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FT 5.12 Determination of the radiation hazards due to tritiated dusts and flakes at JET)

FT 5.12 Determination of the radiation hazards due to tritiated dusts and flakes at JET) Part 1 - Literature review - (L Di Pace, ENEA) Part 2 - Experimental determinations (B Patel, UKAEA) UKAEA November 2005.

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FT 5.12 Determination of the radiation hazards due to tritiated dusts and flakes at JET)

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  1. FT 5.12 Determination of the radiation hazards due to tritiated dusts and flakes at JET) Part 1 - Literature review - (L Di Pace, ENEA) Part 2 - Experimental determinations (B Patel, UKAEA) UKAEA November 2005

  2. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Part 2 - Experimental determinations (UKAEA) Current status A large part of the experimental work as originally envisaged is complete, but some still on-going.(Work being done by NRPB(HPA) and Lovelace Respiratory Research Institute) Samples: Dust from surface layers of MKIIa tile, 2004 poloidal limiter tile, 2004 vacuum cleaner dust, single paper air-samples, multi-stage cascade air samples

  3. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Complete, results received: Size analysis, Specific Surface area, SEM (Lovelace) Complete, awaiting final results: Dissolution (NRPB(HPA)) Repeat analysis: Tritium content (Lovelace)

  4. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Repeat analysis: Tritium content (Lovelace) - Original acid dissolution method very slow - Provided CEA paper on wet-ashing using perchloric acid - Insufficient detail to replicate in lab - Contractual problems, now pursuing an oxidation method - Further time needed to complete this part of the work and check influence on other factors

  5. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET For tritium content, also approached: - Tritium Laboratory Karlsruhe for calorimetry* - JET AGHS for calorimetry* - CEA for wet ashing# *vacuum cleaner dust #tile dust

  6. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET NEW Results of In-Vessel Air Sampling in 2004 SD a) Seven single cyclopore paper samples b) Twenty (9-stage) impactor samples Covered wide range of remote and manual operations in 2004 shutdown

  7. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Twenty (9-stage) impactor samples were taken - cut points from 21um to 0.5um - allows measurement of AMAD, mostly analysed at JET by Liquid Scintillation Counting Scenario 1 (early stage after intake, partial availability of tritium) - all samples counted by LSC Scenario 2 (late stage after intake, full availability of tritium) - 2 samples counted following oxidation technique

  8. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET (Scenario 1, LSC count) Sample # 17, fitted line, AMAD = 11.4um gsd=2.4, manual welding

  9. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET (Scenario 1 (LSC count)) Sample # 3, fitted line, AMAD = 3um, gsd = 3.6, Remote work

  10. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Scenario 1 and 2 - comparison of LSC counting (4.19um) to full oxidation (7.98um)

  11. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET The ratio of the activity values by LSC counting and oxidation

  12. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Findings on the in-vessel air sampling: a) Surface bound tritium - AMAD values range from 3um to 11um b) Some correspondence to nature of work, but not always c) Actual sample activities are mostly non-linear and bi- or multi-modal d) Detailed analysis needed to unfold and calculate % contributions to multiple AMADs e) Can experimentally see a self-absorption effect with particle size

  13. FT 5.12: Experimental determination of the radiation hazards due to tritiated dusts and flakes at JET Findings on the in-vessel air sampling: f) - Allows results by LSC only to be extrapolated to total tritium if needed for remaining samples g) - The availability of tritium to body fluids is a function of desorption characteristics. Using this data, the dose calculation can be applied according to early or late stage after intake. AMAD values will vary for surface bound tritium only and full volume bound, and consequently the dose

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