Part 2 - Contamination Control and Control Levels

Table of Contents (Articles 22x)

• Forward
• 221 Personnel Contamination Control
• 222 Contamination Control Levels
• 223 Airborne Radioactivity Control Levels

Forward

Control of radioactive contamination is achieved by using engineering controls and worker performance to contain contamination at the source, reducing existing areas of contamination and promptly decontaminating areas that become contaminated.

Return to Chapter 2, Part 2 Table of Contents

Article 221 - Personnel Contamination Control

1. Personnel exiting Contamination Areas, High Contamination Areas, Airborne Radioactivity Areas or Radiological Buffer Areas established for contamination control shall frisk for contamination as required by Article 338. This does not apply to personnel exiting areas containing only radionuclides, such as tritium, that cannot be detected using hand-held or automatic frisking equipment.

2. Monitoring for contamination should be performed using frisking equipment that under laboratory conditions can detect total contamination of at least the values specified in Table 2-2. Use of automatic monitoring units that meet the above requirements is encouraged.

3. Personnel found with detectable contamination on their skin or personal clothing, other than noble gases or natural background radioactivity, should be promptly decontaminated as described in Article 541.

Article 222 - Contamination Control Levels

1. A surface shall be considered contaminated if either the removable or total radioactivity is detected above the levels in Table 2-2. If an area cannot be decontaminated promptly, then it shall be posted as specified in Article 235.

2. Surfaces exceeding the values of Table 2-2 for total contamination may be covered with a fixative coating to prevent the spread of contamination. However, reasonable efforts should be made to decontaminate an area before a coating is applied. A fixative coating shall not be applied without the approval of the Radiological Control Manager.

3. In addition to the posting criteria in Article 235, the conditions for establishing and maintaining Fixed Contamination Areas include all of the following:

4. Radiological surveys shall be performed to detect contamination that may become removable over time
5. A formal inventory shall be maintained of Fixed Contamination Areas.
6. Markings shall be kept legible
7. Removable contamination shall not exceed Table 2-2 values and should be reduced as far below Table 2-2 as is reasonably achievable before a fixative coating is applied
8. Fixed contamination should be covered with two layers of fixative coatings having different colors
9. Markings should include the standard radiation symbol, be clearly visible from all directions and contrast with the colors of the surface coatings
10. Additional coating should be applied when the bottom color appears
11. A plan for identifying and adding to the inventory of existing areas of fixed contamination not included in the initial inventory should be developed.

• A Fixed Contamination Area may be located outside Controlled Areas unless unrestricted access is likely to result in a dose to any person greater than 100 mrem in a year.

• A Fixed Contamination Area is exempt from the general posting requirements of Article 231 and entry and exit requirements of Chapter 3.

• For contaminated soil that is not releasable in accordance with DOE 5400.5, a Soil Contamination Area shall be established that:
• Is posted as specified in Article 235. Posting should include instructions or special warnings to workers such as "Consult With Radiological Control Organization Before Digging" or "Subsurface Contamination Exists"
• Meets the requirements of Article 231.1 through 231.8.

• Soil Contamination Areas may be located outside a Radiological Buffer Area. Return to Chapter 2, Part 2 Table of Contents

Article 223 - Airborne Radioactivity Control Levels

1. Personnel should not be exposed unnecessarily to airborne radioactivity. Use of engineering and administrative controls to reduce the potential for internal exposure should be evaluated before allowing personnel, with or without respiratory protection, to enter areas with airborne radioactivity.

2. Occupied areas with airborne concentrations of radioactivity that are greater than or potentially greater than 10 percent of a Derived Air Concentration shall be posted as specified in Article 235. For most radionuclides, air containing 10 percent of a Derived Air Concentration results in a committed effective dose equivalent of approximately 10 mrem if inhaled continuously for one work week. Values of Derived Air Concentrations are provided in 10 CFR 835.

                Table 2-2  Summary of Contamination Values


     NUCLIDE                        REMOVABLE            TOTAL (FIXED +
   (See Note 1)                    (dpm/100 cm2)          REMOVABLE)
                                   (See Note 2)          (dpm/100 cm2)
                                                         (See Note 3)


U-natural, U-235, U-238 and         1,000 alpha          5,000 alpha
associated decay products

Transuranics, Ra-226, Ra-228,          20                   500
Th-230, Th-228, Pa-231,
Ac-227, I-129

Th-nat, Th-232, Sr-90, Ra-            200                  1000
223, Ra-224, U-232, I-125, I-
126, I-131, I-133
200
1,000

Beta-gamma emitters (nuclides      1,000 beta-gamma      5,000 beta-gamma
with decay modes other than
alpha emission or spontaneous
fission) except Sr-90 and
others noted above.  Includes
mixed fission products
containing Sr-90.

Tritium organic compounds,            10,000               10,000
surfaces contaminated by HT,
HTO and metal tritide
aerosols

Notes:

1. The values in this Table apply to radioactive contamination deposited on, but not incorporated into the interior of the contaminated item. Where contamination by both alpha- and beta-gamma-emitting nuclides exists, the limits established for the alpha-and beta-gamma-emitting nuclides apply independently.

2. 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 while applying moderate pressure and then assessing the amount of radioactive material on the swipe with an appropriate instrument of known efficiency. For objects with a surface area less than 100 cm2, the entire surface should be swiped, and the activity per unit area should be based on the actual surface area. Except for transuranics, Ra-228, Ac-227, Th-228, Th-230, Pa-231 and alpha emitters, it is not necessary to use swiping techniques to measure removable contamination levels if direct scan surveys indicate that the total residual contamination levels are below the values for removable contamination.

3. The levels may be averaged over 1 square meter provided the maximum activity in any area of 100 cm2 is less than three times the values in Table 2-2.