Information Notice No. 84-72: Clarification of Conditions for Waste Shipments Subject to Hydrogen Gas Generation
SSINS No.: 6835
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
September 10, 1984
Information Notice No. 84-72: CLARIFICATION OF CONDITIONS FOR WASTE
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
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
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
List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Wednesday, March 24, 2021