Allowable Total Residual Surface Contamination (dpm/100 cm2)

DOE-HDBK-1106-97

Allowable Total Residual Surface Contamination

(dpm/100 cm2)1/

Radionuclides 2/

Average 3/, 4/

Maximum 4/, 5/

Removable 4/, 6/

Transuranics, I-125, I-129, Ra-226,

500

1500

Ac-227, Ra-228, Th-228, Th-230,

Pa-231. Th-Natural, Sr-90, I-126, I-131,

1,000

3,000

200

I-133, Ra-223, Ra-224, U-232, Th-232

U-Natural, U-235, U-238, and associated

5,000

15,000

1,000

decay product, alpha emitters.

Beta-gamma emitters (radionuclides with

decay modes other than alpha emission or

5,000

15,000

1,000

spontaneous fission) except Sr-90 and

others noted above. 7/

Figure IV-1 Surface Contamination Guidelines

As used in this table, dpm (disintegrations per minute) means the rate of emission by radioactive material

as determined by correcting the counts per minute measured by an appropriate detector for background,

efficiency, and geometric factors associated with the instrumentation.

Where surface contamination by both alpha- and beta-gamma-emitting radionuclides exists, the limits

established for alpha- and beta-gamma-emitting radionuclides should apply independently.

Measurements of average contamination should not be averaged over an area of more than 1 m2. For

objects of less surface area, the average should be derived for each such object.

The average and maximum dose rates associated with surface contamination resulting from beta-gamma

emitters should not exceed 0.2 mrad/h and 1.0 mrad/h, respectively, at 1 cm.

The maximum contamination level applies to an area of not more than 100 cm2.

The amount of removable material per 100 cm2 of surface area should be determined by wiping an area

of that size with dry filter or soft absorbent paper, applying moderate pressure, and measuring the amount

of radioactive material on the wiping with an appropriate instrument of known efficiency. When removable

contamination on objects of surface area less than 100 cm2 is determined, the activity per unit area should

be based on the actual area and the entire surface should be wiped. It is not necessary to use wiping

techniques to measure removable contamination levels if direct scan surveys indicate that the total residual

surface contamination levels are within the limits for removable contamination.

This category of radionuclides includes mixed fission products, including the Sr-90 which is present in

them. It does not apply to Sr-90 which has been separated from the other fission products or mixtures

where the Sr-90 has been enriched.

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