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Final Meeting

Final Meeting. TW5-TSW-001 Deliverable 2. Culham, October 23–24, 2006. SCK•CEN, L. Ooms. PPCS Model AB. Model AB: Activation analysis R. Pampin UKAEA/ TW4-TRP-002 D2e, April 2005. Dose rate Sv/h. Replacement Schedule. Model AB: Activation analysis

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Final Meeting

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  1. Final Meeting TW5-TSW-001 Deliverable 2 Culham, October 23–24, 2006 SCK•CEN, L. Ooms

  2. PPCS Model AB

  3. Model AB: Activation analysis R. Pampin UKAEA/ TW4-TRP-002 D2e, April 2005 Dose rate Sv/h Replacement Schedule

  4. Model AB: Activation analysis R. Pampin UKAEA/ TW4-TRP-002 D2e, April 2005 Dose rate Sv/h Replacement Schedule

  5. Time Scale • Stage 1: Temporary storage over a time period of maximum 5 years. The storage will be performed in the fusion plant and its major goal is to reduce the dose rate with 1 order of magnitude. • Stage 2: Interim storage over a period of 100 years. The major goal for this on site storage is to reduce the dose rate (a few orders of magnitude) in order to perform off-site transportation. • Stage 3: Final disposal (off site). • Reference: A. Natalizio (ENSEC); In-vessel component storage, EFDA Task TW2-TRP-PPCS17 – Deliverable 4, dd. 10-01-2003 • Storage after irradiation • Recycling of components • separation • recycling of materials • refabrication and testing • Storage awaiting reuse • Reuse • Separation & recycling of materials (1 year). • Refabrication & testing (1 to 2 years) Replacement scheme

  6. Simulation of limits for HOR Limits defined in the past: 1000 Gq/g => 4 µSv/h => 6,4 mSv/y10 µSv/h => 16 mSv/y (full exposure = 1600 h) • Limits are very conservative (they meet the ICRP norm for the operators) • The goal must not be to increase the limits (ALARA) • A simulation with a reduced exposure confirms that materials must not be classified immediately in remote handling recycling if one applies: • Shielding • Reduced exposure • Other measures to reduce the exposure of the operators First conclusion: • The limit for Hands On Recycling has to be kept at 10 µSv/h • Materials with a dose rate above 10µSv/h must not directly be classified as remote recycling

  7. Simulation of limits for HOR Other remarks: • Using dose rates for limits between categories starting from HOR is much more logical than using specific activities. • On the contrary clearance based on 1 µSv/h has no sense, since pure beta-emitting isotopes can still exceed clearance limits. Therefore the principle of clearance index should be applied for those materials • Confinement of the workspace is inevitable, due to the Tokamak dust, Tritium…)

  8. Remote Handling Facilities • Dose rates of fusion components are acceptable for existing facilities • The 5 years of temporary storage will reduce the dose rates of the components. • But! What about build up after a second irradiation cycle • The needed services are very specialised (testing and fabrication), precision ± 10 µm, • Up to now only simple products were fabricated (melting) • Confinement is unavoidable to protect the operators from internal contamination

  9. Fusion classification

  10. SRM is subdivided into two groups • Hands on recycling (dose rate up to 10 µSv/h) • Shielded recycling (dose rate between 10 µSv/h and 2 mSv/h) • CRM + PDW becomes one group Remote Recycling (above 2 mSv/h) • NAW (Clearance) is not defined by the dose rate of the materials but by the Clearance index. New proposal for Classification Ic < 1 Clearance

  11. Report: Precondition of the dose rate limits for recycling TW5-TSW-001 D2 SCK•CEN: R-4377, 276-06-06, L. Ooms, S. Boden, S. Leblanc Draft available, final report after today’s discussion

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