U.S. Nuclear Regulatory Commission
Surveys of Wastes from Nuclear Reactor Facilities Before Disposal
Title: Surveys of Wastes from Nuclear Reactor Facilities
See IE Information Notice 85-92 entitled as above and dated
December 2, 1985. This document supplements IE Circular
81-07 (IEC-81-07) as it applies to surveys of solid wastes
before disposal from nuclear reactor facilities. It also
discusses typical surveys that could be made to preclude
unintentional release of radioactive materials. The health
physics position was written in the context of 10 CFR
20.201 and 20.301, but it also applies to the "new" 10 CFR
Part 20, Sections 20.1501 and 20.2001. HPPOS-071 and
HPPOS-072 contain related topics.
IEC-81-07 was issued by NRC in 1981 (see HPPOS-071) and
provided guidance on the control of radioactively
contaminated material and identified the extent licensees
should survey for contamination (see HPPOS-072). The
criteria in IEC-81-07 addressed surface contamination
levels based on the best information available at the time
and were related to the detection capability of portable
survey instruments equipped with thin-window "pancake"
Geiger-Mueller (GM) probes responding primarily to beta
radiation. The monitoring of aggregated, packaged material
was not addressed. There was no major emphasis on
segregating waste from designated contamination areas in
1981. As a result, large volumes of monitored wastes were
not being released for unrestricted disposal. However,
because of the recent emphasis on minimizing the volume of
radioactive waste, current practices at many nuclear power
facilities results in large volumes of segregated,
monitored wastes with large total surface areas being
released as "clean" waste.
When scanning surfaces with hand-held pancake probes, there
is a chance that some contamination will not be detected or
the total surface area will not be completely scanned.
[See papers by J. F. Sommers, "Sensitivity of Portable
Beta-Gamma Survey Instruments," Nuclear Safety 16 (4), pp.
452-457 (1975), and "Sensitivity of GM and Ion-Chamber
Beta-Gamma Survey Instruments," Health Physics 28 (6), pp.
775-761 (1975).] Thus, when numerous items of "clean"
material are combined, the accumulation of small amounts of
contamination that escaped pancake probe detection may be
detected using detectors sensitive to gamma radiation
(e.g., by using a sensitive scintillation detector in a
low-background area). Such measurements of packaged clean
waste before disposal can reduce the likelihood that
contaminated waste will be disposed of as clean waste.
To avoid the unintentional release of radioactive materials
from nuclear reactor facilities, a good monitoring program
that includes the following is recommended.
1. Surveys made with methods for detecting very low
levels of radioactivity to discriminate between materials
that are contaminated and those that can be disposed of as
clean waste. The survey methods should provide licensees
with reasonable assurance that licensed material is not
released from their control.
2. Surveys using portable survey instruments with
small pancake GM probes should be done only on small items
and small areas. Because these instruments and probes lose
detection sensitivity when moved and because of the
difficulties in completely scanning large areas, this
method of survey should be supplemented with other
techniques for larger items.
3. Final measurements on each package of aggregated
wastes should be done to ensure that an accumulation of
licensed material resulting from the buildup of multiple,
nondetectable quantities has not occurred (e.g., final
measurements using sensitive scintillation detectors in
low-background areas). Regulatory references: 10 CFR
20.201, 10 CFR 20.301, 10 CFR 20.1501, 10 CFR 20.2001
Subject codes: 7.1, 7.6, 9.7