For all the KIZ materials analysed the ANITA-2000 results are in good agreement with the experimental ones (inside the experimental uncertainties) Activity (Bq/kg) for Eurofer-97 (41 days cooling time) Cooling time (s) Experimental data ANITA-2000 EAF E E E E E E E E E-14 Tantalum gamma decay heat (kW) The calculated photon and electron decay heat are in good agreement with experimental data (up to 10% for Ta and 15% for Mo). The ANITA-2000 and EASY-2003 calculations differ by less than 1%. EFDA Task TW5 TSS SEA5.5 (ANITA-2000) Validation of the computer codes and models

Recycling is becoming more and more important in a world which is going to deal with energy and natural resources shortage. Present studies on recycling of slightly radioactive material show positive outcomes while at the same time problems of public acceptability still exist. Safety criteria have been defined, regulations and standards are going to be set in place in many countries, even though the need for harmonising clearance levels is still an issue. Table from EC RP 134: Evaluation of the application of the concepts of exemption and clearance for practices according to title III of Council Directive 96/29/Euratom of 13 May 1996 in EU Member States – Case of tritium (harmonisation of CLs): clearance level from 0.4 Bq/g in UK up to 1.0E+6 Bq/g in the Netherlands EFDA Task TW4-TSW-001 D2-D3 Watching brief and waste management

The experience of decommissioning of an entire generation of nuclear facilities will be exploited by future fusion industry, (i.e. for recycling, reuse or disposal). The real waste management problem will be relative to the in-vessel components (IVCs) similarly as the management of spent fuel is the “problem” in fission. The fusion industry would have the advantage of being able to use activated metal, as it would be employed in a controlled environment, where radiation fields will be monitored. It seems more important to demonstrate the feasibility of IVCs recycling from the technical point of view, rather than try to perform an economic assessment with the present-day terms in mind. It would be greatly more important to concentrate the future activities on: 1.the study of the fusion material and equipment cycle and; 2.on the regulatory framework, within which recycling of fusion material could be performed. Time distribution for generation of slightly radioactive solid material from USA power reactor decommissioning EFDA Task TW4-TSW-001 D2-D3 Watching brief and waste management