RE: Control Room Conditions at Chornobyl NPP

[gj_vargo@ccmail.pnl.gov]

          Reply to Tony Hedges' question about control room conditions at 
          Chornobyl:
          
          Last month I had an opportunity to visit the Chornobyl NPP (yes, 
          that's Ukrainian's preferred spelling) including a tour of the 
          control rooms for Units 1, 2, 4, and the monitoring room for Unit 
          4.  I also spent ~one hour inside the Unit 4 Sarcophagus.  
          
          The control rooms for the operating units are in their equivalent 
          of a controlled area - essentially the entire power block.  
          Workers in this area are dressed out in white coveralls and 
          dosimeters are required.  Visitors in this area wear shoe covers 
          and lab coats and are issued a pocket ionization chamber.  
          Smoking is permitted in these areas, but no eating or drinking 
          was observed.  There were no apparent radiological boundaries 
          between the control rooms and other  areas of the plant such as 
          the operating floor in the reactor building. The only boundaries 
          appeared to be for physical protection (i.e., security).
          
          Dose rates in the Unit 4 control room are ~2-3 mR/h as measured 
          with a commonly available US-made ionization chamber.  All of the 
          remaining equipment in that area (much of it was cannibalized for 
          use in the remaining units) is deenergized and it the area is 
          only entered occasionally by visitors and the small staff 
          assigned to Sarcophagus maintenance.
          
          The Unit 4 monitoring room is a small area inside Unit 3.  It 
          contains data logging equipment for a number of temperature, 
          gamma, and neutron detectors that have been placed in the 
          wreckage.  Again, this area was essentially at background levels.
          
          I have no data on the contmaination levels in these areas, but we 
          passed their portal monitors (they did catch some contamination 
          on some outer PCs when exiting the Sarcophagus.)  We also did our 
          own surveys upon returning to our lodgings in Slavutich using a 
          couple of plastic scintillation-type contamination monitors (100 
          cm^2) and found nothing detectable on skin, clothing, or the 
          equipment we took inside.  All of the whole body counts performed 
          ASAP upon return to the US were also negative.
          
          Given their economic situation, they have done a remarkable job 
          of onsite cleanup.  From what we could see (obviously not 
          everything) housekeeping in the operating units appeared to be 
          fairly good.  The Sarcophagus, on the other hand, has many 
          serious industrial, nuclear and radiological safety problems.
          
          George J. Vargo
          gj_vargo@pnl.gov