Long term storage of RW. Test
Case development and WG
inputs.
28-31 October 2014. IAEA, Vienna, Austria.
Complimentary Safety Reports,
Development and Application to
Waste Management Facilities
CRAFT Project
Objectives
• Test case developed for Long term
Storage using the SAFRAN 2 (release-
2.1.3.0 )
• Storage Working Group document. Main
inputs (proposals) for long term storage
facility
SAFRAN for L-T storage
• Managua WTSF (Existing facility)
• Timeframe. 80 years of operation
• Storage facility: 2 storage chambers (DSS, conditioned wastes)
• Inventory: DSS (60Co, 137Cs, 226Ra) and Conditioning wastes (60Co, 137Cs, 14C)
• Purpose: to evaluate feasibility for L-T storage of RW.
• Software: SAFRAN 2 release: 2.1.3.0
Site WSTF “Managua”
Storage facility
RW Treatment facility
N
Province: La Habana
Storage facility “Managua”
Existing facility
Scenarios LTS
Normal scenario. Periodic monitoring,
package degradation, release of rw. Direct
irradiation and inhalation.
Altered scenario. Container degradation,
water infiltration, release of rw, direct intake
trough water or foods.
Accidental scenario. Fire and release of rw
at: facility, on-site, out site (near town and
dam). Direct irradiation, inhalation, food
consumptions.
Scenarios. Cont.
Intrusive scenario. inadvertent intrusion, unauthorized handling of DSS container, direct irradiation.
(Associated to partial closure of facility (completed inventories), only monitoring, there are not operations of storing or handling and is possible to expect a reduction of the security control as time passes.
Results. Scenarios impacts Impact vs scenarios
normal
disturbed
accidental partial
accidental total offsite
accidental total onsite
human intrusion
Human intrusion (conservative scenario)
more relevant followed by normal
and accidental scenarios
Results. Pathways impacts Impact vs intake pathway
Inhalation
external irradiation
food intake
water consumption
The more relevant were: external
irradiation and inhalation
a) L-T storage of RW is possible with remedial actions
b) Need of maintenance works to fix the identified problems and enhance the facility design
c) Periodical review and monitoring rw, facility, environment
d) Changes in the operational procedures and package design
e) A new and more detailed SA/SC will be needed for license purpose.
f) Now on-going project concluding the maintenance works for the WTSF and implementation IAEA guidelines.
Results
Managua Test Case
Applied the SAFRAN 2 version 2.1.3.0
(long term storage.safx )
Application of SAFRAN 2 tool
• Included more wizards to support the tools application
• A screening tool (DSS Borehole) is incorporated
(improve the SAFRAN scope to disposal facilities)
• Purposes: All included in the standard purposes for
the safety assessment are relevant for long term
storage facilities.
• Scenarios/PIE:
– Included: Fire, degradation of process material, etc
– Not included as predefined PIE: Human intrusion*
Application of SAFRAN 2 for LTS
Comments • The activities (storing, handling, etc) and the related
waste streams are full supported in SAFRAN 2
• There is not available specific models for groundwater or airborne (Gaussian)* transport scenarios (conservative models), but can be added the assessment results and additional material (supported documents) may be included to the Safety Case as attached documents.
• These models (preliminary assessment) could be included using the same approach applied in the screening tools (Borehole) with set of parameters (site hydrology, geochemical, etc) to be defined.
Application of SAFRAN 2 for LTS
Comments
• Conservative models often overestimate
the impacts.
• Additional recommendation: Based in
similarities between SC approaches
(predisposal/disposal facilities) to evaluate
the possibility to enhance/improve the tool
for SA/SC application for RW disposal
facilities. (new models, scenarios, etc)
SAFRAN new release • To facilitate the tool usability for Spanish
users should be:
– Translate to Spanish language the
software and documents (Safran tool, help
off-line, tutorials and examples cases)
• Workshops to SAFRAN applications
• Should be converted the Test Cases
examples (available) compatible to the new
releases (saf/safx).
CSF Facility description (WG) Safety Case Purpose (GSG-3)
• Identification of uncertainties, his relevance and ways to handled
for LTS.
• Demonstration the safety of the storage facility or activity for LTS
Scenarios.
• Provide support for licensing or authorization process (LTS)
• Evaluation and justification of the expected lifetime (LTS) of the
facility;
• Assessment of the maximum inventory of waste that can be
accepted or handled in LTS conditions
• Definition or revision of limits, controls and conditions.
Identification of remedial actions, if needed, (design changes,
procedures, etc) to improve the safety of CSF for LTS. Definition
of new WAC for LTS.
LTS Safety case
Other aspects:
• Timeframe (should be extended) According
the scope (LTS), should be more relevant to
evaluate the Facility safety for timeframe such
as 50 to 90 years.
• Facility description: Relevance aspects
associated to engineering barriers behavior,
the site evolution in the time, etc.
Scenarios LTS
Possible relevant PIEs (postulated initiating events)
• Any natural events (flood, seismic, climatic changes, etc ) relevant for
the defined timeframe
• Loss of containment (associated to natural degradation, accident, etc)
• Loss of confinement (associated to natural degradation, accident, etc)
• Lack of maintenance (full capacity, complex maintenance activities)
• Incorrect determination of characteristics of wastes, this could results
in: degradation/corrosion in the barrier (EBS is not designed for LTS)
• Ineffective personal monitoring;
• Faulty or ineffective security monitoring; (in LTS, full capacity, maybe
less personal available)
• Maintenance activities not well managed; (full capacity, complex
maintenance activities)
• Improper inspection or inappropriate inspection frequency; (full
capacity, complex inspection activities)
Scenarios LTS
• Radiological impact to workers during surveillance
operations, Dose assessment (external, inhalation, dermal
contamination, etc.
• Radiological impact to workers during accidental conditions,
Dose assessment (external, inhalation, dermal
contamination, etc.
• Radiological impact to public members associated to
inadvertent radionuclide release from the facility, Dose
assessment (external, inhalation, dermal contamination, food
intake, water pathways, etc.
• Radiological impact for inadvertent/intentional human
intrusion scenarios associated to partial closure of the facility
(temporal stopped) for long term period … Dose assessment
(external, inhalation, dermal contamination, etc).
MODELS According the previous defined context, scenarios, etc the models
should include:
• Clear definition of which waste (inventory, package, fraction affected,
etc) are implicated (waste streams prediction)
• To include the (probable/possible) natural processes affecting the
facility safety: EBS degradation (corrosion, fracturing, others natural
evolution processes, etc), site flooding (if possible according the site
characteristics and the timeframe)
• Accidental situations… (during inspections, wastes handled and other
related actions)
• Radionuclides transport pathways and exposure pathways, according
the defined scenarios (air, water, biosphere chain, direct irradiation,
etc)
• Human intrusion model, active and passive barriers
falls/bypassed/malfunction
Uncertainties
• Long term period (50-90 years), behavior/evolution
of EBS for the timeframe, expected waste streams.
• Models parameters, Researches/studies (facility
and site) are necessary to decrease information
lacks, …
• Expected/predicted changes in the facility and site
(climatic change, socio-economical, etc) for LTS
Work to be done
• Work in the Storage WG (review and
update the planned tasks)
• Support the final CRAFT activities,
documentation, etc.
Thank you for your
attention.