Residual Radionuclides in Soil - doe-std-1136-20040200

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiation Protection in Uranium Facilities

(CEDE) from radionuclides taken into the body during the year. See DOE/CH-8901, A Manual for

Implementing Residual Radioactive Material Guidelines (DOE 1989b), for procedures for deriving

specific property guidelines for allowable levels of residual radioactive material, based on the dose limit

of 100 mrem (1 mSv).

DOE Order 5400.5,Ch.2, also provides the following guidelines for residual concentratio ns of

radionuclides in soil, concentrations of airborne radon decay products, external gamma radiation, surface

contamination, and radionuclide concentrations in air or water.

10.1.2.1 Residual Radionuclides in Soil

Generic guidelines for thorium and radium(226Ra, 228Ra, 230Th, and 232Th) are 5 pCi/g averaged over

the first 15 cm of soil below the surface and 15 pCi/g averaged over 15-cm-thick layers of soil more than

15 cm below the surface. For other radionuclides in soil (e.g., uranium), specific guide lines shall be

derived from the basic dose limit by means of an environmental pathway analysis using specific property

data where available. Residual concentrations of radioactive material in soil are defined as those in excess

of background concentrations averaged over an area of 100m2.

10.1.2.2 Airborne Radon Decay Products

Applicable generic guidelines are found in 40 CFR 192 (EPA 1992b). In any occupied or habitable

building, the objective of remedial action shall be, and a reasonable effort shall be made to achieve, an

annual average (or equivalent) radon decay product concentration (including background) not to exceed

0.02 WL. Remedial actions are not required to comply with this guideline when there is reasonable

assurance that residual radioactive material is not the source of the radon concentration.

10.1.2.3 External Gamma Radiation

The average level of gamma radiation inside a building or habitable structure on a site to be released

without restrictions shall not exceed the background level by more than 20 uR/h.

10.1.2.4 Surface Contamination

DOE guidelines on surface contamination levels are similar to those in Regulatory Guide 1.86,

Termination of Operating Licenses for Nuclear Reactors, except that no guidance is provided for surface

contamination levels of transuranics. DOE is holding the TRU limit in reserve pending development of

standards more clearly applicable to DOE facilities. For TRU waste, the limits in Regulatory Guide 1.86

are as follows:

Regulatory Guide 1.86 Limits

20 dpm/100 cm2

Removable Contamination

100 dpm/100 cm2

Fixed Contamination

300 dpm/100 cm2

Maximum Contamination

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