RE: ALARA

[DamschenGA <damschenga@mkf.ornl.gov>]

>>The concept of ALARA has been around a long time, and was likely first
>>inroduced in its 'modern' form by the NCRP in 1954.  In  1959, the ICRP
>>introduced the phrase "as low as practicable" or ALAP.  I believe the term
>>ALARA -- ie 'as low as reasonably achievable" which is conceptually and
>>practically identical to ALAP -- was likely introduced by the NRC, perhaps
>>just to be different. 


Ron,

I think this is where the idea that ALARA is expensive and not worth the
effort comes from. Many people in our industry/profession (including many
regulators) consider ALARA and ALAP as being equivalent when they are not.
There is a BIG difference between ALAP and ALARA. The fact that a dose
reduction is "practicable" does not mean it is "reasonable" or "practical."
"Practicable" is only concerned with the whether something is possible or
not. "Reasonably Achievable" also concerns itself with whether or not it
makes sense to do something. In a world of unlimited financial and time
resources the differences may fade to nothing, but in the real world they
are significant.

To paraphrase my dictionary:  It might be practicable to decontaminate a
site to levels one tenth the natural background for the area, but it is not
practical (reasonably achievable) to do so.

As part of our Radworker training, we cover the ALARA concept. After the
concept is explained, we ask what is "reasonable?" When we start the
discussion, there are usually comments that there is no upper limit on what
should be spent to reduce exposure - any sum is "reasonable" (including
$1E6/person-mrem reduction!!) "You're putting a price on safety" is the
usual response. When we ask, "Okay, I have a one million dollar budget for
this year. I can either do one job over 6 months and each person on the job
will get 50 mrem or I can do two jobs over 12 months and each person will
get 100 mrem. The difference is due to the cost of reducing the first job's
dose to 50 mrem/person. Which should I do?" the response suddenly becomes,
"Do the year's worth of work and let everyone get more exposure." This is
the difference between ALAP and ALARA. Under ALAP you work for six months,
under ALARA you work for a year.

-Gary Damschen
damschenga@mkf.ornl.gov

The opinion is most definitely mine and not my employer's or the DOE's. All
>the other usual disclaimers apply, too.