hse preliminary general requirements for fcc layout and air management a. henriques & m....
TRANSCRIPT
FCC I&O Meeting
HSE Preliminary General Requirements for FCC layout and air managementA. Henriques & M. Widorski on behalf of the HSE Unit
17/12/2014
FCC I&O Meeting
Tunnel cross-sectionChoice of tunnel cross-section should respect the main Safety
requirements:
17/12/2014
Conventional Safety Radiation Protection
Personnel transportation for egressPersonnel transportation for short transit times between access and intervention point
“Safe zone” in the tunnel (fire resistant, air/gas tightness and in ‘overpressure’)
Parallel service tunnels along all potential high-activation sectors
Air management aspects
FCC I&O Meeting
Single vs. Double tunnelSingle Double
Larger tunnel diameter requiredSmaller tunnel diameter, in total more space available to integrate/handle infrastructure
Larger air volume will lead to higher activity levels
Smaller air volume will lead to a lower total activity.
Fire resistant and ODH proof passage for egress (with dedicated ventilation)
Optimised separation of hazards (activation, cryo, electricity, heavy equipment transport) from evacuation and passage ways
Frequent passage doors between “Safe Area” and tunnel (min. every X meters)
Frequent passages between both tunnels (min. every Y meters)
17/12/2014
Ref: “CLIC Conceptual Design Report”, CERN-2012-007, Geneva 2012
FCC I&O Meeting
Tunnel cross-section1. Ideal solution: Double concept for the whole of the FCC
17/12/2014
FCC accelerator tunnel“Hazard Area”
FCC access tunnel“Safe Area” with personnel transport mean
FCC I&O Meeting
Tunnel cross-section2. Alternative solution: Double concept for high activation sectors
17/12/2014
FCC access tunnels to bypass high-radiation areas
FCC accelerator tunnel with “Safe Area” for egress:
Optimise area w.r.t. Safety
FCC I&O Meeting
Underground infrastructureTopic Requirement
Personnel transport and evacuation
Personnel transport system for fast transfer between access point and intervention locations and for fast evacuation
Equipment transport Autonomous transport devices for equipment and material distribution (“Dispatch service”)
Remote inspection and handling
• Prepare infrastructure for remote handling of highly radioactive equipment
• Integrate remote inspection devices
Sanitary facilities Radiation Safe areas for sanitary facilities
Tunnel walls
• Tunnel surfaces shall be treated to minimise dust production and limit tritium releases from concrete
• Potential need for a cooling system for rock heating and wall insulation
Equipment Cooling of equipment should not rely on HVAC systems
17/12/2014
FCC I&O Meeting
Underground infrastructureTopic Requirement
Fire Fighting Ad-hoc and standard fire fighting and rescue equipment stored underground
Extinguishing system Automatic extinguishing systems for early fire attack
Fire and smoke compartments
Compartmentalization (walls or curtains) to facilitate evacuation and intervention and to limit the extent of damage.
Lifts Feasibility with respect to Safety requirements be clarified for expected depth
Storage/Buffer zonesActivation Safe (shielded) storage areas for highly radioactive equipment removed from the accelerator and for important spare parts
17/12/2014
FCC I&O Meeting
Tunnel & shafts location• Maintain minimum distances to lake bottom
and underground infrastructures• Hydrogeological optimisation to prevent
ground water activation• Place air release sites in less densely
populated areas to minimise impact from air-borne radioactivity
• Environmental impact on the surface sites
17/12/2014
FCC I&O Meeting
Air activationGeneral considerations on the radiological impact by radioactive air:
• The total released activity and activity concentration is determined by the air exchange rate and the effective decay time of the air before being released
• For the environmental impact, only the total released activity is of concern.
• For the exposure of workers surrounded by activated air only the activity concentration is of concern.
• Known beam loss locations may be shielded to minimise air activation (dumps, collimators, forward shielding at interaction points)
17/12/2014
FCC I&O Meeting
Air managementTopic Requirement
Transverse vs. Longitudinal ventilation
Transverse ventilation does not offer advantages without shielded ducts, therefore longitudinal ventilation is a viable option if the smoke/ODH extraction proposal is implemented
Confinement Compartmentalization between high activation, low activation and no activation sectors• Static: air tightness in the civil engineering and
sealing cables, ducts, piping, etc.• Dynamic: pressure difference between
compartments with different activation sectors;
Releases • Air from high activation sectors should be released at distant outlets to maximise the decay time
• Release points shall be placed in less densely populated areas
• Could air compression or condensation be a technical option for temporary decay storage ?
17/12/2014
FCC I&O Meeting
Air management: Smoke extraction
Topic Requirement
Smoke extraction Proposal presented to I&O in July 2014:• Limit propagation and contamination of smoke to
others volumes of the tunnel• Provide the dynamic confinement• Reduced cross section of the ducts compared to
transverse ventilation• Linear pressure drop for
8 km ~5 kPa (EDMS 1396658)10 km ~7 kPa
Smoke filtering Filtration or cleaning of extracted smoke shall be considered
17/12/2014
FCC I&O Meeting
Air management: Operating modes
Topic Requirement
In beam mode Determine optimal extraction flow-rate considering:• Release of short lived emitters• Accumulation of long lived emitters• Tritium concentration in condensates• Guarantee sufficient confinement• Operational parameters (temperature, humidity, air
speed)
In access mode • Only flush the accelerator sectors to be accessed• Temperature, humidity and air renewal adapted to
occupational health requirements
In incidental situations • In case of fire stop the tunnel ventilation and start the smoke extraction
• Helium release same as fire (simulations still need to be done)
17/12/2014
FCC I&O Meeting
Air management: HVAC infrastructure
Topic Description
Operating parameters Extraction rates, temperature and humidity shall be controlled
Parameter monitoring Sufficiently dense monitoring network for temperature, humidity, pressure, air speed and oxygen level
Installation locations Install HVAC on the surface or in accessible locations
Stacks Sufficiently high stacks to be foreseen
Release monitoring All release stacks equipped for radioactivity monitoring
Redundancy Foresee redundancy for full or partial functions
Condensates Consider condensate collection and reduction infrastructure on the surface or in accessible locations
17/12/2014
FCC I&O Meeting
Summary
17/12/2014
• Tunnel cross-section- Ideal solution: Double tunnel- Acceptable solution: Tunnel to bypass high radiation zones +
transport mean inside the “Safe Area”
• Underground infrastructure- Personnel & equipment transport means- Shielded storage areas - Fire compartmentalization - Rescue equipment stored underground
• Tunnel & shafts location- Assess environmental sensitive areas - Hydrogeological study- Extraction points in less densely populated areas
FCC I&O Meeting
Summary
17/12/2014
• Air management- Longitudinal ventilation + smoke/ODH extraction proposal is a
viable option for ventilation- Static and dynamic confinement different activation and fire
sectors- Optimise extraction to maximise the decay time- Filtration of smoke- During beam mode: optimise extraction flow-rate - During access mode: Only flush the accelerator sectors in access
mode
FCC I&O Meeting17/12/2014
Spare Slides