Re: Dirty bombs & dirtier assumptions

["Jim Hardeman" <Jim_Hardeman@dnr.state.ga.us>]

Jerry -



I don't claim for one minute that the calculations I cited are "reality", or anything close to it ... I'm not that naive. The only claim I make is that the calculations cited implement the current "official" US guidance for protective measures, as outlined in EPA 400-R-92-001, and in fact use the published EPA dose conversion factors found on pages 7-9 of this document. I can't speak to how much "imagination" the writers of this document exercised in developing these factors, but as you at least implied, radiological consequence assessment is at least as much art as it is science. Someone far more knowledgeable that I on this subject once said that if you tell him what answer you want, he could figure out some plausible way to perform the calculations to give you that answer.



Jim Hardeman

Jim_Hardeman@dnr.state.ga.us



>>> "Jerry Cohen" <jjcohen@PRODIGY.NET> 02/28/03 17:20 PM >>>



  Those who may be unfamiliar with the methodology for estimating dose consequences of given contamination levels, should be made aware that the results are predominately a function of the imagination of the analyst. Within a very wide latitude, if one were to specify what dose level they want, it is not difficult to find a "credible" (i.e., not impossible) scenario to obtain that result. Fundamentally, it is a phony process that is given official sanction by regulatory agencies. A process that causes an enormous waste of our limited resources, and one that will likely continue until the first regulatory official is fired or jailed for the crime of exercising "excessive caution" I wouldn't hold my breath until that happens.





  ----- Original Message ----- 

  From: Jim Hardeman 

  To: andrewsjp@chartertn.net ; blc+@PITT.EDU ; nardiaj@WESTINGHOUSE.COM 

  Cc: radsafe@list.vanderbilt.edu 

  Sent: Friday, February 28, 2003 11:27 AM

  Subject: RE: Dirty bombs





  A little followup to my previous message. I found the spreadsheet used to make relocation and re-entry calculations, using factors developed by EPA for radionuclide retention out to 50 years assuming only natural removal processes. Running through the calculations, I come up with the following:



  A deposition of 22.2 uCi/m^2 of Cs-137 will result in a first year "occupancy" dose of 1 rem.

  A deposition of 17.4 uCi/m^2 of Cs-137 will result in a second year "occupancy" dose of 0.5 rem

  A deposition of  8.2  uCi/m^2 of Cs-137 will result in a 0-50 year "occupancy" dose of 5.0 rem.



  Don't ask me all the assumptions that went into this calculation ... because I don't know what they are. I'd have to look in EPA 400. Even certain individuals in EPA admit that the 50 year calculations may be somewhat suspect, but I'd venture that any agreed upon cleanup level would be below that 8.2 uCi/m^2 value.







************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/