RADIOTOXICITY

[David_B_Dave_Ottley@rl.gov]

        We have developed a hazard control indices to compare relative airborne 
contamination controls for radiological and non-radiological constituents in 
radioactive mixed waste.  Materials are assigned "Modified Hazard Control 
Indices" which can be compared in order to determine the relative airborne 
contamination controls needed.  The modified indices are based on  airborne 
concentration control levels.  The indices take into consideration the 
resuspension potential (propensity to go airborne) of the material.  Modified 
indices are assigned to four chemical/physical forms of materials:
1.  Removable Contamination
2.  Fixed Contamination
3.  Wet Contamination
4.  Volatile Liquids.
The relative airborne control measures needed for radiological and 
non-radiological materials can be determined from the modified hazard control 
indices and the ratios of material masses present in radioactive mixed waste.   
      The modified hazard control indices indicate that for equal masses of 
radiological and non-radiological materials in mixed waste, the radiological 
constituents generally require airborne contamination control levels many orders
of magnitude greater than the non-radiological constituents.
        The modified hazard control indices indicate that the most restrictive 
radioactive material relative to contamination control is smearable Pu-238, with
an index of 1.00E+8.  Comparatively, the most prevalent isotope of plutonium in 
the Hanford Site mixed waste on a mass basis, Pu-239, has an index of 6.17E+5.  
The most common beta emitter, Sr-90, has a smearable index of 3.52E+5, which is 
comparable to Pu-239.  This is contrary to the common assumption that alpha 
emitting radionuclides are more difficult to control than beta emitters, 
although this is still true on a Curie basis rather than a mass basis.
        The modified hazard control indices also indicate that the most 
restrictive chemical (non-radiological) prevalent in the Hanford Site mixed 
waste is vinyl chloride with an index of 2.54E+01.  This is due to the fact that
although beryllium, with an index of 1.00, is the most toxic chemical on a mass 
basis, vinyl chloride is much more resuspendable than smearable beryllium.
        The modified hazard control indices should be useful to designers and  
safety personnel during the initial assessment of the adequacy of mixed waste  
airborne contamination control features, such as gloveboxes, hoods, facility 
ventilation, etc.  The indices should also be useful in estimating the relative 
degree of clean up required for the radiological and non-radiological 
components of a contaminated area, since clean up standards would logically be 
based on the same factors that the indices were based on (i.e., airborne control
          level).
          A detailed report is available upon request. 
          I am available at: boothe@cbvcp.com.