ROCKY FLATS: A CALL TO
NUCLEAR GUARDIANSHIP
Co-Sponsored by Rocky Mountain Peace and Justice Center
and the Naropa University Environmental Studies Programs
AIRBORNE EMISSIONS AND
MONITORING OF PLUTONIUM FROM
ROCKY FLATS
W. Gale Biggs, PH.D.
March 17, 2011
Most of the information presented
comes from Dr. Biggs’ participation on
the following three committees:
Rocky Flats Scientific Monitoring Panel
(Appointed by Governor Romer)
Rocky Flats Cleanup Commission
(an EPA TAG group)
Rocky Flats Citizen Advisory Board
(a DOE sponsored group)
Two items will be covered:

PU emissions

Monitoring of airborne concentrations
PU EMISSIONS
 Stack Emissions
 Fugitive Emissions


Reflotation / Surface disturbance
High Wind Events
 Events – (Will Not Discuss These Events)


Fires
Accidents
PU STACK EMISSIONS



Stack emissions pass through banks of
HEPA filters
Average size of PU particles in building
ducts is 0.045 microns
Average size of a human hair is about
50 microns
PU FUGITIVE EMISSIONS
How much of the plutonium leaving Rocky Flats was
from fugitive sources?
 The amount is unknown, but
estimates were from 60% to 99%
 Fugitive PU emissions are due to:
 Surface disturbance by human activities
 Wind
Bottom
Line
 Fugitive emissions are unknown
 But they account for the majority of PU emissions from
the Rocky Flats facility
PU PARTICLE SIZE


Soil emissions (fugitive) consist of both small
and large particles
Stack emissions are very small particles since
they pass through several banks of HEPA
filters
ALPHA-RECOIL EFFECT


This effect occurs when the PU molecule
emits an alpha particle (radiational decay)
Alpha decay generates enough energy to
blast a piece of PU off the particle
ALPHA-RECOIL EFFECT


This effect occurs when the PU molecule
emits an alpha particle (radiational decay)
Alpha decay generates enough energy to
blast a piece of PU off the particle
ALPHA-RECOIL RESULT
Due to alpha recoil effect:
 Particles decrease in size
 Increase in number

The fugitive emissions are the
dominate source for airborne PU from
the Rocky Flats
THE NEXT SLIDES WILL DISCUSS THE
STACK EMISSIONS
STACK EMISSION ESTIMATES
Look at an exhaust duct from building
707
 The pitot tube measures the air flow
through the duct and is used to
calculate emission concentrations
 The radiological monitors are designed
to measure radiation through the duct

BUILDING EXHAUST DUCT
Pitot
Air Flow
Radiological
Monitors
Top View
Stack
exiting
roof
PROBLEMS WITH DUCTS
The pitot tube had not been calibrated
since it was installed when building
707 was built, therefore the amount of
air flow in the duct is unknown
 The air movement for measuring
radioactivity was flowing backwards

NEXT SLIDE SHOWS THIS
Rotary Air Flow in Duct
Pitot
Air Flow
Radiological
Monitors
Top View
Stack
exiting
roof
PU STACK EMISSIONS
The air flow through the duct was
unknown
 The amount of PU in the duct was
unknown
 Therefore the PU emissions from the
stack were unknown

HOW GOOD WERE THE
EMISSION ESTIMATES?
We just showed that the stack
emissions were unknown
 The fugitive emissions were unknown

Bottom line – the DOE did not know
how much PU was being emitted into
the ambient air from Rocky Flats
AMBIENT MONITORING
Since the emissions were not known,
could the monitors perhaps indicate the
amount of PU coming off the Rocky Flats
plant?
Unfortunately –
NO!!!
PU IN THE AIR


We earlier showed that the stack PU
particles going into the air are very
small
The airborne stack particles are
probably smaller than 0.01 microns
PU IN THE AIR
 However, some of the small particles attach
to larger particles in the atmosphere
 Examples of larger particles in the
atmosphere are:
 Pollen
 Organic matter
 Fugitive particles can be either small or
large depending on surface activity and
wind speed
AIRBORNE PU PARTICLE SIZE



The next slide shows the range of airborne
particle sizes for PU and the collection range
of the high volume air sampler
Both the initial particle size as well as those
attached to larger particles are shown
Pollen and organic matter in the atmosphere
usually range in size from about 15 to
several hundred microns
Particle Size Sampling Range for HiVol Sampler
Particle Size Range
for Dispersed PU
0.001
0.01
Particle Size Range
for Wind Blown PU
0.1
1
Particulate Size (microns)
10
100
MONITORS ADEQUATE?
No – the monitors are inadequate
 The air monitors are not sampling the
airborne PU which is being emitted
from the Rocky Flats site.

Bottom line – we do not know the
ambient concentration of PU emissions
leaving the Rocky Flats site
ROCKY FLATS HEALTH
ADVISORY PANEL
The Rocky Flats Health Advisory Panel,
at the end of their Phase I analysis
stated that the most dangerous health
exposure to the public was from the
airborne pathways
 Since we do not know the emissions,
the extent of the health problems is
not possible to estimate

CONCLUSIONS






We do not know how much PU is (or was) being
released from the Rocky Flats site
The majority of the PU emissions are from the soil
being disturbed by both activity on the site and
from wind blown dirt
The ambient air monitors are not representative of
the airborne PU concentrations
PU probably travels some distance before settling
Population is exposed to PU by air pathways before
settling occurs
PU in the air is not taken as seriously as it should
be