1. Neutrino Platform Overall Protodune Risk Mitigation Plan O
Neutrino Platform Overall Protodune Risk Mitigation Plan O. Beltramello,

2. NP02 and NP04 – Neutrino Hall configuration

3. Safety Organization
The safety organization is defined in EDMS “EHN1 Neutrino Platform Work and Safety Organization” – for installation and commissioning phases
Full time safety presence in situ (TSO (territorial), DSO (department), PSO (project), in situ Safety Coordinator)
Every week a coordination meeting is run with all EP/EN teams represented to analyze co-activities
HSE Unit

4. Safety risks in the Neutrino Hall
We are assessing the risks associated to the Neutrino experiments and experimental area activities:
Cryogenics
Gases
Low Pressure Vessel (350 mbars)
Electricity (HV, LV)
Fire
Radiation
Working at height, handling heavy objects, coactivity, etc..

5. ODH risk assessment for cryogenics performed and validated by TE expert (David Montanari, Johann Bremer) and the CERN Health and Safety Unit (HSE experts)
we do not consider a rupture in the cryostat a realistic scenario
the largest credible scenario that could cause an ODH situation is a 500 mm2 rupture in the cryostat bottom line to the LAr pump - medium leak size
In 2mn, without ventilation, we estimate a release of :
713 Kg of LAr
cold gas release of 123 m3
height of the cold GAr is < 1m in the two pits.
In case of abnormal situation (from the cryo system or from external detection):
we stop the LAr pump
switch off the valve inside the cryostat insulation and isolate the vessel
this is done via the safety PLC of the cryogenics system

6. See David Presentation
LAr pump and valves
A SIL2 valve connected to a
SIL 3 safety system
See David Presentation
Special valves engineered with GTT and a specialized firm
2 valves contracted by CERN

7. Cryogenics – ODH Safety Matrix
ODH detection system + red flashing lights (SIL3)
NP02
NP04

8. Cryogenics – ODH Safety Matrix
Pirani vacuum sensors (alarm threshold of 10 mbar) in the vacuum insulation of the cryogenics pipes bringing the cryogenics to the cryostat
early detection leak
In case of detection (fixed ODH or vacuum sensors):
Alarm sent to CERN Control Center and the NP02 and NP04 DSS (detector safety system)
Alarm sent to Fire Brigade for an immediate intervention
Evacuation of the Neutrino Platform Hall
Flashing lights to signal the ODH risk
High-speed gas extraction mode ( m3/h) in the trenches

9. Additional safety measures agreed with HSE
Crane usage on top of the cryostats and cryogenics restricted
No access to the trenches while the cryostat are under filling process
Only exceptional access (maintenance of the LAr pump) to the trenches when the cryostats are filled with LAr.
Evacuation procedure agreed with Fire Brigade, OK
Two ways of egress are always be guaranteed, OK
Pressure safety valves (cryostat and pressure vessels) vented outside the building
Specific safety training required for the NP Hall occupants concerning the hazards, the mitigation actions implemented and the actions to take in case of a leak, on-going

10. Gases
We expect to have N2 gases in the clean room in the detectors test sarcophage. ODH risk assessment on going – not expected to be an issue
cryo door position
material SAS
rails
test box

11. Fire
All fire preventive measures are being put in place in the building following the general fire risk assessment.
Additional temporary fire detection system is required for inside the cryostat and inside the clean room while we start installing.
It will be linked to the evacuation system.
Level 2 fire detection system needs are under investigation for the racks.
The evacuation paths and the evacuation procedure have been agreed. The evacuation signalization is in place already.
We are asking HSE for derogation to use halogenated material inside the Protodune cryostat

12. Evacuation plan - Horizontal
Approved by CERN Fire Brigade and HSE unit
R+1 R
R+1
The complete evacuation plan can be found at EDMS

13. Evacuation plan – Vertical (Jura side)
EDMS

14. Assembly points
There are two assembly points on the sides of the building
NP Hall
EHN1

15. Electricity
The safety grounding scheme is to be presented to HSE unit for approbation soon. An electrical area is planned with transformers inside the dedicated rack area.
This will be closed by fences and put under restricted access.

16. Pressure Vessels
The membrane cryostats are low pressure vessels (opening of safety valves at 350 mbar).
The external warm structure is made of steel and SS and is designed according to Eurocode3.
In close collaboration with HSE unit, we have issued all required FEA calculations for the two vessels and we have received their validation:
EDMS EHN1- NP02/NP04 cryostats warm structure summary structural analysis
EDMS Safety Validation Form - WA105 Warm structure at Building 887
EDMS Seismic analysis procedure for rectangular tanks filled with liquid.
EDMS "Safety Validation Form - Seismic assessment of prototype cryostats"

17. Detector Sub-Systems
We are working in close collaboration with the US teams, HSE Unit to provide the safety clearances for all the sub detector elements.
the required CERN regulation and EU standards applicable have been provided
We are regularly reviewing the design(with HSE)
We will provide intermediate safety clearances.
The CPA, Field cage structural elements have been
Provided for approbation to HSE.
Under assessment, no issue detected for the moment …
We are waiting documentation from APA and
DSS structures ..

18. Radiation Protection
The Neutrino Hall is currently classified conventional. Before beam commissioning, the access will be done with a CERN access card.
It will be classified supervised after the first beam (access with dosimeter).
Only the trenches will be interlocked with beam.
The rest of the hall and the tops of the two cryostats will remain accessible while beam in ON, under certain conditions …
Specific patrol procedures will be created for NP02/NP04 trenches.
Patrollers will be trained to safely empty the NP trenches before beam.

19. Access Strategy – this guaranties safety of personnel
An access strategy document circulated within the involved CERN partners and approved
Under implementation
We install different type of access system with different levels of training and safety controls depending on the risks in the accessed areas

20. NP Hall Safety trainings (Basics and Trenches)
As required by the specific risks related to the Neutrino activities, we are creating a specific safety training for the NP Hall.
It will be web based training.
The training currently is covering the existing risks:
access, impacts, PPSPS
required PPE
fire
evacuation and emergency
working at height, falling objects
etc ...
We will add when coming ( ), the other main risks :
Cryogenics, Radiation Protection

21. To enter the area, people must :
Have the appropriate access rights, signed by the project responsible and the safety manager of the area
Have been trained for the risks inside the area
Have declared the activity he/she is performing in the area (IMPACT) and being authorized by the activity supervisor and the safety responsible (PSO and DSO) .
The CERN IMPACT system enable to declare the activity, the schedule, people allowed to perform the activity and all required safety documents (work package analysis together with associated safety measure, radiations levels collected, fire permit, etc…)
All this is checked by the access system at entrance

22. Access to NP Hall
The doors functions are determined: entry/exit, evacuation, personnel/material entrance.
Access performed with access card (conventional) and then with dosimeter (when supervised).
- Access right : Access_Hall
- Valid IMPACT
- Basic CERN Safety awareness training
- Specific NP_ Basics safety training (risks, evac. procedure, etc…)

23. Access to NP Trenches + NP top cryostats
Access performed with access card (conventional) and then with dosimeter after the first beam.
- Access right : Access_Trenches/Top
- Valid IMPACT
- Basic CERN Safety awareness training
- NP_ Advanced safety training (cryogenics, risks, evac. procedure, BIW), + patrol training, Electrical safety awarness training + working at height + ...
Access via PPE (personnel Protection Entry access blocks): safety panel with access modes, radiation veto, keys box, key lock, card / dosimeter reader)
Trenches access doors are interlocked with beams.

24. Neutrinos VIP visits
A secured visitor path have been created in NP Hall.
We have created the following documentation and safety training:
Neutrinos VIP Visits Procedure – EDMS
Neutrinos guides training – EDMS
Neutrinos Guides List – EDMS
The NP visits path have been approved by HSE unit for the NP Hall
EDMS
All the visits are declared via IMPACT!

25. Conclusion:
The NP safety assessments, the implementation of safety system, procedures and measures are on going.
We are performing the risks assessments in collaboration with CERN safety unit.
The Neutrino Experiment safety strategy have been presented to the CERN Complex Safety Advisory Panel (CSAP).
We had a very positive feedback both on the organization, strategy and implementation.
The Neutrino safety files creation is on going (available for the French/ Swiss authority and also for Neutrino collaboration institutes, if required )