Advantages of isotope tailored tungsten 7th annual meeting of the EU-PWI Task Force, Frascati, 27-29. October 2008 Ir. B.P. Jonker [email protected] +31 224568028.

Advantages of isotope tailored tungsten

7th annual meeting of the EU-PWI Task Force, Frascati, 27-29. October 2008

Ir. B.P. [email protected]

+31 224568028

G.Dowling,Urenco

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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, 27-29. October 2008

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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, 27-29. October 2008

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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, 27-29. October 2008

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Possible Candidates

Enrichment or Depletion technology is possiblefor almost every material. Candidates are :

•Cadmium •Iridium •Nickel •Silicon •Tungsten

•Chromium •Iron •Osmium •Tellurium •Zinc

•Germanium •Lead •Rutetium •Tin •Zirconium

•Indium•Molybdenum

•Selenium•Titanium

Tungsten

7th annual meeting of the EU-PWI Task Force, Frascati, 27-29. October 2008

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Tailoring of Tungsten

Natural isotopes

• 180W (0.12 %) 182W (26.50 %) 184W (14.31%) 185W (30.64 %) 186W (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, 27-29. October 2008

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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, 27-29. October 2008

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Possible Candidates

Enrichment or Depletion technology is possiblefor almost every material. Candidates are :

•Cadmium •Iridium •Nickel •Silicon •Tungsten

•Chromium •Iron •Osmium •Tellurium •Zinc

•Germanium •Lead •Rutetium •Tin •Zirconium

•Indium•Molybdenum

•Selenium•Titanium

Molybdenum

7th annual meeting of the EU-PWI Task Force, Frascati, 27-29. October 2008

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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 95Mo and 98Mo 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, 27-29. October 2008

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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, 27-29. October 2008

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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, 27-29. October 2008