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Radiation Safety Aspects of Nanotechnology:
Update on Development of an NCRP Commentary MD Hoover
1, DS Myers
2, LJ Cash
3, RA Guilmette
4, WG Kreyling
5, G Oberdörster
6, R Smith
7, and BB Boecker
4
1National Institute for Occupational Safety and Health, Morgantown, WV;
2Lawrence Livermore National Laboratory, Livermore, CA;
3Los Alamos National Laboratory,
Los Alamos, NM; 4Lovelace Respiratory Research Institute, Albuquerque, NM;
5Helmholtz Institute, Munich, Germany;
6University of Rochester, Rochester, NY;
7HPA Centre for Radiation, Chemical and Environmental Hazards, Chilton, Oxfordshire, UK
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of their respective organizations or the National Council on Radiation Protection and Measurements.
The National Council on Radiation Protection and
Measurements (NCRP) has established NCRP Scientific
Committee 2-6 to develop a commentary on the current state
of knowledge and guidance for radiation safety programs
involved with nanotechnology.
NCRP originated in 1929 and was congressionally chartered
in 1964 under U.S. Public Law 88-376 as a not-for-profit
service organization to serve in the Nation’s public interest by
collecting, analyzing, and disseminating the latest scientific
information about radiation protection and measurement.
NCRP cooperates with national and international
governmental and private organizations to facilitate the
effective use of combined resources to further develop the
basic concepts of radiation protection and measurement.
Introduction to the Commentary Applications of Radiation in Nanotechnology
The commentary’s focus places strong emphasis on practical operational information for operational health physicists, radiation safety officers, dosimetrists, workers, managers, and regulators. Information applicable to the radiation safety aspects of nanotechnology has been derived from studying naturally occurring nanoparticles, ultrafine aerosols of actinides, and aerosols from atmospheric testing. An analysis is being performed on how traditional health physics program practices may need to be modified to provide adequate safety for working with radioactive nanomaterials and nanotechnology applications involving radiation. Knowledge gaps are being identified regarding information needed to implement a comprehensive and effective radiation safety program.
Key Questions
The commentary intends to provide guidance on contamination control, engineered
and administrative controls, personal protective equipment including respiratory
protection, performance of safety training, waste disposal, and emergency response.
The commentary also intends to provide specific guidance on conducting internal
dosimetry programs if nanomaterials are being handled. Possible differences in the
biological uptake and in vivo dissolution or translocation of radioactive nanoparticles,
compared to more commonly encountered micrometer-sized particles, may impact
the design and conduct of internal monitoring programs and dose calculation
methods.
Model parameters and other considerations will include: how nanometer-sized
particles are addressed in current respiratory tract and systemic biological models;
deposition efficiency, total and regional retention patterns, and cells and tissues at
risk; and the potential for multifactorial biological effects from radiation, chemical, and
physical properties of the nanoparticles.
Contact Information
Questions and comments are welcome via
email: [email protected], or phone: 304-285-6374.
How should radiation dosimetry be conducted
for nanomaterials?
What are the sources
of radiation-related
nanomaterials? How can exposure be assessed
over life-cycle processes?
Nanotechnology in Radiation Settings
• Nano-synthesis methods
• Annealing processes
• Characterization tools
• Aging studies
• Special systems • Plasma-focus-based
radiation sources
www-pub.iaea.org/MTCD/publications/PDF/te_1438_web.pdf
• Nano-enabled materials for
components and structures • Are carbon nanotubes
“the new steel” ?
• Noble-metal enrichment
using Pd for self-healing of
cracks
• Coatings and barriers
• Coolants
• Cooling piping
• In-core reactor applications
• Sensors • Physical, chemical,
radiological
• Separations / Sorbents
• Enhanced concretes
• Security applications
www.tms.org/meetings/2012/nanonuclear
We can partner to develop a
comprehensive risk management scheme to:
• Anticipate,
• Recognize,
• Evaluate,
• Control, and
• Confirm
by applying a science-based approach to understanding and managing
the critical elements over which we have control.
Hoover et al., Synergist 22(1): 10, 2011.
success in our management
of the radiation safety aspects of nanotechnology
Training
A Hierarchical Vision of Hazard and Exposure Control for Comprehensive Health Protection, Health Promotion, and Well-being
Draft for discussion
Potential Hazard x Potential Exposure = Potential Risk
We have retrospective,
contemporaneous,
and prospective
opportunities.
Multiple hazards
may be relevant.
Containment
and other
engineered
controls
Elimination
Substitution
Work
Practices Personal
Protective
Equipment
Modification
Su
stai
nab
ility
Safety, Health, and Well-being
Safety, Health, and Well-being by Design
Safety, Health, and Well-being by Procedure
What adjustments are needed for the
radiation safety aspects of nanotechnology?
Particle size-dependent deposition in the human
respiratory tract is a critical factor.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0.001 0.01 0.1 1 10 100
Total
Head Airways
Tracheo-Bronchial
Alveolar
Particle Diameter (µm)
Dep
osit
ion
Fra
cti
on
Calculated from the ICRP 66 model for an adult male, light exercise, nose breathing.
Considerations of Particle Size Comprehensive Control of Hazards and Exposure
A Dosimetry Example for Plutonium A Comprehensive Basis for Decision-Making
Committed effective dose
per unit measured activity
in urine is higher for larger particles.
Thus, bioassay interpretation
based on the default particle size
should be protective.
Better sizing of particles will lead to better dosimetry.
Courtesy of LJ Cash
Radioactive nanoparticles
need to be studied in more detail.
Preliminary data analyses suggest
higher urinary excretion
of nano-Pu-239
compared to the default
5-µm particle size.
Focus, Intents, and Status of the Commentary
Finally, it is intended that the approaches taken to develop the commentary will
be an example to the broader nanotechnology knowledge infrastructure
community on how to determine which information is relevant, and then to
collect, validate, store, share, mine, analyze, model, and apply that information
for the efficient use of future work in the area of nanotechnology safety.
It is expected that preparation of the commentary will take about 12 months.
LA-UR-13-21445