Re: To Bioassay or not to Bioassay!!

[loesch@viper.eh.doe.gov (Robert M. Loesch)]

>I would appreciate comment on what I have come up with (see below).
>
>
>Routine bioassay is required if the sum of the total activity of all
>radioisotopes in unsealed form measured as the number of Annual Limits on
>Intake (most restrictive ALI for each isotope) manipulated by a radiation
>worker within 12 months exceeds 30ALIs.
>
>
>REASONING:
>
>Assume that 1% of the activity of all unsealed radioisotope manipulations
>are depositied in the worker and set the "monitoring level" at 30% of the
>yearly effective dose limit.
>
>To receive an effective dose of 30% of the limit 0.3ALIs must be
>ingested/inhaled. Since 1% is ingested/inhaled, the number of ALIs required
>to be handled is 30 (ie 0.3/0.01).
>

What are the Regs down-under for when individual monitoring is required?
I assume from your basis that they are no less stringent than 30% of an ALI.
This seems a bit relaxed (IMHO).  For comparison purposes, the USNRC
requires monitoring when an individual is likely to exceed 10% of an ALI and
the USDOE requires monitoring at 2%.  Assuming that your Regs limit total
effective dose equivalent (EDE + CEDE) to 0.05 Sv, and doesn't specify when
to establish bioassay monitoring, I would suggest a monitoring level of 10%
as being adequate.  I personnally would not be comfortable in establishing a
bioassay program where the "missed dose" was as high as 0.015 Sv (1.5 Rem).
Would you not require TLDs (or film) when external exposures were of the
order of 0.01 Sv (1 Rem)?



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        * Robert M. Loesch         U.S. Department of Energy *
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