Advantages of isotope tailored tungsten 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008 Ir. B.P. Jonker G.Dowling, Urenco

2 Contents Introduction Possible Candidates Tailoring of Tungsten Possible Application Areas Isotope tailored molybdenum Status Questions/Discussion 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

3 Introduction Aim Inform you about the possibilities of isotope tailoring of materials Show the possible advantages Check your ideas about the topic 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

4 Introduction Isotope tailoring Remove specific isotopes of materials -Reduce short term or long term activation -Possible for virtually all metals, f.e. Zn, W, Mo, Mechanical behaviour unaffected, only chemical composition tailored Various applications known -depleted zinc in nuclear power plants. Add depleted zinc in primary cooling water circuit to reduce dose rate of the personnel by a factor two -Enriched iridium sources, made for Medical Treatment (brachy therapy) 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

5 Possible Candidates Enrichment or Depletion technology is possiblefor almost every material. Candidates are : CadmiumIridiumNickelSiliconTungsten ChromiumIronOsmiumTelluriumZinc GermaniumLeadRutetiumTinZirconium IndiumMolybdenumSelenium Titanium Tungsten 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

6 Tailoring of Tungsten Natural isotopes 180 W (0.12 %) 182 W (26.50 %) 184 W (14.31%) 185 W (30.64 %) 186 W (28.43 %) Under influence of irradiation, about 30 different isotopes can occur Removing the isotope tungsten 186, the production of the radioactive tungsten 187 is limited. As a result, the radiation dose rates will be reduce. Tungsten 187 is main source of activity 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

7 Possible Application Areas Tungsten divertor parts. Especially in case of ELM. Highly active W-dust probably not favoured because of radioactive waste after cleaning Coating of plasma facing components to extend lifetime Mirrors Advantages Reduce activation No compromise on thermo-mechanical properties Possibly reduced He production Disadvantages (Much) more expensive than regular W 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

8 Possible Candidates Enrichment or Depletion technology is possiblefor almost every material. Candidates are : CadmiumIridiumNickelSiliconTungsten ChromiumIronOsmiumTelluriumZinc GermaniumLeadRutetiumTinZirconium IndiumMolybdenumSelenium Titanium Molybdenum 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

9 Isotope tailored Molybdenum Possibilities for Molybdenum in mirrors Currently about 40 Mo mirrors planned. Lifetime of mirrors close to plasma limited due to irradiation consequences Eliminate 95 Mo and 98 Mo isotopes drastically reduces cross section. Reduced activation could extend mirror lifetime by a factor 2 to 10! 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

10 Status Status now Currently the first steps are taken to investigate the activation behaviour of the different isotopes, i.e. determine effect of individual isotopes and neutron energy influence Investigation of possibilities for isotope tailored materials in ITER Next steps Analyse tailored isotopes to prove characteristics Optimise isotope ratios for activation behaviour 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008

11 Questions/ Discussion Is aim achieved? Inform you about the possibilities of isotope tailoring of materials Show the possible advantages Check your ideas about the topic Questions? What advantages do you see? 7th annual meeting of the EU-PWI Task Force, Frascati, October 2008