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Meeting on Meeting on Revision of the Revision of the OOccupational ccupational

RRadiation adiation EExposure assessment xposure assessment for the Port-Interfacing Systems for the Port-Interfacing Systems

(WBS5.0)(WBS5.0)

Garching / Cadarache 25/04/06Introduction and objectives

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Occupational Radiation Exposure (ORE) Occupational Radiation Exposure (ORE) evaluation: main objectivesevaluation: main objectives

• The main general objectives of the ORE optimisation has The main general objectives of the ORE optimisation has important impact on:important impact on:– The safety of the operation personnel – The availability of the machine– The overall impact of fusion

• For the safety analysis and the licensing, the ALARA For the safety analysis and the licensing, the ALARA approach of the operation of the machine is important approach of the operation of the machine is important and makes part of the overall safety approach of the and makes part of the overall safety approach of the fusion plant.fusion plant.

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In the RPrS In the RPrS 3 chapters 3 chapters

– Radiological zoning

– Network survey

– Proof of the ALARA into the design

KOM RadioprotectionKOM Radioprotection 23rd of March 200623rd of March 2006From

CEA:

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ALARA approach and radioprotection ALARA approach and radioprotection optimization in the overall safety approachoptimization in the overall safety approach

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The ALARA approachThe ALARA approach

• Not only the reduction of dosesNot only the reduction of doses• Not only the “good practice”Not only the “good practice”• But mostly an optimization (…as But mostly an optimization (…as ReasonablyReasonably

Achievable) based on other factors like economical Achievable) based on other factors like economical factors, industrial safety, ethical values, etc…factors, industrial safety, ethical values, etc…

• A complete ALARA approach should need to review the A complete ALARA approach should need to review the process from A to Zprocess from A to Z including the waste management, including the waste management, disposal etc. (NB this is in reality never done; but the disposal etc. (NB this is in reality never done; but the overall principle should be kept in mind) overall principle should be kept in mind)

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The tasks involvedThe tasks involved

• There is an ITER/ITA task proposal (ITA 81-11), in the There is an ITER/ITA task proposal (ITA 81-11), in the process to be signed, concerning “Occupational Safety process to be signed, concerning “Occupational Safety to ensure worker safety and preliminary assessment to to ensure worker safety and preliminary assessment to support licensing”.support licensing”.The present analysis and report belong mostly to the The present analysis and report belong mostly to the second deliverable of this task.second deliverable of this task.

• Within EFDA it belongs to the task TW4-TSS-SEA2.1.a, Within EFDA it belongs to the task TW4-TSS-SEA2.1.a, contract 04/1205contract 04/1205

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After various studies and reports, the current After various studies and reports, the current report summarizes the findings on the WBS 5.0report summarizes the findings on the WBS 5.0

• S. Sandri, “Analysis of the ORE assessment process applied to S. Sandri, “Analysis of the ORE assessment process applied to ITER project”, ENEA FUS-TN-SA-SE-R-50, September 2002 ITER project”, ENEA FUS-TN-SA-SE-R-50, September 2002

• J. Uzan-Elbez, “Justification of ALARA for ITER (design 2001)”, J. Uzan-Elbez, “Justification of ALARA for ITER (design 2001)”, CEA/DEN/CAD/DTAP/CASI DO 389 25/11/03, Cadarache (France)CEA/DEN/CAD/DTAP/CASI DO 389 25/11/03, Cadarache (France)

• A. Natalizio, M. T. Porfiri, "Worker Dose Estimates for NB & LH A. Natalizio, M. T. Porfiri, "Worker Dose Estimates for NB & LH Heating & Current Drive Systems", ENEA FUS-TN-SA-SE-R-132, Heating & Current Drive Systems", ENEA FUS-TN-SA-SE-R-132, October 2005October 2005

Some of the main reports/studies previously available:

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Definition of WBS 5.xDefinition of WBS 5.x(following ITER documents) (following ITER documents)

• WBS 5.1 ITER Ion Cyclotron Resonance Heating and WBS 5.1 ITER Ion Cyclotron Resonance Heating and Current Drive Current Drive (Task Officer :(Task Officer : David Swain and A.Sakasai)David Swain and A.Sakasai)

• WBS 5.2 Electron Cyclotron Resonance Heating WBS 5.2 Electron Cyclotron Resonance Heating Systems (ECRH) Systems (ECRH) (Task Officer :(Task Officer : A.Sakasai)A.Sakasai)

• WBS 5.3 ITER Neutral Beam WBS 5.3 ITER Neutral Beam (Task Officer :(Task Officer : A.Sakasai)A.Sakasai)

• WBS 5.4 WBS 5.4 no info on ITER site (formerly LH&CD?)no info on ITER site (formerly LH&CD?)

• WBS 5.5 WBS 5.5 ITER Diagnostic ITER Diagnostic (Task Officer :(Task Officer : ?)?)

• WBS 5.6 Test-Blanket Module WBS 5.6 Test-Blanket Module (Task Officer :(Task Officer : Masaaki Morimoto)Masaaki Morimoto)

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The analysis of the ORE has been carried out The analysis of the ORE has been carried out with a “best practice” engineering approachwith a “best practice” engineering approach

• The occupational exposure evaluation needs three main elements:– The dose rate or better the radiation field in the concerned areas

• These data are only partially known, and request often to make assumptions

• Only “general” values for the different working areas could be taken without taking into account the actual geometry, inner sources, ACP, etc.

• Internal exposure was not taken into account for this analysis

– The work force (in terms of number of individuals concerned): • here also, the data are based on assumptions for the main

maintenance activities to be carried out

– The duration (and frequency) of the intervention: • the best engineering practices have been taken, based on the

known design. But the actual design and maintenance scheme is important to better define this aspect

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Some other uncertainties Some other uncertainties also affect this analysisalso affect this analysis

• The effects of difficulties for the workers (e.g. working in The effects of difficulties for the workers (e.g. working in height, use of scaffolding, the wearing of masks or height, use of scaffolding, the wearing of masks or pressurized suits, the temperature in the rooms, the pressurized suits, the temperature in the rooms, the accessibility of the components to be worked on, etc…accessibility of the components to be worked on, etc…

• The use of portable/removable shielding; the potential for The use of portable/removable shielding; the potential for partial decontamination of hot spots, the use of semi-partial decontamination of hot spots, the use of semi-autonomous tooling, etc…autonomous tooling, etc…

• The actual frequency of maintenance (probably to be The actual frequency of maintenance (probably to be discussed here) of the different concerned componentsdiscussed here) of the different concerned components

• Etc…Etc…

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Therefore, only important factors susceptible Therefore, only important factors susceptible to change the figures are relevant to discussto change the figures are relevant to discuss

• The approach being still at the “pre-design” level, we The approach being still at the “pre-design” level, we must regard this study in view of the needs of the must regard this study in view of the needs of the licensing documents and of what would then be asked licensing documents and of what would then be asked for the “final” safety reports after the construction (it for the “final” safety reports after the construction (it would be difficult to justify an important increase in the would be difficult to justify an important increase in the operators exposure at the time of start up !)operators exposure at the time of start up !)

• So for this approach we need to remain So for this approach we need to remain pragmaticpragmatic, , realisticrealistic (in the limits of the current design) and, if (in the limits of the current design) and, if possible, possible, conservativeconservative..

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The main goals of this meeting are thusThe main goals of this meeting are thus

• To review briefly the analysis done and the principles used To review briefly the analysis done and the principles used throughout the studythroughout the study

• To analyze and discuss the comments and remarks gathered from To analyze and discuss the comments and remarks gathered from designers and specialists of the concerned equipmentsdesigners and specialists of the concerned equipments

• To look how these comments can be integrated in the current study To look how these comments can be integrated in the current study to improve it and tend towards the objectives (to improve it and tend towards the objectives (pragmatic, realistic pragmatic, realistic and conservativeand conservative))

• To define how the interaction between designers, physics specialists To define how the interaction between designers, physics specialists and health physics analysts can be enhanced to avoid too much and health physics analysts can be enhanced to avoid too much discrepancies between the analyzed machine and the current onediscrepancies between the analyzed machine and the current one

• To define how the potential detection of dose distributing events or To define how the potential detection of dose distributing events or components can be taken into account in the design, or how components can be taken into account in the design, or how collaboration can be set up to decrease these levels.collaboration can be set up to decrease these levels.

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Proposal of agendaProposal of agenda

9:00 Short introduction on the main objectives of the meeting V. Massaut (EFDA-S&E)

9:15 Summary report of the ORE study; methods and principles M-T Porfiri (ENEA)

09:45 Coffee Break

10:00 Needed input for improving the analysis M-T Porfiri (ENEA)

10:15 Comments on the main received comments M-T Porfiri (ENEA)

10:45 Discussion on the comments from ITER C. Walker (ITER)

11:15 Discussion on the comments from ITER (cont’d) S. Chiocchio (ITER)

11:45 Discussion on the main comments from the Physics group E. Ciattaglia (EFDA – Physics)

12:15 Discussion on the main comments from the Physics group (continued) NN (EFDA – Physics)

12:45 Lunch

13:45 Remote Handling aspects and approach; limit of applicability - the ITER approach : discussion

C. Walker (ITER IT)

14:15 General discussion on how to improve the ORE analysis All

15:00 Improvement of information exchange All

15:30 Coffee Break

15:45 Any other business All

16:00 Closing address W. Gulden (EFDA-S&E)

16:15 End of the meeting

Pro

posa

l

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Thanks for your attentionThanks for your attention