[Hallb-engineering] Fwd: Clearance of Cold Cathode Gauges

Douglas Tilles tilles at jlab.org
Fri Feb 23 06:33:23 EST 2018


----- Forwarded Message -----
From: "Keith Welch" <welch at jlab.org>
To: "Anthony DiPette" <dipette at jlab.org>, "Jessie Butler" <jbutler at jlab.org>, "Tom Carstens" <carstens at jlab.org>, "Doug Tilles" <tilles at jlab.org>, "Walter Kellner" <kellner at jlab.org>, "Dave Meekins" <meekins at jlab.org>
Cc: "Adam Hartberger" <adamh at jlab.org>, "David Hamlette" <hamlette at jlab.org>, kennell at jlab.org
Sent: Thursday, February 22, 2018 5:02:32 PM
Subject: Clearance of Cold Cathode Gauges


As some of you know from recent discussions with our team, we are 
currently investigating an issue with our ability to detect activation 
in cold cathode vacuum sensors.  The powerful permanent magnets in these 
devices produce a field that interferes with detection in the meters we 
use for our approved protocols for clearance of materials.  We can 
achieve good detection with other instruments, but those meters are not 
currently approved for the release of materials.

We are currently working with your groups to spot check and screen 
sensors that are in storage to verify they are not activated.  But since 
we technically do not have an approved process for unrestricted release 
for the magnets, these devices /*must not be shipped offsite or disposed 
of as waste or scrap*/, even if they've been surveyed.

If the gauges are disassembled, we can release the non-magnetic 
components.  But any fully assembled gauge, or the separated magnets are 
to be considered "conditionally released" and must remain onsite.  As we 
spot check these devices, we will label them to remind the users of 
their conditional release status.

If you wish to dispose of any gauges, please notify us and we will 
arrange to have them disposed as radioactive waste.

This is a precautionary measure, as our investigation has indicated that 
it is unlikely for any significant activation levels to have evaded us.  
Because of the number of these gauges that are in use or storage around 
the site, we're asking for your assistance in ensuring that they are 
controlled as described above.  Please help us communicate this 
information to all your staff that may work with these devices.

If you have any questions about this, please don't hesitate to contact 
me or David Hamlette.
Thank you,


Keith Welch
RadCon Manager
Jefferson Lab
12,000 Jefferson Ave.
Newport News, VA 23606
(757) 269-7212

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