Transcript H2 Safety Review - response paul drumm MICE VC, March 29th,2006 Osaka CM • Point by point answers were shown by Yury in Osaka •

H2 Safety Review - response
paul drumm
MICE VC, March 29th,2006
Osaka CM
• Point by point answers were shown by
Yury in Osaka
• Mostly in agreement with review
• One or two places where robust
(analytical) answers are needed.
• My thoughts and suggestions…in red
Review Item
Response
1
The use of the bolted connections for the
absorber module windows, with pressure
monitoring between the two indium seals
was considered to be an appropriate choice
given the practical experience of this type of
seal within a vacuum environment.
An issue for the absorber
group – and we
should reflect an
answer from them?
2
The use of a non-flammable super insulation
material within the hydrogen system should
be investigated.
This will be done – we will
use polyimide material.
Is there any impact?
3
The effect of helium on the performance of the
hydride bed should be investigated as a
matter of urgency as this may impact the
design. However, the need to maintain a
positive pressure in the system, to avoid
oxygen ingress, was agreed.
This has been investigated
with the manufacturer
and there is no effect.
Document?
4
Quality control, configuration management and
security of the hydrogen system software
need to be assured.
Agreed – but what is the
proposal?
5
Positive independent feedback of valve positions
etc. should be implemented in the control
system.
Agreed
6
It is recommended that the build up of explosive
atmospheres within the Hall as well as within the
test rig be fully considered and that compliance
with The Dangerous Substances and Explosive
Atmospheres Regulations 2002 and the
European Directives ATEX 137 (procedures) and
ATEX 95 (equipment) is addressed.
We will implement external
hydrogen sensors. We have
considered the release of
hydrogen into the hall and
incorporated fans and vents
in the roof space. Is this a
sufficient answer? Are
there places where H gas
can accumulate despite
the fans/vents?
7
Although the estimated volume of gaseous
hydrogen in the cryogenic system is less than 2%
of the total volume of the Hall, there can be local
concentrations that exceed this particularly at the
ceiling level due to the fact that the hydrogen will
rise. Suitable venting should be provided.
This has already been
considered and fans and
vents are being installed in
the roof space. As above
8
Hydrogen detectors and oxygen depletion
sensors should be installed in the Hall, with
associated evacuation alarms. Upon detection of
hydrogen within the Hall, all non-compliant
electrical systems should be automatically shut
down. Certain sub-systems such as evacuation
lighting, ventilation and safety systems should be
made compliant and remain operational.
Agreed. What is the
implication? Does this
mean all systems in the
hall are to be shutdown?
And does this affect ISIS?
Are there safety systems
that should not be
shutdown? This needs to
be reviewed.
9
The reliable performance of the hydrogen
detectors and oxygen depletion detectors, within
the atmosphere in which they will be required to
work, must be assured (type of sensor, location,
maintenance, etc.).
This was an issue as we
planned to have hydrogen
sensors in the exhaust line
of the exhaust pumps where
they could suffer from
contamination. The sensors
will be subject to a
maintenance schedule.
What is the life cycle of a
sensor? I don’t know how
to assess this.
*
The original
assesment
was that the
hydrogen
zone did not
extend out of
the absorber
vessel/pipe
work. Is this
changed or
can the
original view
be
defended?
10
Suitable Uninterruptible Power Supplies (UPS)
should be provided for the control and safety
systems.
Agreed.
11
The location of vent pipe outlets, particularly their
height above the roof, should be designed to
prevent fire hazards (the industry standard is
3m).
Implemented.
12
Suitable fire detection and extinguishing
equipment should be provided in the Hall.
There is lab policy on this
which will be followed.
13
It is recommended that the procedures for access
to the Hall should be reviewed.
Agreed
14
A permit to work system should be adopted for
people who need to work in the MICE Hall.
Agreed
15
Suitable personal protective equipment (fire
retardant / anti-static clothing and footwear)
should be worn in the Hall when hydrogen is
present in the system.
Agreed – a policy will be
developed as part of the
overall risk assessment.
16
Activities permitted to be carried out in the Hall
whilst liquid hydrogen is present should be
carefully considered (for example, hoisting and
rigging activities should be prevented).
Agreed
17
Clearly defined operating procedures which
include responses to abnormal conditions should
be developed and presented at the operations
review.
Agreed
18
All persons involved with operating the hydrogen
system must be trained in both safety aspects
and operating procedures.
Agreed. What are the
terms of the proposed
training?
19
Consideration should be given to procedures to
be adopted in worst case scenarios such as
crane accidents, aeroplane crash etc.
Agreed. What are the
chosen worst case
scenarios to be
investigated?
20
The CERN safety system (DSS) for LHC
experiments could be studied as a possible basis
for the MICE safety system.
This will be investigated.
This needs a mechanism
for discussion? D&S?
Finally
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Additional items in report not covered in above list:
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The Panel concluded that the HAZOP study as presented is incomplete. A full HAZOP study,
and a failure modes effects analysis (FMEA) carried out with the aid of an external
specialist, should be completed as a priority. 
What are the terms of the request to AP on the HAZOP? 
The findings of these studies and the response of the MICE team should be independently
examined before the designs finalised and accepted.
Keep this in mind! We may have an idea of this, but how is this to be done?
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We wish to stress that the above remarks are restricted to the safety issues associated
with the handling of liquid hydrogen. We have not considered the wider risks that may be
encountered in carrying out the R&D activity. We suggest that a full qualitative risk
assessment is undertaken by the MICE team to ensure that all hazards have been identified.
Presumably this should also have explicit agreement?
Finally, the Panel is of the opinion that no further external safety review of the Hydrogen
Delivery System, R&D stage, is required before the proposed operations review, provided
that the HAZOP study and FMEA are satisfactorily completed.
We agree with the MICE team that a review of how the Hydrogen Delivery System interacts
with an absorber focus coil module as well as with the full control and interlock system of
the MICE experiment will be needed before the implementation of the next stage.
Operating procedures, systems of work
RISK Assessment
FMEA
HAZOP
Timetable
• Review response at D&S
– meeting being arranged ~soon!
• Finalise Response ~mid April
• Response sent to TB  EB  RAL
Management ~ end April
• Timely discussions in D&S group