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

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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

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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