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Category: Fukushima

California Beach Radiation Not From Fukushima

A lot of concern has been expressed about recent reports and videos showing high levels of radiation on a beach in Half Moon Bay, just South of Pillar Point Harbor. It has been attributed to Fukushima. Local officials have been quoted as saying they donʻt know what it is, but donʻt worry about it. See local story.

Here is what we have learned so far: The radioactive areas of the beach seem to be associated with dark sand below the high tide level. The levels detected are about 5 to 10 times what you would normally expect to find on a beach. This level of contamination indicates just how massive the environmental remediation project will be across the pacific.

The radionuclides are in the NORM class of radioactive substances, not from Fukushima. NORM stands for Naturally Occurring Radioactive Material. We put a sample in a Multichannel Analyzer and found Radium 226 and Thorium 232. See the measured spectra below.

This is the spectra from the beach sample
This is the spectra from the beach sample

If the sand were contaminated by radiation from Fukushima it would show Cesium 137. See spectra below from contaminated area of Fukushima Prefecture. The same instrument is identifying Cesium 137 rather than Radium and Thorium.

Sample of deck material from contaminated area of Fukushima Prefecture
Sample of deck material from contaminated area of Fukushima Prefecture

 

The picture below is a geiger counter measuring the activity in a sample bag of the sand. The radiation level is elevated, but roughly equivalent to some granite counter top material from Brazil.

 

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This is a geiger counter with 2 inch pancake detector measuring the activity in the sand sample

 

Whether this material is naturally occurring at this beach or not remains a question. There are also reports that a pipeline was once at this location. We hope the State will do further testing to determine the origin and full nature of the hot spots on the beach. But we are confident that it is not related to Fukushima, based on the spectral signature. We expect more news later today.

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Fukushima Spent Fuel Removal Delayed?

Work was to begin as early as this Friday to remove spent fuel rods from the unit 4 reactor site at Fukushima Daiichi.  Japan Times reports that there will be a delay of up to two weeks while tests are conducted.  Read their scoop here.

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Geiger Counters, Radioactive Water and a Wall of Ice

We are generally dedicated to Geiger Counters – the noble tool that lets us see and learn about the invisible realm of radiation that ionizes.

We also post about  radiation detection in general.

We get many questions about radiation detection.  We use this blog as a tool to answer as many of them as we can in one place that we can refer people to.   We try to keep the content understandable by lay people to the best of our abilities, while keeping it also relevant and useful for professional health physics, public safety and security people.

Radiation detection is a big conversation.  There are new technologies to discuss, basic physics for those just entering the arena, and general learning about equipment.

Unfortunately, news about Fukushima Daiichi is troubling, and it is dominating peopleʻs attention these days.  We apologize for diverging from the geiger counter conversation, but it is becoming evident that Daiichi is something we need to be concerned about.  See CNN story.  Itʻs not as bad as some people claim it is, but there are many challenging problems yet  to be overcome.   We wish those responsible for the cleanup good luck, and we hope the workers will get medals, recognition, lifetime medical care, health monitoring, and benefits for their families.  Itʻs a gnarly situation and they are some of the heroes who are risking their personal well being for the rest of us.

Itʻs heartening that the Japanese government is jumping in to play a greater role in managing the emergency, and that outside advisors are being used.   See related Reuters article.  The situation is forcing “outside the box” thinking.   A “Wall of Ice” is being proposed as a way to stabilize the problems with groundwater.   See MIT Technology Review article.

Finally back to Geiger Counters: Japan Post (think the equivalent of US Postal Service) is partnering with nonprofit Safecast to get more granular data into the maps jointly developed with MIT Media Lab and Keio University.  See video (in Japanese).

Letʻs all wish Japan luck getting the Fukushima Daiichi situation under control.  Weʻll try to get back to more articles on geiger counters and radiation detection, including how to do basic testing of water, air, food.

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