[Federal Register Volume 60, Number 93 (Monday, May 15, 1995)]
[Notices]
[Pages 25893-25894]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11870]



=======================================================================
-----------------------------------------------------------------------

DEFENSE NUCLEAR FACILITIES SAFETY BOARD

[Recommendation 95-1]


Improved Safety of Cylinders Containing Depleted Uranium

AGENCY: Defense Nuclear Facilities Safety Board

ACTION: Notice; recommendation.

-----------------------------------------------------------------------

SUMMARY: The Defense Nuclear Facilities Safety Board has made a 
recommendation to the Secretary of Energy pursuant to 42 U.S.C. 2286a 
concerning improved safety of cylinders containing depleted uranium. 
The Board requests public comments on this recommendation.

DATES: Comments, data, views, or arguments concerning this 
recommendation are due on or before June 14, 1995.

ADDRESSES: Send comments, data, views, or arguments concerning this 
recommendation to: Defense Nuclear Facilities Safety Board, 625 Indiana 
Avenue, NW., Suite 700, Washington, DC 20004.

FOR FURTHER INFORMATION CONTACT:
Kenneth M. Pusateri or Carol C. Morgan at the address above or 
telephone (202) 208-6400.
John T. Conway,
Chairman.

    The three large gaseous diffusion plants that were operated by the 
Department of Energy (DOE) and its predecessors produced enriched 
uranium, some for defense use and some for incorporation into nuclear 
fuel for civilian reactors in the United States and other countries. In 
the course of isotope separation, most of the uranium ended up as the 
part depleted in U-235, designated as ``tails'' or ``tailings''. 
Enriched uranium at all desired assays was simultaneously extracted 
from the [[Page 25894]] plants, for all purposes, and so no amount of 
tails can be identified as related to enrichment solely for either 
defense or civilian purposes. Most of all uranium ever mined in the 
United States or imported into the United States remains in tails at 
the gaseous diffusion plants. These tails are stored onsite at the 
three plants in large steel containers, normally termed ``cylinders'', 
as the chemical compound UF6.
    Members of the staff of the Defense Nuclear Facilities Safety Board 
recently had an opportunity to visit the gaseous diffusion plants, to 
follow up on information that had been obtained on safety of storage of 
the tails. A short report documenting the results of their review is 
attached. It was found that DOE has approximately 50,000 cylinders in 
outdoor storage at the three diffusion plants, containing more than 
500,000 metric tons of UF6. Poor maintenance and storage 
conditions, combined with mechanical damage suffered during handling, 
have led to corrosion and subsequent breaching of several of these 
carbon steel cylinders.
    Cylinders have surface coatings (paint) of varying quality and 
integrity, which in a large number of cases is severely degraded. 
Cylinders are kept outdoors, some stacked on pads and some directly on 
the ground. Some older cylinders have been in storage in excess of 
forty years. Although general external corrosion seems to increase with 
time, handling damage and localized corrosion attributable to 
electrolytic attack appear to be more important factors in 
deterioration.
    The corrosion-resistant coatings have not been maintained, leaving 
the vast majority of cylinders vulnerable to localized corrosion. 
Visual inspections have shown abundant pitting and crevic corrosion of 
the cylinders, as well as galvanic attack near bronze valves and plugs. 
Since neither localized corrosion rates nor the extent of existing 
defects in the cylinders are well known or well understood, it is 
uncertain how many cylinders may be expected to fail in the near 
future. DOE and MMES (Martin-Marietta Energy Systems) are attempting to 
evaluate the extent of the erosion rates and their consequences; 
results are very preliminary, but they indicate that more than 1,000 
cylinders have a potential to breach before the year 2020 of no 
remedial actions are taken, with the result that their components of 
more than 10,000 tons of uranium could become accessible to release to 
the environment.
    In section 1016 of Public Law 102-486 (October 24, 1992), Congress 
directed the Department of Energy to provide within one year a uranium 
inventory study that would include among other matters recommendations 
for the future use and disposition of inventories of all Government-
owned uranium or uranium equivalents, including depleted tailings. The 
Department has not yet complied with this requirement, presumably at 
least in part because the matters addressed by Congressional action are 
very comprehensive and require extensive decisions on future courses of 
action.
    It is clear to the Board that directions developed in response to 
section 1016 of Public Law 102-486 will affect the long-term future of 
the vast inventory of depleted uranium tails. However, the very size of 
that inventory means that no matter what actions may be taken, they 
will require a long time to consumate, with deterioration of the 
cylinders continuing all the while.
    To protect against the dispersal of large amounts of uranium to 
soil and ground water in years to come, an early start to remedial 
action should be planned and then instituted. The alternative could be 
a massive problem with extraordinary financial costs.
    Therefore, the Board recommends that:
    1. An early program be started to renew the protective coating of 
cylinders containing the tails from the historic production of enriched 
uranium.
    2. The possibility of additional measures be explored, to protect 
these cylinders from the damaging effects of exposure to the elements, 
as well as any additional handling that may be called for.
    3. A study be instituted to determine whether a more suitable 
chemical form should be selected for long-term storage of the depleted 
uranium.
    The Board designated Mr. Steven Krahn as its principal staff member 
for discussions with those in DOE whom you may designate to act on this 
recommendation and matters that may arise concerning it.
John T. Conway,
Chairman.
[FR Doc. 95-11870 Filed 5-12-95; 8:45 am]
BILLING CODE 3670-01-M