Is red Fiestaware radioactive?

[Neutron_Activation]

In your answer to the radioactive Fiestaware question you wrote, “the actual amount of radioactivity is extremely low–less than the normal background radiation you get from rocks and stuff”. I was wondering if that information was provided by the manufacturer?

http://www.straightdope.com/classics/a4_099.html

I’ve found that this is to be far from the case, I have a pre-war red Fiestaware plate that registers slightly less than 17mR/h or about 300 counts per SECOND at the surface. Background radiation in the Wash. D.C. area is about 12 counts per MINUTE(17-24 CPM during and after some rainstorms due to rain-out). While 17mR/h is considered low level radiation it is by no means background levels. The only rocks I’ve found with levels comparable with Fiestaware’s activity are my collection of Uranium ore samples and the plate still out shines many ore samples.

The National Institute of Standards and Technology has done extensive testing of the glazes used in pre-war ceramics and glass, Fiestaware registered the highest activity levels of any commercial product tested not deadly but well above background levels.

http://nvl.nist.gov/pub/nistpubs/jres/105/2/j52hob.pdf

According to the Nuclear Pharmacy newsletter vol 2, No. 2 Mar. 2004 “it was found in 1994 that the red pieces were leaking radon gas through cracks in the glaze at levels that are seven times higher than is considered safe.” I have had trouble corroborating this story.

http://www.nuclearonline.org/newsletter/March04.htm

According to the Health Physics Society fact sheet on radioactive consumer goods:

“Ceramics. Ceramic materials (for example, tiles, pottery) often contain elevated levels of naturally occurring uranium,
thorium, and/or potassium. In many cases, the activity is concentrated in the glaze. Unless there is a large quantity of the
material, readings above background are unlikely. Nevertheless, some older (for example, pre-1960) tiles and pottery,
especially those with an orange-red glaze (for example, Fiesta ware) *can be quite radioactive.” *

consumerproducts.pdf

This article from the Oak Ridge Associated Universities gives a detailed description of tests done on Fiestaware by the NRC

http://www.orau.org/ptp/collection/consumer%20products/fiesta.htm

I don’t wish to alarm the individual who asked the original question as the levels are still below regulatory concern, but to say that Fiestaware’s activity levels are lower than the background levels of soil and rocks is wrong.

[remguy]

I actually work with radiation and nuclear instrumentation.

I located an actual large 1940’s fiestaware plate of the red-orange variety. Using a 2" mica-windowed gieger detector that registered 55 counts per minute for a timed 30 minute background at my location, I found the plate to read 65,213 counts per minute with the probe placed at the plate’s surface. (10minute averaged). Thus, this plate was found to be almost 1200 times the normal background radiation.

The glaze was indeed Uranium Oxide. Refined uranium oxide, (U238) emits only alpha radiation in the 5 million electron volt energy range (high speed helium nuclei). This radiation will not pentrate the glaze for the most part!

Uranium decays over time to many other radioctive byproducts called “daughter products”. Each daughter, in turn, decays to yet another radioactive atom until the sequence ends in stable lead over many billions of years.

In only 1 year following the refining of Uranium oxide, a very intense beta particle emitter, (high speed nuclear electrons), is produced via the above mentioned decay process. These intense emitters are Thorium 234 and Protactium 234

The primary radiation detected in my tests was this very pentrating beta radiation.
Unbroken glaze prevents any acutally uranium or any of the daughter products to escape or enter food. No danger here for ingestion.

So far as exposure external to the plate, a distance of only 3 feet was enough to bring the count down to near normal background. Range from a nuclear source is always the best protection. For a normal dinner time setting while eating from such a plate, no harmful dose would be recieved. For collectors who do not hover over such an item within 1 foot or more, the continous, long term exposure would be virtually nil.

No radon will escape from even a cracked plate. Radon gas is a radium daughter product. When pure uranium oxide is refined or extracted from uranium ore minerals, it will take about 200,000 years for the radium daughter to grow back into the Uranium oxide. Thus, plates made in 1942 would have little or no radium in it, thus, no significant radon levels.

To sum up, all pre-WWII red-orange fiestaware is strongly radioactive at short range, but not dangerous over even long periods to any owner provided, the glaze is uncracked and the owner doesn’t spend protracted periods of time within 1 foot of the item.

Few collectors dine regularly off of expensive, pre-WWII, red-orange fiestaware. However, if the glaze is sound, there would be no problem in eating off the plate on occasion.

Remguy