1. IAEA
IAEA activities and experience
relevant to LeTrench
P. Ormai
Waste Technology Section
Division of Nuclear Fuel Cycle and Waste Technology
1st Environet Technical Meeting of the LeTrench Environet Project, 12-16 Sept.2016, Sellafield, UK
5. IAEA
• Unpacked waste tumble tipping into shallow unlined trenches
• Waste packaged in a variety of container types and randomly dumped or stacked into the
trenches
Trenches were backfilled using materials removed during trench excavation, compacted, and
graded to create an earthen mound cap necessary to prevent rain water ponding and to
promote runoff.
Early disposal practices (1)
6. IAEA
Early disposal practices (2)
• Disposal in `RADON`- type facilities
Unpacked or packaged in a variety of container types, randomly dumped or stacked into
the prefabricated subsurface vaults
“RADON” facilities in Russia (Source: A. Guskov)
Azerbaijan, Belarus, Estonia, Georgia,, Kazahstan, Latvia, Lithuania, Moldova,
Tadzhikistan, Uzbekistan,…Bulgaria, Hungary
Standard design: near surface vaults (6m depth), shallow borehole for DSRS
“RADON” facilities in Ukraine (Source: N. Rybalka)
7. IAEA
Evolving recognition: several disposal solutions used before
current modern requirements were established may not meet
all the requirements.
These facilities / sites may be:
• still operational
• operation suspended
• closed down
• abandoned
Early disposal practices (3)
8. IAEA
Concerns
• Siting shortages
• No site selection
• No site characterisation
• Poor design
• Information shortages
• existing information on the site /
facility is deficient (evaluation of the
safety is difficult)
• lack of SA methodology
• Infrastructure shortages
• lack of resources
• handling DSRS
• waste characterisation
• Operational shortages
• no WAC (disposal of long
lifeLwaste)
• no Quality Management system
(e.g insufficient record keeping)
• lack of appropriate monitoring
• lack of expertise
• lack of safety culture
• operation for decades with no
modernization to improve
operational safety
• Facility evolution
• more rapid deterioration of the
engineered structures, surface
systems, etc.
Design and construction based on safety criteria of 50’s and 60’s
9. IAEA
Safety of the existing facilities / sites
The fundamental questions:
• Is the facility / site safe? Has it been demonstrated ?
• Is there any safety concern?
• What to do if safety concerns obviously exist?
Different status:
• Long term safety has not been demonstrated (or adequacy of the assessment
has been questioned) although safety has been questioned because revisions to
the operating conditions or monitoring results;
• Long term safety was (re)evaluated, concerns were identified, but no corrective
actions have been implemented;
• Long term safety was (re)evaluated and corrective actions were made or
initiated
safety upgrading measures
waste (partial or full) retrieval
10. IAEA
• Pu line carboys
• Glass vessels
(contents unknown)
• Incinerator ash
(drummed)
• Tractors
• Trailers
• Cs-137 crane
• Pile filters
• Tritium furnace liners
• Flasks (up to 2 tons)
• Building rubble
• Asbestos
• Pipes
• Scaffolding
• Pond lamps
• Pond tools
• Lead castles
• Wheels
• Drums of oil
• Steel tanks
• Tank sludge
Examples of identified issues with legacy sites
Lack of knowledge of trench contents
11. IAEA
Examples of identified issues with legacy sites
Radionuclide releases and plumes
Groundwater contamination, Canada
Surface Pu contamination,
Australia
13. IAEA
International Commission on Radiological
Protection (ICRP) recommendations
These recommendations call for:
• obligatory intervention above
100 mSv/a and
• a more optimised intervention
where doses of between 10 and
100 mSv/a are observed.
mSv/a
Intervention is not likely
to be justifiable
Intervention may
be justifiable
Intervention almost
always justifiable
1
10
100
3
30
Existing
Annual
Dose
There are existing international recommendations (ICRP, IAEA) covering
such situations, i.e. criteria to be applied and action to be taken in the case of
exposure resulting from past practices.
14. IAEA
ICRP recommendations (2)
Basic principles for practices
Justification (production of sufficient
benefit to the exposed individuals or
to society to offset the radiation
detriment caused)
Optimisation (magnitude of
individual dose, number exposed and
likelihood of incurring exposure
should all be kept as low as
reasonably achievable)
Individual dose and risk limits
Basic principles for intervention
The intervention should do more good
than harm
The form, scale and duration of the
intervention should be optimised
Dose limits do not apply (recognition
that higher doses may need to be
accepted)
PRACTICES - human activities that are undertaken as a matter of choice, but
which may result in an increase in exposure.
If action is taken to reduce the exposure arising from an existing situation, then this
is an INTERVENTION.
15. IAEA
• The ICRP framework for intervention is based on the
recognition of an imminent risk (e.g. contaminated surface
soil).
• The trade-off between public risk and worker risk during intervention is
therefore relatively straightforward.
• For waste disposal sites, the situation is less clear. Risks
associated with waste disposal are potential future risks.
• When assessing the advisability of an intervention, the
decision maker must therefore balance these potential
future risks against certain risks (both radiological and
non radiological) to workers during intervention.
,
ICRP recommendations (3)
16. IAEA
The situations for many legacy facilities / sites do not fall
within the current ICRP framework for radiation protection, in
that they are
• neither a justified practice
• nor a clear intervention
Such sites may be appropriate:
• for continued existence as a justifiable practice, or
• they may require intervention, after which they may be
appropriate for continued use as a justified practice or closed as
brownfield
ICRP recommendations (4)
17. IAEA
JC Article 12. EXISTING FACILITIES AND PAST PRACTICES
„Each Contracting Party shall in due course take the appropriate
steps to review:
…the results of past practices in order to determine whether any
intervention is needed for reasons of radiation protection bearing in mind
that the reduction in detriment resulting from the reduction in dose should
be sufficient to justify the harm and the cost, including the social costs of
the intervention.
…”
Joint Convention on the Safety of SF Management
and the Safety of RW Management
PAST PRACTICES
INTERVENTION
18. IAEA
IAEA Basic Safety Standards
For chronic exposure conditions:
• …protective actions shall be undertaken whenever
they are justified;
• The form, scale and duration of any such protective
or remedial action shall be optimised …;
For intervention situations:
• Intervention is justified only if it is expected to
use more good than harm, with due regard to
health, social and economic factors.
• Optimised intervention and action levels shall
be specified in plans for intervention situations,
taking account of local and national conditions
...
19. IAEA
Requirement 26: Existing disposal
facilities
• The safety of existing disposal facilities shall be
assessed periodically until termination of the
licence.
During this period, the safety shall also be assessed
when a safety significant modification is planned or
in the event of changes with regard to the conditions
of the authorization.
In the event that any requirements set down in this
Safety Requirements publication are not met,
measures shall be put in place to upgrade the
safety of the facility, economic and social factors
being taken into account.
IAEA Safety Requirements
20. IAEA
IAEA technical documents (1)
Summary report of the CRP
Coordinated Research Project (2008-2011)
Participating MSs:
Argentina, Bulgaria, Cuba, France, Hungary, India, Romania,
Ukraine
Provide guidance on approaches and technologies that can
be used to:
(a) identify potential corrective action needs;
(b) assess options and select appropriate corrective actions; and
(c) plan and implement the corrective actions selected to enhance
repository performance and safety
Examples: Belarus, Bulgaria, Canada, Czech Republic, France,
Hungary, Latvia, Lithuania, Russian Federation, UK, Ukraine, USA2005
21. IAEA
For establishing the safety of the facility and also for
planning or implementing an upgrading programme the
availability of and accessibility to records (in particular waste
inventory} on the contents of a disposal facility, is a pre-
requisite.
Valuable experience has been gained and relevant
information is now available on actions and procedures that
may be employed for the retrieval and restoration of waste
inventory records for existing storage and disposal
facilities.
IAEA technical documents (2)
22. IAEA
IAEA meetings dealing with the subject
• Upgrading of near surface repositories for radioactive waste, Technical
Meeting, Budapest, Hungary, 25–29 August 2003
• RER 9107/9003/01 Workshop on experience of RADON
storage/disposal facilities aiming to identify problems and options for
safety upgrading, Russian Federation, Sergiev Posad, 17–21 June 2013
• Legacy waste retrieval from the Maisiagala repository, IAEA organized
National Workshop, Lithuania, 2013
• Reassessing historical and current practices to ensure safe disposal:
addressing incomplete knowledge of the properties of historical waste in
storage or in disposal, DISPONET Technical Meeting, Cape Town,
South Africa, 24–28 November, 2014
23. IAEA
IAEA ASAM project (2002-2006)
ASAM: Application of Safety Assessment Methodology for
near-surface radioactive waste disposal facilities
Objectives:
• Development of an approach and methodology for
assisting decision making in selection of options /
alternatives for corrective actions;
• Comparison of different options of corrective actions
and assist decision for future development of these types of
facilities.
• Provide practical demonstration on using ISAM
methodology to address real problems;
24. IAEA
ISAM Safety Assessment Methodology
Assessment Context
Describe System
Develop Scenarios
Formulate and
implement Models
Consequence Analysis
Interpret Results
Compare with Safety
criteria
Review and
modification
Adequate
Safety Case
Effective to modify
componentsAccept
RejectYes No No
Yes
• The ISAM methodology itself is a decision analysis approach
• A structured approach for quantifying and understanding uncertainties
• Considerable elaboration of evolution through iterations
• Focus is on long-term post-closure assessments
26. IAEA
Common problems in managing legacy
trench sites
• lack of site-specific information
Characteristics of buried wastes
Flow paths and exposure pathways
Previous management interventions
• unclear responsibility and ownership
• limited availability of technical expertise
• scientific uncertainty
• societal issues
• various constraints and limitations
Financial, technical, legislative, etc
27. IAEA
• Review the results of past practices in order to determine whether any
intervention is needed is performed or planned in a number of MS.
• Systematic approach:
• Analysis (safety evaluation)
• Identification of the problems
• Identification of preferred corrective actions (feasibility studies)
• Implementation
• Some countries still are at the very beginning of the process
• Others have decided to implement appropriate corrective actions to their
disposal facilities.
• There are sites where extensive corrective actions have been
completed.
Review of past practices
28. IAEA
Corrective actions
Different terminologies: remediation, rehabilitation, safety upgrading,
refurbishment
• All activities and measures, undertaken to address actual or perceived
issues or problems associated with legacy repositories for radioactive
waste.
• Corrective actions are generally undertaken to improve existing
conditions. However, in some cases, corrective actions may be directed
to preventing future problems.
Corrective actions generally address one or more of the following
objectives:
• Rectify an existing unsafe condition
• Prevent an unsafe condition from occurring in the future
• Achieve compliance with modified regulatory requirements
• Respond to societal demands
29. IAEA
Risks associated with remedial actions
Assessment criteria considered
• Public risk
– Long term
– Operational
• Worker risk
– Radiological
– Non-radiological
• Environmental risk
• Monetary risk
• Programmatic risk
(engineering feasibility and project
risk, timescale for implementation)
• Socio-economic risk (Socio-
political acceptability)
The benefits, in terms of risk or dose
averted, should be balanced against
cost, both dosimetric and monetary, for
any proposed intervention.
• Decisions on upgrading need to be
robust against uncertainty
• May need sensitivity analyses and
alternative interpretations
• Further data collection or monitoring
may be required to justify expensive
remediation options
30. IAEA
Potential corrective actions
Engineering Issues
Effects on other components
of the facility and disposal
system
Increase or decrease in
disposal volume or other
limits
Safety Issues
Regulatory requirements
Worker safety
Public safety
Radiological impacts
Non-radiological impacts
During implementation of
corrective action
During subsequent operation
and closure of facility
Post-closure
Accident situations
Analysis,
Prioritization,
Documentation and
Justification
Implementation
Issues
Engineering practicability
Timescale for implementation
Availability of resources
including funds
Stakeholder acceptance
Cost
Estimates and uncertainties
Identification of preferred
corrective action
• There are usually several alternatives for achieving the desired end-state (i.e., alternatives
that meet all of the health, safety and environmental objectives).
• Risks and costs associated with each alternative should be evaluated to facilitate selection of
preferred alternative. Public participation in the process is also advised.
31. IAEA
Remediation options
• New data (site investigations, re-inventorization) New iteration of SA
• Modified assumptions
• Design changes
• sophisticated cap design
• improvement of the drainage system
• leachate management control
• backfill
• improve local physical containment (reconditioning, repackaging)
• additional EBs (cut-off wall)
• Long-term management arrangements (enhanced environmental
monitoring, longer institutional control, permanent site marker, extend site
boundary, prevent certain activities in the region of the facility, relocate local
inhabitants)
• Modified inventory (removal of waste)
32. IAEA
Legacy waste records
• A typical problem with historical waste inventory records is
the loss of data.
• For many of the older facilities the records (inventory, information
about site, monitoring results, modifications, etc.) need to be
restored, revised and verified.
• During retrieval of legacy items there is potential for
significant discrepancies between historical records.
• To rectify the inventory and disposition of the discrepancies
a supplemental historical review of records is
needed.
34. IAEA
Relevant issues / questions (1)
Analysis (safety evaluation)
• Legacy waste records (exist? how reliable?....)
• Are further investigations or monitoring necessary?
• Assessment of hazards and risks
• How should uncertainty be dealt with?
Identify the problems
• Is intervention required (how much intervention)?
• What is the desired end-state?
Identification of preferred corrective actions
• What remedial actions are possible and what are the issues for the regulator?
• Choosing between remedial options (data required to underpin decisions)
• How to optimised the intervention?
• How to quantify the risk and the benefit?
• Need to disturb waste (re-characterization, reconditioning and repackaging)?
• How to estimate the risk for workers and members of the public?
35. IAEA
Relevant issues / questions (2)
Implementation
• Interactions between various actors (operator, regulator)
• Regulatory issues (licensing)
• How to address socio-political concerns?
• Challenging working environment
• worker safety (dose, accidents)
• presence of chemical and other hazards
• constrained space
• aging facility
• security
• Constraints (technical, political, societal, economical)
37. Australia
Little Forest Legacy Site (LFLS)
79 TRENCHES
25m x 3m x 0.6m
• 1675 m3 waste: ~150 GBq activity,
~1100 kg beryllium, ~7 g of Pu (est.)
• Waste buried in unlined trenches
spaced 2.7m apart
• Covered with ~1m soil
38. Argentina
Ezeiza Waste Management Site (Age)
There are two solid waste trenches at the Ezeiza facility.
The first trench (700 m3 capacity) opened in 1975. It was
built in natural soil without any type of
engineered improvement and was subsequently closed in
1988 with some historic waste in it.
The second trench (1120 m3 capacity) started operation in
1989.
In 2006, the CNEA decided to permanently suspend
operation of the final disposal systems at the EMASource: Maset and Andresik
39. France
• In Centre de la Manche initially (1969) the
waste, packaged in various forms, was either
buried in earth trenches or placed in concrete
lined trenches.
• After one year of operation, the earth trenches
were deemed unsafe and abandoned.
• The earth trenches, which had been built, were
dismantled. Waste packages were retrieved,
reconditioned and disposed of in other disposal
units.
• Later waste was disposed in long trenches
provided with walls consisting of concrete
prefabricated slabs.
Source: l. Pillette-Cousin, AREVA TA, France
40. Source: J. Gisca
Moldova
Size 5х4х16 m, divided into 4
compartments by 50 m3
DSRS (Pu-239, Ra-226, C-14 , etc.), soil
contaminated with Ra-226
High contamination of soils and ground
water (Ra-226 and Sr-90)
Plan to retrieve all legacy RW
followed by remediation of the site
43. Lithuania
Maišiagala repository
• Institutional waste burial started in 1964 (waste
disposal stopped in 1988)
• Sections of the concrete vault were filed in
chaotic way with unconditioned solid
radioactive waste (about 60% of the 200 m3
volume was filled), LL-DSRS
• In 1989, the vault was covered by a concrete
slab and a layer of sand was filled above it
A repository’s upgrading project financed by EU was implemented in years 2004-2006
Plastic membrane was installed to improve safety of the repository
Source: A. Vaidotas
44. Estonia
Tammiku RADON type disposal facility (in operation: 1963 to 1995)
Under decommissioning since 2008
All waste is retrieved, sorted, packed and stored in Paldiski site interim
storage
Structures de-contaminated
Waiting for free release
Source: Ivo Tatrik
45. Ukraine (1)
Source: N. Rybalka
• 6 State Interregional Specialized Enterprises (RADON)
• Built in 1960s according to the typical design which is not comply with modern safety
requirements
• Long term safety assessment was not performed
• Engineering barriers lost integrity
• Emergency situations with spreading contamination happened at Kiev and Kharkiv SESI
in 1990th
Planned measures:
• Safety reassessment of ‘legacy’ RW disposal
• Development of Projects for removal, treatment and conditioning of the “legacy” radwaste
and spend sources, transport them for centralized storage or disposal
46. Ukraine (2)
Layout of waste burials in RWTSP “Red Forest” in Chernobyl Exclusion zone
Source: D. Bugai
trench in “Red Forest” site
47. Hungary
safety requirements and standards in the 1960s.
• commissioned in 1976
• Capacity: total 5040 m3
Safety assessment called for corrective
actions (due to presence of long life nuclides)
Source: P. Ormai
Corrective actions:
• Improvement of the engineered barriers
• Partial waste retrieval
48. Norway
Retrieval of radioactive waste took place in 2001
Source: Sørlie, A.A.
1970: all LILW generated before was disposed of in a shallow land disposal at the Kjeller site
(ca.1000 drums of 19 other waste items).
The waste drums were embedded in clay and stacked in 2 horizontal layers. The area covered
11.5 m × 23 m.
The upper layer of drums was covered by 1.5–2 m of clay and soil with no engineered
barriers.
49. Mexico
Source: D. A. Mut Chable
Uranium mining tails and
contaminated soil buried
radioactive wastes (old disposal
practices not allowed nowadays)
Radioactive Waste Storage Facility
(CADER)
50. Thabana trench disposal site
start of operation: 1968
• previously known as ‘Radiation Hill’
• very little is known about selection criteria used
• no waste acceptance criteria (mixed LL, SL, chemically hazardous waste,
DSRS, SF, etc.)
• trenches have no license for disposal or “permanent storage” only a preliminary
safety assessment for interim storage (1996)
• questions about its suitability as disposal site
CURRENT STATUS
• uncertainty about suitability as a disposal site;
• uncertainty about nuclide inventory;
• uncertainty about waste types;
• uncertainty about future
– upgraded as disposal facility?
– retrieve waste?
– repackage waste?
– closed and rehabilitated?
South Africa
51. UK (1)
• The Drigg Low Level Waste Disposal
Site has been in operation since 1959.
• The disposal concept initially used was
tumble tipping into trenches cut into
the host geology.
• This practice was continued until seven
trenches, taking in excess of 800,000 m3
of waste, had been filled.
• At this stage the trenches were covered
with a low permeability cap to limit
rainwater infusion.
Source: R.G.G. Holmes1, S. Richardson, R.A. Robbins
52. UK (2)
The Southern Storage Area (SSA), Harwell
From 1946 the site was used for a variety of waste storage and handling operations
and for the landfill burial of mixed chemical, beryllium and low level radioactive
waste.
The Southern Storage Area prior to
remediation
Trench Remediation
The SSA ceased to be operational in 1980 and during the 1980’s was left under minimal care
and maintenance with some minor clean up activities.
In the early 1990’s some initial characterisation was carried out and then in 1994 a campaign
of decommissioning dealt with much of the significant surface contamination and wastes.
The primary remediation project evolved as a key part of UKAEA’s mission to restore the
environment.
The restored site
Source: P. Booth
53. UK (3)
Legacy Trenches at Sellafield
• The Windscale Trenches were unlined excavations used by the Windscale Plant
in the 1950s to bury lower level wastes and some items too large for
intermediate level waste stores
• Information on their contents is largely derived from indirect and anecdotal
sources rather than contemporary records
• The trenches represent an accumulation of radioactive matter and are not
managed to the current standards for waste disposal to ground
• Pu line carboys
• Glass vessels
(contents
unknown)
• Incinerator ash
(drummed)
• Tractors
• Trailers
• Cs-137 crane
• Pile filters
• Tritium furnace
liners
• Flasks (up to 2 tons)
• Building rubble
• Asbestos
• Pipes
• Scaffolding
• Pond lamps
• Pond tools
• Lead castles
• Wheels
• Drums of oil
• Steel tanks
• Tank sludge
• Mononitrotoluene
• Dinitrotoluene
• Acid degredation
products
• Solvent
• Asbestos
• Hydraulic fluid
• Oil
• Lead and other
heavy metals
Source: J. Cruickshank
54. USA (1)
• Six commercial repositories opened in U.S. since 1962
• Two of six open today (Barnwell & Richland)
• Extensive corrective action & ongoing maintenance at some sites
– Sheffield, Illinois
– Maxey Flats, Kentucky
– West Valley, New York
– Beatty, Nevada
• Waste retrieval not required as corrective action at any U.S. site
55. USA (2)
Savannah River Site Slit Trenches
During the operational phase, stormwater naturally
infiltrates into the soil column overlying the buried
waste and impacts the migration of tritium to
groundwater.
The durability of the interim geosynthetic cover
material could impact the stormwater runoff cover
performance to minimize infiltration.
Source: Jon Richards, U.S. Environmental Protection Agency
56. DOE Oak Ridge Reservation NPL Site
33,000 acres
USA (3)
• High levels of rainfall, coupled with shallow groundwater, carry contaminants
to local waterways
• Excess large-scale, deteriorating, and contaminated industrial/nuclear facilities
require periodic, significant maintenance activities
Source: Jon Richards, U.S. Environmental Protection
Agency
