Nuclear Material Packaging, 13482-13485 [05-5450]

Agencies

• Defense Nuclear Facilities Safety Board

[Federal Register Volume 70, Number 53 (Monday, March 21, 2005)]
[Notices]
[Pages 13482-13485]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-5450]



[[Page 13482]]

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

DEFENSE NUCLEAR FACILITIES SAFETY BOARD

[Recommendation 2005-1]


Nuclear Material Packaging

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(a)(5) regarding the issuance of a requirement that nuclear 
material packaging meet technically justified criteria for safe storage 
and handling outside of engineered contamination barriers.

DATES: Comments, data, views or arguments concerning the recommendation 
are due on or before April 20, 2005.

ADDRESSES: Send comments, data, views, or arguments concerning this 
recommendation to: Defense Nuclear Facilities Safety Board, 625 Indiana 
Avenue, NW., Suite 700, Washington, DC 20004-2001.

FOR FURTHER INFORMATION CONTACT: Kenneth M. Pusateri or Andrew L. 
Thibadeau at the address above or telephone (202) 694-7000.

    Dated: March 15, 2005.
John T. Conway,
Chairman.

Recommendation 2005-1 To the Secretary of Energy Pursuant to the 42 
U.S.C. 2286a(a)(5), Atomic Energy Act of 1954, As Amended

Dated: March 10, 2005.

Background

    In Recommendation 94-1, Improved Schedule for Remediation in the 
Defense Nuclear Facilities Complex, the Defense Nuclear Facilities 
Safety Board (Board) urged the Department of Energy (DOE) to improve 
the packaging and storage conditions of its large inventory of nuclear 
materials once used for weapons manufacture. In particular, the Board 
recommended that DOE place plutonium metals and oxides in storage 
configurations meeting DOE's standard for long-term storage (DOE-STD-
3013-2004, Stabilization, Packaging, and Storage of Plutonium-Bearing 
Materials). Some sites applied Recommendation 94-1 to excess materials 
only. The Board has continued to evaluate whether other categories of 
nuclear materials are stored in a safe manner.
    DOE has made progress in the stabilization and storage of its 
excess nuclear materials. The storage requirements for other categories 
of nuclear materials, however, are not as well defined and controlled. 
Specifically, DOE Order 5660.1B, Management of Nuclear Materials, does 
not address safe storage requirements. Other than two narrowly focused 
standards--DOE-STD-3013-2004 and DOE-STD-3028-2000, Criteria for 
Packaging and Storing Uranium-233-Bearing Materials--there is no 
explicit DOE-wide requirement to ensure the safe storage of nuclear 
materials. Currently, the technical adequacy of packaging--the 
combination of containers and other components providing a 
contamination barrier--for nuclear materials, including liquids, is 
dependent on the safety bases of individual facilities. Typically, 
facilities have credited engineered features, such as the confinement 
structure and ventilation system, for protecting offsite individuals 
and collocated workers. For facility workers, however, the controls are 
generally administrative, such as continuous air monitors, personal 
protective equipment, periodic contamination surveys, and other aspects 
of the radiological control program, in conjunction with proper 
evacuation training. In accordance with DOE Standard 3009, Preparation 
Guide for U.S. Department of Energy Nonreactor Nuclear Facility 
Documented Safety Analysis (DOE-STD-3009-94, Change Notice 02), 
accidents that pose the risk of significant radiological exposure to 
workers, such as a breached nuclear material storage package, should be 
prevented or mitigated using safety-significant controls. The preferred 
hierarchy of controls favors engineered, preventive features over 
administrative controls.
    Establishing packaging requirements for nuclear materials within 
the DOE complex requires consideration of a diverse population of 
material types for storage for uncertain periods of time. From a safety 
standpoint, nuclear material packaging must protect against a number of 
challenges that could breach the container and release radioactive 
material. Many of the materials of concern generate gases that result 
in container pressurization and may be pyrophoric or highly reactive. 
The container design must take into account corrosion, oxidative 
expansion of stored metal, effects of radiolysis, diurnal pumping, and 
damage due to impacts from drops and tooling during handling. The 
Board's recent review of nuclear material packaging at Lawrence 
Livermore National Laboratory (LLNL) revealed that many of these 
insults had not been fully considered when packaging choices were made 
for nuclear materials not covered by Recommendation 94-1. In fact, many 
of these current packaging configurations are similar to the inadequate 
configurations addressed in Recommendation 94-1, and are documented as 
being susceptible to eventual failure in the report of the 
Recommendation 94-1 Materials Identification and Surveillance Working 
Group, entitled Summary of Plutonium Oxide and Metal Storage Package 
Failures (LA-UR-99-2896).
    In general, the hazards posed by nuclear materials covered under 
DOE's Implementation Plan for Recommendation 94-1 are the same as those 
for nuclear materials not considered excess. When nonexcess materials 
are removed from glovebox confinement for interim storage, relocation 
to another work station, assay, or other purposes, the packages are 
susceptible to the same types of failures as those addressed in 
Recommendation 94-1. The longer the materials are stored, the greater 
are the chances that the packaging will fail, especially if the 
packaging has not been designed appropriately for the actual duration 
of storage. The Board found that approximately 15 percent of the 
nonexcess items at LLNL's Plutonium Facility are stored in packaging 
more than 5 years old. Some of the older items, previously declared 
excess, remain in their existing packaging while awaiting stabilization 
and packaging under DOE-STD-3013-2004. This situation emphasizes the 
need to establish a technical basis for packaging, such as designating 
the time period for which a particular container is confirmed to 
perform its function adequately, in conjunction with tracking the age 
of containers in use.
    Two recent events serve as further reminders of the importance of 
using packaging that is properly designed for its function:
     An August 5, 2003, event at Los Alamos National 
Laboratory's (LANL) Plutonium Facility resulted in multiple workers 
receiving plutonium-238 uptakes as a result of the degradation of a 
package stored longer than planned. This event is documented in a DOE 
Type B investigation report (HQ-EH-2004-1). The release of material and 
the resulting contamination and worker uptakes were due, in large part, 
to the inadequate packaging of plutonium being stored and handled 
outside of a glovebox.
     An October 6, 2004, incident at LLNL involved the 
accidental drop of a package containing salt-bearing

[[Page 13483]]

plutonium oxide. This event is documented in an Occurrence Reporting 
and Processing System report (OAK--LLNL-LLNL-2004-0046). Although no 
plutonium was released, this event highlights the need to specify 
robust packaging requirements for materials handled outside of a 
glovebox.

State of Nuclear Material Packaging

    DOE-STD-3013-2004 sets forth requirements for a robust storage 
configuration for long-term storage of plutonium-bearing materials. The 
requirements ensure containment through a combination of material form, 
packaging design, and surveillance of containers. However, the robust, 
welded configurations in the standard may not be desirable when a short 
storage period is anticipated pending use of the material.
    There are no equivalent requirements for interim storage. As part 
of its response to Recommendation 94-1, DOE finalized guidance for the 
storage of plutonium-bearing materials not packaged for long-term 
storage under DOE-STD-3013. This guidance, identified in a January 25, 
1996, memorandum from Deputy Secretary of Energy Curtis entitled 
Criteria for Interim Safe Storage of Plutonium-Bearing Solid Materials, 
provides a technically justified approach to safe packaging and storage 
of plutonium-bearing materials for a period of up to 20 years. Although 
these Interim Safe Storage Criteria (ISSC) were not intended to apply 
to materials in working inventory, much of the guidance remains germane 
to storage of all nuclear materials outside of approved engineered 
contamination barriers (e.g., gloveboxes or certified shipping 
containers).
    The ISSC were only implemented for selected excess materials and 
were never formally issued as part of the DOE Directives System. In 
practice, the sites use a wide variety of packages, many of which do 
not meet the ISSC. According to the lessons learned from the DOE Type B 
investigation of the worker uptakes at LANL, packages containing 
radioactive material should be assumed unsafe until proven otherwise or 
the materials are repackaged to current standards. Yet sites continue 
to rely on container types that have been used historically, but have 
no technically justified safety or design basis. These container types 
are generally forms of packaging typically used in non-nuclear 
applications (e.g., paint cans, food pack cans). Thus, they are not 
designed to protect against the hazards of the nuclear materials they 
contain for the duration of storage.
    Several commonly used containers and their potential inadequacies 
are briefly summarized in an attachment to this Recommendation. Many 
other containers are in use for specialized applications.

Remaining Problems

    In response to the Board's May 20, 2002, correspondence on safety 
of nuclear materials storage, the National Nuclear Security 
Administration (NNSA) established the Inactive Actinide Working Group 
(IAWG), with the goal of developing a comprehensive approach to the 
characterization, packaging, and storage of a subset of nuclear 
materials. As presented in a February 7, 2003, letter from NNSA to the 
Board, the IAWG was to meet this goal through the development of three 
strategies for the following: acceptance and retention of nuclear 
materials, material characterization and storage adequacy, and 
disposition. The Board has been observing the IAWG's efforts and has 
made three observations.
    First, a key product of the IAWG effort will be the strategy for 
material characterization and storage adequacy. Based on discussions 
with IAWG participants, the delivery of this strategy has been delayed, 
in large part because of disagreements among member sites on the 
requirements necessary for justifying adequate storage. The Board 
believes these requirements should provide for sufficient 
characterization based on an appropriate combination of analysis and 
process knowledge to determine the appropriate packaging. 
Characterization information should also be used to develop a 
surveillance program prioritized according to expected material and 
container risk (including, for example, material type, material form, 
and the age and type of container).
    Second, in a June 2000 report entitled A Strategic Approach to 
Integrating the Long-Term Management of Nuclear Materials, DOE 
recognized the need to update the existing DOE Order on nuclear 
materials management. In particular, this report urged improvements to 
the nuclear materials management process. However, neither the current 
Order nor the report explicitly considers storage safety. The Board 
believes that DOE should require a technical basis for nuclear material 
packaging and storage safety. Efforts to meet this requirement should 
take advantage of the knowledge about storage adequacy being developed 
by the IAWG, as well as existing guidance, such as the ISSC.
    Third, the IAWG strategy does not include other program offices in 
the defense nuclear complex, such as the Nuclear Energy, Science, and 
Technology (DOE-NE) facilities involved in defense nuclear activities. 
Currently, materials and activities in transition between the 
facilities of different program offices have the potential to be 
overlooked. For example, operators at the Savannah River Site have 
begun converting the neptunium-237 solutions covered under 
Recommendation 94-1 to oxide and placing the oxide in packaging 
intended for 1 year of storage at that site prior to offsite shipping. 
The long-term storage of large quantities of neptunium oxide has not 
been performed previously in the complex, and the technical basis for 
ensuring the safety of such storage is incomplete. Nonetheless, these 
materials will be transferred to DOE-NE for use, where they may 
continue to be stored in their existing packaging for a period of up to 
20 years. In addition, the Board has learned that DOE-NE intends to 
assume more direct control of activities involving plutonium-238, which 
have to date been performed at NNSA sites. The significant radiological 
hazards associated with this material necessitate appropriate storage 
containers for the expected storage period. The Board believes the 
requirement for a technical basis for nuclear material packaging and 
storage should encompass all program offices in the defense nuclear 
complex. DOE may wish to consider implementing this requirement for all 
program offices, including those outside of the defense nuclear 
complex.
    The Board is encouraged by other efforts currently under way to 
improve nuclear material packaging. As a result of discussions between 
the Board's staff and LLNL, the Livermore Site Office, in a December 3, 
2004, letter, directed LLNL to develop a technical basis for the 
adequacy of storage packages as part of a Special Nuclear Materials 
Storage Plan covering ``all packaging activities.'' LLNL replied in a 
letter of January 31, 2005, outlining the required activities, 
milestones, and funding to develop and implement an approved packaging 
and storage program. Implementation of the plan is contingent upon the 
availability of key personnel and funding. Likewise, the proposed 
Documented Safety Analysis (DSA) for the LANL Plutonium Facility 
requires the use of a proposed facility packaging standard and 
designates material containers as a safety-related component. However, 
the new DSA has been awaiting NNSA approval. In general, these efforts 
represent an improvement, but they do not represent a comprehensive 
DOE-

[[Page 13484]]

wide effort, and significant differences remain in the quality of the 
efforts at individual facilities.

Recommendation

    Nuclear material packaging provides the primary containment 
boundary to protect facility workers during storage and handling 
activities. The Board believes the development of technically justified 
criteria for packaging systems for nuclear materials is necessary on a 
DOE-wide level. Therefore, the Board recommends that DOE:
    1. Issue a requirement that nuclear material packaging meet 
technically justified criteria for safe storage and handling. Packaging 
should, in general, provide a robust barrier between facility workers 
and the stored nuclear materials once they are removed from an approved 
engineered contamination barrier. It may be appropriate to include this 
requirement in an updated nuclear materials management Order.
    2. Identify which nuclear materials should be included in the scope 
of the above requirement and then determine the technically justified 
packaging criteria needed to ensure the safe storage and handling of 
those materials. The scope need not include waste materials, fully 
encapsulated forms, or de minimis quantities such as analytical 
laboratory samples. The criteria should account for the nuclear 
material form and properties, expected future use, and duration of 
storage. It may be appropriate for this information to be included in a 
packaging Manual.
    The ISSC may provide the beginning of a sound technical foundation 
for developing such criteria. Although some modifications may be 
necessary to make the ISSC more applicable to short-term storage, the 
Board believes the basic ISSC principles--for example, the requirement 
for a minimum of two contamination boundaries for high-hazard materials 
such as plutonium, assurance that leak-tightness is maintained for 
materials requiring a sealed environment, ability of the containers to 
withstand maximum expected internal pressures, and protection against 
common insults such as drops--should be maintained. The criteria should 
also include provisions for surveillance programs to verify that the 
container and any limited-life components are performing in a manner 
consistent with the duration of storage.
    3. Prioritize implementation of the improved nuclear material 
packaging requirement consistent with the hazards of the different 
material types and the risk posed by the existing package 
configurations and conditions.

John T. Conway,
Chairman.

Attachment

Selection of Commonly Used Nuclear Material Packaging

Food-Pack Cans
    Food-pack cans are thin-walled tinned carbon steel containers used 
in the food industry. No additional manufacturing or structural 
requirements have been specified for application with nuclear 
materials. These cans typically rely on a double-crimped metal-to-metal 
closure with a thin layer of sealing compound to provide leak-
tightness. Historically, many sites have reported failures of food-pack 
cans. Lawrence Livermore National Laboratory (LLNL) has reported 
anecdotal evidence suggesting that none of its food-pack cans have 
failed to the point of detectable contamination outside the container 
(UCRL-ID-11733). However, this same report states further that some 
degree of oxidation was observed in all of the examined food-pack cans 
containing plutonium metal, suggesting the lack of an airtight seal. 
Leakage of oxygen through nonairtight food-pack cans has been 
responsible for a number of container failures reported at other sites, 
due to oxidative expansion of plutonium metals (LA-UR-99-2896).
    Improvements have been made to the technology, including better 
sealing equipment, as discussed in a May 1984 report entitled The 
Effectiveness of Corrective Actions Taken to Preclude Events Involving 
Tin Cans and Plutonium (RHO-HS-SA-59 P). Some evidence suggests, 
however, that these containers still may not be adequate for prolonged 
storage of nuclear materials. Approximately half of the sampled lot of 
food-pack cans sealed 10 to 14 years earlier at the Hanford Plutonium 
Finishing Plant using the improved methodology failed leak testing, and 
nearly all showed further indications of a potential lack of seal (LA-
UR-99-3053).
    Additional testing performed at Pacific Northwest National 
Laboratory confirmed that the performance of food-pack cans is highly 
dependent on the quality of the seal (PNL-5591). During these tests, 33 
industry-standard food-pack cans were sealed according to federal 
specifications. The testing revealed leak rates ranging from less than 
10-5 cubic centimeters per second (cc/sec) to more than 2 
cc/sec. These findings should receive due consideration when food-pack 
cans are used for storage applications in which a hermetic seal is 
required. LLNL continues to use food-pack cans as inner and outer 
containers for the storage of plutonium metal and oxide, and other 
sites may be storing nuclear materials previously packaged in food-pack 
cans.
Paint Cans
    Paint cans are thin-walled cans with a press-fit lid that are 
commonly used to store paint. They have been used as both inner and 
outer containers for the storage of some nuclear materials, including 
plutonium metal. The press-fit lid is typically placed by hand using a 
mallet, which results in a questionable seal lacking any evidence of 
quality control. According to a January 16, 1987, LLNL site report 
entitled Incident Analysis/Plutonium Burn in Storage Can, oxidation was 
found to be common for plutonium metal stored in paint cans (memorandum 
from R.H. Condit to K. Ernst). The report goes on to calculate that a 4 
micron gap integrated across the seal area would be sufficient to 
permit complete oxidation of 100 grams of plutonium metal in 1 year. A 
leak of this size can reasonably be assumed to be present in the press-
fit closure; therefore, the adequacy of these cans for nuclear material 
storage applications requiring a seal cannot be ensured. Although LLNL 
reports that ingress of air is expected because the lid and rim of the 
can are not designed to be airtight (UCRL-ID-117333), paint cans remain 
approved for use for certain applications at the laboratory. Other 
sites may also be storing nuclear materials that were previously 
packaged in paint cans.
Taped Slip-Lid Cans
    Slip-lid cans are thin-walled cans with a loose-fitting cover that 
is often taped. While convenient and inexpensive, the use of these 
containers has resulted in several breached storage packages, including 
the plutonium-238 package that led to the Type B event at Los Alamos 
National Laboratory (LANL). Many nuclear material packages consisting 
of nested taped slip-lid cans remain at the Department of Energy's 
defense nuclear facilities. By design, these cans were never intended 
to serve a containment function. Furthermore, except for tape, a 
mechanical closure is absent, resulting in a container that may not be 
able to provide even gross retention of the materials within. The 
effectiveness of tape in performing this sealing function over time and 
under high radiation conditions is poorly understood. For this reason, 
the Interim Safe Storage Criteria (ISSC) specifically prohibit

[[Page 13485]]

crediting slip-lid cans as one of the two required contamination 
barriers. Yet several sites continue to use this type of packaging. For 
nonmetallic plutonium, including items containing plutonium-238, LANL 
plans to rely on stainless steel taped slip-lid cans only as an inner 
container; currently, however, a large number of items remain at the 
laboratory in nested slip-lid cans. Moreover, several varieties of 
slip-lid cans continue to be approved for use as inner and outer 
storage containers for certain materials at LLNL.
Hagan Can
    LANL's Comprehensive Nuclear Material Packaging and Stabilization 
Plan approves the use of a standard container known as the Hagan can, a 
robust, screw-top container with an O-ring seal and filtered vent. The 
Hagan can generally meets the expectations of the ISSC and has 
undergone testing to certify its performance (Wickland and Mataya, 
PATRAM 98, 1998). However, drop testing was performed at a height lower 
than the expected maximum storage height; therefore, additional 
analysis or testing is required. Under the proposed Documented Safety 
Analysis for LANL's Plutonium Facility, the Hagan can is classified as 
a safety-significant engineered feature. The Hagan can appears to be an 
appropriate outer package for nuclear material storage, although, as 
recognized by LANL, the service life of the Viton (an organic 
fluorocarbon compound) O-ring requires verification through a 
surveillance program. Currently, Hagan cans are widely used only at 
LANL; however, their use may be under consideration at other sites.
Conflat Can
    A can fabricated with a Varian-type Conflat flange results in a 
hermetically sealed, robust container that can be used to store 
plutonium metal. A copper gasket on a bolted flange closure is designed 
to maintain a long-term hermetic seal against oxidation of plutonium 
metal. This closure type has been standard in the high-vacuum industry 
for many years and has been certified to maintain a leak-tight seal 
under various temperature and pressure conditions. The Conflat can is 
identified in LANL's Comprehensive Nuclear Material Packaging and 
Stabilization Plan as the inner container for the storage of plutonium 
metal. The use of Conflat cans for storage of other nuclear materials 
requiring a sealed environment may also be appropriate. Conflat cans 
have been used periodically at some sites for special storage 
applications, but their use is not widespread or uniform.
Metal Drums
    Several sites commonly use U.S. Department of Transportation (DOT) 
Type A containers and similar types of metal drums for overpacking of 
packages of nuclear materials for onsite transportation and storage. 
These containers have been certified as Type A radioactive material 
packages per DOT specifications. For transportation purposes, this 
certification usually is limited to a single year. The use of these 
containers for interim storage beyond the certification period appears 
appropriate, but consideration should be given to periodic inspection 
and replacement for limited-life components, such as lid gaskets. The 
Criteria for the Safe Storage of Enriched Uranium at the Y-12 Plant (Y/
ES-015/R2) allow interim storage of enriched uranium materials for a 
period of up to 10 years in DOT Type A or Type B containers.
Y-12 Prolonged Storage Container
    The Y-12 Y/ES-015/R2 criteria specify the use of stainless steel 
cans similar to food-pack cans for prolonged low-maintenance storage 
for up to 50 years. While the reliance on a single robust barrier for 
the storage of enriched uranium may be appropriate, it is unclear 
whether the requirement to maintain mechanical and seal integrity 
during normal handling includes protection against drops. In addition, 
a lid sealant compound is specified in the appendix to Y/ES-015/R2, but 
no discussion of its longevity is provided. While fewer radiological 
hazards and less chemical reactivity are associated with enriched 
uranium than with plutonium and some other nuclear materials, further 
testing of these containers would better demonstrate their reliability 
for long-term storage. Currently, the Y-12 container specification is 
planned for use only at the Y-12 National Security Complex.
Plastic Bags and Bottles
    Historically, plastic bags have been relied upon to provide 
contamination control for a limited period. Bag materials, which 
include polyethylene, polyvinyl chloride, and related polymers, play an 
important role in the overall packaging system. Their principal use is 
for contamination control during the ``bagout'' operation, when the 
nuclear material container is removed from the glovebox. Unfortunately, 
some types of bags have proven to be detrimental to the integrity of 
packages left in storage for prolonged periods of time. For example, 
the radiation-induced degradation of polyvinyl chloride bag material 
led to the production of hydrochloric acid, which in turn contributed 
to the corrosion and eventual failure of containers that occurred 
during the Type B event at LANL. The choice of material also impacts 
the generation of radiolytic gas and effectively defines the service 
life of a package when the outer container is not leak-tight. In 
repackaging campaigns at LLNL, as well as at other sites, such as 
Hanford, bags commonly have been found to be in a discolored or 
otherwise degraded state (UCRL-ID-117333 and WHC-SD-TRP-067). While 
plastic bags have been in use for a long time, little quantitative 
information exists on the effects of time, temperature, and radiation 
field exposure on maintenance of an effective contamination barrier. It 
is recognized that plastic bags may be necessary for contamination 
control, but they should not be relied upon as a long-term 
contamination barrier.
    In some cases, plastic bottles (e.g., safe bottles) have been used 
for the storage of solutions containing nuclear materials, especially 
enriched uranium, outside of processing equipment. While bottles are 
constructed of thicker plastics than are bags, they undergo the same 
chemical and radiolytic degradation with time and must be compatible 
with the chemical properties of the contained liquids. Furthermore, 
whereas bags provide only contamination control, bottles are relied 
upon to provide a complete contamination barrier, including structural 
integrity. Any reliance on plastic bags or plastic bottles for extended 
periods of time should be informed by the available knowledge of 
polymer degradation, in combination with information gleaned from 
surveillance programs.

[FR Doc. 05-5450 Filed 3-18-05; 8:45 am]
BILLING CODE 3670-01-P