[ RadSafe ] Fwd: Incidental Radiation Generating Device Leakage
achris1999 at gmail.com
Wed Sep 5 18:08:41 CDT 2012
Is it just me, or is there something quite strange about the Tennessee
definition of "accelerator":
“Accelerator” means any device used to impart kinetic energy to
electrically charged particles
including but not limited to electrons, protons, deuterons, and helium
ions. For the purpose
of this chapter “accelerator” includes equipment designed for and used
only for the
production of x-rays of 0.9 MeV or greater and equipment capable of
particles into a medium external to the accelerating device. ?
So, they use 0.9 MeV as a threshold, where the regs I remember use
1.0, but that is not a big deal. The second phrase though, refers
only to nuclear particles. Do they intend to exclude electrons from
that secondary definition, and why, pray tell?
---------- Forwarded message ----------
From: <roseb at gdls.com>
Date: Wed, Sep 5, 2012 at 5:33 PM
Subject: Re: [ RadSafe ] Incidental Radiation Generating
Device Leakage Radiation Limits
To: "The International Radiation Protection (Health Physics) Mailing
List" <radsafe at agni.phys.iit.edu>
I am pleased to have wowed you!
I referenced the OLD DOE manual because I was not able to readily find the
most recent manual online yesterday. After a bit more digging, I was able
to locate the following:
DOE STANDARD: RADIOLOGICAL CONTROL (DOE-STD-1098-99), July 1999
DOE O 420.2C, Safety of Accelerator Facilities (2011)
Article 365.3 in the 1999 DOE Radcon manual is the same as in the 1994 DOE
Radcon manual, that article leaves the establishment of radiological
controls for such devices to line management AND the Radiological Controls
Organization (RCO) (DOE, p. 3-24, pdf p. 75/189). The policy also remains
substantially the same.
The DOE order O 420.2C (2011) defines what constitutes and accelerator. An
electron beam welder would fall under the definition of an accelerator.
This order appears to still leave determination of the device exposure
limits to management and the RCO.
Compliance Guide for Cabinet X-Ray Systems
The FDA does not appear in the above guide or 21CFR Subcahapter J to
provide any specific or general guidance regarding leakage radiation
limits for devices such as electron microscopes or electron beam welders.
Applicability of State regulations to the B&W Y-12 or other DOE site -
State radiological health regulations, though possibly useful as a guide,
might not be applicable at DOE sites or operations. Such sites are often
considered federal enclaves or exclusive federal jurisdictions. Assuming
the device is actually located in Tennessee at a DOE site or operation,
and that the device is an electron beam welder, the following Tennessee
rule could be applicable or used as guidance, since an electron beam
welder appears to meet the definition of an accelerator in the rule
CHAPTER 0400-20-09, REQUIREMENTS FOR ACCELERATORS
The above rule does not provide any specific or general guidance regarding
leakage radiation limits for an accelerator device. The guidance or
requirements provided as to permissible radiation levels in the
accelerator facility appear to be less stringent (2 mrem or 10 mrem, 0.02
mSv or 0.10 mSv) in any one hour) than those in ANSI N43.3 for an Exempt
Shielded Installation (0.5 mrem or 0.005 mSv in any one hour). The ANSI
N43.3 radiation level criteria for an Exempt Shielded Installation appears
to be a reasonable and feasible leakage radiation control limit for
devices such as electron microscopes and electron beam welders, especially
if the available data for these devices (i.e. manufacturer's data, site
survey data, etc.) indicate reasonable entitlement for this control limit.
Boyd H. Rose, CM, CIH, CHMM, EI
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