Information Notice No. 84-72: Clarification of Conditions for Waste Shipments Subject to Hydrogen Gas Generation

                                                           SSINS No.:  6835 
                                                           IN 84-72        

                                UNITED STATES
                          WASHINGTON, D. C. 20555  

                             September 10, 1984 

                                   SHIPMENTS SUBJECT TO HYDROGEN GAS 


All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP) and certain registered users of NRC Certificates of
Compliance for transport packages. 


The NRC's Office of Nuclear Materials Safety and Safeguards (NMSS) has 
identified a need to clarify conditions relating to the use of NRC-certified
packages for shipment of wastes. 


A potential exists for the generation of combustible quantities of hydrogen 
for certain waste forms containing radioactive material. This is pertinent 
to shipments of resins, binders, waste sludge, and wet filters. It is not 
pertinent to dry compacted or uncompacted waste and irradiated hardware. 

In general, applications for waste package certificates of compliance have 
not addressed the potential for generation of combustible gas mixtures. 
Generic requirements have recently been included in certain NRC Certificates
of Compliance to preclude the possibility of significantly reducing 
packaging effectiveness in use. These conditions are typically stated as 

(1)  For any package containing water and/or organic substances that could 
     radiolytically generate combustible gases, it must be determined by 
     tests and measurements of a representative package whether or not the 
     following criteria are met over a period of time that is twice the 
     expected shipment time: 

     (a)  The hydrogen generated must be limited to a molar quantity that 
          would be no more than 5% by volume (or equivalent limits for other
          inflammable gases) of the secondary container gas void, if 
          present, at STP (i.e.,  no more than 0.063 g-moles/ft-3 at 14.7 
          psia and 70F) or 

     (b)  The secondary container and cask cavity must be inerted with a 
          diluent to ensure that oxygen must be limited to 5% by volume in 
          those portions of the package that could have hydrogen greater 
          than 5%. 


                                                       IN 84-72            
                                                       September 10, 1984  
                                                       Page 2 of 2         

     For any package delivered to a carrier for transport, the secondary 
     container must be prepared for shipment in the same manner in which 
     determination for gas generation is made. The shipment period begins 
     when the package is prepared (sealed) and must be completed within 
     twice the expected shipment time. 

(2)  For any package containing materials with radioactivity concentration 
     not exceeding that for low specific activity (LSA) material, and 
     shipped within 10 days of preparation, or within 10 days after venting 
     of drums or other secondary containers, the determination in (1) above 
     need not be made, and the time restriction in (1) above does not apply. 

The generation of combustible gases is dependent on the waste form, 
radioactive concentration and isotope, free volume, total mass and 
accumulated dose in the waste. In addition, packaging limitations such as 
effective shielding provided may preclude the radioactive concentrations and
hence the generation of combustible gases. 

It is believed, in most cases, that the above combustible gas criteria for 
waste not exceeding LSA concentrations will be met by ensuring that waste 
packages are shipped within 10 days of preparation. However, in those cases 
where this is not feasible, licensees may request a specific approval for 
their proposed shipment. The application should address those factors that 
would preclude the generation of combustible gases over at least twice the 
expected shipment time. Such applications should be directed to NMSS. 

In all other cases, a determination must be made in accordance with the 
provisions of the certificate that the requirements of (1) above are met. 
Any tests and measurements that are representative of the waste to be 
shipped and address the factors that affect gas generation may be used. The 
determination should be documented and retained as part of the records for 
the shipment. 

Recipients of this notice should review the information discussed for 
possible applicability to their waste shipments. No written response to this
information notice is required. If you have any questions regarding this 
matter, please contact NMSS. 

                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:  C. E. MacDonald, NMSS 

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