INL/CON-05-00706
PREPRINTManaging Spent Nuclear
Fuel At The Idaho
National Laboratory
NATO/IAEA Advanced ResearchWorkshopThomas J. Hill
Denzel L. Fillmore
October 2005

This is a preprint of a paper intended for publication in a journal orproceedings. Since changes may not be made before publication,
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MANAGING SPENT NUCLEAR FUEL AT THE IDAHO NATIONALLABORATORYSHORT TITLE: MANAGING SPENT NUCLEAR FUEL AT INLTHOMAS J. HILL
Idaho National Laboratory, Idaho

DENZEL L. FILLMORE
Idaho Closure Project, Idaho

Abstract: The Idaho National Laboratory (INL) has a large inventory of diverse
types of spent nuclear fuel (SNF). This legacy derives from the history of the
INL as the National Reactor Testing Station, and from its mission to recover
HEU from SNF and to test and examine SNF after irradiation. The INL also
has a large diversity of SNF storage facilities, some 50 years old.
SNF at INL has many forms—from intact assemblies down to metallurgicalmounts, and some fuel has been wet stored for over 40 years. SNF is stored bareor in metal cans under water, or dry in vaults, caissons or casks. Inspection
shows varying corrosion and degradation of the SNF and its storage cans.
SNF has been stored in 10 different facilities: 5 pools, one cask storage pad,
one vault, two generations of caisson facilities, and one modular Independent
Spent Fuel Storage Installation (ISFSI). The pools range in age from 40 years
old to the most modern in the US Department of Energy (DOE) complex. The
near-term objective is to move SNF from older pools to interim dry storage,
allowing shutdown and decommissioning of the older facilities. This move
involves drying methods that are dependent on fuel type.
The long-term objective is to have INL SNF in safe dry storage and readyto be shipped to the National Repository. The unique features of the INL SNF
requires special treatments and packaging to meet the proposed repository
acceptance criteria and SNF will be repackaged in standardized canisters forshipment and disposal in the National Repository. Disposal will use thestandardized canisters that can be co-disposed with High Level Waste glass logs
to limit the total fissile material in a repository waste package. The DOE
standardized canister also simplifies the repository handling of the multitude

of DOE SNF sizes and shapes.
Keywords: Spent Nuclear Fuel, Dry Storage, Wet Storage, Drying Spent Nuclear Fuel______*To whom correspondence should be addressed: Thomas J. Hill, Space Nuclear Systems & Technology,
Idaho National Laboratory, PO Box 1625, Idaho Falls, Idaho 83415, USA; e-mail: Thomas.hill@inl.gov

1

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1.

MANAGING SPENT NUCLEAR FUEL AT INL

Introduction

The Idaho National Laboratory (INL) was established in 1949 as the National
Reactor Testing Station. As the name implies, the mission was reactor testing.
Over the years, 52 reactors were constructed and operated by a variety oforganizations for a variety of programs. Portions of the site operated under
different Federal Agencies and field offices of the Atomic Energy Commission/Department of Energy (DOE). Most of the spent nuclear fuel (SNF) generated
by these reactors has remained on site. A chemical reprocessing facility wasconstructed in 1950 for the recovery of fissile materials from SNF. SNF was
also sent to the INL from many other locations for testing, examination, andreprocessing. Sources of this SNF included naval reactors, DOE and university
test reactors, and even some commercial reactors.
SNF was stored in a number of facilities at several different locations,
including: Test Area North (TAN), Materials and Fuel Complex (MFC)[formerly Argonne National Laboratory–West], Idaho Nuclear Technology andEngineering Center (INTEC), Reactor Technology Complex (RTC), and Power
Burst Facility (PBF). Much of the fuel was reprocessed for the recovery ofenriched uranium. At present, 257 Metric Tones of Heavy Metal (MTHM) withover 250 different types of SNF is being managed at four facilities at the INL.
This paper addresses management of all SNF at the INL, except for naval fuel.
2.

INL Current Status

2.1

SPENT NUCLEAR FUEL DESCRIPTION

There are many characteristics of SNF important to its management. Chemical
characteristics of its fabrication materials, such as the fuel meat and cladding,and other constituents, determine how it can be stored and what treatment may
be required for it to meet geologic repository acceptance criteria. Physicalcharacteristics such as length, weight, heat generation rate, radiation levels,
fissile content and enrichment, and its physical condition, dictate storage andhandling requirements.
The INL has a large inventory of diverse types of SNF, possibly the mostdiverse and varied inventory in the world. To illustrate the point, Table 1 gives
some of the materials of fabrication and Table 2 describes the variety inphysical characteristics of the fuel. The fuel also consists of several different
fissile materials of varying enrichments. Much of the SNF is highly enriched in235
U (>60%) and was sent to the INL for 235U recovery. There is also asignificant quantity of typical commercial light water reactor fuel that was
brought to the INL for examination and testing. The INL also stores fuel that
contains 233U and thorium. Specialized test reactor fuel such as the sodium-

MANAGING SPENT NUCLEAR FUEL AT INL

3bonded metal fuel used in the Experimental Breeder Reactor-II is also stored
on-site.
In order to understand the inventory and quantity of the SNF, the projected
2035 inventory was placed into groups based on fabrication materials. Table 3
describes the 16 groups.
TABLE 1. Typical INL SNF Fabrication Materials
Cladding material

Fuel Meat
Composition

Other Materials

Aluminum
Stainless Steel
Zirconium

Uranium Metal
Uranium Oxide
Uranium Alloy
Uranium Carbide

Stainless Steels
Thorium Carbide
Beryllium Oxide
Metallic Sodium
Thorium Oxide

TABLE 2. INL SNF Physical Characteristics
Characteristic
WeightLengthHeat generation rate
Radiation field
WeightRange
0.01 to 1600 kg
10 to 410 cm
0 to 600 w
0 to 10,000 R/hr
Scrap to excellent

The SNF is stored in a variety of configurations. Some is stored dry incasks, caissons, underground silos, or vaults, and much is stored underwater inspent fuel pools. Some fuel is stored unencapsulated as bare units, either intact
or having had structural material removed. Some fuel is stored in containers,
sometimes referred to as cans, having been previously disassembled for
destructive examination or security purposes. At one time the cans were dry on
the inside; however, a number are now known to have leaked. Some cans havebeen replaced underwater to retain the fuel handling capability. Some fuel has
been in storage for >40 years and physical degradation has occurred.
2.2 STORAGE FACILITY DESCRIPTION

2.2.1 Wet Storage Facilities
Both wet and dry storage are used at the INL. The fuel stored wet is in concrete
pools, some lined with stainless steel, either at the INL reactor site or at INTEC,
the non-reactor facility formerly the Idaho Chemical Processing Plant (ICPP).

MANAGING SPENT NUCLEAR FUEL AT INL

4

TABLE 3. SNF Inventory Groups at INL
Group
1
2
3

Group Description
Intact, low enriched (<5%), UO2
clad with Zr or stainless steel
Intact, medium enriched (5- 20%),
UO2 clad with Zr or stainless steel
Intact, highly enriched (>20%) UO2
clad with Zr or stainless steel

4

Disrupted, low enriched, UO2

5

Disrupted, highly enriched UO2

6
7
8
9
10
11
12
13

Intact medium enriched U-zirconium
hydride clad with Al, Zr,or stainless steel
Some disrupted, highly enriched Uzirconium hydride clad with Zr
or stainless steel
Low enriched, U metal or U alloy
or Zr or Mo with various claddings
Highly enriched, U metal or U alloy
or Zr or Mo with various claddings
Highly enriched UC in SiC coatedparticles in a graphite matrix
Highly enriched UCin non-SiC coatedparticles in a graphite matrix
Highly enriched UC in a non-graphite
matrixHighly enriched U-233 with thorium
in Zr cladding

14

Metallic sodium bonded

15

Aluminum clad U compounds

16

Others not included above

Quantity
31 types; 30 m3
76.8 MTHM
8 types; 1.4 m3
4 MTHM
21 types; 9.3 m3
8.7 MTHM
34 types; 145 m3
87.5 MTHM
44 types; 24 m3
6.2 MTHM

Fuel Example
Typicalcommercial

97 types; 6.6 m3
1.8 MTHM

Standard
TRIGA

24 types; 1.3 m3
0.2 MTHM

TRIGA Flip

14 types; 0.8 m3
2.0 MTHM
6 types; 2 m3
3.9 MTHM
1 type; 196 m3
23 MTHM
7 types; 35 m3
3 MTHM
2 types; 5 m3
0.06 MTHM
1 type; 52 m3
39 MTHM
33 types; 15 m3
60 MTHM
14 types; 43 m3
3.4 MTHM
5 types; 4.3 m3
0.2 MTHM

PBF
Shippingport
PWR
TMI-2
TORY

HWCTR
Fermi
Fort St. Vrain
Peachbottom
graphite
SRE
Shippingport
LWBR
Fermi blanket
EBR-IIATRThe CPP-666 pool is the most up-to-date storage pool in the DOE complex(Figure 1). Built to store SNF waiting for reprocessing, it is lined with stainlesssteel and has modern leak detection and water purification systems. Other
pools—such as the unlined TAN concrete pool (TAN-608) built in 1955 for the
Aircraft Nuclear Propulsion program and used to store TMI-2 fuel—have been
emptied and theSNF put in dry storage casks. The Advanced Test Reactor poolsupports reactor operations and stores SNF until transfer to the pool at INTEC.

MANAGING SPENT NUCLEAR FUEL AT INL

5

Figure 1. The modern steel-lined CP-666 Storage Pool at the
Idaho Nuclear Technology and Engineering Center (INTEC)

2.2.2 Dry Storage Facilities
Dry storage facilities are now consolidated at INTEC, MFC and Fort St. Vrain,
Colorado. The dry storage casks at TAN SNF storage pad have been relocatedto INTEC on a new pad. Commercial light water reactor fuels, bare andconsolidated assemblies, have been in various commercial storage casks for up
to 15 years under a joint DOE and Nuclear Regulatory Commission (NRC)
testing program; Figure 2 shows the casks at the INL.

Figure 2. Commercial Dry Storage casks used in SNF tests at the INL
Left to Right: REA 2023; VSC-17; TN 24P; V21; 125B; MC-10

6MANAGING SPENT NUCLEAR FUEL AT INL

INTEC has four different types of dry storage, not counting the dry storage
cask systems. The Irradiated Fuel Storage Facility (IFSF) is an air-cooled vault
originally built to store the Fort St. Vrain SNF. It presently stores manydifferent types of SNF. The first generation of storage caisson, CPP-749, has
steel-lined below-grade individual vaults, built to store Peachbottom graphite
SNF (a general view of the CPP-749 facility is shown in Figure 3). The second
generation caissons were a significant improvement in design and were built tostore the Shippingport light water breeder reactor SNF.

Figure 3. The Below-grade Storage Facility CP-749 at the INL
Used to Dry Store Peachbottom Reactor SNF

MFC operates a below-grade silo storage facility (Radioactive Scrap andWaste Facility) which was built in 1965. This facility stores spent fuel andremote handled mixed and radioactive waste, primarily from the EBR-II.
The newest dry storage facility is a modified NUHOMS® design built tohold TMI-2 reactor SNF removed from the damaged core after the accident.
This was the second DOE facility licensed by the NRC, and the first one forwhich DOE actually prepared the license application.
2.3 RECEIPT AND TRANSFERThe INL has an active SNF generation and receipt program. The ATR is one of
the few operating reactors in the DOE complex, and it is scheduled to operate
through 2025. The ATR produces over 30 spent fuel assemblies each year.

MANAGING SPENT NUCLEAR FUEL AT INL

7

The SNF is cooled in the reactor pool for a short time and then transferred to
INTEC for interim management.
The DOE programmatic Environmental Impact Statement (EIS)1 and theForeign Research Reactor EIS2 both identify the INL as the receiving location
for non-aluminum based SNF presently located at the DOE sites as well as SNF
generated in foreign, domestic and university reactors. This includes all SNF
containing metallic sodium. The INL will, according to the EIS record ofdecision, ship all existing INL aluminum-based SNF to the Savannah River
Site. MFC will receive sodium-bonded fuel removed from the Fast Flux Test
Facility at the Hanford site for treatment. The INL will receive non-aluminumclad SNF from 16 universities, 8 domestic sites, 18 foreign sites and 5 DOE
sites.
3.

INL Short -Term Objectives

3.1

SAFE INTERIM STORAGE

Some of the INL SNF facilities have been in operation for over 40 years,
although they had an operating lifetime when constructed of 20 years. Thesefacilities do not meet present standards and needed to be shut down anddecommissioned. Some of these older facilities contained SNF that has been instorage for over 40 years. The condition of these SNF types deteriorated andpresented problems in safe management. Both of these situations wereidentified as vulnerabilities to the INL and corrective actions taken to eliminate
the vulnerabilities. The DOE reached an agreement with the State of Idaho3 in
1995 to move the SNF to safe dry storage by 2023 and have it removed fromthe state by 2035.
3.1.1

Consolidate SNF and Shut down Older Facilities

The INL had several older, wet SNF storage facilities that did not meet present
standards4. As the SNF was removed from these facilities, these facilities havebeen shut down and decommissioned. The first facility targeted for this activity
was the CPP-603 pool.
The CPP-603 pool consisted of three bare concrete pools that contained alarge variety of SNF. The north and middle pools stored SNF that hung from amonorail on hangers that kept the fuel in the proper configuration. There had
been considerable corrosion of the carbon steel hangers and the SNF containers.
The south pool kept the SNF units in racks that sat on the basin floor. The North
and Middle pools were emptied of SNF by 1996. This was accomplished by

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MANAGING SPENT NUCLEAR FUEL AT INL

transferring the SNF that was in relatively good condition to CPP-666 andconsolidating the SNF that would require additional treatment into the south
pool. Remaining fuel in the CPP-603 pool was repackaged into new storagecans or buckets and transferred to CPP-666 or to IFSF. A total of 1340 units of
SNF were transferred between 1994 and April 2000. The project was complete
8 months ahead of schedule. Decontamination and decommissioning of the
facilities is now underway.
The SNF Storage Pool located at the TAN was also a bare concrete poolthat stored SNF in metal racks. The primary SNF type that was stored in the
TAN pool was the TMI-2 SNF debris contained in stainless steel containers.
There was also some commercial and Loss of Fluid Test SNF in the pool. The
TAN facilities, located 20 miles from INTEC, were emptied of SNF in 2002
and the material moved to INTEC.
The MTR canal was a pool that was constructed to support the operation of
the MTR reactor and had been maintained to store SNF that was left over fromthe research and testing programs at the INL. It was a bare concrete pool that
contained SNF in storage racks. This SNF was moved to INTEC in 2001.
The PBF pool was a small stainless steel lined pool that was built to support
the operation of the PBF reactor. The reactor has been shut down and defueled.
The only fuel stored in the pool was the PBF fuel. The INL moved this SNF to
INTEC in 2002.
The INL SNF management plan called for moving all the SNF from theseolder, remote facilities into modern wet or dry storage and eventually all into
dry storage. Significant projected cost savings have been realized from the
shutdown of these older facilities.
The IFSF plays an important part in the INL consolidation plans. The
transfer of all of the INL SNF from wet storage to dry storage is an important
step in reducing storage costs as well as meeting the State of Idaho agreement.
The IFSF was constructed to store all of the SNF from the Fort St. Vrain reactor
in Colorado. Because two thirds of the fuel will remain in Colorado until it istime to prepare it for repository disposal5 there is excess room for the storage ofother SNF types. SNF was moved out of the older facilities into IFSF and theolder, wet storage facilities were shut down without having to wait for new
facilities to be built. Much of the SNF that was moved out of the CPP-603
pools was moved into IFSF. The foreign research reactor fuel that is now being
received is being put into IFSF, as well as all the SNF removed from the MTR
and PBF facilities.
The radioactive scrap and waste facility (RSWF) is used for the bulk ofinterim fuel storage at MFC. Spent fuel is stored dry, below grade, in passively
cooled cathodically protected carbon steel liners or silos. All of the sodiumbonded fuel destined for electrometallurgical treatment will pass through RSWF
and the high level waste forms will be stored there awaiting geological disposal.

MANAGING SPENT NUCLEAR FUEL AT INL

9The INL constructed an NRC-licensed facility6 for the dry storage of theTMI-2 SNF. DOE decided to make this facility the first NRC licensed facility
at a DOE site. This design is a modification of an existing NUHOMS® designthat was adapted for the TMI-2 SNF.
DOE authorized the construction of a privatized SNF storage facility. The
project is called the spent nuclear fuel dry storage project (SNFDSP) and thecontract was awarded to Foster Wheeler Environmental Corporation7. Thisfacility would initially accept three types of INL SNF but it can be expanded toaccept the entire INL SNF inventory. The facility would have the capability to
dry and characterize the SNF to meet the repository acceptance criteria. Thisfacility is currently on hold as DOE decides its long-term SNF management
approach for the INL.
3.1.2

Maintaining Capabilities

MFC has two large inert hot cells which will be maintained in their current
operational status. Electrorefining of fuel takes place in the Fuel Conditioning
Facility while final waste form production is carried out in the Hot Fuels
Examination Facility (HFEF). In addition, HFEF is actively providing spent
fuel characterization services to DOE and non-DOE customers alike.
The TAN hot shop is the largest operational hot shop in the United States.
It was constructed as part of the Aircraft Nuclear Propulsion program in the
1960s. It was used to service the dry storage casks located on the SNF dry
storage pad at TAN. It was also used to dry the debris from the TMI-2 reactor
which has been stored underwater at TAN for over 20 years. It is currently
being used to support decontamination and decommissioning activities at TAN.
This facility is scheduled for shutdown in the Fall of 2006 and will eventually
be dismantled.

3.1.3 Technology Development
The technology needed to characterize the INL SNF and prepare it to meet
repository acceptance criteria did not exist when reprocessing was terminated.
The INL began a technology development program to ensure that thetechnology would be available when it was needed. The program focused on
three major areas: drying, conditioning, and non-destructive characterization.
The first technology developed and implemented at the INL was anultrasonic system to non-destructively look inside sealed stainless steel cans todetermine if there was water inside and also to determine the condition of thefuel inside the cans. Many research projects investigated the effects of water on
the SNF for long periods of time, and methods to ensure water removal from
SNF. The technologies needed for long term dry storage and dispositioning

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MANAGING SPENT NUCLEAR FUEL AT INL

include: 1) removing the free and bound water, 2) determining the effects ofhydrogen from the radiolysis of water on the materials, 3) material interactions
between the SNF and the containers, and 4) material corrosion modeling for allof the SNF and container materials. The technologies needed for conditioning
the fuel for repository dispositioning include: 1) removal and stabilization of
metallic sodium 2) removal of metallurgical mount epoxy, and 3) methods toensure that the condition of the fuel after 40 years of dry storage will still meet
the transportation and repository acceptance criteria. The technology needed
for characterization included non-destructive assay to determine theradionuclide inventory of the container, including the fissile material inventory,
and non-destructive examination of the SNF condition.
3.2 PREPARE FUEL TO MEET STORAGE CRITERIAMost of the INL SNF inventory has been stored underwater for many years.
Some of the fuel stored as been bare assemblies and some of it has been in cans.
For the fuel that has remained intact, the drying is fairly simple. For the fuelthat is not intact or that is stored in cans that are not intact, the drying is more
involved. One example of the dry process is that designed for fuel being moved
into the IFSF from CPP-603 basins. The fuel needed to be hot vacuum dried.
The SNF had insufficient decay heat for drying so it had to be actively heated aswell as vacuum dried. However, the SNF included aluminum clad SNF what
could not be dried at high temperatures. In addition, a drying system had to be
designed to fit with in the existing IFSF SNF receiving area.
A second example of a unique drying station is the one designed for the
TMI-2 SNF. The debris has been stored in stainless steel cans full of water forover 20 years. The stainless steel canisters also contained low density concrete
as well has the SNF debris that had become saturated with water. It wasnecessary to design a heated vacuum dry system that would heat the debris toover 800 C to drive all of the free as well as the bound water.
4.

INL Long -Term Objectives

4.1

REPOSITORY AND TRANSPORTATION REQUIREMENTS

The SNF and its container will need to meet strict transportation and repository
acceptance criteria in order to be transported and dispositioned in a repository.
The existing transportation criteria are contained in 10 CFR 71. The INL
assumes that these requirements will not change significantly over the next 30
years and plans to package the SNF now so that it will meet these requirements
and will not have to be re-packaged prior to shipment to the repository. This

MANAGING SPENT NUCLEAR FUEL AT INL

11involves treating the fuel and ensuring the structural and criticality control
features employed during packaging will meet the 10 CFR 71 criteria.
The repository acceptance criteria are still evolving as the design of therepository is being developed. There are many of the criteria that are firm
enough that design solutions to address them can be developed andimplemented now.
4.1.1

Treatment to meet repository requirements

Nuclear criticality in the repository was an issue that surfaced early in therepository planning. The initial repository design called for large diameter
waste packages. For HEU fuel this design represented a difficult task to showthat no criticality would occur over the life time of the repository. During
discussion with DOE-Office of Civilian Radioactive Waste Management (RW)
the idea of putting only small quantities of HEU in a waste package wasdetermined to simplify the criticality analysis. However, the idea of having tohandle a very large number of small diameter waste packages was not appealing
to the repository operators.
A concept was identified where the SNF and the HLW glass logs could bepackaged together in the same waste package. This allowed the repository to
use large diameter waste packages, yet limited the quantity of fissile material ina waste package. This concept was named co-disposal.8,9 A design of a waste
package that contained a ring of five HLW glass logs around the outside andone SNF canister in the middle was prepared. The utilization of this “extra”
space in the waste package would allow the disposition of small quantities of
HEU yet not increase the number of waste packages or increase handling costs.
The original design has been expanded, the concept has been adopted by RW.
The co-disposal concept also simplified the handling of the INL SNF in thesurface facility. Because of the diversity of SNF sizes DOE-RW felt that it
would be impossible to design an effective means to handle all of the SNF
assemblies one at a time. The original RW surface facility design for SNF
handling included moving one assembly at a time from the transportation cask
to the waste package. This is still the plan for the commercial SNF, where there
is some consistence in the design of the handling fixtures. The standard canister
design simplified the handling process for the DOE SNF. Four standard
canisters were design. The dimensions of 18 inch and 24 inch diameter werechosen with lengths of 10 feet and 15 feet.
Forty years of research, development and operation of liquid metal cooled
fast breeder reactors have generated ~60 metric tons of heavy metal of sodiumbonded spent nuclear fuel. The bulk of the fuel is from the EBR-II reactor (~25
MTHM) and the Fermi reactor (34 MTHM) and is stored at facilities on the
INL. This fuel is distinguished from commercial uranium oxide fuel by use of

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MANAGING SPENT NUCLEAR FUEL AT INL

uranium or plutonium metallic alloy fuel bonded to the cladding by metallic
sodium. The presence of sodium potentially complicates disposal certificationand licensing for geological disposal because the draft waste acceptance criteria
does not allow spent fuel which contains explosive, pyrophoric, or chemicallyreactive material10. The Record of Decision for the Treatment and Managementof Sodium-Bonded Spent Nuclear Fuel chose the electrometallurgical treatment
at the MFC as the means to stabilize the chemically reactive sodium found in
the EBR-II fuel type. An electrorefiner, using a molten salt electrolyte, is used
to separate the sodium and fission products from the fuel meat, resulting in highlevel radioactive ceramic and metallic waste forms which will be qualified forgeological disposal. Treatment of the Fermi fuel has been postponed pending
further study of the electrometallurgical and alternative treatment technologies.
A number of INL SNF types consist of small quantities of unique fuel,sometimes referred to as “dogs and cats”. A few of these SNF types consisted
only a few quart size cans of severely disrupted SNF. In one of the INL SNF
task team meetings an observation was made that “ if we could just make thisfuel as durable as other fuels it would be acceptable”. The idea of a highintegrity canister (HIC) was born9. A HIC would be constructed out of
extremely corrosion resistant materials, such as zirconium with diameters smallenough that the container would be critically safe by geometry. The HIC as
designed will not corrode over the life of the repository, will not break open
even under beyond design basis accidents, and will not go critical. Nuclear
criticality analysis will still be necessary because several HICs may be placed
into a standard canister.
The presence of organic material in the repository is as yet an unanalyzed
potential problem10. Several potential scenarios have been hypothesis. Some of
the INL SNF contains epoxy in the form of sample mounts for metallurgicalexamination. These may be considered an organic material. The INL ispresently evaluating technologies that might be used to remove epoxy as part ofa treatment program to meet repository requirements.
The chemical reactivity of uranium spent fuel is another issue being
addressed by researchers at the INL in order to meet repository safety criteria.
Uranium hydride can form as a byproduct of aqueous corrosion and its
pyrophoric nature is well known. Experiments sponsored by the National SNF
Program (NSNFP) at MFC have resulted in a clearer understanding of theoxidation kinetics of uranium hydride under repository conditions11.
4.2

REPOSITORY DISPOSITIONING

Soon after the decision was made by DOE to terminate reprocessing of SNF forthe recovery of enriched uranium and plutonium, the INL began exploring otheroptions for treatment and final disposition of SNF. Initial contacts were made

MANAGING SPENT NUCLEAR FUEL AT INL

13with DOE-RW in 1996 and a task team was set up with INL and DOE-RW toevaluate possible options for dispositioning SNF. This task team prepared areport that outlined the direct disposal options for the INL SNF. The INL has
also been working very closely with the National SNF Program located at the
INL to ensure that all Yucca Mountain planning, recommendations, andlicensing activities include the INL SNF. The INL has also opened contacts
with the NRC through DOE-RW and the NSNFP8,9.
Because of the diversity of the INL inventory it was concluded that each
SNF type could not be individually addressed in the repository analysis. An
evaluation was performed and it was determined that the SNF types could begrouped by characteristics important to the particular analysis. The group could
then be represented by one fuel. This approach greatly simplified the analysis9.
The INL SNF was included in the Yucca Mountain Environmental Impact
Statement as part of the SNF inventory, and the electrometalurgical products ashigh level waste (HLW) products. The data included chemical, physical andradiological properties of the material. The INL inventory was included in theanalysis of all of the potential impacts. There were no adverse impacts
attributed to the INL SNF.
INL SNF is also included in the Yucca Mountain Site Recommendation
report that is presently being prepared by DOE-RW and will be included in therepository license application that will be submitted to the NRC. The samegrouping approach is being used in these two documents that were used in the
EIS, with additional in enhancements in the characterization data.
4.3

KEY MILESTONESThe following key milestones relate to the Consent Order and Settlement
Agreement. These milestones, if not met, could result in halting all shipmentsof SNF into the State of Idaho per the terms of the Settlement Agreement.
x Commencement of TMI-2 fuel debris movement from TAN wet basins Completed 03/31/1999,
x Removal of all SNF from CPP-603 wet storage by 12/31/2000 –Completed 04/28/2000,
x Removal of TMI-2 fuel debris from TAN wet basins by 06/01/2001 –Completed 06/2001,x Begin loading spent fuel into dry storage (excluding TMI-2 fuel debris
covered separately) by 07/01/2003 – Completed 06/2003,x Removal of all SNF from wet storage by 12/31/2023,x Completion of shipment of SNF from the State of Idaho by 01/01/2035.

MANAGING SPENT NUCLEAR FUEL AT INL

14
5.

Conclusions

A legacy of the INL was a large, diverse inventory of SNF in a large number ofaging facilities. With termination of reprocessing there was no path forward for
disposition of SNF. Managing this legacy has included: characterization of the
SNF and facilities, resolving SNF storage vulnerabilities, consolidating SNF
and closing facilities, managing domestic and foreign assigned fuel receipts,
developing technologies needed, and ensuring that the SNF inventory or its
treatment byproducts are acceptable in a federal repository.
References
1. Department of Energy's Record of Decision for Programmatic Spent
Nuclear Fuel Management and Idaho National Engineering Laboratory
Environmental Restoration and Waste Management Programs, (60 FR
28680) May 30, 1995 and Amendment, March 1996
2. Department of Energy's Record of Decision for Nuclear Weapons
Nonproliferation Policy Concerning Foreign Research Reactor Spent
Nuclear Fuel, (61 FR 25092), May 13, 1996.
3. Settlement Agreement, State of Idaho and the Department of Energy,
October 16, 1995 re: Public Service of Colorado v. Batt, No. CV 91-0035S-EJL (D. Id.) and United States v. Batt, No. CV-91-0054-S-EJL (D. Id.)
4. Defense Nuclear Facilities Safety Board Recommendation 94-1 to theSecretary of Energy, May 1994 and DOE Implementation Plan, February
28, 1995
5. Settlement Agreement, Contract No. DE-AC07-96ID13425, February 9,
1996, between the United States Department of Energy and Public Service
Company of Colorado, Modifying Contract at (04-3)-633, as amended, andAgreement No. DE-SC07-79ID01370, as amended.
6. INEEL ISS Facility Project DE-AC07-99ID13727
7. Spent Nuclear Fuel Dry Storage Project DE-AC07-00ID13729
8. Technical Strategy for the Treatment, Packaging, and Disposal of
Aluminum Plate Fuels, June 1996
9. Technical Strategy for the Management of INEEL Spent Nuclear Fuel,
Volume I, March 1997
10. Civilian Radioactive Waste Management System, MGDS Waste
Acceptance Criteria, B00000000-01717-4600-00095, Rev. 00, Draft A,
September 1997
11. “Oxidation Kinetics of Hydride-Bearing Uranium Metal Corrosion
Products”, T.C. Totemeier, R.G. Pahl, and S.M. Frank, Journal of Nuclear
Materials 265 (1999) 308-320.