Showing posts with label ORAU. Show all posts
Showing posts with label ORAU. Show all posts

Sunday, July 6, 2014

Plant Site Boundary Radiation Measurements and More Unreasoning ALARA

Measuring Low Level Radiation At the Site Boundary

The NRC requires careful control of the maximum radiation dose at the site boundary of a nuclear power plant.  For a non-specialist like myself, the NRC document 10 CFR Part 20 is not easy to interpret.  Plus, power plants in Vermont must meet even more stringent state requirements.  To explain the situation, I will quote a  Vermont Department of Health press release on site monitoring at Vermont Yankee:
The U.S. Nuclear Regulatory Commission limits radiation doses for the general public to 100 millirem per year. The limit set by the U.S. Environmental Protection Agency is 25 millirem per year from radioactivity in water, air and soil. The Vermont Department of Health limits are more restrictive – 20 millirem per year.
In other words, the plant-caused radiation at the site boundary in Vermont must be less than 20 millirems above background radiation, total, per year. Indeed, the radiation at Vermont Yankee plant boundary is at a such a low level that it  cannot be measured easily and reliably, except by specialists.

Detecting 20 millirems per year over the background level of around 300 millirems per year: this is not easy.

Measurements disagree

Predictably, at the low levels of radiation required by Vermont,  measurements are difficult and results can conflict.  Sure enough, Entergy measurements and Vermont Department of Health measurements disagreed.  Basically, low levels of radiation release have to be measured by specialists in measuring low-level radiation.

To resolve the conflict between the Entergy measurements and the Vermont measurements, Entergy engaged Oak Ridge Affiliated Universities (ORAU) to do a third set of measurements.  ORAU has a group that specializes in radiation measurements. The local opponent groups objected to this choice.

The opponents' main accusation was that ORAU was part of the industry and could not be trusted.  Another accusation was that hiring ORAU was a way to fool Vermont citizens into thinking that Entergy had hired Oak Ridge National Laboratory.  (ORAU is basically part of Oak Ridge National Laboratory. It's complicated, and has to do with the difficulty the government has in hiring temporary employees, graduate students, etc. )

Meanwhile, the opponents objections to ORAU and the measurements were not mild-mannered. There were shouted accusations.  I saw a man from VPIRG completely blindside an Entergy employee at a public meeting. The Entergy man on the panel had no idea that the contract with ORAU was going to lead to shouted accusations of being a liar.  It was a sad sight.

However, the Entergy measurements were correct.

But finally, the whole thing was over. The measurements were reviewed, and the Vermont Department of Health issued a final report on the boundary measurements. Here's a quote from the Vermont Department of Health report:

The report concludes that the measurement methodology used by the Vermont Department of Health since 1973 was less accurate than current methods used by Vermont Yankee.

And yes, here's another quote from the same report:

At no time has the dosage from the Vermont Yankee plant posed a measurable risk to public health.

Vermont Yankee was in compliance with Vermont's strict radiation protection laws.

ALARA strikes again


A great deal of money and energy was spent on the boundary-line dose issue, and nuclear opponents took every opportunity to humiliate people from Entergy about the measurements and the contractor.   But what did it all mean?  What was accomplished?

  • Was anybody protected from harm by these repeated measurements of the very small amounts of radiation? No. 
  • Was a great deal of money spent on these measurements? Yes
  • Do ALARA and LNT encourage the fear of the least little bit of radiation, and do they imply that we must constantly strive to reduce even tiny amounts of radiation? Yes.
  • Must we strive to reduce amounts of radiation that are actually so low they are hard to measure? Yes.
  • Do ALARA and LNT help our country have reliable, affordable electricity? No.


I encourage my readers to share their own ALARA stories.