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DOE-HDBK-1129-99
APPENDIX D: CONTAMINATION AND SURFACE
ACTIVITY THRESHOLDS
D.1 Appendix D to Part 835 - Surface Radioactivity Values
The data presented in Appendix D are to be used in identifying contamination and high
contamination areas as defined in Sec. 835.2(a), identifying the need for surface contamination
monitoring and control in accordance with Sec. 835.404, identifying the need for radioactive
material controls in accordance with Sec. 835.1101.
Surface Radioactivity Values {1}
[In dpm/100 cm2]
Total (fixed +
Radionuclide
Removable
removable) {2},
{2}, {4}
{3}
U-nat, U-235, U-238, and associated decay products
1,000
5,000
Transuranics, Ra-226, Ra-228, Th-230, Th-228, Pa-231, Ac-
20
500
227, I-125, I-129
Th-nat, Th-232, Sr-90, Ra-223, Ra-224, U-232, I-126, I-131,
200
1,000
I-133
Beta-gamma emitters (nuclides with decay modes other than
1,000
5,000
alpha emission or spontaneous fission) except Sr-90 and
others noted above {5}
Tritium and tritiated compounds {6}
10,000
N/A
{1} The values in this Appendix, with the exception noted in footnote 6, apply to radioactive contamination deposited
on, but not incorporated into the interior of, the contaminated item. Where surface contamination by both alpha- and
beta-gamma-emitting nuclides exists, the limits established for alpha- and beta-gamma-emitting nuclides apply
independently.
{2} 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 observed by an appropriate detector for background, efficiency, and
geometric factors associated with the instrumentation.
{3} The levels may be averaged over one square meter provided the maximum surface activity in any area of 100
cm2 is less than three times the value specified. For purposes of averaging, any square meter of surface should be
considered to be above the surface radioactivity value if (1) from measurements of a representative number of
sections it is determined that the average contamination level exceeds the applicable value; or (2) it is determined
that the sum of the activity of all isolated spots or particles in any 100 cm2 area exceeds three times the applicable
value.
{4} The amount of removable radioactive material per 100 cm2 of surface area should be determined by swiping the
area with dry filter or soft absorbent paper, applying moderate pressure, and then assessing the amount of
radioactive material on the swipe with an appropriate instrument of known efficiency. (Note--The use of dry material
may not be appropriate for tritium.) 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 swiping 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.
{5} 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.
{6} Tritium contamination may diffuse into the volume or matrix of materials. Evaluation of surface contamination
should consider the extent to which such contamination may migrate to the surface in order to ensure the surface
radioactivity value provided in this Appendix is not exceeded. Once this contamination migrates to the surface, it may
be removable, not fixed, therefore a "Total" value does not apply.
D-1


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