Some Isotopes Were Not Calculated, Per New Huntington Pilot Plant Response, Lengthier Residue Decays Possible

Updated 4 years ago by Tony Rutherford HuntingtonNews.Net Reporter
Some Isotopes Were Not Calculated, Per New Huntington Pilot Plant Response, Lengthier Residue Decays Possible

A June/July 2013 report contains detailed responses of scientists to NIOSH findings related to the Huntington Pilot Plant (Reduction Pilot Plant), which processed enriched uranium and recycled the material from diffusion plants.

At first reading of the documents, it is unclear whether the newest “finding” responses and observations will benefit workers seeking compensation for health risks stemming from a variety of cancer related illnesses. Why? A statement reveals that instead of 36% enrichment (assay) assumptions, NIOSH has determined that 2% is more accurate.

Further, the report finds a gamma decay period of 50-100 years for all isotopes. Earlier documents calculated only “short-lived progeny of U-238 and U-235.” (p. 21) nor were residues assumed to be stored in 20 gallon containers in prior site profiles.

The 2004 document stated, “Pu-239 and Np-237 are the contaminants that are likely to have contributed to significant dose at the RPP” [Reduction Pilot Plant]. No basis or reference for making this statement is provided. Additionally, the site profiles for Paducah [ORAUT-TKBS-0019-5 (ORAUT 2012)], Portsmouth [ORAUT-TKBS-0015-5 (ORAUT2004b)], and K-25 [ORAUT-TKBS-0009-5 (ORAUT 2006)] all indicated that Technetium-99 is the fission product of concern from a dosimetry standpoint for recycled uranium. Paducah also indicated that americium-241 was also “present in small amounts in the feed material produced from RU (recycled uranium).”

Since nickel came to the HPP from all three diffusion plants, NIOSH has been asked to provide a basis for why Pu-239 and Np-237 are the only concerns. Other isotopes that may have been present as contaminants would include Th-230, the aforementioned Tc-99, and Uranium 234, 235, 236 and 238. Generated decay times range from ten to fifty and 100 years. The review did not discover significant decay time differences for the uranium gamma spectrum.


Residues are now assumed to have not been stored in so-called “birdcages”, rather in 20 gallon drums stored on the ground floor of the plant spaced over a 40 foot by 105 foot area.

“These assumptions of the configuration of the residues differ from what had previously been assumed”, the draft report states.


Calculations of airborne nickel at the HPP per a 1982 report apparently mixed data calculations for both then modern and historic data.

“In other words, the modern nickel concentrations are likely SMALLER than what the historic concentrations would be”, the new report said.

An observation made --- but which does not have to be adopted by NIOSH --- is that “appropriately used” the airborne nickel concentration distribution can be used to “make favorable exposure estimates” for individual workers. Now, NIOSH calculations favor only one in four workers, where three of the four workers should be favorable.


The 20 gallon drums contained the residue from 150,000 pounds of (diffusion plant) feed materials spaced “uniformly” on the ground floor (p. 13). The dose receptor was “30 cm from the center of the drum and 77.9 cm above the surface.”

Radioactive isotopes do not decay into a stable state. A series of transformations occur. Intermediate stages of decay often emit more radioactivity than the original radioisotope (per Wikipedia). The online encyclopedia sites an example of U-238 as not significantly radioactive; however, a radioactive element may decay into a decay product (or daughter) that can be more radioactive.

Hence, the report stressed that the “full equilibrium of U-238, U-235 and U-234 with their decay products” should have been considered, not just so-called “short-lived progeny”.

To understand the implications of waste products, you must realize that nuclear decay does not behave like ordinary chemicals, which may eventually go away. Instead, the unstable nuclear residue elements mutate into other elements with other properties. 

According to Reaching Critical Will Nuclear Fuel Cycle:

The nuclei of radioactive elements are unstable, meaning they are transformed into other elements, typically by emitting particles (and sometimes by absorbing particles). This process, known as radioactive decay, generally results in the emission of alpha or beta particles from the nucleus. It is often also accompanied by emission of gamma radiation, which is electromagnetic radiation, like X-rays. As radioactive atoms decay, alpha, beta and gamma rays are emitted. Alpha rays are heavy positively charged particles travelling at high speed (several kilometres a second). These rays emanate from heavy elements such as uranium, plutonium and americium. Beta rays are negatively charged electrons seven thousand times lighter than alpha particles. Gamma rays are electromagnetic radiation which emanates from most though not all radionuclides.

These three kinds of radiation have very different properties in some respects but are all ionizing radiation--each is energetic enough to break chemical bonds, thereby possessing the ability to damage or destroy living cells. Uranium-238, the most prevalent isotope in uranium ore, has a half-life of about 4.5 billion years; that is, half the atoms in any sample will decay in that amount of time. Uranium-238 decays by alpha emission into thorium-234, which itself decays by beta emission to protactinium-234, which decays by beta emission to uranium-234, and so on. The various decay products, (sometimes referred to as "progeny" or "daughters") form a series starting at uranium-238. After several more alpha and beta decays, the series ends with the stable isotope lead-206. (Source: Institute for Environment and Energy Studies)

Click on the downloadable attachment to view the full preliminary draft, which includes "typo" corrections of previous versions. These "typo" errors apparently did not alter most conclusions, the report indicated.


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