Release Criteria - doe-std-1136-20040093

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities

order to allow a longer count time at the location of the detected pulse, until it is determined whether the

response indicates random background noise or detected contamination.

The most critical factor affecting a scan survey measurement is the speed at which scan surveys are

performed. Counting time is inversely proportional to scan speed. For instruments with larger detector

faces, the scan speed is faster for a given rate of meter movement because a point on the surveyed surface

remains beneath the window longer. To ensure that low levels of contamination can be detected, it is

necessary that a maximum scan speed be mandated and that this speed be implemented during field

measurements. Empirical information is available indicating that, for most instruments in current use, a

maximum scan speed of 2 in./s (5 cm/s) can detect contamination at or above the total contamination

values specified in Table 4.1 for nearly all radionuclides with 67% confidence.

4.2.3 Rele ase Criteria

Material in contamination, high contamination, or airborne radioactivity areas, shall be treated as

radioactive material and shall not be released to controlled areas if either of the following conditions

exist:

Measurements of accessible surfaces show that either the total or removable contamination

levels exceed the values specified in Table 4-1.

Prior use suggests that the contamination levels on the inaccessible surfaces are likely to exceed

the values specified in Table 4-1 (10 CFR 835.1101).

Material that has never been in a contaminated or airborne radioactivity area may be removed to

controlled areas without survey. If the history of the item is unknown, it is appropriate to assume that it

may have been in a contaminated or airborne radioactivity area.

To release material from radiological control, a methodology has been developed to reduce the time

required to perform a survey while meeting DOE requirements. A logic diagram of the protocol is shown in

Figure 4-2. The methodology ensures, with 67% confidence, that the guideline values of DOE Order 5400.5

and 10 CFR 835 are met. Note that Figure IV-1 of DOE Order 5400.5 does not specify values for the

allowable residual surface contamination levels for transuranics. For this discussion, the residual

contamination levels for transuranics given in 10 CFR 835, Appendix D are used.

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