HIGH LUMINOSITY LHCWP1 - CERN SAFETY REQUIREMENTS

Stefan Roesler - Phillip Santos Silva – Ralf Trant EDMS# 1141248 HSE Unit April 2011

WP1 - Safety

All equipment to be installed and operated on the CERN site must comply with the CERN HSE regulatory framework to ensure a high level of Safety commensurate with relevant best safety practices.  During the proposal phase the following needs to be defined:

Duties and responsibilities on HSE matters of the participating parties ;

Procedures to be followed and documentation to be established in the

different project phases ;

Set of applicable CERN rules, design standards and certifications to be supplied.

 The high Luminosity LHC (HL-LHC) design study will address the two principle HSE aspects:

RADIOLOGICAL and CONVENTIONAL

HSE Unit will assist the project in the integration of all safety aspects at the earliest stage. 2

WP1 – Conventional Safety Aspects

The focus among the conventional HSE aspects will be at this early stage

on:

Support on the hazard identification

Support on the risk analysis and on the definition of mitigation

actions

Safety engineering support

(e.g. on cryogenics, mechanical and handling equipment, or others) 

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Applicable CERN Rules for Mechanical Safety

The HSE Unit will verify the design report and shall grant safety clearance for special equipment, installations, experiments and projects with major Safety implications.

“special equipment”: mechanical equipment which, due to its designated function, cannot comply with European Directives or standard mechanical equipment classified by the Department as equipment of high Safety relevance(refer to SR-M).

All main design assumptions, including choice of the safety factors, must be fully

described and justified in a design report, together with the results of the

calculations.

Whenever applicable, existing Codes or Standards must be used.

Should complementary measures during fabrication or testing be needed, they

must also be described in the design report.

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In Kind Contributions to CERN

A Memorandum of Understanding is aimed at defining the interaction between CERN and the international laboratories for what concerns Safety issues of special equipment to be provided by this lab.

For all equipment to be installed and operated on the CERN site, CERN Safety Rules must be complied with. However, CERN may accept, under certain conditions, that collaborating institutes may use equipment, design standards other then those referenced in CERN Safety Rules.

The different phases of the MoU are: 

Definition of the set of Safety rules to be used Conceptual design Engineering design Manufacturing design Installation and commissioning Operation Decommissioning

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WP1 – Radiological Safety Aspects

Radiation protection aspects to be considered:

• Choice of material in view of

- dose to personnel during maintenance and repair.

- future radioactive waste disposal.

• Calculation of material activation and associated residual dose rates due to beam

collisions and losses.

• Optimization of the layout according to the ALARA principle for handling during

installation, maintenance and removal of components.

• Activation and releases of cooling liquids and air.

• Shielding of personnel against stray radiation.

• Study removal and installation scenarios and tools for the upgrade work.

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Choice of material

• A project on radiological guidelines for materials to be used in CERN’s accelerator

environment has been created.

• Strategy of the project:

1) Characterization of radiation fields with regard to activation properties

2) Development of a tool (ActiWiz) allowing for a fast classification of materials according the

activation properties in the different radiation fields

3) Survey on material data used at CERN’s accelerators

4) Creation of material catalogue that provides a ranking in terms of radiological properties

• Three-fold benefit:

safety lower dose rates and intervention doses

operation faster access, less restrictions, lower accelerator downtime

waste disposal smaller volumes of radioactive waste, cheaper disposal

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Residual dose rates – Inner triplets

Assumption:109 7TeV-pp/s for 180 days (180 /fb)

Example: LSS5

Significant residual dose rates, even at long cooling times (~100μSv/h in the aisle, >1mSv/h close to vacuum pipe)

M.Fürstner et al., EDMS 1006918

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Residual dose rates – TAS

Assumption:109 7TeV-pp/s for 180 days (180 /fb)

Example: TAS at Point 5

M.Fürstner et al., EDMS 1006918

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Residual dose rates - Experiments

Example: CMS

1.0e-03

2.7e-03

7.2e-03

1.9e-02

5.2e-02

1.4e-01

3.7e-01

1.0e+00

2.7e+00

7.2e+00

1.9e+01

5.2e+01

1.4e+02

3.7e+02

1.0e+03

2.7e+03

7.2e+03

1.9e+04

5.2e+04

1.4e+05

3.7e+05

1.0e+06

uSv/h

109 7TeV-pp/s for 180 days (180 /fb) one month cooling

C.Theis et al., EDMS 980242

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Optimization of layout

• Estimation of job doses during design• Optimization of layout and components (ALARA principle) to allow later for easy and fast handling, maintenance and repair

Example: collimation regionsM.Brugger et al., EDMS 689164

• Use of fast plug-in system• Vacuum connections with chain clamps

Installation of permanentbakeout system

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Study of removal scenarios

Scenario 1 - Grinding toolPrecise, no damage to magnetsSlow, dust, smoke

Scenario 2 – Remotely controlled cutterFast, no splints or dustDamage to instrumentation and magnets

Factor of 20 reduction in individual doses !12

Shielding

Example: ATLASI.Dawson, V.Hedberg., ATL-TECH-2004-001

Assumption: luminosity of 1034/cm2/s

15 μSv/h

3 μSv/h

USA15: Supervised Radiation Area13