RE: comparing individual and collective doses

["Wright, Will (DHS-PSB)" <WWright2@DHS.CA.GOV>]

Regardless of the semantics, alara cannot be construed to apply in any way

except to any individual and any activity. The driver that squashes a

philosophical discussion on its meaning and applicability is the monitoring

requirement for each individual and each activity/process/machine.  This

requirement places exposures and/or releases to the absolute regulatory

minimum and RA of alara will drive the "further down" approaches.  Under

certain circumstances(for instance the current concern for older

workers;individuals with predisposing genetic conditions, circumstances

involving exposures to radiation mimicking  (mutational spectrum resembles

that of radiation) chemicals), RA may be the intent of the rule in spite of

having met the regulatory minimum. these were the kinds of concerns in mind

with the ALARA rule, the uncertainty with respect to radiation effects at

any level and the shere probablelist aspects of any radiation exposure.

With the individual and the collective dose, the monitoring requirement and

the regulatory limit will set the first level alara for the individual

regardless of concerns for a collective minimum.  The collective minimum

will be controlled by the regulatory limit on the individual regardless of

expectations for a collective dose.



Anytime one has individual dose measurements, a collective dose has no

meaning. that is different from saying a population has a possible exposure

of x due to ambient levels without knowing true individual exposures. In

this instance alara drives the "further down approaches". We generally stop

at 1/million at risk of a y outcome from x ambient exposure in z time frame.



-----Original Message-----

From: Roger Pedersen [mailto:RLP1@NRC.GOV]

Sent: Thursday, December 04, 2003 6:37 AM

To: BLHamrick@AOL.COM; idias@interchange.ubc.ca; mcnaught@LANL.GOV;

radsafe@list.vanderbilt.edu

Subject: Re: comparing individual and collective doses





In the US reactor world we generally think of ALARA as reducing collective

dose from various licensed activities to As Low As Reasonably Achievable.

Although, this sometimes means that an individual is allowed to receive a

higher dose to reduce the collective dose for an activity, I can't agree

with the statement that ALARA does not apply to individuals.  By definition,

collective dose is the sum of individual doses.  You can not reduce the

collective dose if you don't control the individual doses contributors.



10 CFR Part 20.1101(b) is a program requirement.  Licensees are required to

have a program in place to insure doses are ALARA.  The Statements of

Consideration (Federal Register, Vol. 56, No. 98, Tuesday, May 21, 1991)

published when Part 20 was revised (making ALARA a requirement), provides

additional guidance on the Commission's intent.  The penultimate paragraph

to Subpart B (page 23367) states that "Compliance with this requirement will

be judged on whether the licensee has incorporated measures to track and, if

necessary, to reduce exposures and not whether exposures and doses represent

an absolute minimum..."   It goes on to state that this is "admittedly

subjective criteria," and "the level of effort expended on the radiation

protection programs should reflect the magnitude of the potential exposures,

both the magnitude of average and maximum individual doses and, in

facilities with large numbers of employees, collective (population) doses."



Roger Pedersen

Sr. Health Physicist

U.S. NRC





>>> <BLHamrick@AOL.COM> 12/03/03 09:39PM >>>

In a message dated 12/3/2003 5:38:57 PM Pacific Standard Time, 

idias@interchange.ubc.ca writes:

That is, ALARA does not apply to individual dose.



What this means for regulations depends on the "regulator" :)!

I'd like to hear from other regulators on this, because I don't think the 

above is the way 10 CFR 20.1101(b) is generally applied.



Barbara



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