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Re: Area Postings for Beta
The NRC Questions and Answers provides the "answer" to your question ....
available on the NRC internet site.
The most applicable questions and answers are:
Question 221: Since the posting requirements are all in
terms of deep dose equivalent, what requirements should be
followed when posting for low energy beta radiation?
Answer: Unless the beta particle can deliver a dose at a
issue depth of 1 cm, the area does not require posting as
a radiation area (20.1902 (a)), high radiation area
(20.1902 (b)), or very high radiation area (20.1902 (c));
however, posting for airborne radioactivity area (20.1901
(d)) and for areas or rooms in which licensed material is
used or stored (20.1901 (e)) needs to be considered for
beta emitters. See Questions and Answers 57, 74, and 85
for more information. (Reference: 10 CFR 20.1902, 10 CFR
20.1901)
Question 74: Dose rates are used to establish posting
requirements for radiation areas, high radiation areas, and
very high radiation areas. 10 CFR 20.1601 (a) (1),
"Control of Access to High Radiation Areas," refers to a
"deep-dose equivalent" in describing when a control device
should be provided to reduce radiation doses below 0.1 rem
in one hour, thus implying that the "dose equivalent" in
the definition of a "high radiation area" is the "deep dose
equivalent" [at a tissue depth of 1 cm (1000 mg/square
cm)]. Are the "dose equivalent" in the definitions of
"radiation area" and "high radiation area" and the "dose"
in the definition of "very high radiation area" all
considered to be at a tissue depth of 1 cm (1000 mg/square
cm)?
Answer: Yes. In addition see Question 57. (References:
10 CFR 20.1003, 10 CFR 20.1601)
"x" <netngatr@magnolia.net> on 09/10/99 12:51:30 AM
Please respond to radsafe@romulus.ehs.uiuc.edu
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
cc: (bcc: Brent Robinson/Psl/Nuclear/FplNuc)
Subject: Area Postings for Beta
This is a multi-part message in MIME format.
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charset="iso-8859-1"
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Fellow RADSAFERS,
=20
I've searched the RADSAFE archives and can't find exactly what I'm =
looking for. I know someone out there has the solution, I haven't seen =
a question yet go unanswered.
I would appreciate any opinions, practices, and references you may have =
dealing with the posting of areas due to beta radiation where DDE from =
beta is not a concern.
Assume the only source of radiation is power plant components with mixed =
fission/corrosion products and no significant gamma contribution to dose =
rates. The beta energies are low enough that DDE from beta is not =
significant, documented in past studies.
1. Do you post 'Radiation Area' signs for those areas that exceed 5 =
mrem/hr beta @30 cm from the source, or HRA signs for 100 mrem/hr beta =
@30cm? Since the 10CFR20.1003 definition of RA and dose equivalent do =
not differentiate between DDE and SDE, it seems clear to me that posting =
is required.
2. Assume these high levels of contamination are now wrapped with =
plastic to preclude requiring protective clothing for handling the item, =
but >100 mrem/hr beta @30 cm penetrates the plastic. Does anyone use a =
"Beta High Radiation Area" posting or similar to ensure SDE or extremity =
monitoring when handling such wrapped items?
3. Do all of the normal requirements for a HRA entry apply? (Tech Specs =
similar to RegGuide 8.38)
Thanks for your help,
Richard Sumrall
HP Instructor
Grand Gulf Nuclear Station
rsumral@entergy.com
My personal questions and musings only, not reviewed or endorsed by my =
employer.
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charset="iso-8859-1"
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type><!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 =
HTML//EN">
<META content=3D'"MSHTML 4.72.3616.1301"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Fellow RADSAFERS,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>I've searched the RADSAFE archives and can't find =
exactly what=20
I'm looking for. I know someone out there has the solution, =
I=20
haven't seen a question yet go unanswered.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>I would appreciate any opinions, practices, and =
references you=20
may have dealing with the posting of areas due to beta radiation where =
DDE from=20
beta is not a concern.</FONT></DIV>
<DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV></DIV>
<DIV><FONT color=3D#000000 size=3D2>
<DIV><FONT color=3D#000000 size=3D2>Assume the only source of radiation =
is power=20
plant components with mixed fission/corrosion products and no =
significant gamma=20
contribution to dose rates. The beta energies are low enough that =
DDE from=20
beta is not significant, documented in past studies.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>1. Do you post 'Radiation =
Area' signs for=20
those areas that exceed 5 mrem/hr beta @30 cm from the source, or HRA =
signs for=20
100 mrem/hr beta @30cm? Since the 10CFR20.1003 definition of RA =
and dose=20
equivalent do not differentiate between DDE and SDE, it</FONT><FONT=20
color=3D#000000 size=3D2> seems clear to me that posting is =
required.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV>2. Assume these high levels of contamination are now wrapped =
with=20
plastic to preclude requiring protective clothing for handling the item, =
but=20
>100 mrem/hr beta @30 cm penetrates the plastic. Does anyone =
use a=20
"Beta High Radiation Area" posting or similar to ensure SDE or =
extremity monitoring when handling such wrapped items?</DIV>
<DIV></FONT> </DIV>
<DIV><FONT size=3D2>3. Do all of the normal requirements for a HRA entry =
apply?=20
(Tech Specs similar to RegGuide 8.38)</FONT></DIV></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks for your help,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Richard Sumrall</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>HP Instructor</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Grand Gulf Nuclear =
Station</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2><A=20
href=3D"mailto:rsumral@entergy.com";>rsumral@entergy.com</A></FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>My personal questions and musings only, not reviewed =
or=20
endorsed by my employer.</FONT></DIV></BODY></HTML>
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