Nanoparticles are those particles that range in size from 1 to 100 nanometres (nm).
At this size, materials begin to exhibit unique properties that affect physical, chemical, and biological behavior. ... Studies have indicated that low solubility nanoparticles are more toxic than larger particles on a mass for mass basis. There are strong indications that particle surface area and surface chemistry are responsible for observed responses in cell cultures and animals. Studies suggests that some nanoparticles can move from the respiratory system to other organs.
Nanomaterials that can be inhaled, ingested or can penetrate skin indicate a potential for exposure and present the possibility of potential health effects. Processes that lead to airborne nanometer-diameter particles, respirable nanostructured particles (typically smaller than 4 micrometers) and respirable droplets of nanomaterial suspensions, solutions and slurries are of particular concern for potential inhalation exposures.
Results from experimental animal studies with engineered nanomaterials have provided evidence that some nanoparticle exposures can result in serious health effects involving pulmonary and cardiovascular systems and possibly other organ systems.
From: NIOSH (2017) Nanotechnology
DEQ never mentions alpha recoil on their website, despite me documenting this fatal flaw since my 3rd year of doing their job, in 1991. Silence is golden but plutonium is NOT good to inhale!
This is just the simple version of my official draft comments, of one of the 13 issues I submitted in my scoping questions. All 13 were ignorantly dismissed by DOE. Sincerely ... Peter Rickards
Here is the DOE dismissal url and one of my correcting OSTI url below:
On Webpage 13/17
Comment Summary: A commenter requested DOE address the “fatal flaw” of plutonium and uranium moving through high-efficiency particulate air (HEPA) filters due to “alpha recoil.” DOE Response: The real-world performance of multiple stages of HEPA filters has been well demonstrated and experimental testing confirms the performance of HEPA filters for uranium and plutonium particles. The independent Defense Nuclear Facilities Safety Board (DNFSB) thoroughly evaluated the use of HEPA filters by DOE) and has issued multiple reports on the performance of HEPA filters within the DOE complex. HEPA filters used in support of the VTR activities would conform to the latest version of DOE Standard “Specifications for HEPA Filters Used by DOE Contractors,” DOE-STD 3020-2015. Performance testing required by this standard for all HEPA filters credited for safety would ensure that the filters meet or exceed the performance requirements assumed in safety evaluations.
Consequently, the entire particle of which that Pu-238 atom is a constituent experiences a movement similar to the recoil of a gun when a bullet is ejected. Furthermore, the particle often fractures in response to Pu-238 atom disintegration (yielding an alpha particle), with a small particle fragment also being ejected in order to conserve momentum. This process results in the continuous size reduction and transport of particles containing Pu-238 atoms, thus explaining movement of contamination along surfaces and through HEPA filters.