HPS Position Paper

[bflood@SLAC.Stanford.EDU (Bob Flood)]

I wish to place a few ideas before the Radsafe community for discussion.

1. I believe that the technical issue of health effects arising from low
level occupational radiation exposure is fairly well understood: health
effects, if any, from low level exposure occur with insufficient frequency
to be distinguished from the ambient rate of occurrence of those effects in
the working population. Arguments about hormesis aside, the existence or
absence of the effects cannot be proven. Appropriately, our regulations
limit exposures to this realm to limit the risk, if any. However, we have
more than technical issues here. There is what may be an overriding social
issue: the public is fearful of radiation, and is very unlikely to be
receptive to a sudden deregulation of radiation controls ('trust me, it
never was dangerous'). And if the public isn't receptive, the politicians
won't be (something to do with voting, I think) and that drives regulations.
This is the third set of issues, the political ones. We can't prove a
negative (give me a list of all the things that radiation doesn't cause?)
and we are faced with a population already convinced that radiation is
harmful. My opinion: The position statement is technically sound, but the
associated social and political aspects may prevent implementing changes to
regulated radiation protection programs.

2. Try to explain to a person who has little or no scientific education that
radiation is clearly harmful at higher doses, that we have calculated a rate
of cancer occurrence from the dose versus cancer data at high doses,
projected downward in risk and dose to set occupational dose limits based on
an agreed-to risk level, but no one should use these same data to estimate
risk at occuoational levels because the data are unreliable. I believe you
will get blank stares from all but those who see this as a reason to
question the validity of the occupational limits and their basis!

3. The position paper says that individual and collective risk should not be
estimated from dose values if those dose values are below the 5 rem/10 rem
thresholds. However, the courts will always reserve the option to consider
risk in all litigation, and that being the case, won't regulators also have
to consider these same risks?

4. By not associating risk with individual dose or collective dose, does
this eliminate the dollars/man-rem values used by so many operations to
evaluate the appropriateness of dose reduction expenditures? Does this mean
that, unless one can show that regulatory compliance is at issue, no money
should ever be spent to reduce legally permissible occupational exposures?

An example: my theoretical nuclear power plant monitors 2,000 people in a
full calendar year with a collective dose of 150 man-rem. Under the position
statement, we won't care to take any actions if doses rise, as long as the
dose do not exceed the regulatory limit of 5 rem/y. Are we willing to stand
by and watch collective dose at my nuclear plant go from 150 man-rem to
9,500 man-rem, and tell the workers not to worry? What can we expect lawyers
to do with this in court?

Complicating factor: How does one manage exposure controls and investment in
dose reductions based on the 10 rem lifetime action level? If no one ever
exceeds 200 mrem/y, one's dose over a 50-year working lifetime would not
reach 10 rem, but that works only if the worker is employed exclusively by
companies that comply with the 200 mrem/y idea. And, if you take the
NRC-permitted exclusion to not badge workers who receive less than 500
mrem/y, how could you show compliance with the lifetime goal? If a new
employee at your company was occupationally exposed at a previous employer's
facility, but not monitored (<500 mrem/y), for a period of several to many
years, what does that do to your radiation protection practices? There is an
obvious effect on your company's need to invest in exposure controls, but
the lack of a dollar/man-rem value confounds the justification process.

I don't see the position statement as eliminating the need to HPs or the
work HPs do. But it could change the things we worry about dramatically. It
will also make controlling exposures and justifying dose reduction projects
more difficult, even though they will be as necessary as ever.
Bob Flood
Unless otherwise noted, all opinions are mine alone.
(415) 926-3793
bflood@slac.stanford.edu