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.