U.S. Nuclear Regulatory Commission
Lower Limit of Detection (LLD) for Potentially Contaminated Oil
Title: Lower Limit of Detection (LLD) for Potentially
See the memorandum from F. J. Congel to D. M. Collins dated
January 30, 1985. For cases in which no release of
radioactive material is authorized, the appropriate lower
limit of detection (LLD) is the "operational state of the
art" value used for laboratory measurements of
environmental samples. This is the LLD value given in the
standard Radiological Effluent Technical Specifications
(RETS) for environmental samples. The health physics
position was written in the context of 10 CFR 20.302, but
it also applies to "new" 10 CFR 20.2002. HPPOS-071 and
HPPOS-072 contain related topics.
Region II requested that licensee guidance be developed for
acceptable surveys of potentially contaminated oils and
referred to IE Circular No. 81-07 (see HPPOS-071) as
espousing the use of operational state-of-the-art
measurements for release of materials. However, IE
Circular No. 81-07 does not establish criteria for
releasing radioactively contaminated materials from
restricted areas for unrestricted use (see HPPOS-072).
The regulations applicable to nuclear power reactor
licensees do not provide for the release of materials 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 intent of the above IE
circular was to provide guidance on acceptable limits of
detection of portable survey equipment, thus defining "how
hard you have to look" for the case in which no release of
radioactive material is authorized.
When no release of radioactive material is authorized, the
appropriate LLD is the "operational state-of-the-art" value
used for laboratory measurements of environmental samples.
This is the LLD given in the standard RETS for
environmental samples (e.g., 15 pCi/L, or 1.5 x 10-8
micro-Ci/ml for Co-58, Co-60 and Cs-134). 49 FR 36653,
PRM-20-15 states that the measured radioactivity for major
sources of waste oil at BWRs and PWRs are typically 1 x
10-7 to 1 x 10-6 micro-Ci/ml.
For cases in which disposal of radioactively contaminated
oil has been authorized by the NRC pursuant to 10 CFR
20.302 [or 10 CFR 20.2002], the necessary LLD need only be
sufficiently low to ensure that the particular limits are
not exceeded. Therefore, these LLDs may be substantially
above the technical specification environmental LLD if the
NRC authorized release limits correspond to radioactivity
concentrations substantially above these levels. Since the
release limits authorized pursuant to 10 CFR 20.302 [or 10
CFR 20.2002] are established on a case-by-case basis, the
corresponding LLDs necessary to ensure that the release
limits are not exceeded will vary accordingly.
Regulatory references: 10 CFR 20.302, 10 CFR 20.2002
Subject codes: 3.6, 6.8, 7.6, 12.8