The first step in Low-Level Rad Waste Reduction is a change in culture. I have found that attempts to limit the production of waste has been quite successful. Of course this is dependant on your situation. As a Physicist in Nuclear Power, I have found that limiting the number of Rad-Trash receptacles in the plant has prompted radworkers to limit that which they take into the plant. Questions we ask then to consider include: Do you really need that entire notebook in the plant? Could you use less of any particular supply? Typically, the answer is yes.
If you are faced with a disposal issue, I recommend focusing on Free-Release as well (as Mr. Vickers pointed out). For smaller items, in a low background setting, the SAM-11 will provide you with 20-40% efficiency with approximately a 10 second count time. The instrument is also quite durable. For larger issues, I recommend the NE Bm-285 bag monitor. The instrument will provide you with 10% efficiency, although count times are adjustable. Setpoints are a different story. For practical free release, develop a baseline of expected clean materials (ie, office trash) and a standard weight per bag. Simply set your setpoints at 3 sigma above the mean. This will give you 95 percent confidnence for Type 1 and Type 2 errors.
Feel free to contact me directly if you have any questions, I have been addressing waste reduction issues for the past few months.
Good luck to you
---------------------------------------------------------
Stephen M. Trickett
Physicist
Exelon Nuclear
Peach Bottom Atomic Power Station
------------------------------------------------
*all thoughts are my own, and not that of my employer*
----Original Message Follows----
From: glen.vickers@EXELONCORP.COM
Reply-To: glen.vickers@EXELONCORP.COM
To: stephane_jeanfrancois@MERCK.COM, radsafe@list.vanderbilt.edu
Subject: RE: Low level Radwaste management
Date: Tue, 20 Nov 2001 10:55:36 -0600
Instead of using a compactor, it might be better to ship your DAW off to be
incinerated... I work at a nuclear power plant in the U.S. and incineration
provides good volume reduction, reasonable cost, and we eliminate having to
maintain a compactor. We have a compactor for 55 gal drums, but it just
gathers dust.
We collect our DAW in sea-land containers. I would suspect that you could
get by with a 20 foot container every 6 months or so.
We have a trash sorting table and attempt to free-release trash, but that
takes significant cost to purchase the table and have personnel spend the
time to operate the table. Being that a trash sorting table has detectors
which cannot be shielded 100%, our count time is about 60 seconds to see
5000 dpm (1 photon/dpm) at 95% confidence. If you are a lab with many
plastic bottles, you may want to try a different instrument. The
cylindrical shapes do not work well on a trash table with a maximum
monitoring height of 1.5 inches or so. There's more baggage that comes with
this type of monitor, such that I'd probably look at a bag monitor first.
There a many that would say that incineration is cheaper than attempting to
sort trash...
An enclosed and shielded monitor like the NE/Bicron SAM-11 would be a good
instrument to meet the same specs in about 10 seconds. The primary use of
the monitor is to release tools and other items at the survey point, but
there's not reason it can't do trash duty one day a week. Some monitors may
have larger volumes, but there cost may be significantly more and are not as
useful as tool monitors. You can get detectors on 4 or 6 sides of the
"box". Bottles can be counted singly or entire bags of plastic bottles can
be counted at a time. The SAM-11 is probably $30k, and the training would
be pretty simple.
The true practicality of any of the options rests with the volume of
material, mix of radionuclides at your facility, procedural restrictions,
and cost.
Good Luck
Glen Vickers
> -----Original Message-----
> From: Jean-Francois, Stephane [SMTP:stephane_jeanfrancois@MERCK.COM]
> Sent: Tuesday, November 20, 2001 8:05 AM
> To: radsafe@list.vanderbilt.edu
> Subject: Low level Radwaste management
>
> I would like to know if any of you have experience in reducing volume of
> low level rad waste (compaction, shredders etc.) that you would like to
> share. In Canada, we are facing a steep increase of rad waste disposal
> fees and I am contemplating for next year, any ways to reduce our volumes.
> We are taking about biotech research radioisotopes, any type, from 1
> microcurie to 10 Ci in waste. Can you indicate the compactor you use ?
> the shredder ? anyone here is familiar with High Throughput Screening ?
> For me, this process means tons of contaminated plastics that I would like
> to wash and recycle instead of sending them to rad waste. Anyone is doing
> that already ?
>
> I did prepare the way with an aggressive segregation campaign , by
> increasing the decay in storage space to allow other radioisotopes, but
> there is obviously limitations. Also we don't want to dilute any of the
> stuff in regular waste, even if some limits are generous.
>
> I am preparing a strategy for 2002-2003 but I would like to consult other
> RSOs or specialists. So if you have any idea of what I am talking about,
> let me know. If any of your solution may be of interest to this list,
> please post them, if not, use my address for direct reply.
>
> Thank you in advance.
>
> Stephane Jean-Francois, eng., CHP,
>
> Specialiste en radioprotection/Radiation Safety Specialist,
> Gestion des risques/Risk Management
> Merck Frosst Canada & Co.
> tel: 514.428.8695
> FAX: 514.428.8670
> email:stephane_jeanfrancois@merck.com
>
>
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