Neutrino Platform Overall Protodune Risk Mitigation Plan O Neutrino Platform Overall Protodune Risk Mitigation Plan O. Beltramello, 07.12.2016

NP02 and NP04 – Neutrino Hall configuration

Safety Organization The safety organization is defined in EDMS 1716049 “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

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..

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

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

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

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 (13.000 m3/h) in the trenches

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

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

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

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 1718784

Evacuation plan – Vertical (Jura side) EDMS 1718784

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

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.

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 1531442- EHN1- NP02/NP04 cryostats warm structure summary structural analysis EDMS 1724219 - Safety Validation Form - WA105 Warm structure at Building 887 EDMS 1709071 - Seismic analysis procedure for rectangular tanks filled with liquid. EDMS 1724223 - "Safety Validation Form - Seismic assessment of prototype cryostats"

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 ..

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.

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

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 (2017-2018), the other main risks : Cryogenics, Radiation Protection

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

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…)

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.

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 1722535 Neutrinos guides training – EDMS 1722536 Neutrinos Guides List – EDMS 1725576 The NP visits path have been approved by HSE unit for the NP Hall EDMS 1728543 All the visits are declared via IMPACT!

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 )