pc43_ivaniouchenkov_hazop

Preliminary HAZOP Analysis of the MICE Hydrogen System

Node 5

Node 3

Node2

Node 1 Chiller/ heater

unit

Vent outside flame arrester Ventilation

system

H2 Detector

Hydrogen module enclosure

VP

X 2 X 2

VP

P

VP

Evacuated vent buffer tank

Node 4

P P

P

P

H2 Detector

H2 Detector

2.1 bar

1.7 bar

Vent valve

Vent valveVent outside flame arrester

Non-return valve

He / N2 Purge system

Vent outside flame arrester

Metal hydride hydrogen storage unit

(20 m3 capacity)

Fill valve P P

H2 Gas bottle

70 K Safety window

Internal Window

Hydrogen flow and safety system (option with a metal hydride storage unit)

LHe Heat exchanger

Vacuum vessel

Vacuum

LH2 Absorber

Liquid level gauge

14 K He from Cold box

18 K He to Compressor via Radiation

Pressuregauge

Pressureregulator

ValvePressure relief valve Bursting disk Vacuum VPP P

Version: 06/08/2003

Node 5

Node 3

Node 2

Vent outside flame arrester Ventilation

system

H2 Detector

Hydrogen module enclosure

VP

X 2 X 2

VP

P

VP

Evacuated vent buffer tank

Node 4

P P

P

P

H2 Detector

H2 Detector

2.1 bar

1.7 bar

Vent valve

Vent valveVent outside flame arrester

Non-return valve

He / N2 Purge system

Vent outside flame arrester Hydrogen tank

Volume: about 30 m3

1.6 bar abs > Pressure > 1.1 bar abs

Node 1

Fill valve PP

H2 Gas bottle

70 K Safety window

Internal Window

Hydrogen flow and safety system(option with a hydrogen tank)

LHe Heat exchanger

Vacuum vessel

Vacuum

LH2 Absorber

Liquid level gauge

14 K He from Cold box

18 K He to Compressor via Radiation shield

Pressuregauge

Pressureregulator

ValvePressure relief valve Bursting disk Vacuum VPP P

Version: 09/06/2003

Node 1: Option: Hydrogen storage unit.

Intent: To keep hydrogen gas in the storage unit-absorber vessel closed system.

Working conditions: P = … bar abs , T = 300 K, V = … m3 .

No Parameter Guide word Cause Consequence Safeguards Recommendations

1 Pressure Lower 1. Storage unit is leaking.

2. Pipe is leaking.

3. Absorber vessel is leaking.

1-2. Hydrogen is leaking out in the experimental hall.

3. Hydrogen is leaking into vacuum jacket.

Pressure gauge to trigger an alarm.

Hydrogen ventilation system collects and vents hydrogen out.

Hydrogen detector to trigger an alarm.

Implement an active pressure gauge.

Implement ventilation system.

Implement an active hydrogen detector.

2 Pressure Higher 1. Fill valve is accidentally open

2. Storage unit is overheated

3. Venting path is blocked ?

1-3. Absorber windows can break.

Pressure relief valve to vent outside.

Implement a pressure relief valve.

Node 1: Option: Hydrogen tank

Intent: To keep hydrogen gas in the tank - absorber vessel closed system.

Working conditions: P = … bar abs , T = 300 K, V = … m3 .


1 Pressure Lower 1. Tank is leaking.

2. Pipe is leaking.

3. Absorber vessel is leaking.

1. Air can leak in the tank and in the hydrogen vessel and an explosive mixture can be formed.

1-2. Hydrogen is leaking out in the experimental hall.

3. Hydrogen is leaking into vacuum jacket.





Implement ventilation system.


2 Pressure Higher 1. Fill valve is accidentally open.

2. Tank is overheated.

3. Venting path is blocked ?

1-2. Absorber windows can brake

Pressure relief valve to vent outside.

Implement a pressure relief valve.

Node 2: Hydrogen absorber internal vessel with hydrogen windows.

Intent: To keep hydrogen liquid inside hydrogen absorber module.

Working conditions: P = … bar abs, T = 19 – 300 K, V = 25 l.


1 Temperature Lower Too much cooling power from the He cooling system.

1. Pressure in the hydrogen system drops.

2. LH2 level in hydrogen vessel rises.


Liquid hydrogen level meter to trigger an alarm.


Implement an active liquid level meter.

2 Temperature Higher 1. Not enough cooling power from the He cooling system.

2. Power cut.

1-2. Liquid hydrogen evaporates and LH2 level goes down.

1-2. Hydrogen pressure rises.

Liquid hydrogen level meter to trigger an alarm.


Implement an active liquid level meter.


3 Pressure Lower 1. Window is leaking or broken.

2. Pipe is leaking.

3. Hydrogen tanks is leaking.

4. Absorber is over

1. Hydrogen leaks into vacuum vessel.

2-3. Hydrogen is leaking out.

4. Pressure in the system drops and air can leak in the system in case if the



Absorber temperature control system


Implement absorber temperature control

cooled. system seal is broken. maintains temperature. system.

4 Pressure Higher Temperature isincreased.

Windows can break. Pressure relief valve to dump hydrogen into a buffer tank

Implement a pressure relief valve and a buffer tank.

Node 3: Hydrogen absorber vacuum jacket with safety windows.

Intent: - To insulate thermally the internal hydrogen vessel .

- To provide additional barrier for air .

Working conditions: P = … bar abs, T = 19-300 K, V = ? l.


1 Pressure Higher 1. Hydrogen window broken

2. Vacuum pump failure

Hydrogen bursts into vacuum jacket

Vacuum drops.

Pressure relief valve to dump hydrogen into a buffer tank and then to vent it outside.

Implement a buffer tank.

2 Hydrogenconcentration

Higher Hydrogen leaks due to window is broken .

An explosive mixture can be formed if there is an air leak in as well.

Active hydrogen sensor detects hydrogen and trigger s an alarm.

Implement an active hydrogen sensor.

Node 4: Buffer tank.

Intent: - To quickly relief pressure in the absorber module in case of window burst .

Working conditions: P = … bar abs, T= 300 K, V = … l.


1 Pressure Higher 1. Venting path is blocked.

2. Vacuum pump failure

1. Absorber vacuum jacket windows can break.

2. Buffer tank can’t be used for dumping hydrogen in case of accident with absorber.

1-2. Active pressure gauge triggers an alarm.


Keep a spare pump.

Node 5: Hydrogen module enclosure.

Intent: - To localize and vent hydrogen in case of hydrogen leak .

Working conditions: P = … bar abs, T= 300 K, V = … l.


1 Hydrogenconcentration

Higher 1. Hydrogen leaks out absorber module

2. Hydrogen leaks out hydrogen pipes

3. Hydrogen leaks out storage unit.

1-3. Explosive oxygen-hydrogen mixture can be formed

Ventilation system to quickly vent hydrogen out.

Hydrogen detector to trigger an alarm and to start a high rate mode for the ventilation system.

Implement ventilation system equipped with hydrogen detector.

pc43_ivaniouchenkov_hazop

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