DEVELOPMENT OF DUST DISPERSION
SUPPRESSION TECHNOLOGYPUBLIC PRESENTATIONFEBRUARY 2024
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Project Organization

A.
B.
C.
D.

BACKGROUND & PURPOSE
GENERAL OVERVIEW – USE OF COATINGS, METHODOLOGY OF SELECTION & TESTS OF PROPERTIESITEMS OF WORK – WORK PACKAGESSCHEDULE OF THE PROJECTTechnical PresentationI.

INPUT DATA ANALYSIS, FUNCTIONAL ANALYSIS, DEFINITION OF REQUIREMENTS FOR THE APPLICATION ON SITEII.

FUEL DEBRIS SIMULANT MANUFACTURINGIII.

SELECTION OF COATINGSIV.

PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSIONV.

CUTTING TESTS – MEASUREMENT OF IMPACTS

VI.

APPLICABILITY & OPERABILITY TESTS

VII. ASSESSMENT OF IMPACTS
VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPSIX.

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CONCLUSION OF THE PROJECT

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)2

DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

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Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)3

DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

A. BACKGROUND & PURPOSE
Why the project is needed?
Dust resuspension and scattered sludge could cause safety and security issues regarding the containment of radioactive airborne particles. Therefore, elemental technologies are being
investigated in order to minimize or even suppress the dispersion of dust when Fuel Debris is processed inside the Primary Containment Vessel (PCV).
Usage of the project results
The project results shall support the development of technologies contributing to the decommissionning of Fukushima Daiichi Nuclear Power Station(1F). More specifically, the results of the
project shall help in the implementation of technologies for suppressing the dust dispersion.
Contribution of the project results
Currently, solutions such as local collection of dust or implementation of water spray have been studied inorder to suppress the dust dispersion during the fuel debris processing. Nevertheless, dust dispersion can becaused not only during fuel debris processing but also by several other phenomenas: fuel debris removal,
movement of remote controled arm inside the pedestal, fall of an object… This project focuses on
implementation of solutions that shall allow to suppress dust dispersion by applying specific coating.

1.
2.
3.

Particles that could deposit on the walls or on the ground
Airborne particles that could exit the pedestal
Particles that could fall into the water

Project goal:
The project aims at developping technique of injection and/or spraying of material (coatings) for dust suppression technology. Studies and tests will integrate as much as possible on site
conditions and scenarios. Impact studies will be realized in order to verify the applicability of the solution.
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B. GENERAL OVERVIEW – USE OF COATINGS, METHODOLOGY OF SELECTION & TESTS OF PROPERTIES
Coating characteristics need to be consistent with its application. Indeed, coating characteristics shall be adapted whether it isapplied in dry air, in wet air, with water dripping, on a vertical surface, by gravity, etc.
Furthermore, coating characteristics must be ajusted to the 1F conditions: high dose rate, remote controled operation, tight andcluttered area, etc.
Therefore, the first task of the project is to define what an applicable coating is, for what purpose (coating of Fuel Debris, coating of
metallic equipment (such as a stainless steel beam), etc.) and for which location (considering the entry inside the pedestal by theX6 penetration, coating can be carried out oriented upwards or down).
For the upper elements, it shall be necessary to use a coating that can be sprayed and with a short pot life in order to avoid drips
and have a good chance to reach as much surface as possible. On the other hand, it shall be necessary to use a coating more thick
and with a longer pot life to be used with gravity for the bottom part. In this case, it is better to let the coating spread as much as
possible to cover as much surface as possible. Also, coating properties must be searched whether it is intended to apply the
product in air or underwater.
Picture from FY2018 Supplementary Budget Subsidy Program for the Project ofDecommissioning and Contaminated Water Management
International Research Institute for Nuclear Decommissioning (IRID)
Final Report for “Development of Technologies for scaling up Retrieval of Fuel
Debris and Internal Structures (FY2020)”, released in August, 2021

A market survey was needed in order to look after possible coating candidates: a possible candidate is a coating that can comply
with operational characteristics (application by spray, by spreading, etc.) and that can comply with the 1F conditions (nodegradation under high dose rate, works in high humidity rate or even under dripping water, etc.)

On the possible candidates, it is necessary to carry out essential tests in order to ensure they are fully applicable: for example, verify that a coating can properly cross-link under dripping water.
The more accurate we get about coating selection, the more we focus the next tests on the coating candidates still in contention. More complex lab tests can be then carried out (such as
irradiation tests) because the number of candidates is lower. Also, efficiency tests and operability tests can be carried out for the same reason: these tests are carried out only with the lastcandidates.
Finally, with the results of lab tests, efficiency tests and operability tests, it is possible to study and assess the impacts, whether it is positive or negative, of the use of coating, for the dust
suppression of fuel debris inside the pedestal.

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B. GENERAL OVERVIEW – USE OF COATINGS, METHODOLOGY OF SELECTION & TESTS OF PROPERTIESThe objectives of the project being to provide data and as much as possible conclusions about the future use of coating inside the pedestal of the units 1, 2 & 3 of 1F, the project has been
through the following items:• Definition of an « applicable coating » (which characteristics does the coating must comply with?) and first selection• It is mandatory to analyse the conditions on site by establishing the functional analysis of the future system• A market survey is conducted so it is possible to list the existing coatings that present interests of use• By comparing the analysis of the situation on site (functional analysis that gives all the requirements that a coating must comply with to be applicable) allows to reduce the number ofcoating candidates• To reduce the number of candidates, it is necessary to carry essential simple tests. Depending on the results of the tests that must determine if the tested coating comply with amandatory requirement, the coating is excluded or kept in the list of coating candidates for the next steps of the project• Verification that the selected coatings are efficient in various situations (= how the coating suppresses the dust resuspension phenomena)• Operational situations that can lead to dust resuspension are studied:• Resuspension due to air movement (due to an operating system or by the airflow of the ventilation system)• Resuspension due to water movement (due to the operation of fuel debris retrieval for instance)• Resuspension due to the fall of an object• Resuspension due to a cutting operation, whether it is a mechanical cutting operation or a cutting operation using the laser technology
 For all theses situations, it is important to confirm the efficiency of a complete coating operation but also it is important to assess the gain when the coating cannot be entirely
deposited on a determined area (partial covering of an area)• Furthermore, it is important to determine whether coatings can affect the efficiency of a cutting operation. The questions to be answered are:• Does is it lower the cutting performance of a given cutting tool?
• What and how much « new » particles are produced by the cutting of the coating? Do they represent an additional issue ?

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B. GENERAL OVERVIEW – USE OF COATINGS, METHODOLOGY OF SELECTION & TESTS OF PROPERTIESIn the same time, it is very important to determine whether the coating can be applied on site with the future conditions of use. Future conditions of use concern the following topics:• Determination whether one characteristics of coating not tested yet does not comply with one requirement of the functional analysis• Some more complex tests to be carried out to determine specific coating characteristics are mandatory (resistance to irradiation for instance) These tests allow to reduce again the number of coating candidates (some of them are excluded because they failed to successfully pass a test)• Among these tests, some characteristics are determined only to give an information that will be useful for the study of impacts of the use of coatings on Fuel Debris• Verification that the selected coatings are applicable on site
• It is mandatory to ensure that the selected coatings can be applied on site. Therefore, tests with representative conditions must be carried out:
• Since conditions of application of the coatings are also determined with the functional analysis, a representative mock-up is manufactured in order to carry out the tests withsome representativity: lenght of application, areas of application, in air, with dripping water, underwater. The first step of these tests is to find out the correct settings for the use
on site: they are the tests of applicability• Also, it is very important consider the feasibility of the coating operation on site with remote controled means and with indirect vision. Tests are carried out to verify thisfeasibility and are also meant to determine the limits of the process (verification of effective coating). They are the tests of operability.
Finally, in order to completely determine the applicability of a coating, specific studies are necessary in order to assess the impacts of the use of coating inside the pedestal. Impact studies
concern: criticality, waste management, gas release, temperature exchange of Fuel Debris at the bottom of the pedestal.

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C. ITEM OF WORKS – WORK PACKAGESDevelopment
Progress

Investigate

First selection of coating

Confirm efficiency & selection of
coatings
Cutting tests

Project Items(Steps)
Input Data gathering &Functional Analysis

Core-boring, disk cutter & laser
cuttingWork Package 1
Market survey
Work Package 2
Work Package 3
Work Package 4

Essential tests forcharacteristics determination
Fuel Debris simulants
manufacturing

Efficiency tests (assessment forcomplete and partial coating)Tests with aeraulic, mechanical& water stressConfirm operability

Assess impacts of use

Feasibility tests on representative
mock-up

Global impact assessment regarding
applicability
Impact study on filtration
devices

Feasibility tests in air and withdripping water. Determinationof specifications

Impact study on waste
management

Feasibility tests underwater.
Determination of specifications

Impact study on safety(criticality, gas)

Lab tests of coating candidates toreduce their number

Applicability & Operability tests on
representative mock-up withremote controled robotic arm

Synthesis and conclusions

More accurate coating selection,assessment of efficiency,
evaluation of coating process vscutting operations

Confirmation of applicability andoperability and specifications forapplications

Conclusion, proposal for the next
steps

Preliminary cutting tests in orderto qualify measurement devices
and gather first input data on
particles generated (core boringand disk cutter)

Main Outputs

C1 - InterneFirst selection of coating, Fuel
Debris simulants for the tests

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D. SCHEDULE OF THE PROJECT
2021
09

10

2022
11

12

01

02

03

04

05

06

2023
07

08

09

10

11

12

01

02

FINAL
03

REPORTWP1
INPUT DATA GATHERING

PRE-SELECTION OF COATINGSWORLDWIDE BIBLIOGRAPHYFIRST SELECTION PROCESSESSENTIAL TESTS

Fuel Debris SIMULANTS MANUFACTURINGCHOICE OF COMPOSITIONSPROCUREMENT & MANUFACTURINGREPORT

WP2
PRELIMINARY CUTTING TESTS CORE
BORING WITH ACTIVE FUEL DEBRISSIMULANTTESTSREPORT
CORE BORING TESTSTEST PROGRAMTESTSPRELIMINARY CUTTING TESTS – DISKCUTTINGREPORT

1/3

TESTS
REPORT
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D. SCHEDULE OF THE PROJECT
2021
09

10

2022
11

12

01

02

03

04

05

06

2023
07

08

09

10

11

12

01

02

FINAL
03

REPORT

WP2
FACILITIES PREPATION FORRESUSPENSION TESTSRESUSPENSION TESTS – MECHANICAL, AERAULIC AND HYDRAULIC STRESSRESUSPENSION TESTS ON TOSQAN FACILITY (RESUSPENSION UNDERWATER)RESUSPENSION TESTS ON BERGAME FACILITY (RESUSPENSION DUE TO THE FALL OF OBJECT)RESUSPENSION TESTS ON FAAMUS FACILITY (RESUSPENSION DUE THE MOVEMENT OF AIR)REPORTSDISK CUTTING TESTSCUTTING TESTS WITH DISK CUTTER ON CAPIMIF FACILITYREPORTLASER CUTTING TESTSTEST PROGRAMTESTSTESTS REPORT

2/3
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D. SCHEDULE OF THE PROJECT
2021
09

10

2022
11

12

01

02

03

04

05

06

2023
07

08

09

10

11

12

01

02

FINAL
03

REPORT

WP3
LAB TESTS ON COATING PROPERTIESOPERABILITY TESTS ON REPRESENTATIVE MOCK-UP
MOCK-UP DESIGN
MOCK-UP PROCUREMENTPREPARATION OF TESTEQUIPMENTTEST PROGRAM

ELEMENTARY TESTS OF COATINGCOATING TESTS ON MOCK-UPTEST REPORTREMOTE CONTROLED TESTS ON REPRESENTATIVE MOCK UPTEST PROGRAM
PREPARATION OF TEST EQUIPMENTTESTSTEST REPORT
CUTTING TESTS WITH IMPACT ON FILTRATION

3/3

WP4
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I. INPUT DATA ANALYSIS, FUNCTIONAL ANALYSIS, DEFINITION OF REQUIREMENTS FOR THE APPLICATION ON SITE
1. 1. GENERALITIESBefore implementing the project, it is very important to determine the characteristics of the needed system. For that, it is mandatory to have input data as reliable as possible. The first task isthen to gather all the necessary and available information concerning the situation on site.
Information gathering intends:▪ To identify on-site status important for the application of coating (like ambient temperature, dose rate, humidity rates, water levels),▪ To present values and data about on-site status that will be considered as input data for the studies and the tests on coatings,▪ To identity systems, equipment or safety management items that could be impacted by the application of coating inside the PCV (for example: water filtration system, criticality management
equipment, waste management process, filtration systems in air, heat transfer of Fuel Debris). Then, it could be possible to provide accurate and useful data so it is later possible to assess
impacts on such systems and equipment,▪ To present data that could be provided, at the end of the study, in order to establish specifications or suggestions for more specific studies.
In the same time, a functional analysis is carried out: the goal of this study is to fully characterize the requirements of the future system (such as dimensions, lenght of hoses, maintenanceservice, operability and so on). It is important to carry out the functional analysis alongside with the input data analysis.
The functional analysis and the input data gathering help to determine the tests to be carried out to determine whether a coating can be applicable or not.

GATHERING INFORMATION ABOUTCONDITIONS ON SITE

FUNCTIONAL ANALYSIS TO DETERMINE
REQUIREMENTS OF FUTURE SYSTEM

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GIVE DIRECTION TO THE PROJECT (DEFINITION OF TEST PROGRAMS, DESIGNAND STUDIES FOR APPLICATION ON SITE)

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I. INPUT DATA ANALYSIS, FUNCTIONAL ANALYSIS, DEFINITION OF REQUIREMENTS FOR THE APPLICATION ON SITE
1. 2. INFORMATION GATHERING ABOUT SITUATION ON SITE
1. 2. 1. 1F Status
Important data about 1F status that have been used during this projects are available in the following documents:• Upgrading of the Comprehensive Identification of Conditions inside Reactor – Accomplishment Report for FY2017 – International Research Institute for Nuclear Decommissioning (IRID) , The
Institute of Applied Energy (IAE) - June 2018 (https://irid.or.jp/_pdf/3_Upgrading%20of%20Comprehensive%20Identification%20of%20Conditions%20inside%20Reactor_IRID_2019.pdf)• Development of Technology for Further Increasing the Scale of Retrieval of Fuel Debris and Internal Structures - Research Report for FY2019 (https://irid.or.jp/wpcontent/uploads/2021/01/2019002entoridasikibonosaranarukakudaif.pdf )• TEPCO transportation calculation and Development of Technology for Containing, Transfer and Storage of Fuel Debris – research report for FY2019 (https://irid.or.jp/wpcontent/uploads/2021/01/2019001ensyuunouisouhokanf.pdf)
Main information used during the project:• Range of temperature: 0°C to 40°C
• Humidity rate up to 100%
• Water level depends on the considered unit
• Localization of Fuel Debris, estimated composition and hydrogen generation as described in the references above• Thermal power of Fuel Debris and composition of cooling water as described in the references above• Access into the PCV possible through routes A, B & C described in the references above

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I. INPUT DATA ANALYSIS, FUNCTIONAL ANALYSIS, DEFINITION OF REQUIREMENTS FOR THE APPLICATION ON SITE
1. 2. INFORMATION GATHERING ABOUT SITUATION ON SITE
1. 2. 2. Important considerations
Systems and equipment impacted by coating utilization
The Fuel Debris Retrieval project considers some systems or equipment that could be impacted by coating use: the filtration system associated to the cooling water, the filtration system of
the ventilation system, the pump used to retrieve fuel debris particles and the drying system.

To take into account impact on identified systems, some data are being collected:▪ The impact on filtration systems or the pump is considered by measuring sizes and identifying forms of particles generated by coatings. As far as possible, tests are realized on filtrationequipment. These data should be transmitted to the dedicated teams to be capitalized on.
▪ The impact on the drying system is estimated by heating up to 200 ⁰C the selected coatings and analyzing its behavior (liquefaction or not). As far as possible, the thermal conductivity
and the tightness of the resin is also analyzed (https://irid.or.jp/wp-content/uploads/2021/01/2019001ensyuunouisouhokanf.pdf)
Safety consideration
As far as possible in the frame of this project, some safety considerations will be evaluated like:▪ The management of the heat released by fuel debris (by analyzing thermal conductivity and thickness),▪ The management of the hydrogen produced by fuel debris (by analyzing thickness),▪ The management of the criticality like modification of the criticality calculations, impact on countermeasures, etc. (by analyzing hydrogenous quantity, thickness, etc.),▪ The management of the fire risk (resins flammability and fire load),▪ The management of the corrosion (on covered pieces and about the storage canister in a long term consideration).
Waste management
The waste management will also be impacted. An evaluation of the waste volume added with the resins process will be made.

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I. INPUT DATA ANALYSIS, FUNCTIONAL ANALYSIS, DEFINITION OF REQUIREMENTS FOR THE APPLICATION ON SITE
1. 3. FUNCTIONAL ANALYSIS OF THE SYSTEM
The functional analysis concern two sub-systems of the dust resuspension suppression system:a) The COATING CANDIDATE analysisb) The IMPLEMENTATION SYSTEM analysis

The functional analysis is carried out in order to▪ Identify and classify the CRITERIA for the coating candidates selection▪ Compare INPUT DATA from 1F with the studied criteria▪ Pre-study the IMPACT OF THE COATING on waste, safety and security▪ Defined the RESEARCH PLAN in terms of:o Efficiency tests
o Processing testso Coatings tests and innocuity tests

The functional analysis for the future system to be deployed on site concerns:• Capacity of the system to cover all the areas of interest inside the PCV: on vertical and horizontal surfaces, on gratings, on beams, etc. and for different conditions (in air, under dripping
water, underwater)• Capacity of the system to be deployed inside the PCV and remotely by operators• Capacity of the system to be maintained• Capacity of the system to control the quantity of coating injected• Capacity of the system to resist to the harsh environment• Capacity of the system to respect the interfaces on site
• Capacitiy of the system not to generate inadequate waste
This functional analysis led to the lab tests described in the following chapter of this report.

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II. FUEL DEBRIS SIMULANT MANUFACTURING
2. 1. DEFINITION OF COMPOSITIONS
From the analysis of published data on the fuel debris of 1F and discussions with TEPCO, 3 compositions have been determined to roughly encompass of the possible 1F fuel debris compositions.
1.
2.
3.

A metallic debris, in which solid fuel pellets have been entrained corresponding to the metallic liquid phase obtained for the median composition estimated in 1F2 lower head at the time ofvessel melt-through.
A MCCI (Molten Core Concrete Interation) composition corresponding to median MCCI estimated in 1F1 sump when it was flooded after more than 10 days of dry interaction (average ARC-F
benchmark).
An in-vessel melt composition (oxide+metal) corresponding to 1F3.

In all these compositions, Uranium is replaced by Hafnium and surrogates are also used for the transuranians. Natural isotopic composition is used for Fission Products.

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II. FUEL DEBRIS SIMULANT MANUFACTURING
2. 2. RESULTS OF MANUFACTURING
Manufacturing has been achieved (4 melting operations between December 2021 and March 2022). The manufacturing is compliant with the expectations. Overall, about 68 kg of fuel debris simulants have been
manufactured and are being transferred to other sites form next phases of experimental activities.

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MCCI SAMPLES #1 – First batch

IN-VESSEL SAMPLES #2

METALLIC SAMPLES #3

MCCI SAMPLES #1 – Second batch(CEA ref. VF16)(CEA ref. VF15)(CEA ref. VF17)(CEA ref. VF16)

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III. SELECTION OF COATINGS
3. 1. OVERVIEW OF GLOBAL METHODOLOGYAs already explained, the choice of a coating is driven by the compliance of its characteristics with the requirements for the use
on site. The requirements have been determined thanks to the on-site information gathering and the functional analysis.

1

Here below is explained the global methodology of selection, in 6 steps:

2

1 The market survey of coatings gives a first list of coating candidates. Then, the coatings are compared one to each other+(technical sheets available + technical discussions with suppliers), a shorter list of coatings is sorted out.
2
3

Essential tests have been carried out. Priority criteria, identified from input data and functional analysis studies, have beentested. The results give the final pre-selection of coating candidates. These test have allowed the coatings classification
regarding on-site materials, area and environment inside PCV.

4

Finally, other essential properties are tested on a second campaign (lab tests). Some tests are more complex to implement(such as the irradiation resistance evaluation). By the end of this phase of tests, only 4 to 5 coatings are still in contention

5

Efficiency tests of the coating in terms of dust dispersion suppression is tested.

6

Also, applicability tests will aim at proving that coatings are applicable on site:▪ Real size coating tests on mock-ups, at different locations, for several materials,▪ Coating tests with remote arm,
▪ Coating test taking into account the filtration devices on-site.
The WP4 will synthetize the impact of the use of coatings (waste management, safety, criticality, etc.) to ensure the full
applicability or not.

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CANDIDATESNUMBER

MARKET SURVEY
FUNCTIONAL ANALYSIS45
TECHNICAL DATA SHEETS + XP REVIEW

24
3

ESSENTIAL TESTSBASED ON PRIORITY CRITERIA,
CLASSIFICATON REGARDING ON-SITE
MATERIALS AND ENVIRONMENT4LAB TESTS FOR PROPERTIESDETERMINATIONSELECTED COATINGS CANDIDATESFINAL CLASSIFICATON

5

10

EFFICIENCY (VSRESUSPENSION)
TESTS

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

6+

Target
4-5

COATING TESTS(APPLICABILITY)

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III. SELECTION OF COATINGS
3. 2. MARKET SURVEY – FIRST SELECTION
1

The first step has consisted in a worldwide market survey. This
market survey targetted coatings already used in the industry(whether it is used in nuclear industry or not). Indeed, no
coating development per se was scheduled in this project.

This first selection has been carried out bearing in mind theresults of the functional analysis and the information about
on-site conditions gathering.
Products from 15 international brands have been studied. At
the end of this process, 45 coatings are selected.
Family of products are: Silicone, Polyurethane, Epoxy, Gel,
Aqueous base paint, foam, mineralizing coating and GeoPolymer.

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III. SELECTION OF COATINGS
3. 3. ESSENTIAL AND LAB TESTS – OVERVIEW
2After the first pre-selection of 45 coatings, a preliminary analysis has been carried out inorder to shorten the list of candidates.
The process of this second phase of selection goes through the study of the technicaldata sheets, the comparison of products between themselves and thanks to discussion
with suppliers (OPEX).
Criteria to remove a product from the list of candidates were:• No formulation research is needed to apply the product• If two coatings present too many similarities of properties, only one is selected

At the end of this process, the list is shorten to 24 candidates
3

Essential tests are carried out on the 24 remaining coatings. They focus on obvious
requirements and tests that are easy to implement (for instance, verification if thecoating can be used with water dripping). Each test is noted and coatings are ranked. By
the end of this phase, only 10 coatings are still in contention.

4

Lab tests, that are more complex to carry out (such as irradiation tests), are done on the
10 previously selected coatings.
Tests also focus on properties that are a criteria of acceptance for the application on site,or they focus on a data that is needed to assess the impact of the use on site (forinstance, gas release)C1 - Interne

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III. SELECTION OF COATINGS
3. 4. ESSENTIAL TESTS
Depending the area of application (whether it is on a metallic surface on the upper part ofthe pedestal (in the Control Rod Drive Housing (CRDH) area for instance), or it is a metallic
surface like a beam or grid, or again the bottom of the pedestal full of fuel debris), criteriaof observance may differ.
Indeed, when a coating is applied towards the upper direction on a vertical metallic surface,it needs to be sprayable and it needs to have a short pot life in order not to drip. On theother hand, for the bottom of the pedestal, a coating will need to be injected by gravity andits pot life shall not be too short in order to let the coating cover as much surface aspossible. Also, a coating shall have different characteristics whether it is applied in air, underwater dripping or underwater.
For these reasons, the pedestal is divided in our study in three areas: upper part (upper
than the platform), middle part (platform area) and bottom part (bottom of the pedestal).

UPPER PARTMIDDLE PARTBOTTOM PARTC1 - Interne

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III. SELECTION OF COATINGS
3. 5. LAB TESTSObjective
The aim of these tests is to determine final candidates that can be used on site, and that will be tested for the application tests:
spraying tests, resuspension tests, filtration devices tests, remote arm spraying tests.
Description
As the first campaign focused on the most obvious criteria of application, coating locations and conditions; this campaign
considers complementary and thorough studies on coatings which:▪ Require an external lab for complex tests such as the irradiation resistance tests,▪ Need more time (like the aggressive liquid resistance tests or the corrosion on coating surface analysis).
Each test has been carried out individually or by family of coatings (silicon, epoxy…) in order to determine some specificcharacteristics.
Criteria of tests are determined by the functional analysis. They are divided into the four categories below:

CHEMICAL PROPERTIESFIRE & TEMPERATURETEMPERATURE BEHAVIOR WITHOUT GAS RELEASE MEASUREMENTRESISTANCE TO AGGRESSIVE LIQUIDS (H3BO3 AND SALT)TEMPERATURE BEHAVIOR WITH GAS RELEASE MEASUREMENTWATER ABSORPTIONFLAME BEHAVIOR WITHOUT GAS RELEASE MEASUREMENT

CORROSION ON SURFACEPHYSICAL PROPERTIESCHEMICAL CONTENTTGA DSC ANALYSISVISCOSITY
SHORE HARDNESSPOT-LIFE

RADIOACTIVITYRESISTANCE TO IRRADIATION WITH GAS RELEASE MEASUREMENTTHERMAL CONDUCTIVITYGAS PERMEABILITY ASSESSMENT)

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

III. SELECTION OF COATINGS
3. 5. LAB TESTSFIRE & TEMPERATURETEMPERATURE BEHAVIOR WITHOUT GAS RELEASE MEASUREMENTTEMPERATURE BEHAVIOR WITH GAS RELEASE MEASUREMENTFLAME BEHAVIOR WITHOUT GAS RELEASE MEASUREMENT

Coatings may be used on Fuel Debris that generates heat. It is therefore important to determine the behavior of the coatings towards hightemperatures. Tests focus on the physical properties of the coatings (does the coating lose its properties when heated?) and on gas release.
Loss of properties can lead to the exclusion of a coating, mas release measurement will give an information about the coating, safety studies
will conclude about the applicability of a coating about this parameter.

Content of the tests (overview) :• Gas release measurement: Hydrogen and VOC release were measured when the coating is heated. The lower the gas release is the better it is for the application on site. Coatings shall beheated on site due to the application to Fuel Debris and during the drying operations for the waste management• Temperature behavior without gas release measurement: coatings were heated up to 80°C (estimated temperature of Fuel Debris taken for this project as a reference for underwaterconditions, see references given in p.127)* 200°C (temperature of heating of drying system of Unit Cans, based on information given in p.15). Chemical properties were looked after.
Modifications of consistency (degradation of coating) may imply issues on site
• Flame behavior: tests focused on whether or not a coating will propagate fire

PHYSICAL PROPERTIESVISCOSITY
SHORE HARDNESSPOT-LIFE
THERMAL CONDUCTIVITYGAS PERMEABILITY ASSESSMENT

Some physical properties are studied through lab tests. Viscosity, shore hardness and pot life are not criteria that can exclude a coating fromthe selection. However, depending on the results, it can help sorting them. Indeed, these three parameters are important for the application
on site (for instance, it is easier to apply a coating with a low viscosity, etc.).
Thermal conductivity and gas permeability also are criteria that will help sorting the coatings. Indeed, only safety studies can determine
whether the thermal conductivity or gas permeability are an important issue. The tests will provide input data for these matters.
Nevertheless, it is possible to sort the coating depending on the results of the tests (for instance, a higher thermal conductivity is considered
to be better).

Content of the tests (overview) :• Pot life and viscosity were measured in specific tests at 23°C and 40°C. Both adaptable short pot life and low viscosity are preferred for the application on site.
• The apparent thermal conductivity has been determined by the transient plane heat source (Hot Disk TPS) method ISO 22007-2:2008.
* Calculations carried out by IRSN and CEA in the frame of another project showed that for the given heat power of Fuel Debris, temperature at the surface of the Fuel debris underwater shall not exceed 80°C. It can be seen on site that temperature is
below 100°C since no boiling is observed. This information is true for Fuel Debris underwater, we make no conclusion for Fuel Debris in air.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

III. SELECTION OF COATINGS
3. 5. LAB TESTSCHEMICAL PROPERTIESRESISTANCE TO AGGRESSIVE LIQUIDS (H3BO3 AND SALT)WATER ABSORPTION
CORROSION ON SURFACECHEMICAL CONTENT

These chemical properties are important to determine the applicability of a coating. A coating does not resist to aggressive liquids can not
be selected for the application underwater. It is also important, for all the coatings, and for all the situations on site, to test the behavior
with water (water absorption that could lead to loss of properties). Corrosion on surfaces is an important criteria for coatings that could beapplied on metallic items. Chemical content analysis is important to determine if an element could become radioactive under irradiation.
Finally, TGA DSC analysis gives information about the mass loss under different temperatures.

TGA DSC ANALYSIS

Content of the tests (overview) :• Resistance to aggressive liquid and water absorption tests have been carried out in small tanks. Weighing and visual control were carried out.
• Corrosion tests have been carried out underwater for 30 days at ambient temperature. Coatings were applied on steel plates.
• Chemical content tests concerned the measurement of concentration in sulfur / chlorine / bromine / fluorine. For a classical nuclear application (that means for NPP in exploitation in France)a maximal value concentration of 200 ppm is considered. Atomic compound concentration has been obtained by: Ionometer, Spectrophotometer UV-vis, ICP-AES & ICP-MS, Ionic Liquids
Chromatography.

RADIOACTIVITYRESISTANCE TO IRRADIATION WITH GAS RELEASE MEASUREMENT

Coatings will face high dose rates on site. It is important to ensure that there will be no loss of properties because of the dose rate. If a
coating loses its properties under radiation, it is excluded of the selection.

Content of the tests (overview) :• Coating samples have been irradiated with a Cobalt 60 irradiation source emitting gamma rays with 1.17MeV and 1.33MeV energies, under partial vacuum. Gas release has been measured
and visual control of coatings (modification of properties) have been looked at.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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III. SELECTION OF COATINGS
3. 5. LAB TESTSThe table below details the tests grid. Not all the tests have been carried out for all the selected coatings
EVALUATED CRITERIALOCATION

RTV878

RTV877

RTV 873FEVDISIL PBEPOXYGUARD

SR 8450

FIXAPRO 3

POLYASIM GCP

TEMPERATURE BEHAVIOR WITHOUT GAS RELEASE
MEASUREMENT

Ext. lab

O

O

O

O

O

O

O

O

TEMPERATURE BEHAVIOR WITH GAS RELEASE MEASUREMENT

Ext. lab

O

O

X

X

O

X

O

X

VISCOSITY

BCSN

O

O

O

O

O

O

O

O

FIRE BEHAVIOR WITHOUT GAS RELEASE MEASUREMENT

Ext. Lab

Avail.

O

O

O

O

O

O

X

RESISTANCE TO IRRADIATION WITH GAS RELEASE
MEASUREMENT

Ext. Lab

O

O

O

O

O

O

O

X

RESISTANCE TO AGGRESSIVE LIQUIDS (H3BO3 AND SALT)

BCSN

O

O

O

O

O

O

O

X

THERMAL CONDUCTIVITY

Ext. Lab

O

O

O

O

O

O

O

X

WATER ABSORPTION

BCSN

O

O

O

O

O

O

O

O

SHORE HARDNESS

BCSN

O

O

O

O

O

O

O

X

CORROSION ON SURFACE

BCSN

O

O

O

O

O

O

O

O

CHEMICAL CONTENT

Ext. Lab

PMUC

PMUC

Avail.

O

O

O

PMUC

O

TGA DSC ANALYSIS

Ext. Lab

O

O

O

O

O

O

O

O

O: TestedC1 - Interne

X: Not tested

Avail.: Data already available

PMUC: Product and Material Used in nuclear power plant

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

Ext. Lab.: External laboratory

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III. SELECTION OF COATINGS
3. 5. LAB TESTS
Finally, in order to sort the candidates still in contention to determine the final selection, results are considered as following:• Mandatory criteria:
The test must give a “good” result in order to keep the coating in contention.

1. Resistance to irradiation: the coating, no matter its area of application, must not lose its properties under irradiation. According to the irradiation tests, only the silicone coatings andepoxy coatings can be selected
2. No corrosion of metallic parts and maintain of the grip (concerns mainly upper and middle parts): it is important that the coating used do not corrode the metallic parts on which it isused and keeps its grip. Again silicone and epoxy coatings can be selected
3. No loss of properties with high temperature (concerns mainly the bottom part with the Fuel Debris that generates heat): it is very important that the coating do not lose its properties
under high temperatures. Silicone coatings have a very good behavior under high temperatures, epoxy’s behavior is a bit under but still acceptable•

Important criteria that help to sort the coatings from one to another:
1. Limited water absorption (particularly for the bottom part): the coating will have to be efficient even with water. The bottom of the pedestal may be underwater, all the pedestal may
be under dripping water. The lesser the coating absorbs water the better it is.
2. Gas release: to sort coatings that may be equivalent, the amount of gas release under high temperatures and irradiation must be watched. The coating that releases less gas isconsidered to be better than the others
3. Pot life: depending the area of application, a short pot life will be an asset. Therefore, a short pot life or a pot life that can be adapted is preferred
For the considered application, inside the pedestal, with high rates of humidity, dripping water, high dose rate, etc. as it has been determined in the input data analysis and in thefunctional analysis, silicones coatings and epoxy coatings are the most suitable candidates.

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III. SELECTION OF COATINGS
PCV LOCATION3. 6. FINAL SELECTION OF COATINGS FOR THE APPLICABILITY TESTS➢

Among the 10 candidates retained after the essential tests, only 4 are selected for the applicability
tests

➢

The silicone coatings RTV FA 878 and RTV FA 877 seem both well adapted for the different areas inside
the pedestal and are therefore selected➢

The silicone coating RTV FA 873 is also selected. It is interesting to keep it as well for the applicability
tests because it presents a higher hardness which could represent an asset in certain conditions➢

Furthermore, EPOXYGUARD is also selected because it has shown good results to the different tests
especially underwater. Nevertheless, it has to be noted that, for our application, Epoxyguard has
shown less assets than the silicone coatings: its behavior under high temperatures and irradation are
not as good. Besides, its high viscosity makes it more difficult to use with spray even if it is still
manageable.

UPPER

RTV FA 878
RTV FA 877

The coatings in the upper part are spraying in air andunder rain conditions.

MIDDLERTV FA 873

RTV FA 878

RTV FA 877
The coatings in the middle part are encapsulation of
metallic waste, vertical application, spraying in air andunder rain conditions.

BOTTOM

RTV FA 873
RTV FA 878
RTV FA 877❑ The gas retention must be considered for all coating candidates, especially for hydrogen andmethane gases.

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The coatings in the bottom part are encapsulation andcross-linking under water.

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

RTV FA 873
EPOXYGUARD28

DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 1. GENERALITIESObjective
Decommissioning operations in 1F could lead to particle resuspension and dispersion due to various stress, such as aeraulic stress (ventilation, gas injection), hydraulic stress for underwaterconditions (robots movement, water injection) and mechanical stress (fall of object, vibration). The objective of the tests is to determine the efficiency of the selected coatings in terms of dust
resuspension suppression. Different coating scenario are studied, from “perfect” coating to partial coating of a determined area.
Criteria for particles used during the tests
For a given stress intensity level, particle resuspension coefficient is mainly function of particle size distribution. Because of the unknown size of particle deposit inside PCV of 1F, tests are carriedout with particles whose size corresponds to the most dispersible one (dresuspension) based on aerodynamic diameter considering the particle density which has been determined using CFD
numerical simulations (6 µm).
Tests principle▪ Various samples (Stainless steel plate or pieces, Fuel Debris simulants) are prepared with well controlled particle deposit (dresuspension).
▪ For air environment tests, the resins efficiencies are evaluated by comparing particle resuspension that may occur between non-coated and coated samples, in measuring the airborne particle
concentration.
▪ Tests will consider perfect coating and also degraded coating to assess its influence on resins efficiency.
Particle resuspension is characterized during various stress for non-coated and coated samples:

Fall ofobjectAeraulic
stressFor mechanical stress, the drop height and theresin coverage ratio are the main test parameters.
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For aeraulic stress, the air flow velocity and the resin
coverage ratio are the main test parameters.

Water
stressFor underwater tests, the resins efficiencies are evaluated bymeasuring the ratio between the particle mass transferred to thewater and the initial particle mass deposited on the Fuel Debris.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 2. AERAULIC STRESS TESTS
4. 2. 1. Generalities
Objectives of the tests
Tests are meant to determine the efficiency of the coating when it is applied on a surface (whether it is a metallic surface or a Fuel Debris alike surface). Aeraulic stress can be caused by various
reasons: airstream due to the global ventilation system, airstream due to the movement of a robot or due to a cutting device such as a disk cutter or a laser cutting head (that will generate
important airflows with important velocity).
Therefore, tests have been defined so it is possible to test different air velocities, different angles of airblowing, different surfaces of application and most of all, with different percentage ofcoverage so it is possible to assess the gain even in incomplete coating situations.

Here below are reminded the physical mechanisms involved in the resuspension of particles. For the tests, calibrated particles that will allow high resuspension rates have been selected.
Physical magnitudes of interest for particles resuspension by aeraulics mechanisms are:
➢ Particles geometrical diameter➢ Adhesion forces (function of particles size and roughness of sample)➢ Gas friction velocity depending on mean airflow velocity➢ Airflow acceleration (steady or transient states)

SiC particles deposit
1 µm – 0.01 g/cm2

Physical mechanisms involved in the resuspension of particles

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Physical magnitudes for transport of resuspensed particles➢ Particles aerodynamic diameter➢ Airflow

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 2. AERAULIC STRESS TESTS
4. 2. 1. Generalities
The main objective of the tests was to evaluate the gain in terms of suppression of dust resuspension, for various conditions, even in a case of a partial coverage. Indeed, if there was no doubt
concerning the efficiency of coatings, it shall be difficult to ensure perfect coverage on site due to the complexity of the situation. The idea was therefore to determine in which conditions apartial coverage is beneficial compared to the complexity of the coating operation remotely operated.

The same methodology has been applied for all the tests:▪ 2 types of surfaces to be covered have been used: either a stainless steel plate whose dimensions are 150 x 150 x 3 mm or a stainless steel basket, whose dimensions are 150 x 150 x 30
mm (thickness = 3 mm) containing a Fuel Debris simulant bed. These dimensions have been determined to fit inside the experimental set-up while ensuring quantity of particles is enoughto carry out conclusive tests.
▪ On each surface, a deposit of alumina particles Al2O3 (particle aerodynamic diameter = 6.4 µm) is carried out. The deposit is implemented on a controlled surface 10 x 110 mm by sieving
with a surface mass deposition around 15 mg/cm². Therefore, the quantity of particles is controlled.
▪ Before each test, it is decided to coat the surface with the deposit of particles or not
The parameters of the tests are the following:▪ Coatings: none (for reference tests), RTV FA 878, RTV FA 873▪ Percentage of surface coverage: from 0% coverage (for reference) to 100% (full coverage) with 50% coverage in between to study the case of a partial coating on site
▪ Sample: stainless steel plate and Fuel Debris simulant bed▪ Tilt α: to assess the influence of the angle α between airflow and surface▪ Velocity: two flow velocities have been used. 2-3 m/s represents a range of velocity, quite low, such as induced by ventilation or by the movement of a robotic arm (for instance). 100 m/s
represents the airflow velocity representative of a cutting tool such as laser cutting.

SiC particles deposit
1 µm – 0.01 g/cm2

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 2. AERAULIC STRESS TESTS
4. 2. 2. Tests parameters & overview of the experimental set-up
Laser sheet optic

High speed camera

View of FAAMUS enclosure
Two types of air injector are used. The first one (picture on the left) generates a low
airflow. The second one (picture in the middle) generates a high velocity airflow that
reproduces the laser cutting airflow.
Particles are deposited in front of the air injector. In the pictures, particles aredeposited onto metallic plates (pictures in the middle and at right).
The picture on the left shows a metallic plate with deposit of particles and 100% of RTV
FA 878 coverage. The metallic plate has been tilted with an angle of 40°.
Mass and number concentrations of particles evolutions are measured inside theenclosure thanks to probes.
The enclosure is cleaned before each test so it prevents the measurements to be
distorted.
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PIV technique has been used in order to assess the efficiency of coating. Characteristics of the setup are the following:• Implementation of high speed PIV• Laser 30 mJ at 1 kHz at 527 nm – Camera CCD 1kx1k• Test with particles deposit on horizontal plate with and without resin coating• 2 types of airflow are generated:• Low velocity up to 3 m/s to be representative of natural and forced convection flows due
ventilation or robot implementation• High velocity up to 100 m/s to be representative of gas jet injection through laser cutting
head

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 2. AERAULIC STRESS TESTS
4. 2. 3. Results of PIV measurements for particle resuspension visualization for airflow colinear to the plaque (α=0°)Here are presented the views obtained thanks to the PIV instrumentation for the low and high velocity airflows. It can be seen that 50% of resin coverage is enough to lower the resuspension
rate of powder. With a total coverage, no powder is resuspended even at high velocity which can be representative of laser cutting process.

Image 1

Image 1

Image 2

Image 2FAAMUS VESSEL

Results for 3 m/s without resin

Results for 3 m/s with 50% resin
coating (878)

Image 1

Image 1Results for 3 m/s with 100% resin
coating (878)

Image 2

Results for 100 m/s without resin

Image 1Results for 100 m/s with 100% resin
coating (878)

No particle detected by laser sheet Lighting
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 2. AERAULIC STRESS TESTS
4. 2. 4. General overview of tests results
Configurations:Tests have been successively carried out on a stainless steel plate seeded with particles. It is first tested non-coated with different tilts then coated with RTV FA 873 and RTV FA 878 with half thenfull coverage. The two velocities (low and high) have been successively tested.
The objective is to evaluate the impact of the coating on the resuspension rate for all configurations.

FAAMUS VESSEL
Tests criteria:
Mass concentrations evolution for each test configuration is monitored.

Example of stainless steel plate seeded with particles and covered with resin

Main results:
Efficiency of coating has been evaluated according the formula below:
𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 = 1 −C1 - Interne

σ 𝑎𝑖𝑟𝑏𝑜𝑟𝑛𝑒 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑤𝑖𝑡ℎ 𝑐𝑜𝑎𝑡𝑖𝑛𝑔
σ 𝑎𝑖𝑟𝑏𝑜𝑟𝑛𝑒 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑤𝑖𝑡ℎ𝑜𝑢𝑡 𝑐𝑜𝑎𝑡𝑖𝑛𝑔

Example of results: evolution of mass concentration of particles inside the enclosure fordifferent angles

In conclusion, coatings provide a major asset in terms of suppression of dust resuspension. In a case of aresuspension due to a low velocity, partial coating will improve slightly the dust resuspension. However,for high speed velocity, even partial coating is beneficial.

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 3. MECHANICAL STRESS TESTS
4. 3. 1. Experimental set-up – Fall of objects in enclosure
The main objective of the mechanical stress tests was to determine the efficiency of the coating, implemented on the Fuel
Debris bed, in terms of suppression of dust resuspension due to the fall of an object. Again, the idea was to determine thegain from the use of coatings even with a partial coverage of the Fuel Debris bed.

Falling object

Tests have been carried in the BERGAME facility of IRSN here described. Particles, with the same characteristics than theones used for the aeraulic tests, have been seeded successively on stainless steel plates and on a bed of Fuel Debris
simulant. Fall of objects were successively a stainless steel ball, then more complex objects. No coverage, partial coverageand full coverage have been tested.
Experimental set-up:▪ For the stainless steel ball, a magnetic system for unhooking the metallic sphere has
been used, so reproductilibilty of tests was ensured (due also to the metallic sphereitself). The magnetic system for unhooking ensures that the parameters of the fall
(height, starting velocity) are also reproductible.

Monitoring ofparticle
concentration

BERGAME facility
C1 - Interne▪ Mass concentrations are monitored inside the enclosure at the bottom of the tests
facily.

NC/C fuel debris simulants withparticles deposit

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 3. MECHANICAL STRESS TESTS
4. 3. 2. Tests for dust resuspension suppression efficiency measurement

9 cm

Protocol of the tests:
Tests have been carried out with the following conditions:o Drop of the stainless-steel ball on a stainless plate alone or Fuel Debris simulant bed (so it is possible to evaluate the blank of the experimental set-up)o Drop of the stainless-steel ball on a stainless-steel plate or Fuel Debris simulant bed covered with airborne particles deposit (so it is possible to measure the concentration number ofparticles that are resuspended)o Drop of the stainless-steel ball on a stainless-steel plate or Fuel Debris simulant bed covered with particles deposit and coated with resin (so it is possible to determine the influence of thecoating on the resuspension rate)o Drop of the stainless-steel ball on a stainless-steel plate covered or Fuel Debris simulant bed with airborne particles deposit and partial coating so it is possible to study the influence ofdegradation of resin coating

Stainless steel plate with alumina particles deposit (left), with 100% coverage of
RTV FA 878 (center) and 90% coverage of RTV FA 873 (right)

(a)

(b)

(c)

Dropped objects on the stainless steel plates or Fuel Debris
simulants bed
Example of stainless steel plates coated with RTV FA 73 resin. Partial coverage isrealized as the above.

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Preparation of Fuel Debris simulant beds. Different coverage can be seen. Weight of
coating has been measured in order to simulate the different coverages

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 3. MECHANICAL STRESS TESTS
4. 3. 3. Main results & conclusions

As expected, with a total coverage on
stainless steel plates, no dust isresuspended

On the other hand, these results show that suppression of dust resuspension is not linearwith the percentage of coverage. (Tests also carried on stainless steel plates with the metallic
ball, with stainless steel plates covered with 0%, 50%, 70%, 90% and 100% of their surface.)

Tests on Fuel Debris bed: both RTV FA 873 and RTV FA 878 are efficient. As long as the area is covered with coating, even with a thin layer,
dust resuspension is prevented. Tests showed that RTV FA 783 has a slight benefit compared to RTV FA 878 for Fuel Debris bed stabilization
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Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

Tests on Fuel Debris simulant bed: for one
particular coating, as soon as the area ofimpact is covered with coating, dust
resuspension is lowered. (Results for RTV FA
873 (up) and RTV FA 878 (down)

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 4. HYDRAULIC STRESS TESTS
4. 4. 1. Generalities
Tests were designed to verify the efficiency of coatings underwater, in static conditions or under water stress, by measuring the particle transfer to the water. They took place in TOSQAN facilityof IRSN.

Definition and qualification of protocol for measurement of particle transfer from the Non
Covered / Covered samples to the surrounding water:➢ Fluorescein particles are deposited on NC/C samples.
➢ Particle transfer to water is quantified by fluorimetry measurements which gives thetotal mass of particle transferred to the water.
➢ Resin efficiency is determined for each coated sample by comparing the particles masstransferred to the water and the initial particle mass deposited on the coated sample.
➢ Particle transfer to the water for non coated sample is also considered as reference.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 4. HYDRAULIC STRESS TESTS
4. 4. 2. Principle of the tests
The fluorimetry technic for determining the aerosol fraction transferred to the water can
described as following: Fluorimetry is a very accurate diagnostic leading to a conservative
approach to assess resin coating efficiency and to highlight leaks of resin coating.
➢Laser visualization for underwater trial with Fuel Debris coated by resin FA RTV 878

Fluorimeter
instrument

Water sampling is performed before and after fuel debris simulant implementation
with various scenarios:▪ Underwater static scenario without stress➢ Aerosol transfer versus time▪
▪

Underwater scenario with stresses induced by gas jet➢ Aerosol transfer due to gas jet interaction with Fuel Debris

Air jet used for stress

Coated fuel debris
Water sampling after various scenarios(static, gas jet stress, water jet stress)

Underwater scenario with stresses induced by water jet➢ Aerosol transfer due to water jet interaction with Fuel Debris
Tests protocol:➢

Fluorimeter signal is function of fluorescein concentration in water.

➢

Knowing the water volume in the sump, the total mass of fluorescein transferred fromthe coated Fuel Debris is then determined for each trial.

➢

Limit of detection is 10-10 (g/L).

▪

Underwater scenario with stresses induced by gas jet during 600 s➢

Resin efficiency (%) is calculated in considering fluorescein mass transferred to thewater and the initial fluorescein mass deposited on Fuel Debris before its coating withresin.

▪

Underwater scenario with stresses induced by water jet during 600 s▪

Underwater static scenario without stress during 7 days

C1 - Interne➢

Water sampling is performed before and after fuel debris simulant implementation withsuccessive scenarios:▪ Underwater static scenario without stress during 600 s

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 4. HYDRAULIC STRESS TESTS
4. 4. 3. Main results
Test for RTV FA 878
Deposit of 96.4 mg of fluorescein particle of 3 µm on the surface of the fuel debris
simulant
100% resin coating is achieved on fuel debris simulant piece

Resin thickness = 5 mm

StaticAeraulic stress

For all scenarios (TOSQ1_1 to TOSQ1_4) , the resin efficiency to avoid fluoresceintransfer to the water was over 99.9%

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Deposit of 97.5 mg of fluorescein particle of 3 µm on the surface of the fuel debris
simulant
100% resin coating is achieved on fuel debris simulant piece

Resin thickness = 5 mm

StaticAeraulic stress

For all scenarios (TOSQ2_1 to TOSQ2_4) , the resin efficiency to avoid fluoresceintransfer to the water was over 99.8%

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

IV. PERFORMANCE TESTS, VERIFICATION OF DUST RESUSPENSION SUPPRESSION
4. 5. CONCLUSIONS➢

Efficiency towards dust resuspension with aeraulics stress▪ Coating with resins is very efficient to avoid particles resuspension due to airflows (low and high velocity)▪

Benefic effect of resins was underlined on fuel debris simulants and stainless-steel plates. Whatever the cause of airflows (ventilation, robot displacement, cutting technics such laser
or high-pressure water jet) resin coating will mitigate dust dispersion➢

Efficiency towards dust resuspension following the fall of an object▪ Resin coating mitigates dust resuspension due to various objects fall with total efficiency if the coating is complete. In case of un-complete resin coating, benefic effect is still
underlined due to the stabilization of the fuel debris bed, limiting dust resuspension➢

Efficiency towards dust resuspension underwater▪ Complete resin coating ensures a total efficiency to avoid aerosols transfer from the fuel debris to the surrounding water

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 1. GENERALITIESOperations for the retrieval of the Fuel Debris will most certainly go through cutting operations. This is why it is important to determine whether coating could have an impact on such operations.
Cutting tests that have been carried out in the frame of this project were meant to:▪ Assess the impact on airborne particles production. (Does the coating lower or increase the airborne particles production? Does the coating modify the characteristics of the airborne
particles that are normally generated?)▪ Assess the impact on the cutting performances
Therefore, for these cutting tests, data that are monitored are: number and mass concentrations of airborne particles, morphologies of particles produced, cutting performances
Three cutting tools have been studied:1. Core boring tool: two phases of tests have been carried out.
• First phase of tests was implemented in CEA Cadarache’s facility FUJISAN at the very beginning of the project. This first phase of tests was meant to get preliminary results for thefollowing steps of the project• Second phase of tests was implemented in CEA Saclay’s facility DELIA. Tests have been carried out with a more industrial tool with Fuel Debris simulant
2. Disk cutter: tests have been carried out in IRSN’s facility CAPIMIF
3. Laser cutting: tests have been carried out in CEA Saclay’s facility DELIA

Core boring tests. FUJISAN facility (left) and DELIA facility (right)
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Disk cutting tests in CAPIMIF facility

Laser cutting tests in DELIA facility

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 2. CORE BORING TESTS PHASE 1
5. 2. 1. Experimental set-up
Experimental core boring cell used in order to gather input data on the generation ofparticles during cutting with core boring of Fuel Debris simulant coated with preselected coatings:

Analyzed criteria
Aerosols characterization has been carried out through:▪ Particles size distribution,▪ Particles mass and number concentration,▪ Morphology for cut particles and their related atomic composition.
To collect particles during cutting, the front wall of the airtight enclosure contains four collection lines. They
have been designed to ensure a good aerosol measurement by specific instrumentation:▪ Pegasor® PPS-M (aerosol number & mass concentration)▪ Filter sampling (aerosol mass concentration)▪ DLPI+ (aerosol mass size distribution)▪ Mini Particle Sampler (MPS) (aerosol morphology with post-test TEM analysis)
MPS

The cutting evaluation has been carried out through the observation of:▪ Behavior for block coated with resins during cutting.
▪ Behavior for the core boring tool in presence of resins.
The resin efficiency in term of aerosols mitigation has been evaluated by:▪ The airborne particles analysis during and after cutting.
▪ The removed silicone resins operations after cutting.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 2. CORE BORING TESTS PHASE 1
5. 2. 2. General overview of the tests
Tests have been carried out in the FUJISAN facility with active prototypical Fuel Debris (with depleted Uranium dioxide) blocks (MCCI, In-Vessel and Ex-Vessel Fuel Debris simulants). This has beenpossible thanks to URASOL project with JAEA. Results are presented for the tests carried out with two silicone resins: RTV FA 877 and RTV FA 878.
#1 MCCI block + RTV FA 878#6 In-Vessel block + RTV FA 878

Main results:• Core boring of silicon coating produces a very thin mode of airborne particles (median diameter centeredaround 400-500 nm)
Aerodynamic median diameter 𝐷

MCCI #1

With coated resin RTV FA 878#8 Ex-Vessel block + RTV FA 878#6 In-Vessel block + RTV FA 877

0.6

Airborne
particlecoefficientWithcoated resin
RTV FA877
With resin RTV FA 878 only
• Airborne particle coefficient expressed by:

Cutting Parameters
The cutting tools is a diamond surface deposit tool withan external diameter to 15 mm.
The cutting force, the rotation speed and the cutting
duration are chosen to ensure good aerosols
generation without damaging the tool.

𝐾𝐴 =In-Vessel #6
5.0(+ 2nd mode at 0.2 µm)
4.1(+ 2nd mode at 0.4 µm)
0.4(+ second mode at 3.5 µm)

Ex-Vessel #8
0.5

𝒎𝒂𝒊𝒓𝒃𝒐𝒏𝒆∆𝒎𝒃𝒍𝒐𝒄

The airborne particle coefficients have been determined around 10-3.
𝐾𝐴 (average)

MCCI #1

In-Vessel #6

Ex-Vessel #8

With coated resin
Without coated resin≈ 4x10-4≈ 7x10-4≈ 8x10-4

Metallic
Ex-Vessel #8≈ 3x10-4≈ 10-3

According to URASOL project, the airborne particle coefficient is until 10 times more important for cutting trials without
the use of silicone resin.
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 3. CORE BORING TESTS PHASE 2
5. 3. 1. Overview of the tests

DELIA vessel

General description:▪ Tests take place in DELIA facility - CEA Saclay.
▪ Core boring is carried out in the airtight vessel in which sampling of aerosols is done thanks to specific iso-kinetic probes.
▪ Data are monitored thanks to Pegasor® PPS-M, filter sampling and DLPI+®.
▪ Specific airflow is created inside the vessel in order to homogenize the particles concentration inside the vessel.
Analyzed criteria:
For the aerosols characterization :▪ The particles size distribution thanks to DLPI®,▪ The particles mass and number concentration with Pegasor® PPS-M and filter sampling,▪ The morphology for cut particles and their related atomic composition MPS.

For the cutting evaluation :▪ Behavior for block coated with coatings during cutting.
▪ Behavior for the core boring tool in presence of coatings.
The coating impact on aerosols generation:▪ The airborne particles analysis during and after cutting in the exhaust and in the vessel.
▪ The influence of a nitrogen atmosphere.

Control station
for the cutting machine

Fuel Debris Simulants:▪ MCCI sample (partially)▪ In-Vessel sample

Selected coatings:▪ RTV FA 878 (Silicone)▪ RTV FA 873 (Silicone)▪ EPOXYGUARD (Epoxy)Sampling probe connected to airborne
monitoring devices, near the cutting point
to collect the airborne particles

Main parameters & Conditions:▪ Qualification cutting tests have been carried with Zirconia samples.
▪ Cutting duration was between 5 and 10 min for Fuel Debris simulant with and without coatings.
▪ Tests have been performed in air and under nitrogen atmosphere.
▪ Coatings have been applied previous to the tests in order to comply with the manufacturer’s recommendations
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Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

Core boring tools with sample
block positioned(MCCI/epoxy block)45

DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 3. CORE BORING TESTS PHASE 2
5. 3. 2. Tests program✓ 4 Fuel Debris simulants tested (cast fused Zirconia blocks for qualification tests, InVessel and MCCI (partially) Fuel Debris simulants),✓ 3 coatings tested (RTV FA 878, RTV FA 873 and EPOXYGUARD,✓ More than 40 cutting tests with various parameters have been carried out.

Tests have been scheduled as follow:✓ Cutting tests on Fuel Debris simulant block without coating✓ Cutting tests on the same Fuel Debris sample with specific coating applied,✓ Cutting tests on specific coating alone (to compare and determine the influence of each coating),✓ Cutting tests on Fuel Debris simulant In-vessel with and without coatings in N2 conditions,✓ Complementary cutting tests with simulated aerosols on which coating has been applied.

TESTS GRID
STEP 1 : REFERENCE TESTS ON SAMPLES AND ON COATINGS IN AIR••••

Fused zirconia block: qualification test to check installation• RTV FA 878
Fuel Debris In-vessel #2• RTV FA 873
Fuel Debris MCCI #1• EPOXYGUARD
Fuel Debris VF03 with aerosols deposit(In-vessel Fuel Debris simulant from previous project) WITHOUT COATINGSTEP 3 : SPECIFIC TESTS IN N2

WITHOUT SAMPLE• Fuel Debris In-vessel #2• RTV FA 878
REFERENCE TESTSSTEP 2 : CUTTING TRIALS ON FUEL DEBRIS SAMPLES IN PRESENCE OF COATINGS IN AIR
RTV FA 878
In-vessel
3 cuts

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MCCI
1 cut

RTV FA 873
VF03 (aerosol)
2 cutsIn-vessel
3 cuts

MCCI
1 cut

EPOXYGUARD
In-vessel
3 cutsMCCINA

RTV FA 878
In-vessel
3 cuts

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 3. CORE BORING TESTS PHASE 2
5. 3. 3. Tests results – Overview▪ For all the tests of the test grid, mass and number concentrations have been monitored▪ Morphologies of particles, for some tests, have also been studied
Mass and number concentrations monitoring:
The cutting tools is a diamond surface deposit tool with an external diameter to 15 mm.
The cutting force, the rotation speed and the cutting duration are chosen to ensure goodaerosols generation without damaging the tool.

Illustrations of core boring tests:
In these pictures, we can see core boring of Fuel Debris simulant “In-Vessel” covered with RTV
FA 878 (red coating), RTV FA 873 (grey coating) and Epoxyguard (white coating).

Results on particle size distribution:
As during the first phase of core boring tests, it can be seen that silicone
coatings produce a very mode of particles, which is not the case for the
Epoxyguard coating.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 3. CORE BORING TESTS PHASE 2
5. 3. 3. Tests results – Overview
Objective: Evaluate the capability of resin coating to mitigate resuspension of already deposited particles close to the cutting area
→ Comparison between Fuel Debris simulant In-vessel VF03 (Fuel Debris manufactured in FY 2018) with particles deposit without and with RESIN coating – RTV FA 878→ Al2O3 particle (6 µm, 3 mg/cm2) have been deposited on Fuel Debris simulant before the cutting with and without resin coating

82% average massefficiency increase
with the coating

Strong decrease of airborne particles
generation with resin coating – aeraulicmechanisms involved in particles
resuspension are reduced and resin
coating limits resuspension du to othermechanism such vibrational one.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 3. CORE BORING TESTS PHASE 2
5. 3. 4. Conclusions
During FY2021, the core boring tests performed are:
• In air on Fuel Debris simulant In-vessel #2 with and without coating• In air on Fuel Debris simulant MCCI #1 with and without coating• In air on Fuel Debris simulant In-vessel VF03 with and without coating + aerosols deposit• In nitrogen on Fuel Debris simulant In-vessel #2 with and without coating (analysis of results in progress and to be provided at a later date)
The summary of the results obtained is:
AVERAGE MASS EFFICIENCY OF COATING

CONDITIONSRTV FA 878

RTV FA 873

EPOXYGUARD

Fuel Debris Simulant #2 (In-vessel - VF15)

Air

20%

42%

-132%

Fuel Debris Simulant VF03 + aerosol
deposit(In-vessel Fuel Debris simulant from previous
project)

Air

82%

NA

NA

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During mechanical core cutting in air condition, silicones can reduce aerosol emissions
by 20% in mass on Fuel Debris simulant In-vessel.
With an aerosol deposit, the efficiency of the RTV FA878 silicone coating reaches 82%
in mass → the coating allows to confine a part of the covered aerosols.
On the opposite, the epoxy type coating (EPOXYGUARD) generates an increase inaerosol dispersion of 132% in mass. This increase is due to the epoxy dust that is
generated during the cutting process.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 1. CAPIMIF facility overview
The aims of the CAPIMIF preliminary trials are:
▪ To pre-estimate resins behavior on stainless steel plates during Disk cutter cutting (disk diameter 350 mm),▪ To evaluate the resin efficiency by comparing during cutting trials with Disk cutter tool for non coated andcoated (NC/C) samples.

The cutting operating parameters are managed through dedicated pneumatic equipment controlled and monitoredby operators outside the CAPIMIF enclosure (the applied force on sample during cutting (100 N), the number of
cutting).
The characterization of generated aerosols is carried out by a dedicated collection line.

Disk cutter test at CAPIMIF

The instrumentations for aerosols characterization are connected to these collection line:▪ a Dekati ELPI+® to measure the particles size distribution in real time,▪ a HEPA filter to measure the particles mass concentration,▪ a PEGASOR® analyzer to measure the particle number concentration in real time,▪ a Mini Particle Sampler for particle collection and post-analysis by microscopy (TEM) and energy-dispersive X-ray
spectroscopy (EDS),▪ Surface temperature measurement of disk and stainless steel plate by infrared sensor

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 2. Cutting test on a stainless steel plate covered with RTV 878 coating
A 5 mm thick layer of RTV FA 878 has been applied onto the stainless steel plate on its two faces. One stainless steel plate is uncoated so it is possible to compare the results of the two
configurations
Particles TEM visualization: stainless steel

Particles TEM visualization: stainless steel with resin

Results show:•
Higher particle number generation for coated sample in comparison with non coated sample (by factor 2)•
Lower particle mass generation for coated sample in comparison with non coated sample (by factor 3)•
Good repeatability in terms of particles generation for consecutive cuttings

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 3. Cutting tests on stainless steel plates covered with RTV 878, RTV 877 and RTV 873 coatings
RTV FA 873:
• Highest cutting time
• Lowest particle mass generation• Lowest instant particle number concentration➢ Efficiency: 67 %RTV FA 877:
Results between 873 and 878 for:• Time of cutting• Mass concentration• Instant number concentration➢ Efficiency: 50 %RTV FA 878:
• Lowest cutting duration• Highest particle mass generation (with coating)• Highest number concentration➢ Efficiency: 64 %•••Difference between resins in terms of cutting duration (tc) for a same thickness of stainlesssteel: tc878 < tc877 < tc873
Higher particle generation in number for coated stainless steel in comparison with non coatedsample regardless of the type of coating
Lower particle generation in mass for all coated samples than for non coated samples

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Stainless steel without coating:•••Lowest cutting time
Highest particle mass generation
Lowest instant number concentration

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 3. Cutting tests on stainless steel plates covered with RTV 878, RTV 877 and RTV 873 coatings
Analysis of resin and metal particles▪ TEM and SEM visualizations allow to highlight the interaction between airborne particles and chips particles with resin leading to the impact of resin on particles resuspension during cutting

Airborne particles – TEM visualization
Stainless steel + resin RTV FA 877 cutting

Stainless steel cutting

Resin RTV FA 877 cutting only

Si
S
Cl

Si
S
Cl
Fe

Fe
Cr

Melted iron ballVery fine iron particles are collected with resin

Fe
Cr

Si
S

Resin particles generation, mainly submicronic
Main elementary species of resin RTV FA 877: Si – Cl - S

2 µm

Metal particles with various morphologies (irregular and spherical)
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 3. Cutting tests on stainless steel plates covered with RTV 878, RTV 877 and RTV 873 coatings
Chips particles (deposited on ground) – SEM visualization and EDS analysis
Stainless steel + resin 877 cutting

Stainless steel cutting
Main target: iron – N°4

Main target: iron – N°6

FeFe

Main target: resin – N°1

Iron chips particles areagglomerated with resin

Si
Cl

Resin coating tends to increase the size of chips particles due to agglomeration phenomenon
between iron and resin particles.
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 3. Cutting tests on stainless steel plates covered with RTV 878, RTV 877 and RTV 873 coatings
Influence of the resin layer thickness on efficiency during cutting▪

Resin thickness

Efficiency

Efficiency of resin has been tested for various resin layer thicknesses (2 mm – 5 mm – 12 mm) for FA RTV 878.

68 %
12 mm

77 %
2 mm

0 mm

The global tendency is that the decrease of resin layer thickness do not degrade the resin efficiency
Cutting issues occurred for the highest thickness due to increase of friction between disk and cut material
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 3. Cutting tests on stainless steel plates covered with RTV 878, RTV 877 and RTV 873 coatings
Synthesis of results of efficiency for various resins and thicknesses
Resin

Total airborne particle
mass (mg)(<10 µm)

Efficiency %Type

Layer thickness

Particle number
concentration (#.cm-3)

Stainless steel– 4 mm

NANA

1.14E+07

6604-(P)C_16|R877

Stainless steel – 4 mm

877

2 mm

2.08E+07

3330

50%

(P)C_18|R873

Stainless steel – 4 mm

873

2 mm

2.37E+07

2199

67%

(P)C_28|R878_LT

Stainless steel – 4 mm

878

2 mm

2.01E+07

1532

77%

(P)C_15|R878

Stainless steel – 4 mm

878

5 mm

2.98E+07

2357

64%

(P)C_29|R878_BT Stainless steel – 4 mm

878

12 mm

1.95E+07

*2121

*68%

Name of test

Cut material(P)C_14|NR* Cutting was not completed due to high friction intensity with resin layer
Resin Efficiency:
E=1-(Airborne particle mass with resin coating / Airborne particle mass without resin coating)C1 - Interne

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 4. Cutting tests on Fuel Debris simulant covered with RTV 878, RTV 877 and RTV 873 coatings
Cutting tests have also been realized on Fuel Debris simulants. The pictures illustrate the coating of MCCI samples
A: Use of blocks of MCCI simulant (VF19), in total 6 blocks were used, 2 with RTV FA
878, 2 with RTV FA 873 and 2 without coating.

RTV FA 878: 24h

B & B’: Application of resin after blending of two components according to theirblending ratio. Polymerization of the resin for the recommended time, i.e. 24h for
RTV FA 878 and 7 days for RTV FA 873
C: Use of coated samples on CAPIMIF facility with implementation as close as
possible to ensure the most stable hold possible of the Fuel Debris simulant block.

RTV FA 873: 7 days

A

B

B’

C

For the test, the block of Fuel Debris simulant is held in position by joint clamps. Then the grinder is started and a pneumatic cylinder ensures the contact of the disc with the block during the
cutting at a given force of 100N. Stopping and raising the disk cutter is done manually when the block of Fuel Debris simulant is completely cut.
The tests aimed at characterizing :▪ The impact on number concentration of particle generate during the cutting of Fuel Debris simulant by disk cutter▪ The impact on mass of particle generate during the cutting▪ The feasibility of cutting resin-covered Fuel Debris simulant

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 4. Cutting tests on Fuel Debris simulant covered with RTV 878, RTV 877 and RTV 873 coatings
Comparison between trials with and without coat of resin
Results▪ The cutting tests with coatings present a numerical concentration of particles 1000 times higher
than for the Fuel Debris simulant cutting test without coating. This difference can be explained by
the combustion of the coating during cutting (for the RTV FA 878)

▪ However, in terms of mass they only present a ratio 2 to 3 times greater. We are therefore in thepresence of significant generation of particles which would come mainly from resins.

Particle number concentration time evolution - comparison during cutting of between
simulant corium without (brown) and with a coat of RTV FA 873 (blue) or RTV FA 878 (red)Simulant of corium after a cutting by wheel grind without coat (left), with RTV FA 878 coat (middle) and 873 (right)

Zoom on particle number concentration time evolution during cutting of simulant
corium without coat of resin (brown)
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 4. DISK CUTTING TESTS
5. 4. 4. Cutting tests on Fuel Debris simulant covered with RTV 878, RTV 877 and RTV 873 coatings
First results of TEM analysis on Fuel Debris simulant with coat of resin
A sample of about ten seconds is taken during a cut in order to analyze the aerosols by TEM analysis.
These TEM analysis aimed at:▪ Obtaining keys to understanding the interactions between coatings and Fuel Debris simulant particles during cutting▪ Obtaining a qualitative visual of the shape and size of the particles produced

For each set of pictures, TEM picture (left) and spectrum associate (right) of particles generate when cutting with disk cutter with coating, from left to right of RTV FA 877, RTV FA 878 and RTV 873

Observations▪ The production of two populations of particles is observed, particles of a size of the order of a micrometer and a second much finer population of particles of a few tens of nanometers▪ The second observation that can be made is the encapsulation of large particles by agglomerates of small particles

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. GLOBAL ANALYSIS ON RESIN COATING IMPACT ON DUST GENERATION WITH MECHANICAL TOOLS
5.5.1 Report of main conclusions
3 mechanical tools have been considered- Disk cutter – CAPIMIF trials- Core boring at small scale - FUJISAN trials- Core boring at real scale – DELIA trials▪ For each trial, the efficiency of various resins has been characterized in considering the particle generation in terms of mass and number▪ The objective is now to bring relevant quantitative elements for characterizing the particle production when resins are implemented, in terms of efficiency and particle source term
characterization.
▪ A reduction of the airborne particles mass has been observed for all trials with mechanical cutting when resins coating are used:
o For disk cutter with stainless steel plates : from 50% to 77%
o For core boring at small scale for fuel debris simulant: about 90%
o For core boring at real scale for fuel debris simulant: from 20% to 42%▪ Regarding the airborne particles number, cuttings with disk cutter and core at small scale have shown an increase of the generation whenresins are used (decrease for core at real scale)▪ Regarding the particle size distribution, all trials with fuel debris simulants have shown that the resin coating generates a bi-modal size
distribution with an additional sub-micronic mode, between 0.2 µm to 0.4 µm▪ The core boring of the pure resin (RTV FA 878, core boring trial on FUJISAN) generates a PSD with a single fine mode at 0.4 µm

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. GLOBAL ANALYSIS ON RESIN COATING IMPACT ON DUST GENERATION WITH MECHANICAL TOOLS
5.5.2 Analysis of the aerosol composition
The main issue is to demonstrate that the resin do not generate an additional range of size of radioactive particles which are critical in terms of safety and radioprotection, according to humaninhalation penetration and confinement efficiency. SEM & EDS and TEM & EDS analysis performed on CAPIMIF and DELIA trials have shown that agglomeration occurs between Fuel Debris or
stainless-steel large particles (few microns) and resin particles leading to increase the size of particle emission and an increase of particle deposition.

TEM & EDS and SEM & EDS were able to discriminate qualitatively the composition between resin and fuel debris simulant or stainless-steel

ICP-MS measurements were performed to try to obtain a quantitative value of the content of resin or potential radioactive material in the airborne particle generation➢ Current analysis are not concluding due to the poor sensibility of ICP-MS for measuring the carbon which is the tracer element from resin. Further analysis are underway to increase thesensibility of the detection by the laboratory in charge of the analysis.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. GLOBAL ANALYSIS ON RESIN COATING IMPACT ON DUST GENERATION WITH MECHANICAL TOOLS
5.5.3 Phenomenological analysis the cutting process
The phenomenology and the modelling of particle production by mechanical tool was studied by Khettabi, 2009.
The size of generated particle depends on the energy level transmitted by the cutting tools to the material due the friction. This energy level is function of the material characteristics and thetools rugosity.
➢ Globally, an increase of the energy level tends to reduce the size of the particles. This energy level can not be modified by the presence of a material layer such resin with a very low
hardness and mechanical resistance.
According to this study, the implementation of a coating with resin can not change the basic process of the initial particle formation by the cutting tool.

The apparition of a fine mode on the PSD (~0.4 µm in aerodynamic diameter which represents 0.1 µm in terms of geometric diameter) observed with resin coating is then necessarily
associated with the production of resin particles, non-radioactive particles.
In conclusion we can affirm that the resin coating reduces the total mass of airborne particles for all mechanical tools tested in this study, without generating an additional production ofsubmicronic particles whose composition is the same than the cut radioactive material. This mechanism is due to the increase of the particle's deposition and also to the collection of a partof the particle generation by the he edges of the resin layer on either side od the cutting for disk cutter.

The additional production of fine particles is the consequence of the resin coating cutting by the tool which has low consequence in terms of safety even if this amount of particles has to be
managed from the point of view of the confinement and waste treatment.

Khettabi, 2009. Thesis from University of Montreal, MODELING OF MICRONIC AND NANOMETRICS PARTICLE EMISSIONS IN MACHINING

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 1. General overview
Objective:

Description:

The main objective is to observe, to study and to quantify the impact of the use of coatings on
filtering devices in air & during cutting operations.

This experimental set-up allows to:▪ cutting different samples (stainless steel and Fuel Debris simulant samples with or without coatings),▪ collect and filter cut particles in specific sampling lines:❑ a line connected to a sized cyclonic filter (the main collection line),❑ a line connected to a standard HEPA filter (media in glass microfiber),❑ a line connected to a pulse jet filter (cartridge made of stainless steel).
▪ measure the pressure loss for each filtering devices,▪ collect cut particle samples to characterize them in specific instrumentations.

To do so, it is planned to perform cutting tests with an automatic disk cutter.
This cutting technology is closed to the one currently used for the coatings efficiency WP2 tests in
CAPIMIF facility.

The cut particles that will be generated by the cutting operations will be collected by an extraction
line on which the filtering devices will be implemented.

Methodology:
It is intended to carry out specific measurement listed below:▪ The evaluation of the cut particles total mass deposited in the cyclonic filter’s can.
▪ The determination of the particles number concentration collected upstream from the filtration
devices.
▪ The determination of the mass concentration of cut particles upstream from the filtration devices.
▪ The acquisition on the pressure loss of filtration devices before, during and after cutting operations.
▪ The acquisition of the cut particles size distribution up-stream from the filtration devices.
▪ The determination of the total mass of particles generated during each cutting and trapped inside eachfiltering devices.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 1. Experimental set-up
The tests on the effects of coatings on filtration devices (HEPA filter and metallic self cleaning HEPA filter) were conducted in the process laboratory of ONET TECHNOLOGIES in PIERRELATTE.
Cyclonic filter (spark arrestor)

Disk cutter with collection head

Disk cutter control panel

Pulse jet filter
HEPA filter
Sampling point

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 2. Methodology
Preparation of cutting samples:• 5 mm stainless steel plate• 5 mm stainless steel plate with applied coatings by casting:o 5 mm RTV FA 878 siliconeo 2 mm RTV FA 873 silicone
o 5 mm Epoxyguard• Fuel Debris simulant metallic VF18
Procedure of the tests:
The coated or uncoated steel plates or the simulant are positioned and fixed on the cutting table then a cut of about 500 mm is made for the plates and 80 mm for the simulant. The cutting
aerosols are collected by a specific collection line with a flow rate of 200 m3/h.
The aerosols are filtered on 3 filtration systems, a cyclonic filter with a cut-off of 3 µm, a HEPA filter and a PORVAIR filter (HEPA filter composed of a flushable
3
metallic cartridge).
dP (Pa)200 m3/h

The collection line is instrumented for test monitoring:HEPA

1 Weight of the particles collected in the cyclonic filter
1.
2 Analysis of the particles at the inlet of the HEPA filters (mass concentration and size distribution of the aerosols)
2.
3 Measurement of the pressure drop of the HEPA filter
3.
4 Measurement of the pressure drop of the metallic HEPA filter
4.

Cyclonic
filter1

Sampling
point 2

Metallic
HEPA

16.7 m3/hdP (Pa)4
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 3. Results on main line with cyclonic filter – Evolution of drop pressure

Fuel Debris simulant
VF18

Stainless steel / RTV 878

Configuration• Cutting of 5 mm thick stainless steel plate or 20 to 40 mm thick Fuel Debris
simulant VF18
• 5 mm coating with silicone RTV FA 878• 2 mm coating with silicone RTV FA 873• 5 mm coating with EPOXYGUARD• => About 50 cuts carried out

1

Results
Configuration

Flowrate(m3/h)1dP (Pa)Cyclonic
filterWithout coating

THE

Steel plate with RTV 878

2
Sampling
point

200 m3/h

200

Steel plate
Steel plate with RTV 873

Steel plate withEPOXYGUARD

Without coating
FD simulant
VF18
Metallic
FD simulant VF18 Metallic
with RTV 878

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200

200

1

2

Pressure drop on THE
filtre (Pa)

Average dP variation/
distance of cutting(Pa/m)

Average dPvariation/mass on filter(Pa/g)

dP < 300 Pa

14

0,30

300 Pa < dP < 700 Pa

32

0,55

dP > 700 Pa

201-

dP < 300 Pa

15

0,05

300 Pa < dP < 700 Pa

55

0,15

dP > 700 Pa--

dP < 300 Pa

5

0,05

Mass particles
collected in cyclone /cutting (g)146300 Pa < dP < 700 Pa--

dP > 700 Pa

113

0,75

dP < 300 Pa

5-300 Pa < dP < 700 Pa

87

0,25

dP > 700 Pa

178

0,30

200

dP < 300 Pa

42

0,05

11

200

dP < 300 Pa

23

0,05

3

200

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7

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 3. Results on main line with cyclonic filter – Evolution of drop pressure
Results
On STAINLESS STEEL plates, the pressure drop on THE filter per meter of cut increases similarly for plates with and without RTV FA 878.
With RTV FA 873, the pressure drop evolution per meter is between 2 and 3 times lower than for uncoated plates.
→It seems none or positive impact of coating on pressure drop per cutting length (dp/L)
Note: Differences in the evolution of the pressure drop are observed depending on the initial pressure drop of the filter. This is the reason why the results are presented by pressure drop range of
the THE filter at the beginning of the test.
Moreover, in the presence of resin, the results show that the pressure drop of the THE filter per mass of filtered particles increases less rapidly (from 2 to 6 times lower)→ It seems a positive impact of coating on pressure drop per mass of filtered particles (dp/m)
With Fuel Debris SIMULANT VF18, we observe that the pressure drop per meter of cutting is divided by 2. The coating seems to have therefore an effect on the clogging limitation of the HEPA
filter.
It is observed that with resin, the quantity of aerosols collected in the cyclone is lower (up to 3 times less with the resin RTV FA 873). This phenomenon is due to the fact that with the coating, thecutting aerosols are smaller and are mainly below the cut-off of the cyclone filter (cut-off at 3 µm).
These results were performed on 2 HEPA cartridges. To confirm these preliminary results, a campaign with more cuttings should be carried out using 1 cartridge per configuration.

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 4. Results on main line with cyclonic filter – Particle size distribution

Without coating, on the stainless steel and on the Fuel Debris simulant VF18, the particle size distribution shows a distribution with 2 modes (around 0.10 µm and between 1 and 2 µm).
With the application of a coating, the larger diameter particles do not appear in the collected aerosols (>1 µm). These particles are either deposited in the cutting chamber because they are too
heavy to be collected, or collected in the cyclone. However, the coatings generate finer particles of the order of 0.2 µm.
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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 5. Results on secondary line with cyclonic filter – HEPA filter with stainless steel cartridges
Configuration• Cutting of 5 mm thick stainless steel plate + various coatings• Use of the cyclonic filter

200 m3/h

HEPA

Tests
•
•
•
•

16 cuttings in emerging configuration on stainless steel plate
10 cuttings in emerging configuration on stainless steel plate + 5 mm RTV878
11 cuttings in emerging configuration on stainless steel plate + 2 mm RTV873
8 cuttings in emerging configuration on stainless steel plate + 5 mm Epoxyguard

Cyclonic
filterPORVAIR

Sampling
point

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Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

16.7 m3/h

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DEVELOPMENT OF DUST RESUSPENSION SUPPRESSION SYSTEM
PUBLIC PRESENTATION

V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 5. DISK CUTTING TESTS FOR ASSESSMENT OF IMPACT ON FILTRATION DEVICES IN AIR
5. 5. 5. Results on secondary line with cyclonic filter – HEPA filter with stainless steel cartridges
Results

Secondary line with filter PORVAIR

Configuration

Steel plate with cyclonic filter

Steel plate with RTV 878 andcyclonic filter
Steel plate with RTV 873 andcyclonic filter
Steel plate with EPOXYGUARD
and cyclonic filter

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Reference

QFT-S-P-CL2 --> CL4(emerging)
RFT-S-P-CL1 --> CL3(emerging)
RFT-S-P-CL4 --> CL13
(emerging)
CFT-SR878-P-CL1 --> CL3(emerging)
CFT-SR878-P-CL4 --> CL10
(emerging)
CFT-SR873-P-CL1 --> CL11
(emerging)
CFT-SEpoxy-P-CL1 --> CL8(emerging)Number of
cuttings

Flowrate (m3/h)

dP variation(mbar/m of cutting)

3

16,7

0,47

3

16,7

0,07

10

16,7

0,04

3

16,7

0,13

7

16,7

0,06

11

16,7

0,04

8

16,7

0,08

On the metallic HEPA filter, the evolution of
the pressure drop is very low for all
configurations.
The evolutions of P for each resin are notsignificant and do not show a different
impact on the metal filter cartridge.

For particle size, similar as on the main line,
the coating application shows a single modearound an aerodynamic diameter (dg) of 0.20
µm and removes the peak observed ofparticles around 2.5 µm.

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 1. Overview of the tests
Objectives:
1. Assessment of coatings impact on laser cutting process in term of performances
2. Implementation of aerosols characteristics measurements in order to observe the impacts on the production of airborne particles

General description:▪
▪
▪
▪

Tests take place in DELIA facility - CEA Saclay
Laser cutting tests are carried out in an airtight vessel. The aerosols sampling line integrates iso-kinetic probes.
Data are monitored with Pegasor® PPS-M, filter sampling and DLPI+®
Specific airflow is created inside the vessel in order to homogenize the particles concentration inside the vessel

Analyzed criteria:
Laser cutting process evaluation:▪ Kerf depth variation in NELC-A* configuration for zirconia blocks coated▪ Variation of the cutting limit speed in ELC-A** configuration for stainless steel coated plates▪ Behavior coatings during and after laser cutting
Aerosols characterization (impact of coatings):▪ Particles size distribution (DLPI®)▪ Particles mass and number concentration (Pegasor® PPS-M and filter sampling)▪ Morphology of the cut particles and their related atomic composition MPS
Other parameters of cutting for the assessment of impact of the use of coatings:▪ Influence of nitrogen atmosphere▪ Influence of humidity* NELC-A: Non-Emerging Laser Cutting in Air
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 2. Tests program

Phase 2 : AEROSOLS SUPPRESSION EFFICIENCY TESTS DURING LASER CUTTING

Tests campaign was held from 01/06/2022 to 30/06/2022:✓ Samples : fused cast zirconia blocks, stainless steel plates and Fuel Debris
simulant VF18,✓ 3 coatings tested (RTV FA 878, RTV FA 873 and EPOXYGUARD,✓ 34 types of cutting tests with various parameters have been carried out in DELIA
Facility with or without aerosols characterization
Phase 1 : LASER CUTTING PROCESS EVALUATIONIMPACT OF 3 SELECTED COATINGS
Evaluation of coating impact on laser deep gouging process (NELC)
Uncoated

1
2
3

Fused cast zirconia

RTV FA 878
RTV FA 873
EPOXYGUARD

4

Evaluation of coating impact on laser cutting process (ELC)

No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

5

Uncoated

21

6

RTV FA 878

22

RTV FA 873

23
24
25

7
8

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40 mm stainless steel ( 304L)EPOXYGUARD

26

Configuration

Sample( material)

Type of coating
Uncoated

NELC

Fuel debris simulant
VF18

RTV FA 878
RTV FA 873

Uncoated

ELC

40 mm stainlesssteel

RTV FA 878(304L)RTV FA 873
EPOXYGUARD

Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

Environment

Gas flow rate inside
DELIA vessel

Dry Air
N2 & Humidity
Air & Water SprayN2 & Water spray
Dry Air
Air & Humidity
Dry Air
N2 & Humidity

180 m3/h

Dry Air
Air & Water Spray
Dry N2N2 & Water sprayN2 & Humidity
Dry Air
Air & Water spray
Dry N2N2 & Water sprayN2 & Humidity
Dry Air ( 7 % O2)
Air ( 7% O2) & Water Spray
Dry Air (13 % O2)
Dry Air (13 % O2) & Water Spray
Dry Air
Dry N2
Dry Air

Dry N2120 m3/h

120 m3/h
48 m3/h Air & 72
m3/h N2
48 m3/h Air & 24
m3/h N2
120 m3/h
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 3. Cutting process evaluation – NELC (laser deep gouging)
Analyzed criteria:▪ Kerf depth variation in NELC-A configuration for zirconia blocks coated▪ Behavior coatings during and after laser cutting

RTV FA 878

RTV FA 873

Picture of cast fused Zirconia block coatedConfiguration of cutting

Experimental conditions:• The distance between the cutting head and the zirconia surface (stand-off) is set at its nominal value of 52 mm,• Samples: fused cast zirconia blocks of 50 mm thickness, 100 mm large and 200 mm long with only one facecoated,• Three coatings are evaluated: RTV FA 878(c), RTV FA 873(a), EPOXYGUARD(b). They have been applied
accordingly to the recommandations and self-levelling method has been applied. Their thickness is between 2
and 5 mm depending the sample of test,• Laser power: 8 kW, cutting speed 10 cm/min . Assist gas : dry air.

Pcitures of the tests: three cuts with the RTV FA 873, 2 cuts with Epoxyguard and 1 cuts with RTV FA FA. Trace of calcination is visible on Epoxyguard
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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 3. Cutting process evaluation – NELC (laser deep gouging)For each coating, 3 laser cutting have been carried out. Kerf depths have been measured after each cutting operation. The table below shows the results and the kerf depth average for each configuration:
Coating

Uncoated

RTV FA 873

RTV FA 878

EPOXYGUARD

41
39.5
39

39
30
38
38

34
39
13.5
42

39
40
37
40

Average
(mm)

39.8

36.3

32.1

39.0

Δ (mm)

0

-3.6

-7.7

-0.8

Kerf depth(mm)

Results:▪ These three coatings affect more or less the cutting performances.
• The best performance was achieved for EPOXYGUARD (average kerf depth of 39.0 mm).
• RTV FA 878 coating gave mixed results (average value of the kerf depth of 32.1 mm), has lower adhesion because of the smooth surface of fused cast zirconia and peels off. This phenomenon seems tointerfere with the ejection of the molten material. Nevertheless a very good adhesion was observed for Fuel Debris simulant.
• RTV FA 873 and EPOXYGUARD have good adhesion to zirconia blocks, even after multiple cuttings on the same work piece.
• All three coatings exhibited traces of local calcination.

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 4. Cutting process evaluation – ELC

Tests presented here have been carried out on cast fused Zirconia blocks
Analyzed criteria:▪ Variation of the cutting limit speed in ELC-A configuration for stainless steel coated plates▪ Behavior coatings during and after laser cutting

RTV FA 873

EPOXYGUARDRTV FA 878

Experimental conditions:• Three coatings tested : RTV FA 878, RTV FA 873 and EPOXYGUARD,• Assist gas: 78 m3/h (dry air and nitrogen only for coating behaviour),• Laser power: 8 kW,• Samples: stainless steel plates uncoated (100x150x41 mm3) and coated of thickness 44.8 mm(RTV FA 873), 52.5 mm (RTV FA 878), 48.3 to 50.9 mm (EPOXYGUARD)

Results:• Local coating combustion mainly due to the significant heat accumulation and dissipation in a relatively small volume of stainless steel were observed on some tests in air with assist gas in air. Local flames
were visible on camera installed in DELIA vessel even after switching off the laser beam. Flammes stop by themselves after seconds.
• Adherence of coatings RTV FA 873 and RTV FA 878 on 304L stainless steel surface is very low in comparison to EPOXYGUARD, which has a very strong adhesion to the same surface.
• Local flames occurred to a lesser degree for RTV FA 873 coating, limit-cutting speed was searched only for this resin. A loss of performance was observed: the limit speed value find is 7.5 cm/min, which is
16.7% slower, compared to the limit speed of a 40 mm thick 304L stainless steel plate. An intermittent cut was obtained at 9 cm/min for samples coated with RTV FA 878 that led us to estimate that after all,this coating has maybe the lowest impact on laser cutting performance.

RTV FA 873
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RTV FA 878

EPOXYGUARD

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 4. Cutting process evaluation – ELC

RTV FA 873

Tests presented here have been carried out on stainless steel plates (40 mm thick)

RTV FA 878

EPOXYGUARD

Results:
Laser cutting tests with N2 assist gas and in nitrogen atmosphere or in air with O2 concentration of 7.6%, and 13% showed no evidence of coatings degradation, combustion or ashes in the vicinity of the laser
kerf.
Deep gouging tests were carried out on metallic corium simulant coated with RTV FA 873 and RTV FA 878. Good adhesion of coating to the surface due to roughness of corium was observed, as well as no
combustion of the coatings, even during in air tests, nevertheless a black layer of residues and dust it is to be noticed on the sample surface.

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 5. Aerosols metrology
Laser cutting tests have been carried out on 40 mm thick stainless steel plates

Cutting tests on stainless steel plates with coatings in air and dry conditions

Repeatability tests on stainless steel plates▪
▪

Good repeatability of the aerosol generation in termsof number and mass particle concentration
Stability of the concentration level during the cuttingphase

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3 coatings have been tested: RTV FA 878, RTV FA 873, Epoxyguard▪

In terms of number concentration➢ Globally, resins coating induces an increase of particle generation except for Epoxy (Epo<873<878)➢ Repeatability for RTV FA 873 coating is underlined▪

In terms of mass concentration➢ Strong increase of the mass generation, especially for epoxy and 878 (873<878<Epo) compared to non-coatedstainless steel

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 5. Aerosols metrology
Cutting tests on stainless steel plates with coatings with Nitrogen and dry conditions▪

3 coatings have been tested: RTV FA 878, RTV FA 873, Epoxyguard▪

The refence test without resin coating in nitrogen has failed, so only trials with resins coating are compared.

▪
▪

The ranking of various resins is similar in Nitrogen than for AIR condition for particles number generation
For the particle mass generation, we can observe a strong reduction of the airborne particles quantities in Nitrogen condition compared to air conditions.

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 5. Aerosols metrology
Cutting tests on Fuel Debris simulant in dry air conditions▪

Similar particle generation between non-coated Fuel Debris and coated Fuel Debris with resin RTV FA 878 during the cutting phase. After, an increase is observed for coated Fuel Debris.
➢

Could be explained by the degradation of the resin RTV FA 878 and the soots production▪

Coating with resin RTV FA 873 induces a reduction of the particle generation in terms of mass and number during the cutting phase.

▪

No increase of particles generation is observed after cutting phase in agreement with the fact that no degradation of the resin RTV FA 873 was observed during the trial

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 5. Aerosols metrology
Cutting tests on Fuel Debris simulant with humidity and Nitrogen▪
▪

Similar particle generation between non-coated Fuel Debris and coated Fuel Debris with resin FTV FA 873 during the cutting phase. Reduction of particles generation after for coated Fuel
Debris.
Important increase of particles generation for coated Fuel Debris with resin 878, both in number and mass.
➢ Could be explained by the degradation of the resin RTV FA 878 by pyrolysis.

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V. CUTTING TESTS – MEASUREMENT OF IMPACTS
5. 6. LASER CUTTING TESTS
5. 6. 5. Aerosols metrology
Particles size distribution for laser cutting of Fuel Debris simulant with and without coating (humidity + Nitrogen conditions)
Fuel Debris without resin coating

Fuel Debris with resin coating (RTV FA 873)Fuel Debris with resin coating (RTV FA 878)▪
▪
▪

MET analysis for laser cutting of Fuel Debris simulant with and without coating (humidity + Nitrogen conditions

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Project of Decommissioning and Contaminated Water Management (Development of Dust Dispersion Suppression Technologies)

No significant evolution of the mass
median diameter with resins coatingcompared to Fuel Debris only.
Spread of the PSD increases with resins
coating, especially for RTV FA 878.
Particles morphology seems similar withand without resins.
Resins degradation due to laserinteraction may generate particles withsame fractal morphology as Fuel Debris.

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VI. APPLICABILITY & OPERABILITY TESTS
6. 1. GENERALITIESIn order to determine whether a coating is suitable for a use on site, it is mandatory to ensure it is applicable under on-site approaching conditions. For that, applicability and operability tests
have been scheduled. They are carried out in two separate phases. These two separate phases are meant to focus on the following:
1. Tests in BCSN facilities: tests are realized on a representative mock-up (see below) and with an automatic robotic arm. The objectives of this phase of tests are:i. To determine whether the selected coating are applicable and under which conditions of application
ii. To set the correct parameters of applications depending the area and conditions of application
2. Tests in CEA Marcoule facilities: once the coating parameters have been set, then operability are carried out with a remote controlled robotic arm, with indirect vision. The objectives of thetests are:i. To assess the capacity of a remote controled arm to reach different positions
ii. To assess the feasibility for a remote controled arm to realize a satisfaying coating operationiii. To determine the main constraint of operability on site (vision, determination of the quality of the coating, etc.)

PHASE 1: TESTS ON APPLICABILITY AND
DETERMINATION OF OPERATIONAL PARAMETERS
PHASE 2: TESTS WITH REMOTE CONTROLED ARM AND
UNDIRECT VISION TO DETERMINE THE OPERABILITYCONSTRAINTS

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PHASE 1 + PHASE 2 = GENERAL APPROACH FOR THE APPLICABILITY & OPERABILITY ON
SITE

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 1. Overview of the tests
The objectives of the operability tests in BCSN facilities were to:•
Realize representative feasibility tests with selected resins on real size mockup•
Define parameters with a robotic arm to spread resin on each areas with a specific thickness•
Correlate these parameters and results with industrial representative reference tele-operated equipment
In order to carry the tests, a mock-up has been designed, manufactured and mounted into the test facility. In order to make it representative of the on-site environment, geometries and areas ofcoating application have been reproduced: a few CRD-H have been implemented, so have been gratings, beams, cable tray, etc. The bottom of the mock-up allows water retention, so it ispossible to implement material representative of Fuel Debris (such as gravel for instance) and carry out coating tests under water. At the top of the mock-up (upper part), water spray has been
implemented so it is possible to carry out spraying tests on upper and middle parts of the mock up with dripping water.

Design of the mock-up with the three identified areas as for the tests on the coating properties:
upper, middle and bottom part. Upper and middle parts are in air with dripping water, bottom
part can be either in air or underwater

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Pictures of the mock implement in the test facility. A few representative elements of
CRD-H have been implemented. Tests have also been carried out on gratings

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 1. Overview of the tests
The test equipment is composed of the following items:•
One machine in which the coating is loaded and that pushes the coating into the spraying/injection system•
Flexible hoses which inner diameter is 13 mm•
One « gun » which purpose is to spray the coating after it has mixed the components (in the case the coating is abi-component such as RTV FA 878)•
In order to properly determine and reproduce parameters of tests, spraying tests are carried out with the help of
a robotic arm. In this way, it is possible to reproduce spraying movements (trajectories, speed)
View of the “Matrasur” spraying machine. The coating RTV FA 878 is composed of
two components that are mixed together just before the spraying/injection

Up to 30 meters of flexible

The objective of the tests can be summarized as following:•
Among the four coatings already selected for the tests, determine which one is more suited for eacharea/configuration of test•
Determine the most suitable manner to apply the coating depending on the different areas (injection vs spraying)•
Determine the best parameters of application for area/configuration of test: distance of application, application
speed, number of necessary layers. The main criteria to respect is to obtain a 2 mm thickness of coatingC1 - Interne

Principle of test equipment. The components are loaded and transported throught
flexible hoses (up to 30 meters length). Spraying system needs compressed air

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 2. Definition of the areas for operability tests – 7 mains areas tested
The mock-up present several elements whose characteristics are different. It has
been divided in 7 areas. Indeed, coating parameters are different depending on
the different areas:•

Area 1: Upper part – Space between CRDH. This area is composed ofmetallic and round items. This area needs to be sprayed, movement of
the robotic arm must be circular•

Area 2: Upper part – Bottom area of the CRDH. This area is composed ofmetallic bars. It must be sprayed from below and above•

Area 3: Middle part – Grating. This area is very specific. Coating ofgratings is specifically studied•

Area 4: I Beam (IPE) metallic structure. This part concerns all the metallic
structures of the mock-up•

Area 5: Middle Part – Central mast. This area concerns a vertical metallic
item with a complex geometry. Robotic arm movements have to be set
accordingly•

Area 6: Middle Part – Metal plate. This area concerns a vertical metallic
plate

•

Area 7: Lower Part – Floor tank. This area represents the bottom of thepedestal. It can be filled with water to carry out underwater tests

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 3. Preselection of coating depending on the area
At the end of the lab tests phase, 4 coatings were considered for the operability tests: the silicon coatings RTV FA 878, RTV FA 877 and RTV FA
873 for the upper and middle parts. They were also candidates for the bottom part alongside with the Epoxyguard coating.
Preliminary tests have been carried out on each coating and for each of the 7 areas described in section 6.2.2. The objective of thesepreliminary tests was to determine whether all the coatings are equally applicable or if one of them is better suitable compared to the others.
Spraying tests have been carried out on area 1 to area 6: many items of these areas are metallic and vertical. The parameters that were looked
after were the following: capacity for a coating to be applied and realize a 2 mm thick coating, with viscosity and time of cross linking
compatible with the application (in other words, preliminary tests to ensure that the coating can be applied on vertical surfaces, with effective
parameters that will lead to a well covered surface. A bad result is a coating that continues to pour leading to poorly coated areas).
Results of the preliminary tests:
It is much more difficult to obtain satisfaying coating operations with the RTV FA 877 and RTV FA 873 compared to the RTV FA 878. Indeed, due
to their viscosity, density, lack of grip and high pot life, when applied on vertical elements, RTV FA 877 and RTV FA 873 continued to pour. It
was not possible to obtain an uniform coating. In order to make them efficient, it should have proceeded to modify their characteristices.
Therefore it has been decided, for areas 1 to 6, to focus the tests with RTV FA 878: this coating is the most appropriate because it has a short
pot life (which is very convenient for this application) and has a natural high grip, for this application, there is no need to modify its
characteristics.

RTV FA 878

UPPER

RTV FA 877
RTV FA 873

RTV FA 878

MIDDLERTV FA 877
RTV FA 873

RTV FA 878

BOTTOM

RTV FA 877

EPOXYGUARD

For the lower part (area 7), all the 4 selected coatings have been tested and results are satisfying for all of them.

RTV FA 873

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 4. Test results of Area 1: Upper Part – Space between CRD
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: under dripping water

Characteristics of the area 1:• Narrow space between CRD Housing• Cylindrical shapes + specific elements: cables, threaded bars

Pictures illutrate the robotic arm was able to spray coating between the CRD-H and that all the surfaces are correctly coated with a 2 mm layer.

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 4. Test results of Area 1: Upper Part – Space between CRD
Main results for area 1:•
The full covering of cylindrical elements of the CRD has been achieved•
The coating covering is reproducible: it has been carried out for two different areas of area
1•
The full covering of the top metallic structure has been achieved•
The full covering of specific items such as cables and threaded bar has been achieved

Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• In order to ensure an effective coating, distance between spraying nozzle and the area tobe coated must be between 5 cm and 15 cm• Speed of application must be lower than 10 cm/s
• Number of layers = 3• The average thickness measured is about 4.5 mm

Cable and threaded bar have also been coatedC1 - Interne

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 5. Test results of Area 2: Upper Part – Bottom Area of the CRD
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: under dripping water

Characteristics of the area 2:• Flat vertical metallic part• Horizontal suspended metallic parts• Cylindrical shapes with screw (bottom of CRD-H)• Specific elements: threaded bars

Pictures illustrate the robotic arm is able to properly cover vertical and horizontal flat metallic parts, the cylinders and the screw of the CRD bottom

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 5. Test results of Area 2: Upper Part – Bottom Area of the CRD
Main results for area 1:•
The full covering of flat metallic parts have been achieved•
The coating covering is reproducible: it has been carried out for two different areas of area
1•
The full covering of the cylindrical elements and screws have been achieved•
The full covering of specific items such as cables and threaded bar has been achieved

Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• In order to ensure an effective coating, distance between spraying nozzle and the area tobe coated must be between 15 cm and 20 cm• Speed of application must be lower than 10 cm/s
• Number of layers = 3• The average thickness measured is about 3.5 mm

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 6. Test results of Area 3: Middle Part – Grating
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: under dripping water
Characteristics of the area 1:• Thin metallic structure• Complex shape
Main results for area 1:•
All thin metallic parts are coated•In order to cover all the gratings, it is necessary to carry out 3 layers ofcoating with different angles of application (+45°, 90° and -45°)•
2 mm thickness of coating has not been reached
Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• In order to ensure an effective coating, distance between spraying nozzle
and the area to be coated must be between 15 cm and 20 cm• Speed of application must be lower than 10 cm/s
• Number of layers = 3• The average thickness measured is about 0.8 mm horizontally and 1.2 mm
verticallyC1 - Interne

Coating in progress

Global view after spraying

View before the tests start

Coating in progress

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 7. Test results of Area 4: Middle Part – I Beam Metallic Structure
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: under dripping water
Characteristics of the area 4:• Horizontal metallic part with specific shape• Geometrical shape presenting a retention of water (due todripping water)• Corroded items

View before the tests start

Main results for area 4:•
All metallic shape is covered•
Coating is effective not only on metallic parts but also with corroded items andIPE bars filled with water (retentions)
Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• In order to ensure an effective coating, distance between spraying nozzle and thearea to be coated is about 5 cm
• Speed of application must be lower than 5 cm/s, Number of layers = 2• The average thickness measured is about 3.2 mm
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View after spraying

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 8. Test results of Area 5: Middle Part – Central Mast
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: under dripping water

Characteristics of the area 5:• Thin welded metallic structure• Narrow space between metallic parts• Complex element like mechanical chain

With the remote arm, it is possible to spray entirely the area: it is capable to spray between narrow space and to cover all the faces of the structure
View before the tests startC1 - Interne

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 8. Test results of Area 5: Middle Part – Central Mast
It is more complicated to coversuch complex elements like verticalmechanical chain. However,
because the coating pot life isshort, it is still possible toencapsulate it

On the main frame, all the faces are totally are covered

Main results for area 5:•
It is possible to coat all the items of the area (thin welded structure) as long as therobotic arm is capable to position the spraying nozzle

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Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• In order to ensure an effective coating, distance between spraying nozzle and thearea to be coated must be between 15 cm and 20 cm• Speed of application must be lower than 10 cm/s,• Number of layers = 2• The average thickness measured is about 3 mm

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 9. Test results of Area 6: Middle Part – Metal Plate
Configuration of tests:•
Coating: RTV FA 878•
Type of application: spraying•
Equipment: Spraying equipment + remote arm•
Machine used: Matrasur•
Distance between machine and spraying nozzle : 30 meters•
Environment: without dripping water

Characteristics of the area 6:• Vertical wide metallic plate
Main results for area 6:•
The metallic plate is entirely coated. With this kind of geometry,it is possible to obtain an uniform thickness of coating

View of the area before the test start

Coating in progress – first layer

Main parameters of the coating tests:• Coating has been carried out with the RTV FA 878• Distance between spraying nozzle and the area to be coated must be about 20 cm• Speed of application must be lower than 10 cm/s, Number of layers = 2• The average thickness measured is about 2.5 mm

Coating in progress – secondlayer
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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN RTV FA 878
Tests on the area 7 are representative of the bottom of the pedestal where many items may be found in addition
to the molten Fuel Debris.
Also, the bottom of the pedestal is most likely to be filled with water.

2

1

4
View
3 of the area
5

Therefore, the specificities of the area can be described as following:•
The application of coating is carried out underwater. Water level is about 15 cm•
The application of coating is carried out and evaluated on 5 different types of debris:
1. Concrete bloc: it is representative of molten Fuel Debris or concrete that could be encounteredat the bottom of the pedestal
2. Metallic parts: it is representative of items that could have fallen
3. Sand: it is representative of sediments that be present at the bottom of the pedestal
4. Gravel: it is representative of potential pieces of molten Fuel Debris
5. Concrete pieces: it is also representative of concrete pieces that my be encountered at thebottom of the pedestal
4 coatings have been tested: RTV FA 873, RTV FA 877, RTV FA 878 and the Epoxyguard.

Criteria that are observed to determine whether the coating is efficient or not is its capacity of cross-link and encapsulate efficiently the different items. One effective coating must become solid
and maintain the debris.
Coating is injected by pouring (using gravity) either with an injection machine or by hand. Each tests lasts 24 hours: it is the maximum time to consider the characteristics of the coating.

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN RTV FA 878

Illustrations of coating tests underwater with RTV FA 878 are given below (pouring by gravity with an injection machine, distance injection nozzle – debris around 5 cm):
Observations:
The covering of the concrete block with RTV FA 878 is efficient. The resin
does not pour too much, it grips properly.
It is possible to peel the coating. Small pieces are caught in the coating.

Injection on concrete block

After 24h

View of the coating

Observations:
The coating onto metallic surfaces is also satisfactory. The resin does not
pour, the surface is covered

Injection on metallic parts

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View of the coating

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN RTV FA 878
Observations:
The coating of sand is efficient. When the coating is peeled, it can be seenthat sand has been trapped.

Injection on sandView of the coating

Observations:
The coating onto gravels is efficient. The surface is properly covered. Small
pieces are trapped into the coating

Injection on gravels

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View of the coating

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN RTV FA 878
Observations:
The coating of sand is efficient on concrete pieces.

Injection on concrete pieces

View of the coating

Conclusions about the RTV FA 878:
During the tests, it has been observed for RTV FA 878:
• The RTV FA 878 has a density near 1 (= water density). Nevertheless, when used with an injection gun and because it has a high and a short pot life, coating is efficient for all the items
that represent debris• Thanks to its viscosity (between the viscosities of RTV FA 877 and RTV FA 873) and its grip, the coating is effective and uniform with a ticjkness aournd 7 mm
• The RTV FA 878 capturs the little pieces of gravels
Applicability is considered for: 1) Concrete blocks, 2) Metallic parts, 3) Sand, 4) Gravel, 5) Concrete pieces

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN EPOXYGUARD

Illustrations of coating tests underwater with Epoxyguard are given below (manual pouring):
Observations:
The coating is effective, all the surface is easily covered. The Epoxyguard do
not pour too much, it reticulates properly on the surface of the concrete
block.

Pouring on concrete

View of coating

Observations:
Same result is observed for the metallic surfaces.
However, the Epoxyguard solidifies, it is not possible to peel it after
reticulation. The metallic parts are stuck together.

Pouring on metallic parts

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View of coating

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN EPOXYGUARD
Observations:
The coating is effective. Sand in contact with the Epoxyguard istrapped in the coating.

Pouring on sandView of the coating

Observations:
Again, the coating is effective and the gravels are stuck into thecoating.
The final coating is a solid block.

Pouring on gravels

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View of the coating

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 10.

Test results of Area 7: Lower Part – Floor Tank – RESIN EPOXYGUARD
Observations:
The coating is effective. All the concrete pieces are tight together because of
the coating.

Pouring on concrete pieces

View of the coating

Conclusions about the Epoxyguard:
During the tests, it has been observed for RTV FA 878:
• Epoxyguard has a high density, therefore it pours easily underwater• It has a high grip and a high viscosity and therefore, the coating is effective for every kind of items representative of the debris• The thickness of coating obtained is around 3 mm
• Epoxyguard capturs many little pices of gravels• It is not possible to peal the coating after cross-linking, all the debris become compact and tight together by the resin
Applicability is considered for: 1) Concrete blocks, 2) Metallic parts, 3) Sand, 4) Gravel, 5) Concrete pieces

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VI. APPLICABILITY & OPERABILITY TESTS
6. 2. APPLICABILITY TESTS IN BCSN FACILITIES6. 2. 11.

Main conclusions

At the end of this phase of tests, it is possible to present the following conclusions:• Coating operations have been effective for all the areas with the RTV FA 878 which is a silicone coating and also with the Epoxyguard underwater• It does not mean that this is the only product that has worked, but it clearly showed the best results• Tests prove that with the correct spraying parameters and a good positioning of the spraying nozzle, coating can be done efficiently on all the considered surfaces of the pedestal
Concerning the applicability of the system, tests have proven that:• An efficient coating can be carried out with an industrial machine such as Matrasur• Diameters of flexible hoses remain thin, which means that their implementation on a robotic arm on site can be done without too much difficulties• Tests have been carried out with a 30 meters length of flexible hoses. Tests have also been carried out with 50 meters of flexible hoses. Results were conclusive.
 From these results, we can conclude that the applicability of the solution is proven
The next phase of tests (operability tests) will now focus on the functions that concern the remote controlled operations on site with undirect vision such as the vision, the verification of theeffective coating, etc.

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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 1. General overview
Objective
Objective is to perform coating spraying with industrial tele-operated equipment on a representative mock-up of the pedestal in order to evaluate performances and operational constraints. At
the end of the tests, it shall be possible to give conclusions and leads for the design of an operational prototype.
These tests have been carried out in LSTD CEA facilities at Marcoule site. They made it possible to:▪ Verify the operational implementation of the spraying system with the coverage rate,▪ Evaluate the accessibility of tele-operated and coating equipment inside PCV,
▪ Identify the necessary technical improvements for an operational and remote implementation of this process.
Experimental set-up: mock-up
The mock-up used for the tests is the bottom part already used for the first applicability tests in BCSN facilities. It has been implemented in an enclosure, made up of transparent walls which canbe made opaque using curtains and whose dimensions are 4.5 x 4 x 2.5 m (L, W, H)

Overview of the test enclosure, meant to be representative of a part of the pedestal, under the CRD-H. Picture on the right shows it is possible to darken the walls with curtains
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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 1. General overview
Experimental set-up: carrier, arm and operating equipment
The carrier is a Brokk 90 mobile used for decommissioning work. It is remotely controlled by wire and moves on rubber tracks. A Maestro slave arm is implemented on the carrier: it is an
hydraulic remotely operated robot arm with bilateral control allowing force feedback and with 6 degrees of freedom.
The spraying nozzle is implemented on the tool handler of the Maestro arm. Cameras are also implemented: two are implemented on the carrier Brokk, one is implemented close to the spraying
nozzle. This set-up is considered to be representative of what could be implemented on site.
The spraying system has been simplified: it is composed of a spray gun implemented on the carrier. The mixing of the products A and B that compose the RTV FA 878 coating (coating that is used
for these tests) is therefore done a few meters before the spraying nozzle.

Carrier Brokk 90 mobile with
implementation of Maestro slave arm,
spraying handgun and cameras
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Implementation of spray nozzle andcamera on the tool handler bell of theMaestro arm

Spraying Handgun and accessories

Control room from which the operator drives thespraying equipment. Cameras and screens help him

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PUBLIC PRESENTATION

VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 2. Methodology and tests program
Operating conditions:• Tests have been carried out in the dark with undirect vision• After each test, the performance criteria were quantified• Tests are recorded in video camera• Each test has been carried out in two phases: a first phase was performed to see which area is easy to reach, the second phase focus to the more difficult areas to reachPreparatory phases:• Setting up of the mock-up in the enclosure• Preparation of cartridges (resin part A and part B + retardant)• Setting a temperature of 12°C in an air conditioned chamber• Implementation of cartridges on the remote controlled robot
Tests:• Before each test starts, video recording is launched• Test is carried out on the targeted areas, after compressed air has been opened for the spraying nozzle and for the cartridges• Tests are stopped when a surface is fully covered or if the cartridge of coating is empty
Experimental set-up removal:• After each test, coating is removed carefully from the mock-up. Percentage of coverage is evaluated, the thickness is measured
Tests program• Preliminary tests are first carried out in order to determine most efficient parameters for the spraying• Tests on determined areas of the mock-up are carried out with the determined parameters
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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 3. Tests results
1) Preliminary tests on a simplified mock-up
The first step has consisted in tests on a simplified mock-up (metallic plate). The objective of these preliminary tests was to determine the best parameters for the spraying operation with thetele-operated equipment. Spraying parameters are: displacement ratio, control assistance and moving speed of the slave arm, compressed air pressure, distance between the spraying nozzle andthe mock-up. For that, after each test several measurements have been done: thickness of coating deposited (mm), behavior of coating after dying (???), percentage of surface covered with aminimum of 2 mm thickness (measurements have been done with a digital thickness gauge after the coating has dried). Preliminary tests also aimed at verifying that the vision system is sufficientand effective.
Conditions of most successful tests:• Temperature of RTV FA 878 coating
maintained at 12°C before use• Hose diameter = 10 mm• Compressed air for pneumatic spray handgun(for pushing the coating through hose) = 6/7
bars• Compressed air for spray nozzle (air injection
for spraying) = 3 to 5 bars
Mock-up with remote controlled arm withspraying nozzle implemented

View of the coated metallic plate

Coating removed from mock-up
for thickness measurement

Tests results:
A thickness not less than 2 mm on the totality of the vertical metallic plate has been obtained with the following parameters (average of coating thickness = 3.7 mm):
• Linear motion speed lower than 2 cm/s
• Spray distance between 20 and 30 cm (control assistance of robotic arm has been used in order to block degrees of freedom and therefore ensure flat movement)• 3 passes of coating are needed• Displacement ratio of 0.5 (meaning that when the operator moves the master arm by 10 cm, the slave arm moves by 20 cm)
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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 3. Tests results2) Spray tests on a representative mock-up
Spraying tests have been achieved on representative parts of the mock-up. Following slides illustrate the tests. Here are presented the tests on the mast supporting structure.
Parts that are targetted are highlighted in blue.
Mast supporting structure

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Tests results:
Spraying test has been carried out two times. Percentage of covered area (target) was about 67% and 57%.
Average thickness was 1.12 mm and 1.74 mm.
Front surfaces have all been reached. However, surfaces at the rear faces were not. Indeed, it is difficult theseareas with the experimental set-up (robotic arm with three articulations)

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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 3. Tests results2) Spray tests on a representative mock-up
Lower part of CRD-H

Tests results:
Spraying test has been carried out two times. First test targeted reached 60% coverage with a full coverageof front faces. Average thickness was 1.5 mm and 1.35 mm. Second test focused more on the rear surfaces
and inner and upper surfaces. Percentage of coverage reached 84% with an average thickness of 1.35 mm.
Again, some surfaces were difficult to reach:

Lower part of the representative mockup of Control
Rod Drives area
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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 3. Tests results2) Spray tests on a representative mock-up
Cylindric part of CRD-H:

Grating:

Tests results:
It was carried out 4 tests for the cylindricalpart of CRD:
• The first two tests did not give satisfactory
results on spray thicknesses because there
has been a premature cross-linking in thehoses.
• The last two tests really worked correctlywith a spray that lasted over 40 minutes
and 100% of the mock-up could be covered
with the average thickness of 1.5 mm. For
the last test, 3 cartridges were used, i.e
about 4.2 L of resin.
The parts between the cylindrical part of CRD
are more difficult to access but it is still
feasible. To obtain these results, the robot arm
came into contact several times with the
mock-up.

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Tests results:
It was carried out 2 tests :• For the first test, the spraying of the resin was made in several passes
with first a vertical position of the nozzle, then an inclination to the left, tothe right, forwards and finally backwards. Two thirds cartridges wereused. 100% of the mock-up was covered with an average thickness of
0.98 mm.
• For the second test, the area was reduced which has improved theaverage thickness (100% for 1.3mm).

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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 3. Tests results2) Spray tests on a representative mock-up
Summary of results

The table below summarizes the results of the tests in terms of coating performances (surface covered and average thickness reached)C1 - Interne

Mock-up

Surface covered (%)

Average thickness (mm)Comments

Cylindrical part of CRD

100

1,52

Difficult access to the rear of the cylindrical part of the CRD
but feasible

Lower part of CRD

84

1,35

Mast supporting structure

67

1,12

Grating100

1,3

No difficulties noted

Bottom and side wall

100

3,11

No difficulties estimatedPart between the two metal blades is difficult to access but
seems to be feasible with a lot of resin
Parts at the back of the mock-up are inaccessible with therobot arm used

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VI. APPLICABILITY & OPERABILITY TESTS
6. 3. OPERABILITY TESTS IN CEA MARCOULE FACILITY
6. 3. 4.

Advice for the implementation of the resin process with remotely operated equipment
Sub-setAdvicesNozzle spray

Add a motorization operated from the cockpit to ensure a change of spray angle to improve coverage and accessibility of the resin sprayUse of a nozzle with either very rigid materials to resist to accidental contact with the robot arm and the mock-up or elastic to absorb shocks
Develop an all-in-one nozzle with support, camera and air supply.

Flexible tubes

Integrate the hoses into the robot arm or to provide a flexible sleeve adapted to the robot arm and to these hoses.

Spray Handgun

Have control of the spray handgun in the cockpit
Lower the distance between mixer of products A and B and the spraying nozzle.
Study solutions to make cartridge replacement teleoperable

Arm robot
Carrier

Select an arm that has a payload 5kg with a small footprint, with good force feedback sensitivity, with a minimum extension of 1.8m, that is easily decontaminatedor protected by a sealing sleeve
Have control of carrier in the cockpit

Supervision/camera

Investigate solutions for remote cleaning of camera lenses
Add an ambient camera to avoid shadow areas or interpretation problems
Improve steering aids to ensure the correct thickness of resin coverageControl-command

Use a Cartesian control or have an isokinetic master and slave arm system with an articular control
Improve the management of resin thickness and coverage, control laws must be implemented by adding external sensors.

Operating Mode for the resin
elaboration

Make the resin preparation phases more reliable and adapt it to the quantities required to cover the mock-ups correctly.

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VII. ASSESSMENT OF IMPACTS
7. 1. GENERALITIESObjective
Global assessment study of coating including impact on systems and equipment, safety analysis and waste management .
Description
The impact study will include three kinds of analysis :▪ An analysis for systems and equipment identified as IMPACTED BY COATING (7.2)
like:❑ AIR FILTRATION SYSTEM❑ LIQUID FILTRATION SYSTEM❑ PUMP USED TO RETRIEVE FUEL DEBRIS PARTICLES❑ DRYING SYSTEM▪ A SAFETY ANALYSIS (7.3) and careful consideration about:❑ CRITICALITY❑ GASES EMISSION❑ FIRE RISK❑ HEAT MANAGEMENT▪ A WASTE MANAGEMENT ANALYSIS (7.4)

Methodology about systems and equipment identified as IMPACTED BY COATING:❑ Identification of the possible impact on the equipment❑ Reminder of results from tests about each possible impact❑ Analysis about the real impact expected

Methodology about SAFETY ANALYSIS:❑ Identification of the origin of the risk
❑ Reminder of results from tests about❑ Analysis about the level and the management of the risk

Methodology about the WASTE MANAGEMENT:❑ Identification of waste classification for coating depending on threshold values about
radiological activity coming from contamination.
❑ Analysis of coating impact in the waste for mid- and long-term disposal based on French
experience.

This assessment is based on some assumptions and limited by the current stage of other studies. For each case where the assessment could not conclude, some possibilities are proposed to
be studied at a later stage.

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VII. ASSESSMENT OF IMPACTS
7. 2 IMPACTS ON SYSTEMS AND EQUIPMENT
4 identified systems
In the frame of the project, 4 systems and equipment have been identified to be potentially impacted by the use of coating inside the PCV:• Air filtration system: due to the spraying of coating, and the cutting of coated equipment, airborne particles could affect the filtration systems in air• Liquid filtration system: when applied underwater, coating may generate particles that could impact the liquid filtration system• Pump used to retrieve Fuel Debris particles in water: same as for the liquid filtration system• Drying system of Unit cans: because the process of heating could modify the chemical structure of the coating and lead to gas release Studies and tests carried out in the frame of the project proved that, for the three first points above, the system and equipment identified are not affected by the use of coating
 However, concerning the drying system of Unit cans, further tests have been carried out
Drying system & gas release under high temperature
The drying system is based on a temperature rise to 200°C and blowing or vacuuming for several hours. The risks identified are related to a modification of the physical characteristics of the resin(softening and melting, liquefaction) and to the emission of gases potentially caused by this treatment. The risks associated with the drying system are:
• Reduction in drying efficiency,• The release of gases not foreseen by the gas treatment process (type of gas or quantity too high)• The creation of an airtight barrier preventing the escape of the gases produced over time.
The data needed to analyse these risks is related to the behaviour of the resin at 200°C: observation of the physical changes of the resin (visual and viscosity measurement) as well as an analysisof the gases released by the resin.

Tests were carried out so it has been possible to assess the behavior of the resin under high temperature and irradiation. (See « Physical proprieties » in chapter 3: Selection of coatings). Results
showed no softening and melting or liquefaction for RTV 878 and epoxyguard coating. Coatings seem to be harder with the rising of the temperature.
The gas released analysis is presented in the following pages. Several tests were carried out and gases are emitted from the coating under heat rising or irradiation
Conclusion:
Resins have a low impact on the drying system. As the resin becomes harder as it dries, there will be no formation of a waterproof barrier as a result of softening or liquefaction. Furthermore,this behavior should not reduce the drying efficiency. However, the gases emitted by the resin during the drying process must be taken into account for the sizing of the equipment.
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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 1. Gases emission
Origine:Preliminary tests showed that resins generate gases under high temperature and irradiation.
The gases come from the degradation of the resins components.
Depending on the kind of gases, the emission could lead to different kind of risk:• An explosion risk for explosive gases,• A risk of toxic gas spread• A risk of overpressure when the waste is in a tight container
The results of the analysis must be taken into account for all equipment related to the gas emitted by waste (for instance: gas filter size, ventilation of PCV and all room where waste could be
stored, assessment of overpressure for the transport step)
To analyze the gas rate, resins (RTV 878 and Epoxy guard) were heated or irradiated.
Tests realized:•
Measurement of the following gas rate under heating at 200°C : Hydrogen (H2), methane (CH4), carbon dioxide (CO2), and main Volatil Organic Component (VOC).
•
Measurement of COV and H2 gas rate under irradiation (1 kGy/h for a cumulated dose of 1 MGy)
Methodology:•
Samples are implemented in a thermo degration vessel of a tubular furnace.
•
Thermal programmation of the furnace is: heating ramp from 20°C to 200°C during 3 hours (1°C/min) then 5 hours of heating at 200°C leading to 8 hours of analysis.
•
An air flow goes through the vessel continously, 1 analyse of gas composition inside the vessel is carried out every 6 minutes.

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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 1. Gases emission under 200°C heating
Results of measurement for RTV FA 878 of the following gas rate under heating at 200°C (8 hours with a ramp up) : Hydrogen (H2), methane (CH4), carbon dioxide (CO2), and main Volatil
Organic Component (VOC)

CO2 and CH4 generation over the time

Synthesis:

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VOC generation over the time

Global mass flow over the time

Measurements show that the gases emission of the resin is very low. The most part is coming from CO2. A little
amount of CH4 is emitted an no hydrogen is detected. For VOC, only two components are detected. We canobserve a start of decrease in the mass flow of the cumulated gas production over these 8 hours of test.
Thes data represent a starting point regarding gas emission during storage. It would be interesting to perform
such kind of tests but on a longer period to confirm gas emission from resin addition should not be an issue forstorage and even more for disposal phase.
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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 1. Gases emission under 200°C heating
Results of measurement for Epoxy coating of the following gas rate under heating at 200°C : Hydrogen (H2), methane (CH4), carbon dioxide (CO2), and main Volatil Organic Components (VOC)

CO2 and CH4 generation over the time

VOC generation over the timeC1 - Interne

VOC generation over the time

VOC generation over the time

Global mass flow over the time

VOC generation over the time

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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 1. Gases emission under 200°C heating
Synthesis for Epoxy Guard:•••

Measurements show that the gases emission of the resin is very important. The most part is coming from VOC.
A little amount of CO2 and CH4 is emitted an no hydrogen is detected. For VOC, many components are detected, especially xylenes.
A strong decrease in the global mass flow is observed after a few hours (even if the value remains quite high after 8h – around 3500 mg/m3)

GLOBAL GAS MASS FLOW over the timeC1 - Interne

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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 2. Gases emission under irradiation
3 resin samples were submitted to a dose rate of 1 000Gy/h for a cumulative dose of 1 000 kGy (gas measurements were performed once at the end of the test).
Considering constraints for this test to be performed, there were performed by family (3 kinds of silicone and 3 kinds of epoxy) :•Measurements presented H2 and COV gases emission (values are after irradiation and cumulative for thes 3 silicone samples : RTV878, 873 and 877)
Gas identification

Gas measurements in the enclosure (ppm)

H2

782

VOC

22

•

Rk : values regarding Epoxy family showed global values higher for H2 (>2000ppm - limit of detection of the probe) and 105 ppm for COV.

•

Pictures before and after irradiation for silicones are presented below => no significative structural modification observed :Silicones (RTV 878/873/877) before irradiation

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Silicones after irradiation (1 MGy)

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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Objective:
The main objective is to analyze the impact of coating about criticality.
To do so, two different studies are carried out:
▪ The first study concerns the impact of the coating inside the PCV.
▪ The second study concerns the impact of the coating in storage canisters for a storage
configuration
Global Hypothesis:
Studied coatings have a silicone base:

Silicone base coating▪ To be conservative, simulations will take methylene molecule (CH2) as coating. This
molecule is a standard used for plastic and synthetic components in criticality
simulations.
▪ Simulations take a conservative fissile environment: UO2 with 5% enrichment with
optimum on moderation.
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Methodology:
Studies are made with CRITSTAL V2.0.2 formulary based on the CEAV5.1.2 library.
All calculations are made in two steps :• The study of the fissile environment by the APOLLO2 code,• The study of the keff by Monte-Carlo code
For the analysis of the coating impact inside the PCV, 3 types of calculation are considered :▪ An infinite plate of fuel debris and one layer of water and on layer of concrete (to beconservative)▪ A 7m diameter cylinder of concrete with 1 m thickness (similar but conservative to the pedestal)▪ A concentric spherical geometry, a usual geometry for criticality study used as the mostconservative case
The parameter studied is the thickness or amount of resin. For each calculation, the objective is tofind the limit of reactivity (keff). The criteria about keff is: keff + 3σ (σ ≤ 0,001) = 0,950.
[0, 95 is the usual threshold considered for subcritical system in the preliminary criticality studies].
To reach this limit, one thickness or amount of resin is chosen and the amount of fissile mass is
adapted to find the limit of reactivity.
For the coating impact analysis in storage canisters for a storage configuration, 2 types ofcalculation are considered :▪ A 10*10 array of storage canisters with a distance of 33 cm between two storage canisters
centers (similar to IRID’s criticality study).
▪ An infinite array of storage canisters with a distance of 33 cm between two storage canisters
centers (to be conservative).
The parameter studied is the keff depending on the amount of resin inside canisters for thedifferent volumetric humidity rate inside the Fuel Debris (20 %, 10% and 1%).

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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Coating impact inside the PCV – Calculations models and main results
Air (100 cm thickness) or
Water (20 cm)
Resin (variable thickness)
UO2 at optimum of moderation(variable thickness)
Concrete (100 cm thickness, 3% ofwater)First model: Infinite plate model

Second model: Simulation of PCV

Hypothesis for the calculations:Parameters for the calculations are the following:• Variable thickness of UO2 moderate by water• Variable thickness of resin (0,5 cm and from 0 cm to 10 cm with a pitch of 1 cm)• Calculations are carried out in air and underwater: 100 cm air thickness or layer of 20 cm of water
except for spherical model (2,5 cm or 20 cm of water)• Concrete is considered to be 3% of water and 100 cm thickness
Main results
For each model of calculation, results show that coating has a limited impacts on the criticalilty:• No impact with a 20 cm layer of water• Limited impact of coating in air (from 4-8% with 0.5 cm thickness of coating)• About the pedestal, results show that the resin should have no impact on the current criticality state
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Third model: Spherical model

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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Storage configuration – Hypothesis• The storage canisters geometry and the storage configuration is based on IRID’s publication. There are two unit cans in astorage canister. The geometry of unit can and storage canister are detailed on the right.
• Each unit can is filled with UO2 enriched at 5wt% and resin (simulated by CH2).
• For calculations the volumetric water content in UO2 is 1%, 10% or 20%.
• The center to center distance between two storage canister is 33 cm.
To be conservative, it is important to add some reflective component around the storage canisters:• Storage canisters are stored on a slab of 1m of concrete• Around the storage canister, there is a wall of 1m of water• Above the storage canisters, there is a wall of 20 cm of water• A layer of water of different thickness around each storage canisters has been studied to be the most conservative. The mostconservative case is reach with no water layer.

20 cm of water

Storage canister1 m of water

1 m of concrete

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Unit canCenter to center
distance: 33 cm

Air

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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Storage configuration – 10*10 storage canisters
For each volumetric humidity rate (1, 10 and 20%), the impact of the addition of resin in storage canisters is studied by comparison of the effective neutron multiplication factor (keff).
The variation of the amount of resin in storage canister is chose as the ratio between fissile material volume (UO2) and moderator volume (resin and water converted in resin equivalent) is from
20% to 100% by step of 10%.
Volumetric humidity rate in corium : 20%
Moderator volume /UO2 volume (%)

Keff + 3σ

UO2 (cm3)

Resin
(cm3)

Water incorium (cm3)Resin equivalent ofwater in corium (cm3)

20
30
40
50
60
70
80
90
100

0,731
0,800
0,857
0,903
0,940
0,971
0,997
1,020
1,039

10527
9618
8854
8203
7640
7150
6719
6337
5996

620
1528
2292
2944
3506
3996
4427
4809
5150

2105,3
1923,6
1770,81640,51528,1
1430
1343,81267,41199,31485,6
1357,41249,6
1157,6
1078,31009,1
948,3
894,4
846,3

Volumetric humidity rate in corium : 10%
UO2 (cm3) Resin (cm3)
9869
9066
8384
7798
7288
6841
6445
6093
5777

1277
2080
2762
3349
3858
4306
4701
5054
5369

Water inResin equivalent ofcorium (cm3) water in corium (cm3)
986,9
906,6
838,4
779,8
728,8
684,1
644,5
609,3
577,7

696,4
639,8
591,6
550,2
514,3
482,7
454,8
429,9
407,7

Volumetric humidity rate in corium : 1%
UO2 (cm3)

Resin
(cm3)

9343
8621
8002
7466
6997
6584
6217
5888
5593

1803
2525
3144
3680
4149
4562
4930
5258
5553

Water inResin equivalent ofcorium (cm3) water in corium (cm3)
93,4
86,2
80,0
74,7
70,0
65,8
62,2
58,9
55,9

65,9
60,8
56,5
52,7
49,4
46,5
43,9
41,6
39,5

Results show that the Keff increase with the amount of resin. The limitation (Keff + 3σ = 0,95) is reached for:• 3506 cm3 of resin (31% of the storage canister usefull volume) for a volumetric humidity rate in corium of 20%, for a UO2
volume of 7640 cm3• 3858 cm3 of resin (35% of the storage canister usefull volume) for a volumetric humidity rate in corium of 10%, for a UO2
volume of 7288 cm3• 4149 cm3 of resin (37% of the storage canister usefull volume) for a volumetric humidity rate in corium of 1%, for a UO2
volume of 6997 cm3
To conclude these preliminary calculations, it seems important to not reach more than 30% of resin in a storage canister.
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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Storage configuration – Infinite array of storage canisters
As for the 10*10 storage configuration, for each volumetric humidity rate (1, 10 and 20%), the impact of the addition of resin in storage canisters is studied by comparison of the effective neutron
multiplication factor (keff). The variation of the amount of resin in storage canister is chose as the ratio between fissile material volume (UO2) and moderator volume (resin and water converted inresin equivalent) is from 20% to 100% by step of 10%.
Volumetric humidity rate in corium : 20%
Moderator volume /UO2 volume (%)

Keff + 3σ

UO2 (cm3)

Resin
(cm3)

Water incorium (cm3)Resin equivalent ofwater in corium (cm3)

20
30
40
50
60
70
80
90
100

0,781
0,848
0,905
0,950
0,984
1,017
1,044
1,065
1,084

10527
9618
8854
8203
7640
7150
6719
6337
5996

620
1528
2292
2944
3506
3996
4427
4809
5150

2105,3
1923,6
1770,81640,51528,1
1430,01343,81267,41199,31485,6
1357,41249,6
1157,6
1078,31009,1
948,3
894,4
846,3

Volumetric humidity rate in corium : 10%
UO2 (cm3) Resin (cm3)
9869
9066
8384
7798
7288
6841
6445
6093
5777

1277
2080
2762
3349
3858
4306
4701
5054
5369

Water inResin equivalent ofcorium (cm3) water in corium (cm3)
986,9
906,6
838,4
779,8
728,8
684,1
644,5
609,3
577,7

696,4
639,8
591,6
550,2
514,3
482,7
454,8
429,9
407,7

Volumetric humidity rate in corium : 1%
UO2 (cm3)

Resin
(cm3)

9343
8621
8002
7466
6997
6584
6217
5888
5593

1803
2525
3144
3680
4149
4562
4930
5258
5553

Water inResin equivalent ofcorium (cm3) water in corium (cm3)
93,4
86,2
80,0
74,7
70,0
65,8
62,2
58,9
55,9

65,9
60,8
56,5
52,7
49,4
46,5
43,9
41,6
39,5

As for the 10*10 storage configuration, results show that the Keff increase with the amount of resin. The limitation (Keff + 3σ = 0,95) is reachedfor:• 2944 cm3 of resin (26% of the storage canister usefull volume) for a volumetric humidity rate in corium of 20%, for a UO2 volume of 8203
cm3
• 3349 cm3 of resin (30% of the storage canister usefull volume) for a volumetric humidity rate in corium of 10%, for a UO2 volume of 7798
cm3
• 3680 cm3 of resin (33% of the storage canister usefull volume) for a volumetric humidity rate in corium of 1%, for a UO2 volume of 7466 cm3
To conclude these preliminary calculations, it seems important to not reach more than 26% of resin in a storage canister.
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VII. ASSESSMENT OF IMPACTS
7. 3. SAFETY ANALYSIS
7. 3. 2. Criticality
Conclusion
Three calculations have been made to study the impact of a resin layer in the pedestal :• An infinite plate model• A more realistic pedestal geometry• A spherical geometry, the most conservative model and usual geometry for criticality study.
The three calculations leads to the same conclusion :• The resin have an impact lower than 20 cm of water. Moreover, the addition of resin to this 20 cm layer of water do note modify the criticality state in the pedestal.
• Without water, calculations show that a layer of 0,5 mm of resin have an slight impact on the criticality state of the pedestal (between 5 and 8 %). A 2 cm layer of resin have a bit more impact,
between 13 and 29%.
These results show that the resin should have no impact on the current criticality state in the pedestal.
Two calculations have been made to study the impact of resins in storage canister for a storage configuration:• A 10*10 storage configuration• An infinite array
The two calculations lead to the same conclusion :• The reactivity of the system increase with the amount of resin in storage canisters.
• In the most conservative case, the limit (Keff + 3σ = 0,95) is reached for 26% of resin in storage canisters and in the best case, the limit is reached for 37%.

It is important to keep in mind that these calculations are very conservative. The resin have an impact on the storage step and this impact should be studied in future study with a more realistic
composition for instance. The value of 26% of resin in a storage canister will be compared to resins coating test and retrieval operations considered.

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VII. ASSESSMENT OF IMPACTS
7. 3 SAFETY ANALYSIS
7. 3. 3. Fire risk
Origin of the risk:
Resin is an organic compound which under certain conditions could ignite or burn.

In some tests, the high temperature rise (when the force applied to the disc is very high orat the laser beam) showed that the resin could be locally consumed.
It is therefore necessary to analyse the conditions under which these situations can occur
and what the potential consequences are.

Tests realized:• Selection of coating not flammable (from sheet data) (chapter 3.2)
• Flammability resistance tests for coating (chapter 3.4)
The aim of these tests is to evaluate the flammability resistance for coating candidates.
Flammability is an important criteria of tests: if a coating presents a risk toward the fire risk, it is
excluded of the selection. Criteria of successfully passed test is that the coating is not flammable.
• Core boring tests (Chapter 5)• Disc cutting tests (Chapter 5)• Laser cutting tests under air (Chapter 5)• Laser cutting test under nitrogen (Chapter 5)

Analysis and conclusion:
To limit the risk of fire propagation, the selected resins have to present a strong resistance to flammability. The tests carried out, which are standardized, do however have their limits. The resin is still an organic
compound and in some cases that exceed the test standards, it is possible for it to burn. Flame tests have shown that if the resin burns, the reaction stops by itself when the heat source that caused the hazard is
no longer present.
During cutting tests, under particular conditions (high pressure of the mechanical cutting tool during cutting or at the melting point of the material for air laser cutting), resin was consumed locally but thereaction, located at the cutting point, stopped as soon as the cutting sequence was stopped.
• In the case of the disc cutter (grinder), if the pressure applied is within a controlled range, the resin does not burn. The cutting speed when using the grinder should therefore be considered and potentiallylimited• In the case of the laser, when nitrogen is used instead of air as assist gas, the resin does not burn. The use of nitrogen is recommended for laser cutting. If air is used, the resin could burn up locally.
• The core boring tests carried out have never resulted in burning resin.

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VII. ASSESSMENT OF IMPACTS
7. 4 IMPACT ON HEAT TRANSFER FROM FUEL DEBRIS
Objective:➢ Assessment of the influence of resin coating on the cooling of fuel debris bed➢ Assessment of the potential temperature to which the resin coating is subjected Proposal of a Computational Fluid Dynamics (CFD) study aiming to evaluate the temperature that
resin may reach close to fuel debris and depending on the location on the pedestal floor (aboveor out of sumps)➢➢

Definition of calculation domain:➢ Definition of pedestal floor geometry based on Mitsuda1 publication

Water height = 10 cm
Resin thickness = 5 mm

Presentation of the setup of CFD simulations with ANSYS CFX code for advice and discussion withgiven initial and boundary conditions
Most of initial conditions in relation to 1F site have been provided by the publication of Mitsuda
et al. 2020, Progess in Nuclear Energy

Full geometry for representative study

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VII. ASSESSMENT OF IMPACTS
7. 4 IMPACT ON HEAT TRANSFER FROM FUEL DEBRIS
Calculation description➢

Calculation of thermal diffusion inside the sumps and the concrete taking into account the heat flux of each sump of around 7 kW/m²➢

Heat transfers with the water and the air of the pedestal are taken into account without resin to get a reference state before covering the fuel debris➢

Boundary conditions for each part of the computational domain are presented below➢

Heat fluxes applied to Fuel Debris distributed above the ground and inside the sumps➢

Boundary condition of water flow above fuel debris (10 cm height) with a flowrate of 1.7 m3/h, allowing to evaluate the convective heat transfer coefficient with water HTCw =18 W.m-2.K-1

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VII. ASSESSMENT OF IMPACTS
7. 4 IMPACT ON HEAT TRANSFER FROM FUEL DEBRIS
Here below are presented the calculation results for water with HTC = 18 W.m-2.K-1 (penalizing configuration)

Results:
Resin temperature ranges between 25 °C and 151.6 °C with a mean value of 74 °C
Application of the top temperature field as an initial condition for a calculation
with a resin layer of 5 mm in the 1F2 pedestal

This result is obtained with a very penalizing condition of water velocity above the ground which limits
the heat tranfer with the fuel debris (Vw = 2.10-5 m/s)
 By considering a higher velocity due to the fall of water droplet on the ground (Vw = 0.13 m/s), theconvective heat transfer coefficient grows up to 400 W.m-2.K-1

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VII. ASSESSMENT OF IMPACTS
7. 4 IMPACT ON HEAT TRANSFER FROM FUEL DEBRISIn the case of htc = 400 W.m-2.K-1 corresponding to a velocity of water induced by droplet falling down to the floor, the temperature at the surface of fuel debris is lower than for htc = 18 W.m-2.K-1
and heat exchanges with water are better

The use of this temperature field as an initial condition for a calculation with a resin layer of 5 mm in the 1F2 pedestal allows to produce the results presented after:
 In conclusion of these calculations with a resin layer of 5 mm and awater layer of 10 cm, it appears that the temperature of resin does
not reach levels which could call into question its integrity even forpenalizing configurations
 In order to evaluate the consequences of water absence above theresin, a calculation was done with air conditions and without waterand the results are presented after
Resin temperature ranges between 30 °C and 78 °C with a mean value of 45 °C
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VII. ASSESSMENT OF IMPACTS
7. 4 IMPACT ON HEAT TRANSFER FROM FUEL DEBRIS
The main issue with air is that the heat transfers are very bad and consequently the htc is very low. In the case of water absence (only air), htc = 5 W.m-2.K corresponding to a velocity of air
arbitrarily evaluated to 0.1 m/s

Calculation results for air with htc = 5 W.m-2.K-1 (penalizing configuration)

The use of this temperature field as an initial condition for a calculation with a resin layer of 5 mm in the 1F2 pedestal allows to produce the results presented after:
 For these penalizing conditions, resin temperature ranges between 140°C and 235 °C with a mean value of 211 °C
 These results shows a temperature level very high regarding the
integrity of resins. However, we do not have any information about theventilation of 1F2 pedestal and thus about the airflows close to thefloor. It has strong consequences on the results because the htc for air isclosely linked to the air velocity. An increase of the velocity from 0.1 m/s
to 1 m/s may grow up the htc from 5 to 18 W.m-2.K-1 and involve theconservation of the integrity of the resin.
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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.1

Waste classification of coating

Methodology:▪ Identification of Japanese radioactive waste management regulation (The Reactor Regulation Act).
▪ Fuel debris analysis based on JAEA-Data/Code 2018-014.
▪ Identification of threshold values about radiological activity for coating contamination.

Details about step 1:
The evaluation of the waste classification for fuel debris is based on the results from JAEA calculations
performed for fuel materials (activity per core). For the evaluation of alpha emitters, only activities
from major nuclides are considered: U235, U238, Pu238, Pu239, Pu240 and Am241.
In order to evaluate specific activity of waste in Bq/g, the mass of heavy metals per core is considered(Unit 1 : 68 tHM; Units 2 & 3: 94 tHM).
Results of this preliminary evaluation are detailed in the table below (green: criterion is not exceeded,
red: criterion is exceeded). The fuel debris exceeds the limit for the category 2- L1 waste for the alphaemitters concentration. So fuel debris is a category 1 waste.
Limit categorisation
Japan (Bq/g) –Category 2

Synthesis about step 1:
The main results are that the fuel debris will be a category 1- TRU waste and the threshold to shift tothe category 2-L1 waste is the alpha emitters concentration.
This alpha concentration threshold is 105 Bq/g.
Based on JAEA data about fuel composition, this concentration is reached if 0.5g of fuel isincorporated in 1kg of coating.
At the sight of this value, it seems reasonable to not further study the possibility to sort coating by aspecific treatment. The coating will be sorted as others wastes from inside the PCV (two kinds ofstorage canisters or a waste storage container)

Core 1

Core 2

Core 3

Interm. Depth
disposal(L1)

10 years

50 years

10 years

50 years

10 years

50 years

Co60

Unlimited

9,98E+03

5,18E+01

1,03E+04

5,35E+01

9,35E+03

4,85E+01

Sr90

Unlimited

1,73E+09

6,59E+08

1,60E+09

6,08E+08

1,51E+09

5,75E+08

Cs137

Unlimited

2,36E+09

9,39E+08

2,16E+09

8,58E+08

2,04E+09

8,10E+08

C14

1,00E+10

2,97E+03

2,96E+03

2,60E+03

2,59E+03

2,44E+03

2,43E+03

Ni63

Unlimited

1,67E+05

1,24E+05

1,48E+05

1,10E+05

1,38E+05

1,02E+05

Tc99m

1,00E+11

3,99E+05

3,99E+05

3,55E+05

3,55E+05

3,35E+05

3,35E+05

Cl36

1,00E+06

0,00E+00

0,00E+00

0,00E+00

0,00E+00

0,00E+00

0,00E+00

I129

1,00E+06

9,12E+02

9,12E+02

7,99E+02

7,99E+02

7,55E+02

7,55E+02

alphaemitters

1,00E+05

1,42E+08

1,76E+08

1,13E+08

1,47E+08

1,34E+08

1,71E+08

With the maximal value of the alpha emitters concentration identified (1,76x108 Bq/g), it is possible tofind the maximal amount of fuel debris incorporate in the coating to reach the limit (105 Bq/g). The
value is 0.5 g of fuel debris per kilogram of coating.

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.2

Methodology to study the impact of coating added to the waste for storage and long-term disposal

The global approach consists of verifying that the resins (compositions) and their evolution over time (degradation under the effect of irradiation, temperature, humidity, a.s.o.) do not inducerisks for the management of the waste that could impact the safety of the storage.
Methodology:▪
▪
▪
▪

Listing of General Waste Acceptance Criteria that could be used based on French example
Identification of those that could be impacted by adding coating in waste
Description of the methodology to study the impact
Analysis of the impact when it is possible

Explanation of the methodology:
Requirements applicable to waste packages to be stored originating coming from regulatory constraints, safety analysis and operations constraints. These requirements are called Waste
Acceptance Criteria. As the storage and disposal facility for fuel debris are currently not defined, a list of general Waste Acceptance Criteria is proposed. This list is based on similar projects andinternational accepted practices according to waste characteristics.
To be exhaustive, each criterion is analyzed to know if it could be impacted by adding coating to the waste.
For each criterion impacted, a methodology to analyze the impact is defined.
Depending on the criterion and methodology, there may be several possibilities:• There is no impact• There is an impact and the analysis is possible through test realized previously in the project.
• There is an impact and the analysis will need to carry out additional and specific tests.
• There is an impact that needs more data about the storage or disposal to be analyzed. In this case, the methodology will provide data to take into account potential constraints on the futurestorage / disposal facility.

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.3

General requirements about waste
Main related functions

Criteria

Requirements to be fulfilled considering constraint functions
Storage phase

All functions

Radiological inventoryRadiological inventory per waste package should be declared and could be limited (according to facility license or accidental situations).

Containment of solid substances and aerosols in normal The primary container should be tight (solid materials and aerosols) in order to contain radioactive substances at a level compatible
conditions
with the design of the facility during at least the storage phase.
Surface contamination

Surface contamination of primary packages should be limited at a level compatible with the design of the facility (compliant withregulatory requirements).

Drop resistance of waste package

The tightness of the primary container following a drop from a specific height should be guaranteed during at least the storage phase(height depending on the installation).

To contain radioactive substances

In case of thermal loads, the containment of the solids substances and aerosols should be guaranteed.
External thermal loads resistanceIn case of thermal loads, the containment of gases and volatiles radionuclides should be guaranteed

To limit dose rate in compliancewith shielding design

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Primary container resistance to overpressure andpotential explosion (if leakproof container)

The primary container should be designed to the maximum overpressure due to gas generation within the waste package and its
potential explosion (if not excluded).

Resistance to stacking (if any)

The primary container should resist to stacking position on several levels according to the total height of the pits (consistent with thesizing of the installation)

Maximum dose rate at given distance of the waste
package

Maximum dose rate at a given distance from the waste package should be compliant with the sizing of the facility (radiologicalprotections).

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.3

General requirements about waste
Main related functions

Criteria

Requirements to be fulfilled considering constraint functions
Storage phase

To maintain sub-critical conditions

Reference fissile medium and reflection conditions

The compliance of the waste package with the sub-critical conditions (fissile medium and reflections conditions) defined for the sizingof the facility should be guaranteed (fissile materials inventory, moderator quantities or concentration, reflection conditions, neutron
absorbers).

Geometry of primary container

The primary package geometry should be compliant with criticality analysis.

Primary container resistance to overpressure andpotential explosion (if leakproof container)

The primary container should be designed to the maximum overpressure due to gas generation within the waste package and its
potential explosion (if not excluded).

Resistance to stacking (if any)

The primary container should resist to stacking position on several levels according to the total height of the pits (consistent with thesizing of the installation)

To dissipate heat from fuel debris Heat power at reception

To evacuate gases (radiolysis,
corrosion, etc.)

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The maximal thermal power at reception per waste package should be compliant with the sizing of the facility (ventilation systems) inorder to respect thermal limits (electronic devices, concrete structure, etc.).

Evacuation of gases generated within the waste
package (for a non airtight container)

The primary container should include a system to evacuate the gases for the duration for which gases are likely to be generated

Explosive gases rate

The maximum explosive gases rate per waste package should be compliant with the sizing of the facility.

Radioactive gases

The maximum radioactive gases rate per radionuclide of all waste packages should be limited according to facility design andauthorized release limits

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.3

General requirements about waste
Main related functions

Criteria

Requirements to be fulfilled considering constraint functions
Storage phase

Operations (To guarantee reception
and transfer of waste package)

Identification number

Each waste package should have an identification number (reference) resistant to storage conditions over time.

Mass of the waste package

The mass of the primary package should be less than the maximum allowable weight specified for the storage facility.

Geometry of primary container

The primary package should comply with the specified plan for which the storage facility is sized (pits diameter, dimensions of
NUHOMS®, etc.) (see also criticality)

Gripping interface

The gripping interface should be compliant with the sizing of the facility at reception and over time.

Substances to be declared

Various chemical substances should be declared at the waste package level (aggressive substances for the primary container, sourcesof radiolysis or corrosion gas, chemical toxic inventory, etc.)

Substances (To guarantee
compliance with design and safety Special substances (ex. pyrophoric materials)
assessments)
Prohibited substances

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It should be demonstrated that the waste package with pyrophoric material does not represent a source of danger during the normal
situations and accidental conditions.
Absence of prohibited substances (not covered by the design of the facility) should be guaranteed.

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.3

General requirements about waste
Main related functions

Parameters /Requirements for disposal (post-closure) to be fulfilled considering constraint functions
Disposal phase
Radiological inventory of the waste packages should be declared with a particular attention to mobile and long-lived radionuclides. Potential gaseous radionuclides should also be
declared.
In addition to the radiological inventory, a toxic inventory should be evaluated for the set of waste packages to be disposed of.
The quantity of organic materials and salts (forming potentially complexing species) present in fuel debris should be evaluated for the set of waste packages, and limited as muchas possible.
The compliance of the waste package with the sub-critical conditions (fissile medium and reflections conditions) and its evolution over time defined for the disposal should beguaranteed.
Voids in the waste package, should be limited to limit re-concentration of fissile materials in the disposal cells.

To limit radionuclide release
To control degradation products
To maintain sub-critical conditions
To dissipate heat from fuel debris withrespect to radionucleide mobility andmigration
To limit strains and hydraulic disturbance inthe repository system

The maximal thermal power at reception and the thermal power decay over time per waste package should be limited in a range within which the processes governing changes inthe disposal system could be represented and modelled reliably
Voids within the set of waste packages should be limited as much as possible to limit strains and hydraulic disturbance on the repository system (in order to preserve the hostrock)

To control dose rate according to overpack Maximum dose rate at a given distance from the waste package should not impact repository components and be compliant with the overpack design (if any).
and/or repository design
To control gas build-up according to overpack
Gases rate per waste package (corrosion, radiolysis, etc.) should be declared to verify its compliance with the repository design (including the overpack if any).
and/or repository design
To control overpack internal corrosion
Substances favoring internal corrosion of the overpack (if any) should be declared at the waste package level and limited as much as possible.
(chemical and radiolysis aggressiveness)

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.4

Identification of criteria or requirements impacted by adding coating in waste
Main related functions

Potentially impacted by additionof resin in the waste package

Criteria

Remarks and justification

Storage phase
All functions

To contain radioactive substances

To limit dose rate in compliance withshielding design

To maintain sub-critical conditions

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Radiological inventory
Containment of solid substances and aerosols in normal
conditions
Surface contamination
Drop resistance of waste package
External thermal loads resistancePrimary container resistance to overpressure and potential
explosion
Resistance to stacking

No

The coating does not include any radiological component

No

In normal conditions the containment will not be modified

No
No
No

The external surface of the container is not impacted
The drop resistance is not impacted
The external thermal loads resistance is not impacted

No

The primary resistance to overpressure is not impacted

No

Maximum dose rate at given distance of the waste package

Yes

Reference fissile medium and reflection conditions

Yes

Geometry of primary container
Primary container resistance to overpressure and potential
explosion
Resistance to stacking

No

The resistance to stacking of the container is not impacted
The addition of coating in the waste could lead to lower the maximum dose
rate by shielding or by the limitation of the amount of radioactive material
in the waste
Depending on the composition of coating, the reference fissile medium andreflection conditions could be modified
The geometry of the container is not impacted

No

The primary resistance to overpressure is not impacted

No

The resistance to stacking of the container is not impacted

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.4

Identification of criteria or requirements impacted by adding coating in waste
Main related functions

Potentially impacted by additionof resin in the waste package

Criteria

Remarks and justification

Storage phase
To dissipate heat from fuel debris
To evacuate gases (radiolysis, corrosion,
etc.)

Operations (To guarantee reception andtransfer of waste package)

Substances (To guarantee compliancewith design and safety assessments)

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Heat power at reception

Yes

Evacuation of gases generated within the waste package
Explosive gases rate
Radioactive gases
Identification number

Yes
Yes
No
No

Mass of the waste package

No

Geometry of primary container
Gripping interface
Substances to be declared
Special substances (ex. pyrophoric materials)
Prohibited substances

No
No
Yes
Yes
Yes

The coating could modified the heat transfer, and the irradiation of theresin could increase the heat power of the waste.
Depending on the gases rate generation, it could be possible to impact thesizing of the filter (low probability)
The coating does not generate radioactive gases
The coating has no impact on the identification number of the container
The coating will have no impact on the mass of the waste package, only on
the mass composition inside the waste package
The geometry of the waste package is not modified
The coating has no impact on the gripping interface
Depending on composition and degradation products, some substances
could have an impact

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.4

Identification of criteria or requirements impacted by adding coating in waste
Main related functions

To limit radionuclide release

To control degradation products

To maintain sub-critical conditions

Potentially impacted byaddition of resin in thewaste package
Disposal phase
Radiological inventory of the waste packages should be declared witha particular attention to mobile and long-lived radionuclides.
No
Potential gaseous radionuclides should also be declared.
In addition to the radiological inventory, a toxic inventory should beYesevaluated for the set of waste packages to be disposed of.
The quantity of organic materials and salts (forming potentiallycomplexing species) present in fuel debris should be evaluated forYes
the set of waste packages, and limited as much as possible.
The compliance of the waste package with the sub-critical conditions(fissile medium and reflections conditions) and its evolution over time Yes
defined for the disposal should be guaranteed.

Parameters /Requirements for disposal (post-closure) to be fulfilledconsidering constraint functions

Voids in the waste package, should be limited to limit reconcentration of fissile materials in the disposal cells.
To dissipate heat from fuel debris
with respect to the integrity of
buffer material and near field hostformation
To dissipate heat from fuel debris
with respect to radionuclide
mobility and migration

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The maximal thermal power at reception and the thermal power
decay over time per waste package should be compliant with thedisposal facility in order to preserve the integrity of buffer material
and the host rock formation.
The disposal system evolution in time has to be modelled reliably. For
this, the maximal thermal power at reception and the thermal power
decay over time per waste package should be limited.

Yes

Remarks and justification

The radiological inventory is not modified by adding coating in the waste.

Depending on composition and degradation products, some substances could have an
impact.

Our preliminary criticality studies within canisters presented a potential impact of theresin.
The addition of coating in the waste could have an impact on voids in the waste package
at a long time scale according to time of degradation between resin and other materials(will depend of the conditioning form of the waste)

Yes
The coating could modified the heat transfer, and the irradiation reaction could increase
the heat power of the waste (low probability).
Yes

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.4

Identification of criteria or requirements impacted by adding coating in waste
Main related functions

Parameters /Requirements for disposal (post-closure) to be
fulfilled considering constraint functions

Voids within the set of waste packages should be limited asmuch as possible to limit strains and hydraulic disturbanceTo limit strains and hydraulicdisturbance in the repository system on the repository system (in order to preserve the hostrock).
Maximum dose rate at a given distance from the waste
To control dose rate according topackage should not impact repository components and be
overpack and/or repository design
compliant with the overpack design (if any).
Gases rate per waste package (corrosion, radiolysis, etc.)
To control gas build-up according toshould be declared to verify its compliance with theoverpack and/or repository design
repository design (including the overpack if any).
Substances favoring internal corrosion of the overpack (ifTo control overpack internal
corrosion (chemical and radiolysis any) should be declared at the waste package level andlimited as much as possible.
aggressiveness)

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Potentially impacted
by addition of resin in
the waste package
Disposal phase

Remarks and justification

Yes

The addition of coating in the waste could have an impact on voids in the waste package at a longtime scale according to time of degradation between resin and other materials (will depend of theconditioning form of the waste)

Yes

The addition of coating in the waste could lead to lower the maximum dose rate by shielding or by
the limitation of the amount of radioactive material in the waste.

Yes

The coating could lead to a generation of gases (very low probablity) at long time scale.

Yes

Depending on composition and degradation products, some substances could have an impact

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.5

Methodology to study the impact of resin for each requirement identified
Main related functions

To limit dose rate in compliancewith shielding design
To maintain sub-criticalconditions
To dissipate heat from fueldebrisTo evacuate gases (radiolysis,
corrosion, etc.)
Substances (To guarantee
compliance with design andsafety assessments)

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Criteria

Methodology

Maximum dose rate at given distance of the The maximum dose rate will be lowered by the addition of coating in the waste. No further
study requested for this point.
waste package
Reference fissile medium and reflection
Criticality studies for storage configuration
conditions
Heat power at reception

Determination of the coating effect on the fuel debris thermal power

Evacuation of gases generated within thewaste package
Analysis of gas rate generated by coating under irradiation and high temperature
Explosive gases rate
Substances to be declared
Special substances (ex. pyrophoric materials) Identification of the coating composition and degradation products and analysis based on
the generic list determined for French storage and disposal facilities
Prohibited substances

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.5

Methodology to study the impact of resin for each requirement identified
Main related functions

To limit radionuclide
releaseTo control degradation
products
To dissipate heat fromfuel debris with respect
to the integrity of buffermaterial and near field
host formation
To dissipate heat fromfuel debris with respect
to radionuclide mobility
and migration

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Parameters /Requirements for disposal (post-closure) to be fulfilled considering
constraint functions
DISPOSAL PHASE
In addition to the radiological inventory, a toxic inventory should be evaluated forthe set of waste packages to be disposed of.
The quantity of organic materials and salts (forming potentially complexing
species) present in fuel debris should be evaluated for the set of waste packages,
and limited as much as possible.

Methodology

Determination of a generic list of substances studied for French storage anddisposal.
Identification of the coating composition and degradation products.
Analysis based on the generic list previously determined.

The maximal thermal power at reception and the thermal power decay over time
per waste package should be compliant with the disposal facility in order to Determination of the coating effect on the fuel debris thermal power.
preserve the integrity of buffer material and the host rock formation.
Study to be performed to justify no hot spot creation due to resin above
the maximal temperature of the model (used to evaluate radionuclide
The disposal system evolution in time has to be modelled reliably. For this, the mobility in time)
maximal thermal power at reception and the thermal power decay over time perwaste package should be limited.

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.5

Methodology to study the impact of resin for each requirement identified
Main related functions

Parameters /Requirements for disposal (post-closure) to be fulfilledconsidering constraint functions

Methodology

DISPOSAL PHASE
The addition of coating in the waste could have an impact on voids in the waste package at a
Voids within the set of waste packages should be limited as much as long time scale according to time of degradation between resin and other materials (willTo limit strains andhydraulic disturbance in the possible to limit strains and hydraulic disturbance on the repository depend of the conditioning form of the waste).
system (in order to preserve the host rock).
repository system
This point will have to be studied especially in case of waste blockage inside the waste package(cementation for instance => which is not the current senario)
Analysis of gas rate generated by coating under irradiation and high temperature
To control gas build-up
according to overpack
and/or repository design

Gases rate per waste package (corrosion, radiolysis, etc.) should be
declared to verify its compliance with the repository design (including
the overpack if any).

Additional studies to be performed to evaluate risk of gas emission due to corrosion or
chemical interaction with other waste inside the waste package or interaction with thewaste package itself (very low probability as silicon resin are chemically inactive)

Determination of a generic list of substances studied for French storage and disposal.
To control overpack
Substances favoring internal corrosion of the overpack (if any) should Identification of the coating composition and degradation products.
internal corrosion (chemical
be declared at the waste package level and limited as much as Analysis based on the generic list previously determined.
and radiolysis
possible.
aggressiveness)

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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.5

Analysis about “substances”

To identify the kind of substances that could have an impact in the waste package, the following list is based on prohibited or restricted substances in several French disposal facilities:
Kind of substances
Products or mixtures presenting risks of ignition or explosion or presenting risks of sudden
exothermic reaction with the various constituents of the package
Waste presenting an infectious risk
Free aqueous liquids
Organic liquids
Putrescible materials
Pyrophoric or very highly reactive metallic waste
Friable (loose) asbestos
Explosive substances

Potential impact from coating
No, there is no exothermic reaction between the resin and the stainless steel body of the cannister.
More over, resin (especially silicone ones) are chemically inactive components
No
Yes, Depending on composition and chemical reaction of degradation products, it could be possible tohave some residual free liquid water in the waste
No
No
No
No
Yes, potential generation of explosive gases (H2 and CH4) under irradiation and high temperature or bydegradation
No, the coatings are considered as non-flammable. Tests of behavior under high temperature and flames

Flammable substances if its flash point is inferior to 55°C (value from French regulation)
Toxic chemicals considered: uranium, lead, mercury, antimony, cadmium, selenium, arsenic, nickel,
Yes. It is unlikely but an analysis of the detailed composition of coating is needed.
chromium, boron, beryllium, cyano radical, CMR and asbestos.
Complexant :- Inorganic substances: chloride, fluoride, nitrate, sulphate, carbonate- Organic substances, for instance: EDTA, NTA, DTPA, TTHA, oxalate, citrate, acetate, formate,ascorbate, gluconate, sulfamate, phthalate, picolinic acid, TBP and ethylene-diamine
Yes. The detailed composition and the analysis of degradation products are needed.
Others: sulfonate
Aggressive substances :- Saline substances, including those inducing high ion strength, such as sodium salts or potassium
salts (potassium sulfate for example), and especially sodium nitrates (and nitrites)
Yes, the radiolysis rate is determined by tests and compare to the radiolysis rate from substances in the
Source of radiolysis
Fuel Debris.
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VII. ASSESSMENT OF IMPACTS
7. 5. WASTE MANAGEMENT
7.5.5

Analysis about “substances”

Two coating families are studied : a Silicon based coating (RTV FA 878) and an Epoxy base coating(EpoxyGuard)
Laboratory analysis carried out during the project show that coating have the following
component concentration:
FAMILYCOATINGSSILICONERTV FA 878

EPOXY

EPOXYGUARD

Generic composition of silicone
based coating

Generic composition of epoxy based coating

HALOGEN

SULFUR

9F, 17Cl, 35Br

16S

PMUC component (< 200 ppm) (French Regulation = means product usable in nuclear power plant)> 200 ppm (respectively around 100, 1600 and less than 20 mg/kg)> 200 ppm (around 13300 mg/kg)

Some laboratory analysis showed that de propan-2-ol, triméthylsilanol and some Volatil Organic Component (VOC) are detected for both coating after heating at 80°C and 200°C. Furthermore,
xylene for silicone coating and alkenes, alkanes and alcohol for epoxy coating are detected. So, the coating composition is more complex than the formula presented above.
A complete characterization of the two coatings has been made:Differential Scanning Calorimetry (DSC) to characterize first and second order thermal first and second order thermal transitions (glass transition, melting degradation and associated enthalpies)
for each sample.
•
Thermo-Gravimetric Analysis coupled with IRTF (TGA-IRTF) to follow the evolution of the mass of a sample as a function of temperature and to identify the associated decomposition
gases. Structural analysis by Pyrolysis/GCMS in order to identify the characteristic degradation compounds of the two resins.
•
Liquid Phase Chromatography coupled to QToF Mass Spectrometry, in order to search for observable organic compounds using a screening method.
•
Gas Chromatography coupled to Mass Spectrometry (GC-MS), in order to search for observable organic compounds using a screening method.
•
Fourier Transform Infrared Spectroscopy (FT-IR) to determine the chemical nature of the sample and confirm its general structure.
•
Field Emission Scanning Electron Microscopy coupled with an EDX microprobe (SEM/FEG-EDX) to perform semi-quantitative local chemical observations and analysis to identify chemical
analysis to identify the composition of the residual inorganic charges after TGA (900°C).
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VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPS
8. 1. REAL CASE SCENARIO – APPLICATION ON SITE
The implementation of a coating system requires the use of several equipment and skids:▪ Part 1: Spraying or spreading system implemented on the remote control arm
Located in the▪ The spraying system is used to apply the coating to the top of the pedestal, the vertical walls and various elements (e.g. CRD, platform...)Pedestal▪ The spreading system is used to cast the coating at the bottom of the pedestal on the fuel debris or waste above or under water
Located outside the▪ Part 2: Specific machine for spraying and spreading coating
reactor building▪ Part 3: Skid for automatic feeding coating components
The locations of the feeding and injection skids in the extended building allow to facilitate the operations of intervention or maintenance. A possible implementation of the equipment ispresented below:▪ Placement of the specific injection machine near the access door to the reactor building (about 35m from the injection point)▪ Placement of the feeding skid in an easily accessible area to allow manual charging of the coating components
Spraying system
Injection machine

Spreading system

Reactor
Building

Feeding skid

Extended
Building
Specific machine and Feeding skid implemented outside the reactor building.
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Spraying and spreading system is implemented onto the robotic arm in order tocarry out coating operations inside the pedestal

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VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPS
8. 1. REAL CASE SCENARIO – APPLICATION ON SITE
Part 1: Spraying or spreading system implemented on the remote control arm
This is the system used where the resin must be sprayed/injected.
A specific plate to mix part A and part B is mounted as close as possible to the injection zone,
which limits the number of elements to be cleaned or changed.
Nota: Before mixing the components, there is no risk of reticulation and the circuit does not
require specific cleaning. After mixing, the products has a pot life of a several minutes and must
be injected continuously. If the injection is stopped, the section downstream of the flat mixing
must be removed or cleaned.

Specific spreading
head

Then the resin is injected on a reinforced metallic nozzle and the resin is sprayed with various
specific metallic spraying heads adapted to the environmental accesses to the structures to be
sprayed. Tests of coating application with a remotely operated arm carried out at CEAMARCOULE have shown that the injection head must be reinforced to be more resistant in caseof collision.
For the areas where the resin must be spread (on the floor under water for example), the same
system could be used with a specific head adapted to spread large quantity of resin on fueldebris.
A video network (mono or stereoscopic viewing with cameras + lighting) shall be installed on the
robotic arm tip end and/or on the specific plate in order to help the operator for driving the Specific mixing plate
manipulator’s wrist and the embedded spraying head.

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Reinforced metallic nozzle
and spraying head

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VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPS
8. 1. REAL CASE SCENARIO – APPLICATION ON SITE
Part 2: Specific machine for spraying and spreading coatingThis equipment is a compact specific injection and spraying machine placed in the Extended building
at maximum 50m from the injection point.

Part 3: Skid for automatic feeding coating components
This equipment is the main storage of coating components. The skid can bepositioned in the Extended Building in an accessible area to allow for tank reloading.

The capacity of the skid is around 50 Kg of coating ( 2x 25 Kg ).

The tank have a capacity of around 2 x 200 kg of component.

This machine inject part A and part B of coating inside 2 hoses running along the robotic arm inside
the PCV.

The connection lines between the feeding skid and the specific injection machine are
made by two hose reel of 50m length capacity.

This machine could be automatically reloaded in component by the skid detailed in third part.
An automatic system will control the ratio of part A and B injected in the hoses, together with thecompressed air needed for spraying.

Overall dimensions ( L x W x H ) (tentative) : 1.9 m x 1.1 m x 1.3 m

Overall dimensions ( L x W x H ) (tentative):
0.85 m x 0.85 m x 1.3 m

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VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPS
8. 2. SYNTHESIS FOR THE APPLICATION ON SITE – IMPORTANT PARAMETERS
8.2.1

Implementation & Operation of injection/spraying system• Design of equipment must be carried out in order to facilitate the implementation on site
• Different skids must easily handlable. Because coating is transportable, tanks and pumps can be
implemented in areas with lower dose rates• Mounting of the injection/spraying head on the robotic arm must be carefully designed, good care must be
also brought to the flexible hoses• Even with the long distance between the tanks and the robotic arm inside the pedestal, diameters of flexible
hoses can remain small. However, fluidity of coatings may impact the pressure loss and the design of thewhole equipment• It is important that all useful information is reported to the general post of command: air pressure, flow of
coatings, level of coatings in the tank, etc. so the operators can easily remotely operate the system• Especially, it is important for the operators to access to all injection/spraying parameters in real time so they
can acknowledge if the operation is going accordingly to the expectations• It must be noted that this is an illustration of a possible implementation on site. Many other solutions
may be studied. Especially, it is possible to use other penetrations and other systems to get inside thepedestal (robotic arm, telescopic pole, etc.)• Also, the spraying head presented in this report could be differently designed (number of spraying
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VIII. APPLICATION ON SITE & SUGGESTED NEXT STEPS
8. 2. SYNTHESIS FOR THE APPLICATION ON SITE – IMPORTANT PARAMETERS
8.2.2

Coating parameters for the application inside the pedestal

As the tests highlighted during the project, many parameters must be considered.
• For the spraying on the upper parts, it is important to consider coating easily sprayable (i.e. coating with adapted viscosity)• Because of the gravity and in order to avoid that too much coating drips before crosslinking, it is important to use a coating with a short pot life
• Pot life of a coating will depend on several parameters, including its own properties and the temperature of use. Depending on the room
conditions, retardants may be necessary or not• In order to be effective, spraying operations must consider areas of application carefully: the robotic arm (movements) and the spraying nozzle
specifications must comply with the objectives (coating thickness, percentage of coverage, … ?)• Operational objectives must be clearly determined in order to design properly the final system/operation: different options must be considered
whether the important parameters are the quantity of coating used, the operational time of coating, the percentage of coverage that must be
reached, etc.
• One major point on which further developments are needed is the vision on site and more specifically the control of the coating thickness• Indeed, tests have proven that cameras could be easily dirten. Therefore, solutions must be brought in order to protect them (air blowing, self
cleaning, … ?). Movements of robotic arm and spraying nozzle must also be carefully considered in order to avoid that too much coating dirten thecameras• As for the control of the coating thickness, properties of coating could be improved to ease this control: fluorescent properties could be added tothe coating so with the correct lighting it could be easier to determine whether a coating operation has been effective or not• For the bottom part, viscosity of coating shall also be consistent with the transportation from the skids. But coating pot life shall be longer because
it will be necessary to let the coating to spread widely to ensure a good coverage of the surface• Vision at the bottom of pedestal and control of thickness remain issues that shall be considered

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8. 3. SUGGESTED NEXT STEPS
It could be interesting to continue the work on the use of coating inside the pedestal. Following items are suggested:• Studies & tests to enhance global safety management:• Work on a test program for larger scale tests and carry out the tests. These tests could include fall of larger and heavier objects. Assessment of dust resuspension following a seism
could be carried out• Numerical simulations in order to assess the dust resuspension rates in various situations and the gain that would bring the use of coatings• Demonstrations could be carried out for other areas of interest on site (from the top to the bottom of the RPV, in areas outside the PCV, etc.)• Development of a first operational prototype:• Work with TEPCO in order to determine a realistic implementation scenario with accurate definition of objectives & requirements of operation• Design the operational prototype with determination of the interfaces with the future carrier• Work on the coating itself in order to improve properties that will ease the operation on site
• Related studies of the use of coatings:• Continue the studies about waste management and study system for an eventual sorting of wastes• Study different areas of application considering larger choices of coating candidates (beside the silicone and epoxy coatings)

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8. 4. OTHER APPLICATIONS OF COATING FOR DISMANTLING WORK IN 1F
Other applications may be considered for the use of coatings on site and could besuggested. Indeed, preliminary results show the advantages of their use in order toavoid dust resuspension in the pedestal. But besides the pedestal, many items need
to be dismantled, in the PCV and around, and dust resuspension may be a major
issue for safety considerations.
Use of coatings shall be advantageous for the cutting and removal of any items, suchas pipes for instance or for any opening operations (in the concrete, in metallic
structures). It shall be particurlaly interesting for all the cutting operations using
Abrasive Water Jet or laser cutting because these tools generate a lot of dust
resuspension.
Furthermore, the study of the current project focused on the use of coatings inside
the pedestal with the specific constraints of this specific application. If coatings were
to be used elsewhere, criteria of selection shall be reviewed and some other familiesof products shall become interesting.

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8. 4. OTHER APPLICATIONS OF COATING FOR DISMANTLING WORK IN 1F

Repair of the tightness of a sump

Coating used to remove contamination

Protection against contamination

Repair of the tightness of a ventilation duct

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IX. CONCLUSION OF THE PROJECTJUSTIFICATION OF THE CHOICE OF
COATING

Benchmarking has been carried out to select potential coating candidates which characteristics are compliant with a use inside the pedestal at
the very vicinity of Fuel Debris. Silicone coatings proved to be the most suited for the application.
Other families of coatings can be used in other areas, but they have not been considered in the frame of this project.

JUSTIFICATION OF THE
EFFICIENCY

Tests have been carried out in order to determine in which situations the use of coating is an asset. Conclusions is that the efficiency of coatings
towards the dust resuspension phenomena is total when the coating is applied on the whole surface that is covered with dust. It has been
proven for aeraulic and hydraulic stress and for the fall of objects. Tests proved also that even a partial covering is beneficial in all situations.

JUSTIFICATION OF APPLICABILITYJUSTIFICATION OF THE IMPACTS
OF THE USE OF COATING

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Applicability has been proven with the transportation of coating over 50 meters and the positive results of spraying and injection tests.
Conclusive coating tests have been carried out with a remote controlled robotic arm. However these tests showed that improvements areneeded before it is possible to use coating on site (improvement of spraying nozzles, of vision system, better definition of conditions on site,
etc.)
Among all the impacts that have been studied in the frame of the project, none has concluded that the use of coating shall lead to a prohibitive
impact. Indeed, impacts on cutting operations are low (they barely lower the cutting performances of the tools, no unexpected particles isgenerated), safety risks (gases emissions, fire risk), heat transfer, criticality are manageable. However, these studies shall be continued,
especially the study that concern the waste management.

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