Dose Conversion Factors (DCFs) for ITPs cont'd

DOE-HDBK-1184-2004

To calculate internal dose using the various dose conversion factors for ITPs, it is

necessary to estimate the intake of ITPs. Intake of ITPs (I) can be inferred from air

sampling results using equations 5-10 and 5-11. (See DOE-STD 1121-98 for

considerations to be applied when using air sampling results to determine internal

dose.)

To calculate intake from air sampler measurements use equation 5-10

(

)

A F (Bq ) ⋅ BR m 3 / hr

I (Bq ) =

⋅ T E (hr

)

(

)

(Eq 5-10)

FR m / hr ⋅ TC ( hr )

Where:

AF is the activity on the filter sample (either observed or actual)

BR is the breathing rate of the worker

FR is the flow rate of the air sampler

TE is the time period the worker was exposed to air containing radioactive

material sampled

TC is the time over which the sampler was operated.

NOTE:

It is important to make sure that TC reflects the time the sampler was

operating in an atmosphere expected to contain STPs. Including periods

when the sampler is not in an STP containing atmosphere in the

determination of TC will tend to reduce the estimated STP concentration

in air and thus, lead to an underestimate of intake.

To calculate intake from personal air sampler measurements use equation 5-11.

(

)

A F (Bq ) ⋅ BR m 3 / hr

I (Bq ) =

(

)

(Eq 5-11)

FR m 3 / hr

NOTE:

To ensure that intake is not underestimated, the sampler should never be

turned off when a worker is in an atmosphere expected to contain STPs.

NOTE:

Equations 5-10 and 5-11 assume 100% collection efficiency. The filters

used at the Mound Site (Mound 2000) had collection efficiencies that

ranged between 0.981 0.9999 for 0.3 to 10 um particles.

ANSI N13-1(ANSI 1999) contains a table of collection efficiencies for

various types of filters.

Various types of internal doses for STCs can then be calculated from the product of

equations 5-10 or 5-11 and the various DCFs provided in this handbook. For

example, the DCFs in Table 5-14 table can be used to determine the CEDE from

inhalation of ITPs of various sizes and composition using the observed activity on

an air filter. In addition, Appendix A contains DCFs for STPs of density 11.7

gm/cm3 (Hf ) for absorption types S, M, and F and AMADs of 1 and 5 m.

To calculate internal doses (using air sampling results) from inhalation of ITP

species having particle sizes, densities, and compositions that differ from those

cases addressed in this handbook, it will be necessary to obtain appropriate values

for the self absorption factors for beta and energy, as they are not provided in

tables 5-9 and 5-10. The observed air sample activity would then have to be