Radiation Risks

[halflifer]

gee thanks, Arch, but I was trying to stimulate debate on the merits of the NAS's new pronouncement vs. the 'conventional' (at least the NukeWorker convention) wisdom re: hormesis....not pose the question "should we all run away lest we incur a .000002% increase in the likelihood of developing some biological disorder as a result of our minimal exposure?"
Besides, I know several people who are richly deserving of tails.

[Already Gone]

the National Acadamy of Science sez that ANY radiation exposure results in increased risk. 
How do we square that with our views on Hormesis?

I think that this latest report does not address hormesis.  It is possible that the two theories can coexist.  Even when there was still some question about the existence of a threshold for cancer risk, we always preached that any exposure carried some risk.  The hormesis theory does not contradict this, although I have never heard any solid scientific argument in its favor.
Something can simultaneously be good for you while putting you at risk.  Miost prescription drugs, while designed to be beneficial to health, carry side-effects as severe as sudden death.  Something that kills bacteria, improves circulation, reduces risk of heart attack ... etc. can cause liver damage and make driving a car dangerous.  Of course I'm talking about alcohol.  Even in moderate doses, alcohol kills brain cells, slows reaction times, and hardens the liver.  The positive effects can only outweigh the negative if the damage caused by drinking occurs more slowly and to lesser degree than the damage it is preventing. 
Any doctor will tell most of his adult patients that it would be good to drink one glass of red wine a day.  Drinking two bottles a day will eventually kill you.  Drinking none for a month and making up by having 30 glasses all at once could kill you right away.  But even that one glass each day is causing damage to your body - only it is happening slowly enough that your body repairs most of it and tolerates the rest.

[SloGlo]

the National Acadamy of Science sez that ANY radiation exposure results in increased risk. 
How do we square that with our views on Hormesis?

iz e-z!  iffen ya gots a risk of cancer, then ya gotz a risk of abherrent growth, kerrect?  sew, supposing this abherrent growth benefits the organism.  wutz the prob?

[Marlin]

   I would like to propose the "Little Dipper" curve.

1)It is difficult to claim that there is a point of zero effect as even one interaction with DNA may cause a change.

2)We can observe a linear effect at higher doses.

3)A reduced morbidity rate was observed at a point of slightly increased doses above background at Hiroshima and Nagasaki. Fungus shielded from normal background shows a reduced fecundity rate.

   I think that this is a stellar proposal that all of us junior scientists can grasp (Fecundity is your word of the day, look it up). Keep looking up boys and girls.

[Danielson13fx]

I skipped most of this.. Actually, I only read the first few posts. So, sorry if I missed something.

But, anyway. Isn't it true that most reactor operators get less radiation from working in a plant, than women (or men) do, going to a tanning salon?

[halflifer]

Patrons of tanning salons are exposed to ultra violet radiation which is non-ionizing (unlike the gamma radiiation that makes up the lion's share of the exposure received by nuclear workers). You are right in that Reactor Operators receive minimal exposure though. This is due to the fact that ROs work is performed in the control room which is generally in an area comparable to the Admin Offices from a radiological standpoint. Apples and Oranges, though.

[raymcginnis]

I skipped most of this.. Actually, I only read the first few posts. So, sorry if I missed something.

But, anyway. Isn't it true that most reactor operators get less radiation from working in a plant, than women (or men) do, going to a tanning salon?

True that Senior Reactor Operators (SROs) spend a lot of time in the control room, but before they gain that status they do many plant entries for valving changes, etc.  It is also true that they get less dose by turning a valve than say a fitter who tears the valve apart and the HP who takes the air sample and smears.  They do power entries though, usually with an HP escort.  They do get some dose before making SRO.  This topic is not about operating plants, but mainly about risks to future real estate buyers of released sites or hikers after remediation (the public).

Danielson, read the whole post.  It is not too huge.  There are many great points made by intelligent people.  It is an interesting topic.  Much of what the people say can apply to risks in operating plants though.  If that is where your interest is on this topic, read all of the posts.

[widow_of_a_nuke]

I just read a post from a while ago in which the writer claimed to have been in the nuke field for decades and he had yet to hear of one death due to radiation.

My husband died from an aggressive form of leukemia three years ago. He never came close to the 500 rem allowed per year in the Navy. He worked for the Navy for 20 years as a Shift Refueling Engineer. We were married 20 years and had seven children together.

When I asked my husband's hemoncologist what role, if any, his job played in his acquiring leukemia, especially in light of the fact that his dosimeter never registered even close to the limit imposed by the Navy, he replied that it wasn't necessarily the amount of radiation my husband received, but that a random particle hit his body in a certain way many years ago. So, "Yes," he said, "his leukemia could indeed be attributed to his occupation."

My husband was only 43 when he died after 8 months in the hospital and a stem cell transplant. The treatment was brutal. We "celebrated" our 20th anniversary knowing it was our last. The day before he died he was able to say goodbye to our four oldest kids (our youngest were only 4, 3, & 3--he died on our twin sons' third birthday).  He was the picture of health at 6'2" and 175 pounds.  He hadn't been in the hospital since he was born. There were no weaknesses in his immune system.

I wonder if he knew of the danger of a random particle. We thought he was very safe under the Navy's strict guidelines. He supervised refueling of Los Angeles Class submarines as well as the NR-1.

I would appreciate comments and information on this topic.

Regards,
Kate

[RDTroja]

Did you read the rest of the posts in this thread? There is a lot of good information in there already.

Your husband's doctor was right -- a single gamma ray, from any source, is enough to cause cancer. The odds of it happening are very low, but not zero. The human body is well equipped to deal with most of the insults that we naturally subject it to on a day-to-day basis, but there is always that chance that the protective and reparative functions fail.

The likelihood that radiation exposure caused your husband's death is also low, but not zero. There are many things that cause cancer, and the vast majority of Leukemia victims never have any exposure above background at all. The cause of their cancers is also possibly radiation due to background sources, but is much more likely to be from another carcinogen such as pesticides, water contaminants, air pollution, or even something as simple as grilled meat (yes, grilling meat produces carcinogens -- lots of them.) Even the smoke from the grill could be the cause.

It is impossible to pin a cancer on any single source because it is impossible to isolate a single cause from the sheer number of possibilities. Could the cause be radiation? Absolutely, yes. But you have to look at probability versus possibility. If your husband 'never came close to the 500 rem allowed per year in the Navy' (actually it is 500 millirem) then the majority of the radiation your husband was exposed to was either natural background or medical. You and everyone else that never sets foot inside a nuclear plant or submarine get an average of 620 millirem/year (http://www.new.ans.org/pi/resources/dosechart/) so there is more probability that your husband's cancer, if it was caused by radiation, was caused by a source other than his occupational exposure.

Additional exposure adds additional risk, according to the most conservative theory. Another theory shows additional risk only above a certain threshold level (probably above the level your husband was exposed to) and yet another theory suggests that a certain amount of exposure actually lowers your health risks. Nobody knows for sure which model is correct, because it is impossible to remove all other factors that may influence the results of studies. The biggest (uncontrolled and therefore unscientific) study of all -- those of us who work in nuclear plants -- seem to indicate that we do not as a group have a higher incidence of cancer than the general public. In fact there is evidence that our rate is slightly lower than average. Again, that is not a controlled study so no real conclusions can be reached.

So could your husband's death be related to radiation exposure he received in the Navy? Certainly it is possible, but it in not probable. Statistically, it is much more likely he contracted it from some other source. It is tempting to blame occupational exposure and be able to point to a cause other than just random chance or other factors we have little or no control over. Unfortunately there is no way to tell for certain and the chances are better that it was something other than his Navy exposure.

In either case I am sorry for your loss.

[Marlin]

He is right in only the most most theoretical sense. Comments on cause and effect due to a single interaction have some theoretical validity, but practically it is a false statement to assign a cancer to single radiation interaction and would be impossible to distinguish from background non-occupational exposure. There is no such thing as zero radiation background radiation annually may be equal to or higher than his occupational exposure. The annual limit would be 500mRem (0.5 Rem) not 500Rem.

Here is a link to the Health Physics Society Q&A on background radiation

http://hps.org/publicinformation/ate/q824.html

Here is a link to Radiation Effects Research Foundation (note that the 3.6mSv they cite is 360 mRem.

http://www.rerf.or.jp/glossary_e/backgrou.htm

[Marlin]

Roger we must have been typing at the same time. 

[RDTroja]

Roger we must have been typing at the same time. 

No doubt... I was surprised I didn't get the 'Someone else already responded to this thread while you were typing' message.

[Marlin]

No doubt... I was surprised I didn't get the 'Someone else already responded to this thread while you were typing' message.

I did but I had already typed up a response and didn't feel like deleting it, they say pretty much the same thing with different links.