[Sneap] Information request concerning High pressure safety [SEC=UNCLASSIFIED]
GARTON, David
dbg at ansto.gov.au
Sun Mar 22 21:28:51 EDT 2009
SNEAPers,
I think someone else may have touched on this point but if blow off
plates are used for pressure relief then remember to put some type of
restraint on the plates. We have blow off plates both ends of our FN
with stainless steel cables attached between the plates and the beam
line stands. You could still get hit if you were standing nearby but at
least you have minimised the risk.
Regards,
David Garton
ANSTO
-----Original Message-----
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Sent: Friday, 20 March 2009 11:30 PM
To: sneap at tunl.duke.edu
Subject: Sneap Digest, Vol 54, Issue 6
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Today's Topics:
1. Re: Information request concerning High pressure safety
system in electrostatic accelerators (jonesn7 at comcast.net)
2. Re: Information request concerning High pressure safety
system in electrostatic accelerators (Gregory C. Harper)
3. Re: Information request concerning High pressure safety
system in electrostatic accelerators (Chris Westerfeldt)
4. Re: Information request concerning High pressure safety
system in electrostatic accelerators (Doug Will)
5. Re: Information request concerning High pressure safety
system in electrostatic accelerators (Krause, Bob)
6. Re: Information request concerning High pressure safety
system in electrostatic accelerators (Ian Vickridge)
----------------------------------------------------------------------
Message: 1
Date: Thu, 19 Mar 2009 16:07:21 +0000 (UTC)
From: jonesn7 at comcast.net
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Message-ID:
<591708689.7523751237478841327.JavaMail.root at sz0169a.emeryville.ca.mail.
comcast.net>
Content-Type: text/plain; charset="utf-8"
The ORNL EN tandem had an 8" Conflat flange sealed with a Viton ring
with only light spring pressure (and gravity) holding it together on the
High Energy end pumping tee. I had calculated that it would relieve at ~
1.5 psi internal pressure.
Love 'em all.... Let God sort 'em out!
Nathan Jones
jonesn7 at comcast.net
----- Original Message -----
From: "Augusto Lombardi" <augusto.lombardi at lnl.infn.it>
To: sneap at tunl.duke.edu
Sent: Wednesday, March 18, 2009 4:40:40 AM (GMT-0500) Auto-Detected
Subject: [Sneap] Information request concerning High pressure safety
system in electrostatic accelerators
Dear Sneapers,
I am Augusto Lombardi from Legnaro and some of you know me already.
I am now responsible for the operation of the two single stage machine
in Legnaro the AN 2000 and the CN 7 MeV.
The questions I have for the community is:
1. There are any risk analysis and/or records concerning the high
pressure hazard due to the column breakdown or any other accident that
put in comunication the high pressure vessel with the beam vacuum pipe?
(more than 10 bar vessels versus vacuum)
2. There are any safety systems for this kind of accident? (we do
have break disks and spring loaded valves but ....)
Thank you all for the help.
greetings
Augusto.
_______________________________________________ Sneap mailing list
Sneap at daytona.tunl.duke.edu
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Message: 2
Date: Thu, 19 Mar 2009 09:35:30 -0700 (PDT)
From: "Gregory C. Harper" <gharper at u.washington.edu>
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Message-ID:
<Pine.LNX.4.43.0903190935300.30442 at hymn34.u.washington.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
I have roughly the same scheme as Nathan but at both the high energy and
low energy ends of the machine. Each end has the top flange on a pumping
cross held on by gravity and 3 lightly spring loaded bolts. The top
flanges also house the Faraday cups.
Gregory C. Harper Phone:(206) 543-4084 (Office)
Research Engineer/Scientist IV (206) 543-4062 (Lab)
University of Washington FAX: (206) 685-4634
CENPA NPL Bldg.
Box 354290 email: gharper at u.washington.edu
Seattle, WA 98195-4290
On Thu, 19 Mar 2009 jonesn7 at comcast.net wrote:
>
>
>
>
------------------------------
Message: 3
Date: Thu, 19 Mar 2009 13:23:56 -0400
From: Chris Westerfeldt <cwest at tunl.duke.edu>
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: SNEAP <sneap at tunl.duke.edu>
Message-ID: <C5E7F7EC.7E026%cwest at tunl.duke.edu>
Content-Type: text/plain; charset="iso-8859-1"
Greetings Augusto,
We also built our own gravity/spring sealed ?blow off valves? and
installed them at the exit of our K-3000 and also both ends of our FN.
We feel that a catastrophic failure of accelerator tube is unlikely but
it is possible to develop a leak at a failing glue joint in a tube ? or
more likely at the rf ion source in a single-ended machine that would
trip the vacuum pump interlocks thereby causing the pump gate valve to
close. These valves would limit the fairly slow pressure build up in
the beamline to a couple of psi. We made the valve plates as large as
possible toward this end. Regards,
- Chris
--
Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department &
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC 27708-0308
Tel: (919) 660-2600
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu
From: Augusto Lombardi <augusto.lombardi at lnl.infn.it>
Reply-To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Date: Wed, 18 Mar 2009 09:40:40 +0100
To: <sneap at tunl.duke.edu>
Subject: [Sneap] Information request concerning High pressure safety
system in electrostatic accelerators
??? Dear Sneapers,
I am Augusto Lombardi from Legnaro and some of you know me already. I am
now responsible for the operation of the two single stage machine in
Legnaro the AN 2000 and the CN 7 MeV.
The questions I have for the community is:
1. ??? There are any risk analysis and/or records concerning the high
pressure hazard due to the column breakdown or any other accident that
put in comunication the high pressure vessel with the beam vacuum pipe?
(more than 10 bar vessels versus vacuum) 2.
3. ??? There are any safety systems for this kind of accident?? (we do
have break disks and spring loaded valves but ....)
??? Thank you all for the help.
??? greetings
??? Augusto.
_______________________________________________
Sneap mailing list
Sneap at daytona.tunl.duke.edu
http://daytona.tunl.duke.edu/mailman/listinfo/sneap
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Message: 4
Date: Thu, 19 Mar 2009 11:21:41 -0700
From: Doug Will <diwill at u.washington.edu>
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Message-ID: <49C28D35.6020906 at u.washington.edu>
Content-Type: text/plain; charset=windows-1252; format=flowed
Augusto,
I do not know of a risk analysis but have historical evidence that the
risk is real. The original Van de Graaff system at the Nuclear Physics
Lab of the Univ of Washington consisted of two FN Van de Graaffs in
series: an injector FN with a neutral "ion" source at its low energy
(LE) end and negative terminal (containing an alkali metal e- adder
canal); followed by a tandem FN with positive terminal (this latter,
still in use).
On Sept 20th, 1969, a Septier lens failed in the terminal of the
injector tandem. Large, low pressure relief flanges on both ends of the
injector FN opened and protected valuable ion sources situated at both
ends. This injector FN also had a pumping tube parallel to the "low
energy" neutral beam drift tube leading from the neutral "ion" source at
the LE end up to the terminal. This pumping tube was similar to a beam
tube but with larger openings in the metal electrodes. Outside the tank
at the low energy end was a large (2 meter tall) diffusion pump attached
by a ~30 cm diameter bellows to the pumping tube. There was NO PRESSURE
RELIEF FLANGE on this pumping station. When the Septier lens ruptured
inside the tank, the large bellows expanded to its limit (~1 meter) and
tore completely apart from one of its end flanges, toppling the
diffusion pump stand over on the floor. Most of the tank gas then
vented through this ruptured bellows end (with quite a roar).
The underlying cause was poor design. Careful analysis showed the glass
insulators of the Septier lens were under about 1000 pounds (4400
Newtons) of tension. The kovar seal at one end of the Septier lens
separated over most of its circumference from both its stainless steel
flange and from its glass insulator.
While I was not at the Nuclear Physics Lab in 1969, I have in my
possession our 1970 annual report containing a five page report (p.
14ff) of the incident written by several of my mentors, C.E.Linder,
F.H.Schmidt, and W.G.Weitkamp. If there is interest, I can scan that
report and attach it to a direct email reply. Interested parties should
send a request including your email address.
Doug Will
Research Engineer, U of Washington
Center for Experimental Nuclear Physics and Astrophysics
diwill at u.washington.edu
Chris Westerfeldt wrote:
>
>
>
> ----------------------------------------------------------------------
> --
>
> Greetings Augusto,
> We also built our own gravity/spring sealed ?blow off valves? and
> installed them at the exit of our
> K-3000 and also both ends of our FN. We feel that a catastrophic
> failure of accelerator tube is unlikely but
> it is possible to develop a leak at a failing glue joint in a tube ?
or
> more likely at the rf ion source in a single-ended machine
> that would trip the vacuum pump interlocks thereby causing the pump
gate
> valve to close. These valves would limit the fairly
> slow pressure build up in the beamline to a couple of psi. We made
the
> valve plates as large as possible toward this end.
> Regards,
> - Chris
> --
>
> Chris R. Westerfeldt
> Research Scientist / T.U.N.L. Radiation Safety Manager
> Duke University Physics Department &
> Triangle Universities Nuclear Laboratory
> Science Drive, Box 90308
> Durham, NC 27708-0308
> Tel: (919) 660-2600
> Fax: (919) 660-2634
> Email: Cwest at Tunl.Duke.Edu
>
>
> ----------------------------------------------------------------------
> --
> *From: *Augusto Lombardi <augusto.lombardi at lnl.infn.it>
> *Reply-To: *Symposium of Northeastern Accelerator Personnel
> <sneap at tunl.duke.edu>
> *Date: *Wed, 18 Mar 2009 09:40:40 +0100
> *To: *<sneap at tunl.duke.edu>
> *Subject: *[Sneap] Information request concerning High pressure safety
> system in electrostatic accelerators
>
>
>
>
>
------------------------------------------------------------------------
> Dear Sneapers,
>
> I am Augusto Lombardi from Legnaro and some of you know me already. I
> am now responsible for the operation of the two single stage machine
> in Legnaro the AN 2000 and the CN 7 MeV.
>
> The questions I have for the community is:
>
> 1. There are any risk analysis and/or records concerning the
high
> pressure hazard due to the column breakdown or any other
accident
> that put in comunication the high pressure vessel with the beam
> vacuum pipe? (more than 10 bar vessels versus vacuum)
> 2.
> 3. There are any safety systems for this kind of accident? (we
> do have break disks and spring loaded valves but ....)
>
>
> Thank you all for the help.
> greetings
> Augusto.
>
> ----------------------------------------------------------------------
> --
> _______________________________________________
> Sneap mailing list
> Sneap at daytona.tunl.duke.edu
> http://daytona.tunl.duke.edu/mailman/listinfo/sneap
>
>
> ----------------------------------------------------------------------
> --
>
> _______________________________________________
> Sneap mailing list
> Sneap at daytona.tunl.duke.edu
> http://daytona.tunl.duke.edu/mailman/listinfo/sneap
------------------------------
Message: 5
Date: Thu, 19 Mar 2009 13:52:15 -0500
From: "Krause, Bob" <krause at phys.ksu.edu>
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: "Symposium of Northeastern Accelerator Personnel"
<sneap at tunl.duke.edu>
Message-ID:
<F0712C28C5E30740A5F81252A97E6F3202B8801C at isis.phys.ksu.edu>
Content-Type: text/plain; charset="us-ascii"
We have roughly the same design as Gregory and Nathan has on our High
Energy end.
On the Low Energy end we have a two inch quartz on the top
of a tee with a "O" ring gravity seal.
Bob Krause
James R. Macdonald Lab.
Kansas State University
-----Original Message-----
From: sneap-bounces at tunl.duke.edu [mailto:sneap-bounces at tunl.duke.edu]
On Behalf Of Augusto Lombardi
Sent: Wednesday, March 18, 2009 3:41 AM
To: sneap at tunl.duke.edu
Subject: [Sneap] Information request concerning High pressure safety
system in electrostatic accelerators
------------------------------
Message: 6
Date: Thu, 19 Mar 2009 23:34:36 +0100
From: "Ian Vickridge" <ian.vickridge at free.fr>
Subject: Re: [Sneap] Information request concerning High pressure
safety system in electrostatic accelerators
To: "'Symposium of Northeastern Accelerator Personnel'"
<sneap at tunl.duke.edu>
Message-ID: <001f01c9a8e2$e223c4c0$a66b4e40$@vickridge at free.fr>
Content-Type: text/plain; charset="iso-8859-1"
I know of two incidents along these lines
1) An AN2000 or 2500 in France, I believe under 20 bar N2/CO2, had
a
catastrophic tube collapse. I didn?t see this so this is just
second-hand information. The shock wave down the open beamline shifted
the analyzing magnet and tore a turbo pump off the line. Apparently
no-one was around when this happened and there were no injuries.
2) A Van de Graaff in Algiers, in the 60s, was apparently filled
(either accidentally ? if that is possible ? or as the result of
terrorist
action) with pure oxygen. When they turned it on it went ?boom?. The
tank withstood the internal conflagration so the only damage was inside
the tank. This is second- or third-hand information which I have tried
to distort as little as possible.
The pressure tank people around us, have no idea at all about what might
be the dangers associated with a catastrophic tube failure under
operating pressure. I am not sure they want to know. All they want to do
is put a cap on the (empty) tank and fill it up with water to do the
pressure test. We don?t volunteer any information that is not asked for.
Ours is 20bar N2/CO2 mix.
However, on a T at the exit of the tube we have a gravity+1bar-held
8inch flange, with a restraining bracket to allow it to blow off without
being blasted into the ceiling or bouncing around the accelerator hall
at high speed in case of the tank emptying, for some reason or another,
through the tube. I hope it never gets tested !
Cheers
IV
De : sneap-bounces at tunl.duke.edu [mailto:sneap-bounces at tunl.duke.edu] De
la part de Augusto Lombardi Envoy? : mercredi 18 mars 2009 09:41 ? :
sneap at tunl.duke.edu Objet : [Sneap] Information request concerning High
pressure safety system in electrostatic accelerators
Dear Sneapers,
I am Augusto Lombardi from Legnaro and some of you know me already.
I am now responsible for the operation of the two single stage machine
in Legnaro the AN 2000 and the CN 7 MeV.
The questions I have for the community is:
1. There are any risk analysis and/or records concerning the
high
pressure hazard due to the column breakdown or any other accident that
put in comunication the high pressure vessel with the beam vacuum pipe?
(more than 10 bar vessels versus vacuum)
2. There are any safety systems for this kind of accident? (we
do
have break disks and spring loaded valves but ....)
Thank you all for the help.
greetings
Augusto.
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