Overview of the HVAC system of the Accelerator tunnel

Duy Phan Accelerator Safety Engineer

Reviewed by Mikael Kelfve (CF)

www.europeanspallationsource.se2nd July 2015

Agenda

Main topics addressed

Current design of the Accelerator HVAC system…

Proposed upgrade of the design with respect to safety considerations…

On-going and foreseen safety studies…

Planning for the Accelerator HVAC system…

Accelerator HVAC systemIntroduction

European Spallation Source

(ESS)

Operations, ES&H and QA

ES&H Division QA Division

Project support & Administration

Directorate

Machine Directorate

Accelerator Division Target Division

Integrated Control System

Division

Science Directorate

Conventional Facilities Division

Design Group Construction Group Energy Group

ESS Organization chart (simplified)

① ②

① Specifies the Safety requirements for the design of the HVAC system (e.g. fire control philosophy, minimum air renewal for workers, minimum air flush before access, etc.)

② Specifies the performance requirements for the design of the HVAC system (e.g. temperature and humidity control) and provides support for the mitigation of the safety issues (e.g. CFD simulations, hazard analysis, etc.)③ Designs the HVAC system according to the requirements provided by the Accelerator and ES&H Divisions

Main stakeholders in the design of the Accelerator HVAC system

③*

Accelerator HVAC systemIntroduction

Overview of the Accelerator areas

Main requirements Dissipate heat loads from the

LINAC Maintain a negative pressure

with respect to the outdoors and the klystron gallery

Provide necessary fresh air for occupants during maintenance

Control the smokes in case of a fire

G02: Klystron gallery

G01

FEB: Front-End BuildingAT: Accelerator TunnelHLB: HEBT Loading BayA2T: Accelerator to TargetBD: Beam Dump

G01

HLB

BDA2T

AT

FEBACKNOWLEDGEMENT : N.GAZIS

Accelerator HVAC systemCurrent Design

Air supply system

Climate control system

Air exhaust system Smoke extraction system

T° LINAC tunnel22,5°C ± 2,5°C

4 Ventilation modes① « Beam mode »

② « Flush mode »

③ « Access mode »

④ « Fire mode »

ACKNOWLEDGEMENT : M.KELFVE

Accelerator HVAC systemCurrent Design

① BEAM MODE

Proton beam

Air inlet: 4320 m3/hAir outlet: 7200 m3/hRecirculating air (4 units): 18 000 m3/h

ΔP = -10 Pa with respect to the Klystron gallery

ACKNOWLEDGEMENT : M.KELFVE, E.VAENA, U.ANDERSSON, B.YNDERMARK

Accelerator HVAC systemCurrent Design

② FLUSH MODE

Air inlet: 57 600 m3/h

Air outlet: 60 480 m3/h

ACKNOWLEDGEMENT : M.KELFVE, E.VAENA, U.ANDERSSON, B.YNDERMARK

Accelerator HVAC systemCurrent Design

③ ACCESS MODE

Air inlet: 22 320 m3/hAir outlet: 22 320 m3/h

ACKNOWLEDGEMENT : M.KELFVE, E.VAENA, U.ANDERSSON, B.YNDERMARK

Accelerator HVAC systemCurrent Design

④ FIRE MODE

Max air inlet: 90 000 m3/hSmoke extraction: 5 X 18 000 m3/h

ACKNOWLEDGEMENT : M.KELFVE, E.VAENA, U.ANDERSSON, B.YNDERMARK

≈ 135 m between 2 emergency exits

Closing of the sealed damper

Accelerator HVAC systemProposed upgrade of the Design

Air supply system

Air exhaust system

Main motivations for removing the climate control system Reduce exposure to contamination

coming from ventilation filters and condensate

No elevated ground water activation level

Main motivations for removing the smoke extraction system (currently under consideration) No systematic intervention of the Fire Brigade in

case of a fire No monitoring and filtering of the emissions from

the LINAC tunnel

+ Fire suppression system?2 Ventilation modes① « Beam mode »

② « Access mode »

(③ « Flush mode »)

(④ « Fire mode »)

Accelerator HVAC systemOn-going Safety studies

ODH preliminary assessment

Simple analytical model (CERN & FERMILAB)

Homogenous mixture of helium with atmosphere in case of a cryogenic discharge

Assessment of the O2 concentration with respect to “normal ventilation system” and smoke extraction

Objective: Provide help to Conventional Facilities (CF) in the design of the HVAC systemResponsibility: Accelerator Division

Accelerator HVAC systemOn-going Safety studies

Calculation of the Derived Air Concentration (DAC)*

Use of the ISO 17873 standard – not strictly required but implemented to harmonise the approach regarding HVAC systems at ESS in contaminated atmosphere

Objective: Definition of the architecture of the ventilation system and the necessary under-pressureResponsibility: ES&H Division

Assessment of the radiological impact of air releases from the Accelerator tunnel during normal and off-normal operations

* It is the amount of contamination in air, which, if breathed for 2 000 h, would result in the Annual Limit of Intake (ALI). The ALI has to be calculated using reference conversion factors given by IRCP for each radionuclide. ACKNOWLEDGEMENT : D.ENE

C2 between -80 Pa and -100 Pa

Accelerator HVAC systemNext Safety studies

Studies to come

Hazard analysis of the design of the ventilation system identification of the safety functions

Computational Fluid Dynamics (CFD) of a helium discharge in the tunnel

ACKNOWLEDGEMENT : A.NORDT, M.PUCILOWSKI

Objective: Provide help to Conventional Facilities (CF) in the design of the HVAC systemResponsibility: CF & Accelerator Division

Accelerator HVAC systemNext steps

HVAC timeline

1 Update of the design regarding climate controlJuly 2015

2 Fire strategy regarding the tunnelJuly 2015

Final drawing of the detailed design of the HVAC systemDec. 2015

7

6 Procurement phaseJan. 2016

Installation phaseFeb.-May 2016

8Commissioning phaseAug. 2016

5

Risk analysisNov. 2015

3 Outline design reviewSept. 2015

4

Any Questions…?

Discussion

Back-up slides