U.S. Nuclear Regulatory Commission

Surveys of Wastes from Nuclear Reactor Facilities Before Disposal

HPPOS-073 PDR-9111210176

Title: Surveys of Wastes from Nuclear Reactor Facilities

Before Disposal

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

Applicability: Reactors