EFDA
European Fusion Development Agreement
Close Support Unit - Garching
c/o Max-Planck-Institut für Plasmaphysik
Boltzmannstr. 2
D-85748 GARCHING bei München
Telephone-Switchboard:
(089) 3299-02
________________________________________________________________________________
MINUTES OF MEETING
Kick Off meeting task TW6-TSS-SEA 2.1
Garching, 10/10/2006
Participants:
I. Cristescu (FzK); M-T. Porfiri, T. Pinna (ENEA); F. Vermeersch, E. Cantrel (SCK•CEN by
phone); M. Iseli (ITER Cad, by phone); A. Tesini, A. Tanga (ITER, part time); W. Gulden, C.
Damiani, V.Massaut (EFDA)
1. Agenda and availability of the presentations
The agenda of the meeting is given in appendix.
The presentations from the different investigators are available through the Internet on a dedicated
website (http://efdasql.ipp.mpg.de/safety/ ID=SAFETY pw= werNER_06). The EFDA delegates
want to thank the participants for the effort made for attending the meeting and presenting their
methodology of work.
2. Kick off meeting TW6-TSS-SEA 2.1.
V. Massaut made a short introduction on the objectives and aims of the task (see presentations on
the website).
It was reminded that the legal individual dose limit (following ICRP recommendations) is 20
mSv/12 months, and not 30 mSv/quarter. Moreover, the ITER collective dose target was set by
ITER team at 500 p-mSv/y, i.e. a little below the target set by utilities for new fission power plants
(700 mSv/y). It was also reminded that at Karlsruhe, within the TLK, the dose due to tritium
represents less than 1% of the limit (50 mSv/5y and 20 mSv/12 month).
F. Vermeersch presented the methodology and aim of deliverable nr 2. The choice of Eq. port #1 as
test case was based on different aspects: it is the one which has been used as generic for all
equatorial ports studies, it has been extensively analysed for ORE (and thus allows comparison),
and there are geometry changes during maintenance.
A question was raised about the possibility to link the 3D calculation program with CATIA CAD
data. The code has an interface with CAD Microstation, not yet to CATIA. But following C.
Damiani, data from CATIA could be transformed into generic CAD data readable by MicroStation.
It was also asked if it should not be worth applying this type of analysis for the NBI cell. It seems
that the cell and maintenance operations are still in a too early phase of study to be able to be
implemented in this type of analysis. The work under del.6 will mainly focus on the definition of the
hands on maintenance and preparatory operations.
I. Cristescu presented the methodology foreseen for the del 3 & 4. It is important to define as soon
as possible the main boundary conditions and input parameters. For instance the NBI cell is now
separated physically from the vault space (with some implication on ventilation/detritiation systems
connections). Therefore, the connection between the NBI cell and Vault and SADS (as mentioned in
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the last bullet of slide 11 of Ion’s presentation: “In the present configuration the NB cell is not
served by the S-ADS. Pipe connections between NB cell and S-ADS need to be provided “) would be
taken into consideration for the DCR nr 49. To be included in the documents for the DCR meeting
of November (action: Arturo, Nov 2006).
But the main discussion point concerned the amount of tritium to consider when opening the NBI
box. Following FZK, and data existing for outgassing (considering that the NBI- cryopumps would
have been regenerated at high temperature ~ 470K), the maximum tritium released can be in the
order of 10-3 g. Following A. Tanga (ITER), the source term to be taken should better be in the
range 1-10g. In order to solve this issue, it was decided that the tritium source term in the NBI box
at opening (between 10-x to 10 g), for further studies, will be defined in collaboration Arturo + Ion,
in the following way:
- Ion will give the results of his study/bib research within 2 weeks, i.e. around 25/10 (action:
Ion 25/10/2006)
- then there would be a discussion between Arturo (ITER) and Ion to finally define the value
to consider for the studies on contamination etc..
- The final value should be confirmed in writing by ITER (Arturo) asap, if possible for 31/10
(action: Arturo 31/10/2006).
There was also some doubts raised about the non significant aspects of sorption/desorption of
tritiated species on/from wall surfaces. This should be looked at in more details. Moreover this
considers that the detritiation systems are working.
A. Tanga presented the main aspects of the NBI cell design change request (see presentation on the
website). Most of the design change data are available on the ITER technical website and on the
EFDA/IDM website giving the documents in reference of the task sheet. New documentation will
be produced for the DCR meeting in November 2006. A. Tanga will deliver these documents to the
participants (action: Arturo; November 2006).
It is reminded that several elements to be replaced (including the source) are RH class 1 components
i.e. potentially to be replaced every 6 moths (most probably every 2 years). It is also assumed that
the VVPSS pipe rupture disc has to be inspected at least every year. The upper diagnostic ports
situated in the NBI cell will be changed; the port plugs can no more be removed. Only pipes with a
maximum diameter of 20 cm will be allowed to be removed.
It was also mentioned that for the ORE analysis, one should also take into account the potential
spread of in-VV dust into the NBI box and then into the cell when opening the box.*
A. Tanga will provide estimates of this quantity in normal operation and after a disruption (action:
Arturo; 31/10/2006)
A question was raised concerning the contribution of gamma radiation coming directly from the
Vacuum Vessel. Following E. Polunovsky (invited to the meeting for this point), this contribution is
insignificant compared to gamma coming from the activated materials in the NBI-box.
E. Polunovsky also sent his last computation results for the dose rate in the NBI cell. The document
has been distributed to all participants (by e-mail).
M-T. Porfiri presented the methodology ENEA intends to use for evaluating accident scenarios and
ORE data for maintenance. She pointed out the importance to know the data on the existing
connection between the NBI cell, the vault, the galleries etc.
For the dust source term in VV, ENEA will use the values given in SADL with tritium content in
the dust also from the same source. The transport from the VV to NBI and from the NBI to the cell,
in case of accident will be calculated and be part of the outcome of this task. For the ORE
Note: on the NBI-RH meeting on 10/10/2006, I understood that the internals of the NBI will be transported
“naked” into the cell, hanging at a bridge. There is no cask foreseen for the transport of these components
through the cell. This should be taken into account when assuming the contamination potential in the cell.
*
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evaluation, a large effort will be focused on the maintenance operation definition. For what
concerns the data necessary for the evaluation (slide # 11),
- the NBI design documents are available (DCR meeting report) or will be available (DCR
meeting 2006 documents; action of Arturo);
- the ventilation and detritiation system data can be asked to I.Cristescu
- the radiation field in NBI box and cell have been distributed (doc. Polunovsky)
- the tritium contamination in the maintenance zones will be defined by Ion and Arturo (see
above)
- so the only “unknown” to be assumed (except if ITER can provide the necessary data) will
concern the maintenance frequency.
E. Cantrel gave finally his intended methodology for the “Assessment of the possible
decontamination procedures for tritiated surfaces” as was required by ITER. Nevertheless,
following the discussion at the meeting, it seems that this aspect is not relevant any more for the
task as decontamination procedures and processes for tritiated surfaces have been defined and
developed since long time, and a reorientation of this subtask towards the decontamination of
surfaces contaminated by (carbon) tritiated dust would be worthwhile. A new formulation of the
deliverable will thus be proposed in collaboration between EFDA (VM), ITER (AT) and the
Association (EC). (action: Vincent, Arturo, Eric; 31/10/2006).
The main actions for A. Tanga have been summarized in an e-mail sent to Arturo (with copy to the
other participants) on 11 October.
V. Massaut
Attachment: list of participants with coordinates
Agenda of the meeting
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EFDA Task TW6-TSS-SEA 2.1.
“Occupational Radiation Exposure –
ALARA in ITER: further refinement”
Kick off meeting – 10 October 2006 – Garching
Garching – T1 meeting room upstairs
Agenda
10:00
10:30
11:15
11:30
12:15
p.m.
13:15
14:00
14:30
15:00
Introduction
W. Gulden, V. Massaut (EFDA)
Assessment of previous ORE evaluation by F. Vermeersch (SCK•CEN)
comparison with 3D exposure analysis.
Analysis of the main difference contributors
and optimisation of the calculation
Coffee Break
Analysis of the worker safety implications and exposure due to the design change
proposal in the NBI cell and NBI maintenance procedures:
Evaluation of the total amount of T flow
I. Cristescu (FzK)
rate coming from the maintenance
operations. Assessment of the capacity of
the ventilation system to achieve T
concentration suitable for human presence
in suits or without.
Evaluation of the expected time evolution
I. Cristescu (FzK)
of the Tritium airborne concentration and
order of magnitude of the surface
contamination.
Lunch
Analysis of the worker safety implications and exposure due to the design change
proposal in the NBI cell and NBI maintenance procedures (contin’d):
The NBI cell design change proposal; needs A. Tanga (ITER)
for an ORE review
Engineering approach of the potential
M-T. Porfiri (ENEA)
accident scenario leading to the worst
release possible (evaluating the mobilisable
sources and the available energy to
mobilize) in various configurations of the
barriers in the NBI cell.
Evaluation of external Occupational
M-T. Porfiri (ENEA)
Radiation Exposure and optimisation of the
radioprotection.
E. Cantrel (SCK•CEN)
Assessment of the possible
decontamination procedures for
tritiated surfaces.
15:30
16:00
16:15
Discussion on the performance of the task
Planning, schedule
Available documentation
Coffee Break
Any other business
End of the meeting
Final version
All
All
A. Tanga, V. Massaut
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List of participants with coordinates.
ASSOCIATIONS
Name
Porfiri
Pinna
Vermeersch
Cantrel
Cristescu
Forename
Maria-Teresa
Tonio
Fernand
Eric
Ion
Association
ENEA
ENEA
SCK•CEN
SCK•CEN
FZK
Telephone
+39 06 94005624
+39 06 9400 5820
+32 14 33 27 11
+32 14 33 2660
+49 7247 82 3757
Fax
+39 06 94005314
+39 06 9400 5783
+32 14 31 19 93
+49 7247 82 2868
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
E-mail
Vincent
Werner
Carlo
EFDA CSU-Garching
EFDA CSU-Garching
EFDA CSU-Garching
+49 89 3299 4218
+49 89 3299 4216
+49 89 3299 4175
+49 89 3299 4224
+49 89 3299 4224
+49 89 3299 4224
[email protected]
[email protected]
[email protected]
Arturo
Markus
Alessandro
ITER Cad
ITER Cad
ITER Cad
+33 4 4225 4012
+33 4 4225 3075
+33 4 4225 xxxx
+33 4 4225 2600
+33 4 4225 2600
+33 4 4225 2600
[email protected]
[email protected]
[email protected]
EFDA
Massaut
Gulden
Damiani
ITER
Tanga
Iseli
Tesini
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