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XTAX repair & T9 target modification. S. EVRARD – thanks to J-L Grenard and A. Pardons. Content. Challenging situation Optimisation steps Sequence of actions Collective & individual dose Lessons learnt. XTAX repair: a challenging situation. Failure of motors - PowerPoint PPT Presentation
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XTAX repair& T9 target modification
S. EVRARD – thanks to J-L Grenard and A. Pardons
2 S. Evrard, XTAX repair & T9 target modification
Content
Challenging situation Optimisation steps Sequence of actions Collective & individual dose Lessons learnt
6 May 2013
3 S. Evrard, XTAX repair & T9 target modification
XTAX repair: a challenging situation
6 May 2013
Failure of motors The XTAX are made of
massive blocks put on motorized tables that can move up/down.
They act as primary beam dump or beam aperture limiter.
High radiation environment The TAX blocks intercept
about 10E19 protons/year about 6 mSv/h outside the shielding and probably 30 to 40 mSv/h at the blocks and even higher near the beam impact point
4 S. Evrard, XTAX repair & T9 target modification
XTAX repair: Optimisation steps
6 May 2013
‣PR537 remote control‣Increase PR537 lifting height
‣Lateral shielding stays in place
‣Bunker for mechanical work
‣2 level bunker‣Shielding of 100 mm thick steel plate
‣Pre-defined holes for reducing exposure to hot elements
5 S. Evrard, XTAX repair & T9 target modification 6 May 2013
XTAX repair: Sequence of actions
1 Bunker assembly 2 service disconnection 3
4 table handling
shielding roof removal
6 S. Evrard, XTAX repair & T9 target modification 6 May 2013
XTAX repair: Sequence of actions
5 spring removal
6 old motor removal
7 new motor installation
8 table back handling
7 S. Evrard, XTAX repair & T9 target modification
XTAX repair: on-line monitoring
6 May 2013
The RP supervisor follows in real time more than one person and can react to any alarm
Especially useful during high dose rate job (like proximity work, service connection,…).
Graphical interface
On-line cumulative dose and dose rate monitoring
8 S. Evrard, XTAX repair & T9 target modification
XTAX repair: collective & individual
dose Motor repair procedure very well studied
and optimised real dose <<<< estimates Proximity intervention less optimised real
doses = estimates Ways of improvement : use of robot, cold
cell or new connection design Individual dose: self-commitment 600 uSv
respected
6 May 2013
Dose estimates
Rem
ote
hand
ling
Shie
ldi
ng
9 S. Evrard, XTAX repair & T9 target modification
T9 target modification: a challenging situation
6 May 2013
T9 target station
Inner part of copper blocks : 1 Sv/h T9: transformation to HiRadMat beam dump:
1. Remove target, all collimators & monitor2. Replace upstream collimator with new collimator3. Replace other items with TED-type beam dump4. Close shielding and complete HRM beam dump
Stee
l ups
tream
col
limat
or ν-p
rodu
ctio
n ta
rget
Copp
er d
owns
tream
col
limat
or b
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s
Dow
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am m
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r
10 S. Evrard, XTAX repair & T9 target modification
T9 target modification: Optimisation steps
6 May 2013
Challenges: Each block (2.7t) is not fitted with lifting point and has hot outer surface Axis of 2 blocks is outside range of overhead crane Items not designed for remote handling (installed with forklift on 1993, 4
threaded holes per block) Solutions:
Lifting & shielding plates fixed manually on copper blocks Custom-made lifting beam takes 2 blocks at the time Shielding in place for all manual interventions Extensive tests on mock-up (tools, training, camera)
11 S. Evrard, XTAX repair & T9 target modification
T9 target modification: sequence of actions
6 May 2013
Lifting test before closing roof
Placing block in container
Separating blocks 21
Fixing plates on lower blocks
Moving upper blocks with fixed lifting plates
Blocks in temporary storage location
Sarcophagus withcontainers ready
Dismantling work took ~10 days, collective dose of ~1.2 mSv for Copper block removal
12 S. Evrard, XTAX repair & T9 target modification 6 May 2013
T9 target modification: collective dose
Optimisation, tools, training brings WANF dismantling from est. 210 man.mSv to 60 man.mSv. T9 target modification amounted to 2.7 man.mSv.
The main contributions are from low dose rate but long-lasting activities, impossible to do remotely (by design) or carried out by less experienced personnel.
SAFETYCLEANING
VENTILATION DUCTCABLESCRANE
WATER PIPEST9 TARGET
CABLE TRAYSTRANSPORT
MTR REMOVALPAINTING
HELIUM TUBEPIPE DN250
VACUUM CHAMBER T1TDX COLLIMATOR REFLECTOR
HORNMISCELLANEOUS
T1 TARGETLIGHTING
0 1000 2000 3000 4000 5000 60005870
48984622
41153398
31472673
25832277
21432120
19721689
13401316
115511251120
1069 Collective doses in µSv per activityWANF dismantling
13 S. Evrard, XTAX repair & T9 target modification
lessons learnt
Design of High Radiation Areas Take into account dismantling
needs as from the design stage Include dedicated areas in TA for
remote handling operation, RP supervision (preparation, monitoring,…)
Equip underground areas with most recent technology means (optical fibers, cable network for cameras, Wi-Fi network)
Remote controlled crane with positioning system
6 May 2013
14 S. Evrard, XTAX repair & T9 target modification
lessons learnt
Intervention in High Radiation Areas: preparation and organization are essential Training on mock-up Planning and resources management Systematic dose rate check (remote device
or RP technician) before intervention On-line & daily dose monitoring QAP
6 May 2013
15 S. Evrard, XTAX repair & T9 target modification
lessons learntRepair& dismantling procedure: some valuable concepts Keep inaccessible the most activated parts Avoid time-consuming activities Mitigate time-consuming activities by shielding Standardize repetitive actions Enhanced personnel safety by camera
monitoring Improve reliability of key resources (overhead
crane)6 May 2013