[ RadSafe ] LNT

William Lipton doctorbill34 at gmail.com
Sat Jun 27 13:37:48 CDT 2015

Many thanks for taking the time to reply to my posting.

I am not in a position to evaluate the many studies you cite.  You may be
right, but your view is still far from a consensus.  As you stated, if
there are 2 opposing hypotheses, one of them must be wrong.  However, keep
in mind that I am NOT saying that LNT is a fact, only that it is a sensible
basis for planning, in the absence of overwhelming evidence to the
contrary.  If unsure of which hypothesis is correct, I'll take the
conservative one.

Also, keep in mind that epidemiological studies show association, but not
cause and effect.  We need a lot more knowledge of radiation biology before
a reasonable person can accept hormesis.

In any event, I definitely would not want an expectant mother to be exposed
to 10 rems, or even 5 rems.

My 26 years of experience in nuclear power have convinced me that ALARA
does lead to good work practices.  It forces good work planning.  In the
"good old days," management often ignored ALARA.  They operated with fuel
failures, they exposed workers to 3 rems/quarter (They used to schedule
outages to span a quarter, so they could dose everyone to 3 rems, and then
start all over, again.), and they did sloppy work.  They lived to regret
that, having to live with the extra expense of operating a dirty plant.
Many ALARA practices are cheap and easy, e.g., training on a mock up before
the hot work, keeping a nearby contaminated system filled with water while
the work is in progress, or sequencing the work logically.  Outages are now
much shorter and less costly, as well as lower dose.  Experience has shown
that the industry can operate effectively while maintaining worker
exposures ALARA.

I look forward to seeing how your petitions play out.


On Sat, Jun 27, 2015 at 12:52 PM, Doss, Mohan <Mohan.Doss at fccc.edu> wrote:

> Dear Bill,
>     My comments on the problems you listed:
> (1) When NRC completes its review of the petitions, if it decides they
> have merit, and agrees that LNT model should not be used for regulations,
> NRC can ask EPA to change its stance regarding the LNT model. Since we are
> affected by NRC regulations in our work, it is appropriate to petition NRC
> about the regulations.
> (2) Scientific method requires validation of proposed hypotheses with
> evidence. When evidences support two opposing hypotheses on any subject,
> only one of the hypotheses can be correct, and the other one is wrong.
> This means, evidences quoted on the wrong side are faulty or incomplete.
> The subject will ultimately get resolved in the future, resulting in the
> resolution of the issue. One indication of the resolution of the issue is
> the reversal of conclusions of the evidences on one side.
>   In the case of low-dose radiation (LDR) carcinogenicity, atomic bomb
> survivor data were quoted as the most important data by BEIR VII report and
> other publications. These data (with the recent update) no longer provide
> evidence for LDR carcinogenicity, as indicated by recent publications.  For
> example, in the recent debate on the subject in Medical Physics, Dr. Little
> did not quote atomic bomb survivor data to claim carcinogenicity of LDR.
> Since these are the most important data, if the updated data supported LDR
> carcinogenicity, he would undoubtedly have used the data when he made
> claims of LDR carcinogenicity, as he did in a previous debate.  Another
> data quoted by BEIR VII report, the 15-country study of radiation workers,
> has also had its conclusion of LDR carcinogenicity reversed. The evidences
> for radiation hormesis are on firmer footing, and have not been reversed.
> The reversals of major evidences supporting the LNT model indicate the
> correct side is not likely to b
>  e the LNT model.
>    I have been studying literature on this subject for some time, and I am
> yet to see even a single publication with valid evidence showing low-dose
> radiation causes cancer.  Extrapolation from high dose to low-doses does
> not constitute evidence. Of course there are many publications that make
> such claims, but when they are examined closely, invariably major flaws are
> found in the analysis or data nullifying their conclusion.   Thus, there is
> universal agreement between all the available valid evidences, and so there
> is no need for consensus. The valid evidences speak for themselves.
>   Groups such as ICRP do not consist of superior human beings that have
> better grasp of scientific knowledge that we have to wait for them to give
> their consensus opinions, when all the valid evidences provide a unanimous
> conclusion. There is no law or Congressional mandate that EPA has to follow
> ICRP recommendations.  Their mandate is to protect public and workers from
> harm due to radiation. Since low-dose radiation does not cause any harm but
> reduces cancers, regulating low-dose radiation does not protect the public
> but harms the public, and so EPA's present regulations regarding low-dose
> radiation are illegal. In fact their regulations have caused incredible
> amount of public harm by blocking cancer prevention studies using low-dose
> radiation.
>     You said use of the LNT model is safe, conservative. The experience in
> Fukushima has shown that it is dangerous to use the model, as indicated by
> the deaths its use has caused. LNT model is definitely not conservative.
>     Regarding the 10 cSv dose limit during pregnancy: there is evidence
> that 5 cGy prenatal dose has a protective effect against birth defects
> caused by subsequent high dose radiation in a mouse model
> http://www.ncbi.nlm.nih.gov/pubmed/23109298.
>     (3) I am amused by your statement that ALARA promotes work
> efficiency.  In reality, LNT model and ALARA makes us do a large number of
> steps which have no protective effect for workers, patients or the public.
> These steps all add to the expenses which are ultimately paid for by the
> public, for no benefit to the public. The examples you quoted relate to
> poor work practices that should be discouraged. No need to invoke ALARA for
> preventing such practices.
>    So, I don't see any problems with the petitions. The first seven
> comments that have appeared in the NRC website have overwhelmingly
> supported the petitions.
>     With best regards,
>                                                   Mohan
> -----Original Message-----
> From: radsafe-bounces at agni.phys.iit.edu [mailto:
> radsafe-bounces at agni.phys.iit.edu] On Behalf Of William Lipton
> Sent: Wednesday, June 24, 2015 8:02 PM
> To: radsafe
> Subject: [ RadSafe ] LTN
> The NRC recently received petitions from Carol Marcus, Mark Miller, and
> Mohan Doss requesting that NRC radiation protection regulations be based on
> hormesis rather than the Linear No Threshold (LNT) hypothesis.  A notice <
> http://t.signauxsix.com/e1t/c/5/f18dQhb0S7lC8dDMPbW2n0x6l2B9nMJW7t5XYg7fJZRbW7fKkvK5v_SkHW7fclSC56dwMyf3M8tTM02?t=http%3A%2F%2Fwww.gpo.gov%2Ffdsys%2Fpkg%2FFR-2015-06-23%2Fpdf%2F2015-15441.pdf&si=6310431729123328&pi=3f637c94-a7fb-4341-9402-45c5eadd5fdc
> >
> requesting comments was published in the Federal Register on June 23,
> 2015.  Although flawed, these petitions are probably worthy of some
> discussion.
> The problems with these petitions are best describe in 3 categories:
> (1) procedural - Since NRC rad protection regulations must be based on EPA
> guidance, the NRC cannot change their basis even if it wanted to.  They
> should petition the EPA, which superseded the Federal Radiation Council, in
> 1970.
> (2) scientific - The EPA requires following scientific consensus, as
> published by groups such as the International Commission on Radiological
> Protection (ICRP).  The references quoted by the petitioners do not seem to
> represent scientific consensus.  It's important to keep in mind that LNT is
> NOT presented as being real, only as a safe, conservative basis for
> planning.  One of the petitions even recommends raising the allowed dose
> for declared pregnant workers AND members of the public to 10 rems.  This
> is clearly approaching levels at which teratogenic effects have been found.
> (3) practical - Besides assuring adequate standards for radiation
> protection, the LNT  - based concept of "As Low As is Reasonably
> Achievable" (ALARA) promotes sound practices which generally increase work
> efficiency.  Keep in mind that the definition of ALARA specifies practical
> measures which take economic, technological, and societal factors into
> account.  I've personally found that, at power reactors, the application of
> ALARA concepts promotes sound work planning, which increases efficiency
> and, ultimately, saves money.  (When I began my career in rad protection,
> in the 1970's, there were reports of physicians increasing x-ray exposure
> times rather than replacing weak film developer solutions, as well as
> poorly collimated beams which exceeded the film size.  Also, power reactor
> Radiological Environmental Technical Specifications allowed plant operation
> with failed fuel.  Those reactors which did this have long regretted this
> practice, since it resulted in residual alpha c
>  ontamination which makes work much more difficult.  Such non-ALARA
> practices should not be allowed.)
> Bill Lipton CHP (emeritus)
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