Radiation Dispersal

Radioactive releases can change the levels of radiation in an environment. For example, global nuclear weapons testing in the 1950s-1960s lead to a significant increase in the radiation present in the world. Though some radioactive isotopes decay rapidly, this radiation doesn't just disappear. It moves around and eventually finds some place to settle whether it's on the ground or in water.

The image below shows how radiation can spread through an environment. It's important to model how radiation spreads in order to conclude quantities that will eventually reach living organisms. For example, radiation can affect plants, terrestrial and aquatic. Aquatic plants can lead to contaminated fish while terrestrial plants can lead to animals being contaminated, like the radioactive deer found at Oak Ridge National Lab. By modeling radiation, scientists can determine whether there's any cause for concern to begin with.

Also, here's a really interesting article about why organizations like the FDA are important and just remember, you shouldn't be ingesting nuclear material without asking about how fast it will decay. Things like medical tracers are designed specifically so that it will leave your body within days so you're safe. 

Environmental Pathway Modeling

What are environmental pathway models and what are they used for?

They’re mathematical models that characterize a source, transport path, and effects of hazardous and radioactive material. They’re used to determine the effect of a radioactive release and the necessary actions that must be taken to clean up the radioactive material or to determine remedial options.

Why would you use a model?

Models might be used for one of three overarching reasons; scope, characterization, or remediation. Scope means that actual measurement of radiation may not be possible due to access, budget or time. It could also mean that field data isn’t enough and estimated measurements for locations not immediately affected by radiation releases are needed. Characterization means that the actual measurements may not be possible due to rapidly changing environmental factors such as wind or water flow. Remediation is concerned with how radiation is affected by time and conditions in order to determine a course of action.

Why are they important?

Doses to the public and health impacts can be determined by determining how radiation releases, accidental and routine, move through an environment. It also gives scientist a good way to know what’s ok and what isn’t. Referencing my Fukushima post, are we going to see high levels of radiation carried by air or water to the US? No. We know not just because we haven’t measured anything but because we’ve made tons of models and we see that the maximum quantities expected to reach the US are within safe boundaries.

Some times being a nuclear engineer is tiring...

While researching I realized that there’s something particularly beautiful about the way people who know radiation and radiation events discuss those events. In the past I’ve spoken a lot about how the nuclear media needs a serious facelift and nothing shows that more than the exasperation of the opinionated sources. Take the quote below,

“There seems to be a group of people convinced that we’re all about to drop dead from radiation exposure, that there is some vast disaster unfolding. I’m not sure why people want to believe this for it’s most certainly untrue.”

This author writes for forbes and is just so tired of telling people they’re wrong. And it’s hilarious. The truth is that rad workers are getting tired of having to explain that they’re not going to die. Most people are reasonable and can be made to see the light once you start having an actual conversation. It’s not always so easy though.

I had a friend who once told me her friend in Japan developed cancer in the months following Fukushima so Fukushima must be to blame. Her friend lived on the other side of the country. After further discussion about Fukushima and the effect on Japan, I told her that radiation-induced solid tumors usually take 10–15 years to develop and radiation-induced leukemias typically require 2–10 years to appear. It honestly took showing her sources to convince her.

Part of the problem is that we’ve been told so many lies that the truth doesn’t seem possible. It’s like when you tell people that the Great Wall of China isn’t actually visible from space. They at first will resist because they’ve heard it is so many times! If you’re unwilling to believe me as well, check Google maps! Zoom out to a full view of China and try to find it!

That’s what people in the nuclear field deal with on a regular basis. When I first told my mom I was going to be doing research, she was so scared for me! She asked me if I was going to get cancer. My reply was that as long as I could resist swallowing the sources (I said sarcastically), I was more at risk of dropping something and breaking my foot than getting cancer. That was two years ago. 

I work in the nuclear industry because I know how much security there is built in to every aspect in what I do. I work in the nuclear industry because I believe in the nuclear industry and I’m willing to spend the rest of my life defending it but should I have to? I think the industry has a very long way to go on being more understanding of the general public, of educating rather than belittling the public. However, studies show that the more the industry says that nuclear is safe, the less people believe it. The question now is, how to approach an issue that seems to have no solution?

Radioactive Fish?

We’ve all heard at one point or another about the risk of radioactive fish coming from Fukushima. I’m here to tell you not to be concerned. Seriously. Don’t worry.

Immediately after Fukushima, there were high levels of radiation detected in the immediate area but thanks to ocean currents, most of that radiation has been dispersed. If that sounds scary, it really shouldn’t. Think about labels that warn you that you shouldn’t do something in a poorly ventilated area. Carbon monoxide can be a deadly issue in a closed garage but it isn’t really if the garage is left open and air can flow out. The carbon monoxide that you let out of your garage isn’t going to kill your neighbor because it’s been dispersed by air currents and spread so thinly it’s not much of a risk to anyone.

Radiation in the ocean is much like opening the car garage. The area right next to your exhaust is probably not the best place to be but it shouldn’t cause any problems if you’re outside the garage door. Additionally, the half life of some of the elements is quite short. Iodine-131 has a half life of just 8 days.

One of the big radiation concerns was and still is the seafood in the area. Some fish, referred to as pelagic species, roam the open ocean and can travel across oceans. Tuna made the news when samples of tuna caught off southern California were found to contain radioactivity traceable to Fukushima. Scientists were excited about this – not because of concern about the radioactivity – but because the radioactivity demonstrated that bluefin tuna do routinely travel all the way across the Pacific Ocean. The amounts the fish carried were minuscule — far less, ounce for ounce, than the amount of naturally occurring radiation occurring in a banana— but enough for scientists to gain insight into animal migration.

Additionally, a study done by Oregon State University revealed traces of cesium in albacore tuna. However, “a year of eating albacore with these cesium traces is about the same dose of radiation as you get from spending 23 seconds in a stuffy basement from radon gas, or sleeping next to your spouse for 40 nights from the natural potassium-40 in their body," said Delvan Neville, a graduate research assistant in the Department of Nuclear Engineering and Radiation Health Physics at Oregon State University “It’s just not much at all.”

If you’re still concerned, know this: As of March 10, 2014, FDA has tested 1,345 import and domestic samples specifically to monitor for Fukushima contamination. Two hundred and twenty-five of these were seafood or seafood products.  Of the 1,345 samples, two were found to contain detectable levels of Cesium, but the levels were well below the established Derived Intervention Level (DIL) and posed no public health concern. 

Atmospheric Radiation Release from Fukushima

This post is in honor of the men and women that served on the USS Ronald Reagan in 2011 when Fukushima occurred. These men risked their lives and they’ve experienced the effects of large atmospheric releases first hand.

I figure we’ve all heard about Fukushima and the general events that happened there. What I’m specifically talking about is the atmospheric releases from the event.

First I’d like to start by sharing the image below with you.

I don’t know if you have all seen it but I personally seen it 100 times (not really I’m exaggerating) in connection with radiation released from Fukushima-Daiichi. I’m going to teach you a quick trick for checking how much images actually have to do with radiation, check the scale. The scale for this graph is in centimeters. What do centimeters have to do with radiation release? In this case, absolutely nothing! Especially because this is a map of how wave height was affected by the Tsunami.

This image is a much more accurate representation of the plume, or radiation cloud, that left Fukushima after their nuclear accident. And before you go getting scared on me, the radiation levels “reaching” the US are below 0.01 Bq/m^3. If you remember our conversation about Radon, anything below 4 pCi/L is totally fine. 4pCi/L translates to about 150 Bq/m^3 (which when you compare it with the dose from Fukushima makes the Fukushima dose basically insignificant). So basically you should still be more worried about what’s already in your home.

However, the crew of the USS Ronald Reagan was called in to assist Japan after the tsunami. Unfortunately, they got fully caught up in the plume coming from Fukushima. Radiation dust was being deposited on the decks, it was in their water supply. Most of the crew got some for of radiation poisoning, which meant a lot of puking and generally being ill. It also means that their future cancer risk is way high.

TL;DR : The men and women on the USS Ronald Reagan are heroes. Radiation from Fukushima isn’t going to kill you or cause your pets to mutate even if you live in California. You can also look at this site for more information. You should probably still consider a radon test (they’re only like $10 anyway). 

Regulating Atmospheric Emissions

On Wednesday, we talked about radiation protection standards and how much a nuclear site, whether medical or power producing, is allowed to release to the public. I emphasize the term nuclear plant because the reality is, if you’re not working with explicitly radioactive material, like those regulated by the Nuclear Regulatory Commission (NRC), the rules don’t really apply to you.

In theory, this makes sense. Why regulate if there’s no danger right? Wrong! The truth of the matter is that not just controlled materials produce radiation and without proper oversight, there are big industries that release radiation without ever being controlled. For example, fly ash, a product of coal fire plants, carries into the environment about 100 times as much radiation than a nuclear plant. If this sounds like an ad hominem argument, I don’t mean it to (well, maybe a little).

In fact what I mean to say is that the nuclear sector is thoroughly regulated, to the extent that two inspectors for the NRC are located at each power plant. Every move made at a nuclear plant has includes an insane amount of preparation. And more importantly, our operators are most definitely NOT Homer Simpson. Most plants even require a bachelor’s degree for operators, and that’s before the two to three years of training that precede actually being able to touch something.

Radiation releases are an important thing and preventing them, along with other releases to the public, is a big deal. Or maybe more industries should be as regulated as we are. That would prevent things like this plant in Texas that didn’t even have fire codes.

Radiation Protection Standards

At the start of the twentieth century it became clear that standards would have to be set in order to protect workers and patients from the negative effects of exposure to radiation. First attempts at protecting people created the concept of tolerable doses.  Tolerable doses are those below which no immediate effects occur. Though at first it seemed to do enough, in 1948 the National Council on Radiation Protection (NCRP) introduced permissible doses. These doses differed from tolerable doses in that they were not expected to cause harm during a person’s lifetime and not just the days following initial exposure.

Today, we understand that low-level radiation exposure can lead to stochastic effects, or effects that though they may be predicted statistically, occur spontaneously. Due to these stochastic effects, modern radiation standards are based on probabilistic assessments of radiation effects.

These modern standards are based on the idea that a high standard of safety for a work environment means that no more that 100 per million workers die in a year. To put it in perspective, in a workforce of 100 people, 1 person would die every 100 years. But, this was not considered safe enough so an acceptable risk of 50 deaths per million workers per year. This translates to 1 person every 200 years in a 100-person workforce.

After this definition of “safe” was set, statisticians did a whole bunch of math (that was overly safe and assumed people worked in the industry for 40 years and radiation effects built up and 10 percent of people would reach maximum dosage and blah blah blah) ultimately deciding that a “safe” whole-body dose-equivalent limit for stochastic effects was set for workers was set at 5 rem per year. Then, they released this limit to the industry, and the industry more or less uniformly decided that in order to stay super safe, they would use a limit far below that, and most companies set their own limit at 1 rem per year. The NCRP also calculated the dose limit to the individual members of the public, 0.5 rem per year. Once again, the industry set a standard below this to prevent crossing that line.

Again, these limits were set for stochastic effects so what they’re preventing is lifetime risk not just immediate harm. I guess what I’m saying is, the exposure limits are there to keep people super safe.