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Re: MDA vs. Critical level for DOE Free Release surveys
1. NRC licensees, especially power reactor licensees are not allowed to free
release any licensed material. See HPPOS 72 - I pasted in a copy, below. TN is
known for its easygoing free release standards. It's no coincidence that so
many radwaste, "green is clean" processors are located, there.
2. When you refer to, "The MDA value is what the instrument will detect with XX
% confidence (most people use 95%)..." keep in mind that it is necessary to
specify confidence levels, separately, for Type 1 (false positive) and Type 2
(false negative) errors. You seem to imply that the 95% level applies to both.
Often, the levels are the same, but this is not necessarily true, especially
under MARSSIM.
The opinions expressed are strictly mine.
It's not about dose, it's about trust.
Curies forever.
Bill Lipton
liptonw@dteenergy.com
Guide on "How Hard You Have to Look" as Part of Radioactive
Contamination C ontrol Program
HPPOS-072 PDR-9111210170
Title: Guide on "How Hard You Have to Look" as Part of
Radioactive Contamination Control Program
See the letter from R. C. DeYoung to E. D. Swartz
(Commonwealth Edison Company) dated May 18, 1982. The
intent of IE Circular No. 81-07 (IEC-81-07) was to give
guidance on "how hard you have to look" for radioactivity
when the use of portable survey equipment is necessary as
part of a radioactive materials control program. The
detection limits in IE Circular No. 81-07 (IEC-81-07) are
not release limits. The health physics position was
written in the context of 10 CFR 20.201, 20.301, and
20.302, but it also applies to the "new" 10 CFR Part 20,
Sections 20.1501, 20.2001, and 20.2002. HPPOS-071 and
HPPOS-73 contain related topics.
The intent of IEC-81-07 (see HPPOS-071) was to provide
guidance on acceptable limits of detection of portable
survey equipment; thus, defining "how hard you have to
look" for radioactivity when the use of portable survey
equipment is necessitated as part of a radioactive
materials control program. Low background, fixed
laboratory counting equipment can readily detect levels of
radioactivity several orders of magnitude less than the
detection levels discussed in the circular. However, the
use of laboratory counting equipment is not always
practical for all situations and portable survey equipment
may need to be employed.
The circular did not establish criteria for releasing
radioactivity contaminated materials from restricted areas
for unrestricted use. The regulations applicable to
nuclear power reactor licensees do not provide for release
of materials for unrestricted use that are known to be
radioactively contaminated at any level. Authorization for
disposal of specific radioactively contaminated materials
may be requested as specified in 10 CFR 20.302 [or 10 CFR
20.2002]. The Commission recognizes the need for "de
minimis" classification of wastes and has initiated work to
define "de minimis" levels on a specific waste basis. This
work is continuing. [Note: The statement concerning "de
minimis" classification of wastes is related to the below
regulatory concern (BRC) policy, which has now been
withdrawn.]
With regards to your request for concurrence with release
criteria in your "Radiation Protection Standards," we
cannot concur since the regulations do not contain release
criteria provisions as described above. The method
available to you for obtaining authorized release limits is
to submit to the Office of Nuclear Reactor Regulation (NRR)
a request for license amendment that addresses specific
release limits. Although we have sent a copy of your
letter to NRR for information, the excerpt you provided
from your "Radiation Protection Standards" lacks specifics
which would support a request for specific release limits
for radioactively contaminated materials.
If you desire a specific authorization for disposal or a
license amendment for specific release limits, please
direct your request to the Office of Nuclear Reactor
Regulation.
Regulatory references: 10 CFR 20.201, 10 CFR 20.301, 10
CFR 20.302, 10 CFR 20.1501, 10 CFR 20.2001, 10 CFR 20.2002
Subject codes: 7.6, 9.7
Applicability: Reactors
"Redmond, Randy (RXQ)" wrote:
> Tom,
>
> I refer to statistics as "sadistics" and I'm certainly not an expert at any
> this. I'll tell you what we do (DOE facility, NRC agreement state).
>
> 1. We use the DOE 5400.5 surface contamination values (uranium 5000 dpm/100
> cm2 total and 1000 dpm/100 cm2 removable); at times we also use the 15000
> dpm/100 cm2 maximum depending on the value of the object. Items are subject
> to at least one decon to get the levels down - the ALARA statement in
> 5400.5. The state accepts these values for free release. Of course if its
> metal, then we have to abide by the Richardson memo - no metal released if
> its been in a contaminated area. The 5400.5 values are consistent with Reg
> Guide 1.86 values (even though some folks claim the 1.86 values are not for
> free release).
>
> 2. I'm not familiar with any reference or regulatory standard on whether to
> use MDA or Lc; however, the EM-30 Performance Objective issued by DOE in the
> early 90's basically said to pick one and justify it (for volumetric
> release). In my opinion (sadistically speaking) Lc is the correct value if
> your objective is not to release any radioactive material (at whatever
> confidence you choose). Using Lc is impossible in the field due to varying
> backgrounds, each instrument has a different efficiency, each tech uses a
> different distance to the surface .. . .).
>
> 3. See number 2. The MDA value is what the instrument will detect with XX
> % confidence (most people use 95%). If you have an MDA of 100 dpm and a
> sample is 100 dpm, then you'll have a distribution around your MDA - count
> the sample with exactly 100 dpm in it twenty times and statistically 50% of
> the time the value will be less than 100 dpm and 50% of the time the number
> will be more than 100 dpm 50% of the time (sometimes you'll get exactly 100
> dpm; sometimes, about 5% of the time using 95% confidence you'll get a value
> less than the Lc). Anyway, using the MDA to state that nothing is there is
> not correct, that's where Lc comes in. Check some of Brodsky's work and
> NUREG 1400 contains some good info on MDAs and Lc.
>
> Like I said, don't base anything on what I wrote - "sadistics."
>
> Randy Redmond (32458)
> Radiological Control Organization
> BWXT Y-12 L.L.C.
> Oak Ridge, TN
> 865-574-5640
>
> > -----Original Message-----
> > From: Goff, Tom [SMTP:Tom.Goff@wipp.ws]
> > Sent: Tuesday, October 28, 2003 2:27 PM
> > To: ''RadSafe Send Message'
> > Subject: MDA vs. Critical level for DOE Free Release surveys
> >
> > > Title:
> > >
> > > We are discussing using a critical level for free release surveys.
> > > Please provide answers to the following:
> > >
> > > Are you using critical value or MDA for free release surveys of
> > > materials from your site?
> > >
> > > Does anyone have a reference/regulatory standard on whether to use
> > > MDA or critical value for free release surveys?
> > >
> > > Given that an MDA results in a 95% confidence in detecting
> > > contamination at the MDA value, what is the corresponding confidence if
> > > using the critical level?
> > >
> > > I would welcome any other comments or thoughts on this.
> > >
> > > Tom Goff
> > >
> > >
> > --------------------------------------------------------------------------
> > > ----------------------------------------------------------------
> > > Let me know if you're ok with this.
> > >
> > >
> > >
> > > Tom Goff
> > > WIPP ALARA Coordinator
> > > WIPP Integrated Waste Operations
> > > (505) 234-8861
> > > (fax) 234-8963
> > > e-mail Tom.Goff@WIPP.ws
> > > page (505) 234-8850 (pager 479)
> > > P.O. Box 2078
> > > Carlsbad, NM 88221
> > > Radiological Engineering: Anticipating Problems.....providing
> > > solutions!!!
> > >
> >
> > ************************************************************************
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