DIS Requirements

[Mack Richard <MRICHARD@WPO.IUPUI.EDU>]

Dear Radsafers:

In a recent post, someone mentioned that RIA labs operating under a
"General License" could use the 7 half-life storage period.  Am I mistaken
or aren't General Licensees exempt from all radwaste disposal
requirements specified in 10 CFR 20?  I know that some RIA labs are
required to obtain a specific license due to the fact that they cannot meet
the 200 microcurie possession limit for I-125 and as such must establish
a radwaste disposal program which usually includes DIS.  I have helped
out a couple of local RIA labs on this - boy, was it a shock for them to go
from basically no licensing restrictions to all the stuff they must now do.  
Incidentally, when I helped write one of these RIA licenses a few years
ago, a 7 half-life DIS period was included and approved by the NRC
(was that an "oops" on the NRC's part).  The RIA lab uses a portable NaI
probe to check their DIS radwaste, so the proof is in the measurement.  If
they still measure something above background after 7 half-lives, the
container goes back into storage and is re-surveyed at a later date.

As a part of our last NRC license renewal, we attempted to use a 7
half-life storage requirement rather than the traditional 10 half-life
requirement.  We were turned down and basically told that we would
have to request alternative disposal procedures under 10 CFR 20.2002. 
We submitted such a request on May 22, 1996 and still have not received
any correspondence from the NRC regarding this request.  It seems that
the NRC wheels turn slowly on these types of issues, probably because
of their precedent setting nature.

We basically used the logic as discussed above for RIA labs in our
request to the NRC - seems simple enough.  However, we also deal with
S-35 which really cannot be measured with portable instrumentation
when in a radwaste container.  For that we basically took the approach
that as long as the activity in the radwaste container (as estimated by
the generator) was less than 128 times (2 to the 7th power) of the
quantity listed in 10 CFR 30.71, Schedule B (for S-35 that is 12.8 mCis),
we would hold it for 7 half-lives, survey it, and dispose as non-rad
waste.  Otherwise (i.e., if it was > 12.8 mCis), it would be held for the
traditional 10 half-lives.

It is hard to imagine why the NRC has not been able to act upon this
request for over 6 months.  Rocket science it ain't.  We'll let you
radsafers know of the outcome of our request (if I don't retire first).

Regards,
Mack Richard

Mack L. Richard, M.S., R.S.O.
mrichard@wpo.iupui.edu
Phone:  (317) 274-0330    FAX:  (317) 274-2332