2 TECHNOLOGIES FOR NUCLEAR FACILITIES DECOMMISSIONING “SAFE DECOMMISSIONING OF POWER PLANTS” Project BG/04/B/F/PP-166005, Leonardo da Vinci Programme Module

Проект BG/04/B/F/PP-166005, Програма “Leonardo da Vinci” 2

Contents

4.1 Management of wastes in the process of decommissioning ofnuclear facilities – objectives, principles, time schedules, and activities.

4.2 Methods for processing and conditioning of radioactive wastes

4.3 Interment of radioactive wastes

4.4 Management of exhausted nuclear fuel


Key terms and definitions

Radioactive wastesRadioactive wastesRadioactive material gas, liquid or solid form, which is not to be

used any further, and which is controlled by the regulating authority in its quality of radioactive waste pursuant to the

adopted national legislation

All activities, inclusive those activities associated with decommissioning connected with manipulation, preliminary

processing, conditioning, storing or interment of the radioactive wastes, except for transportation outside the site. This can also

include all emmissions

Management of radioactive wastesManagement of radioactive wastes


4.1 Management of wastes in the process of decommissioning of nuclear facilities

Objectives of trainingThe trainees should be able to:The trainees should be able to:

– Identify the goals of the management of wastes in the process of decommissioning of the nuclear facility.

– Define the activities associated with management of radioactive wastes/non- radioactive wastes.

– List the technical tools and the technological methods for radioactive wastes/non- radioactive wastes processing.

5

Objectives of radioactive wastes management

The objectives of the radioactive wastes management

include all treatment of these using methods or technical tools ensuring:

- both protection of personnel and people’s health, and of environment, now and in the future;

- reduction of the burden that will be inherited by the generations to come within sensible limits.


Basic approaches with radioactive wastes management

For the purposes of radioactive wastes, For the purposes of radioactive wastes, 3 main approaches are aplied either 3 main approaches are aplied either alone or combined:alone or combined:

- delay and decay

- concentrate and contain

- dilute and disperse


Basic approaches with radioactive wastes management

The activities associated with radioactive wastes The activities associated with radioactive wastes management are planned, implemented and management are planned, implemented and controlled meeting 9 fundamental principlescontrolled meeting 9 fundamental principles::

Human health protection Environment protection Ensuring safety beyond the limits of the national boundaries Protection of the generations to come Burden on the generations to come National legal structure Control over formation of radioactive wastes Interrelation between formation of radioactive wastes and

management thereof Safety of installations for treatment of radioactive wastes


Time structure

Preparation and ensuring the following:– equipment for the entire radioactive wastes/non-

radioactive wastes processing complex

– sites and premises for respective waste

Initiation of processing:– radioactive wastes – with the initiation of works on

preliminary decontamination, with formation of first liquid and solid radioactive wastes

– non- radioactive wastes – only after accumulation of needed amount of each of the types of waste


Categorisation of radioactive wastes

Solid radioactive wastes are classified into three Solid radioactive wastes are classified into three categoriescategories

category 1 - transitional radioactive wastes, which can be exempted of control after a certain period of time has passed

category 2 – low and medium-active wastes category 3 – highly active wastes


General safety requirements with radioactive wastes management

Applying radioactive wastes management, measures are taken to guarantee that at all stages of radioactive wastes management, each person, the society, and the environment are adequately protected against radiological or any other risks.


Planning radioactive wastes management

Radioactive wastes management follows Radioactive wastes management follows adopted and controlled:adopted and controlled:

Programme for radioactive wastes management Programme for ensuring quality

Emergency plan


4.1.1 Activities associated with radioactive wastes management

Radioactive wastes management includes the Radioactive wastes management includes the following main activities:following main activities:

Preliminary treatment of radioactive wastes treatment of radioactive wastes Conditioning of radioactive wastes Interment of radioactive wastes


Activities associated with radioactive wastes management

Wastes and materials

Preliminary processing

Processing

Conditioning

Interment

Radioactive materials

Control exempted materials


Preliminary treatment of radioactive wastes

ObjectiveObjective - Reduction of amounts of the radioactive wastes due to be

processed and conditioned

- Correction of the characteristics of radioactive wastes aimed at facilitating processing, conditioning and interment thereof

Preliminary treatment ofPreliminary treatment of radioactive wastes may radioactive wastes may include main operations like:include main operations like:

Identifying characteristics Collection Separation Regulation of chemical composition Decontamination


Treatment of radioactive wastes

ObjectiveObjective Processing streamlines ensuring safety and/or reduction of expenses associated with wastes management applying modification of radioactive wastes characteristics.

Treatment ofTreatment of radioactive wastes includes, when radioactive wastes includes, when necessary, operations associated with:necessary, operations associated with:

- reducing the volume - removal of radionuclides from waste - modification of composition


Conditioning of radioactive wastesObjectiveObjective The Objective of conditioning is producing solid form packed wastes corresponding to the interment option selected and satisfying the requirements relevant to safe manipulation, transportation, storage and / or interment

Conditioning of radioactive wastes includes Conditioning of radioactive wastes includes operations associated with:operations associated with: - Immobilisation of radioactive wastes

- Packing of radioactive wastes


Immobilisation of radioactive wastes

DefinitionDefinition Immobilisation means having wastes shaped into a certain

fixed shape by means of hardening and immobilising thereof inserting them into an appropriate matrix or leak-tight jacket

ObjectiveObjective Fixing (immobilisation) aims at reducing the likeliness of

migration or dispersion of radionuclides in conditions of handling, transportation, storage or interment of radioactive wastes


Interment of radioactive wastes

ObjectiveObjective Interment is the last stage of radioactive wastes

management and aims at their positioning into facilities for continued storage with no intention in terms of withdrawing, long-term monitoring or technical servicing thereof.

Using a system of both natural and artificial barriers, reliable insulation is achieved, which guarantees that leaking of radionuclides into environment will occur at acceptably low levels in all possible climatic, geologic, external or technology related impacts through a long period of time


4.1.2 Technical tools and technologic methods for processing and preparation of radioactive wastes

When liquid wastes are processed, the following When liquid wastes are processed, the following methods are applied:methods are applied:

Precipitation Filtering Sorption Ion-exchange Evaporation


Technical tools and technologic methods for processing and preparation of radioactive wastes

When liquid wastes are processed, some other When liquid wastes are processed, some other methods methods are also appliedmethods methods are also applied likelike::

Reagent coagulation Electric coagulation Micro-filtering Ultra-filtering Reverse osmosis Electrodialisis



When solid wastes are processed, the following When solid wastes are processed, the following methods are applied :methods are applied :

Burning Moulding Smelting



When radioactive wastes are prepared When radioactive wastes are prepared (conditioned), the following methods are (conditioned), the following methods are mainly used: mainly used:

Bituminisation Inclusion into polymers Case-hardening Glazing


4.1.3 Technical tools and technologic methods for processing and preparation of non-radioactive

wastes

When non- radioactive wastes are processed, the When non- radioactive wastes are processed, the following methods are most commonly used:following methods are most commonly used:

Burning (combustible both solid and liquid wastes) Crushing (building wastes) Grinding (building wastes) Smelting (both ferrous and non-ferrous metals) Storage in waste deposits


Selection of technological methods and tools with radioactive wastes

management

Aspects influencing selection of individual technologies

– Universality of technology (i.e. possibility of using thereof for other types of waste as well)

– Resulting secondary waste

– Features of resulting (final) product

– Achievable volume reduction factor

– Relation with existing technologies (for newly set up system of work with radioactive wastes)

– Possibility of using thereof within needed term

– Personnel and environment safety

– Overall expenses (operational here included) and their break-up in time.


4.2 Methods of processing and conditioning of radioactive wastes

Objectives of trainingThe trainees should be able to:The trainees should be able to:

– Explain individual application of technical tools and methods of processing and conditioning of radioactive wastes.

– Identify individual methods of processing and conditioning of radioactive wastes.

– Describe methods of processing and conditioning of radioactive wastes.

– Identify fields of using individual methods of processing and conditioning of radioactive wastes.


4.2.1 Evaporation

DescriptionDescription

Treatment of liquid radioactive wastes using Treatment of liquid radioactive wastes using evaporation in distillersevaporation in distillers.

Application fieldApplication field

Evaporation is a widely used method for Evaporation is a widely used method for reduction of volume of liquid low-, medium-, and reduction of volume of liquid low-, medium-, and high activity radioactive wasteshigh activity radioactive wastes


4.2.2 Bituminisation of liquid radioactive wastes

DescriptionDescriptionBituminisation is a process, which consists in mixing processed concentrates with bitumen heated up to 120-2000С. It allows inclusion of up to 40-50% radioactive dry residue.

Application fieldApplication fieldBituminising may be used to fix both homogeneous (cube residues, hydroxide slams, etc.) and heterogeneous (pulp, ion-exchange resins, perlite, etc.) wastes of either medium of either medium or low activity or low activity


Bituminisation of liquid radioactive wastes

AdvantagesAdvantages

low solubility in water high resistance to water diffusion high chemical inertness good biological inertness high plasticity degree good resistance to radiation impacts high fixing speed availability of the material itself and its affordable price


Bituminisation of liquid radioactive wastes

DisadvantagesDisadvantages

viscosity drops when temperature increases combustibility (although it is hard to ignite) ability of chemical interaction with some chemical

compounds (nitrates) low heat conductivity rate tends to arch


4.2.3 Pack carburising

DescriptionDescription Pack carburising of radioactive wastes is a method for fixing

(achieving shape stability) of both solid and liquid radioactive wastes in a cement case


Widely applicable with hardening of both solid and Widely applicable with hardening of both solid and liquid low-, medium-, and high activity radioactive wastesliquid low-, medium-, and high activity radioactive wastes


Pack carburising

AdvantagesAdvantages low cost relatively simple technology high chemical inertness high rigidness level incombustibility sufficient level of washability of a number of key

radionuclides the high thickness of the product is a prerequisite for

good self-shielding good resistance to radiation impact availability of the material itself and its affordable

price


Pack carburising

DisadvantagesDisadvantages Ability of chemical interaction with some chemical

compounds (citric acid) Need of changing concentrate’s pH Changes both in volume and heat conductivity in the

process of hardening of the mixture.


4.2.4 Thermoplastic and reactive plastics

DescriptionDescription Inclusion into polymers consists in mixing dry

radioactive wastes that are being processed with polymers (e.g. polyethylene, polyester, vinyl ester) heated to above the plasticisation temperature with polymers in appropriate facilities (e.g. extruders) and their successive cooling in cases or packs.

Application fieldApplication field Used as an alternative to fixing using pack Used as an alternative to fixing using pack

carburisingcarburising.


4.2.5 Burning (reduction to ashes)

DescriptionDescription The method consists in burning combustible The method consists in burning combustible

contaminated materials in appropriate premises, contaminated materials in appropriate premises, collecting the solid residue and filtering of exhausted collecting the solid residue and filtering of exhausted gasesgases

Application fieldApplication field This method is applicable in treatment of solid

combustible radioactive wastes such as polymers, organic ionites, textiles, paper, etc., and organic liquids (contaminated oils), contaminated to some extent (starting from low degree of contamination and through to highly contaminated)


4.2.6 Compacting dry solid radioactive wastes

DescriptionCompacting is an operation of mechanical reduction of volumeApplication fieldApplication fieldCompacting is applied to wastes that are stable biologically, glass wadding, materials applied in electric engineering, etc.


4.2.7 High-temperature technologies

High-temperature technologies of processing and High-temperature technologies of processing and conditioning of radioactive wastes may refer to:conditioning of radioactive wastes may refer to:

Treatment of radioactive wastes by means of adding ceramic admixtures

РЕМ radioactive wastes processing technology


Treatment of radioactive wastes by means

of adding ceramic admixtures


Treatment of radioactive wastes by means of adding ceramic

admixtures is a process of mixing, tableting, and successive baking of ceramic mass and radioactive wastes of an appropriate granulometric composition

Application field Application field

Treatment of radioactive wastes by means of adding ceramic

admixtures is used for treatment of powder-like materials of medium and low activity such as contaminated soils, etc.


РЕМ technology

DescriptionDescription This method is based on combining the process of burning

of different materials to ashes on the surface of the melted glass mass and the introduction of solid non-organic products resulting from burning to ashes into glass alloy heated by plasma.

Application fieldApplication field Used in treatment of precipitates, saturated non-organic and precipitates, saturated non-organic and

organic sorbents, oils, organic compounds, contaminated organic sorbents, oils, organic compounds, contaminated soils, filters, glass, concrete, artificial material, rubber, soils, filters, glass, concrete, artificial material, rubber, wood, paper, etc.wood, paper, etc.


4.2.8 Treatment of high-activity wastes

Methods for treatment of Methods for treatment of high-activityhigh-activity radioactive wastes may include the following:radioactive wastes may include the following:

Glazing Plasma melting Cold crucible technology


Glazing

DescriptionDescription Glazing of radioactive wastes is a method for fixing

(achieving shape stability) of solid radioactive wastes in a glass case

Application fieldApplication field Glazing is mainly used for fixing of dry high activity

radioactive wastes such as concentrates and saturated ionites


Plasma melting

Description Description

Melting of radioactive wastes in a shaft-type furnace with a fuel-plasma accelerator of the burning process

Application fieldApplication field Used for treatment of high activity radioactive wastes


Cold crucible technology

DescriptionDescription This technology consists in obtaining melt of

processed radioactive wastes in a cooled induction-heated crucible


Cold crucible is mainly used for treatment of high activity radioactive wastes or in specific wastes such as radioactive precipitates with high contents of alfa-nuclides, saturated sorbents, dichromate, etc.


4.2.9 Treatment and processing of metal radioactive wastes

Metal radioactive wastes are treated as follows:Metal radioactive wastes are treated as follows:

Smelting of metal radioactive wastes Compacting under high pressure Disposal into environment after a preceding

decontamination has been completed


Smelting of metal radioactive wastes

DescriptionDescription Smelting of metal radioactive wastes in metallurgy facilities,

most commonly in induction furnaces

Application fieldApplication field Smelting of metal radioactive wastes is used for the following

Objectives: treatment of low activity metal materials aiming their

disposal into environment reducing the volume of radioactive metal wastes and their

processing into a form appropriate for permanent storage.


4.2.10 Activities with contaminated soil

Treatment of contaminated soils may include the Treatment of contaminated soils may include the following:following:

treatment of radioactive wastes by means of adding ceramic admixtures

Glazing of contaminated soils contaminated soils in situ Storage at sitessites for contaminated soilscontaminated soils


Juxtaposition of methods for fixing of radioactive wastes

Feature Cement Polymer Bitumen

Technology application range high medium high

Volume reduction factor negative positive positive

Cost low high high

Productivity medium high high

Compressive strength high medium low

Fire resistance high medium low

Degradation resistance high high medium

Radiation stability high medium medium

Ability to retain short-life radionuclides

low high high

Ability to retain actinoides high low low


4.3 Interment of treated and conditioned radioactive wastes

Objectives of training

The trainees should be able to:The trainees should be able to:

- Explain the final stage of wastes management.

- Describe the safety requirements and measures applied to transportation of radioactive wastes.

- Describe interment facilities and applicable methods.


4.3.1 Final processing of radioactive wastes

Final processing of radioactive wastes includes:radioactive wastes includes:

Packing of conditioned radioactive wastes in individual packs

Packing of conditioned radioactive wastes in containers


4.3.2 Packing for final neutralisation of wastes using interment

DefinitionDefinition

Packing is deemed to be a packing set inclusive its Packing is deemed to be a packing set inclusive its radioactive contents presented by the consignment radioactive contents presented by the consignment forwarder for shipment. The type of packing is forwarder for shipment. The type of packing is determined in accordance with individual restrictions determined in accordance with individual restrictions concerning the radioactive compounds shipped concerning the radioactive compounds shipped therein and with satisfying certain requirements to its therein and with satisfying certain requirements to its constructionconstruction..


Packing for final neutralisation of wastes using interment

Transportation and interment of radioactive substances is performed using the following types of packing::

1. industrial packing type 1; 2. industrial packing type 2; 3. industrial packing type 3; 4. packing type А; 5. packing type B(U); 6. packing type B(M); 7. packing type C


4.3.3 Transportation to interment site

DefinitionDefinition Transportation means shifting the location of a

certain consignment from its place of origin to its place of destination. The “transportation” activity includes all activities involved in preparation of the consignment for shipping, the activities associated with loading, transportation, unloading and reception thereof, inclusive transit outage and temporary storage of consignment if indispensable.


Transportation to interment site

Ensuring safety is achievable if the following are met:Ensuring safety is achievable if the following are met:1. Adherence and control on requirements to:1. Adherence and control on requirements to: activity of radionuclides activity of packs transport index and criticality safety index labelling, marking and signs in transportation of radioactive compounds construction of packing sets and packs means of transport

2. Working out, endorsement, implementation and control of the following::

radiation security programme; programme for ensuring quality emergency plan


4.3.4 Methods for final neutralisation of radioactive wastes using interment

DefinitionDefinition Interment means depositing exhausted fuel or

radioactive wastes in an appropriate facility with no intention of its successive extraction

Final neutralisation of radioactive wastes Final neutralisation of radioactive wastes using interment is carried out inusing interment is carried out in

underground depositoriesunderground depositories surface depositoriessurface depositories


Artificial and natural barriers

Reliable isolation of depositories from Reliable isolation of depositories from environment is carried out by means ofenvironment is carried out by means of::

1 artificial (engineering) barriers including1 artificial (engineering) barriers including –form of waste (fixed in stable shape case)–container–reinforced concrete construction of depository–multi-layer covering –clay bath around constructive assemblies–drainage system

2. Natural barriers (geologic formations)2. Natural barriers (geologic formations)


4.4 Management of exhausted nuclear fuel

Objectives of training

The trainees should be able to:The trainees should be able to:

- Identify and describe the structure of various types of nuclear-fuel cycles.

- Identify and describe technologies for intermediate storage of exhausted nuclear fuel (“Dry” and “Wet” depository for exhausted nuclear fuel).


4.4.1 Nuclear-fuel cycle


All operations associated with nuclear power production, inclusive mining ore processing, uranium or thorium processing and dressing, production of nuclear fuel, operation of nuclear reactors, processing of nuclear fuel, decommissioning, and any activity referring management and interment of radioactive wastes.


Types of nuclear-fuel cycles

The three basic types of The three basic types of nuclear-fuel cycles are identified depending on whether the exhausted fuel undergoes processing::

closed nuclear-fuel cycle – processing (regeneration of exhausted nuclear fuel);

open nuclear-fuel cycle – exhausted nuclear fuel does not undergo processing and fissionable materials are not returned into the nuclear-fuel cycle,

combination of both an open and a closed nuclear-fuel cycle.


Nuclear power plant

Intermediate/temporarystorage of exhausted nuclear fuel (30 –

40 years?)

Intermediate storage of exhausted nuclear fuel in nuclear power

plants (up to 10 years)

Depository – interment of radioactive

wastes

Controlled storing of solid and hardened

radioactive wastes

Processing of radioactive

wastes

Production of fuel

Extraction and treatment of

uranium

Closed nuclear-fuel cycle

A basic pattern of a A basic pattern of a closed nuclear-fuel cycle


Open nuclear-fuel cycle

A basic pattern of an open A basic pattern of an open nuclear-fuel cycle

Nuclear power plant

Intermediate storage of exhausted nuclear

fuel

Additional site for temporary storage of

exhausted nuclear fuel

Depository – interment of

exhausted nuclear fuel

Production of fuel

Extraction and treatment of

uranium

Up to 100 years


Basic structure of a nuclear fuel cycle

A nuclear fuel cycle includes the following stages and relevant activities:

Initial stage of a nuclear-fuel cycleInitial stage of a nuclear-fuel cycle Includes operations and activities associated with Includes operations and activities associated with

obtaining nuclear fuelobtaining nuclear fuel Intermediate stage of a nuclear-fuel cycleIntermediate stage of a nuclear-fuel cycle Includes operations and activities associated with using Includes operations and activities associated with using

nuclear fuelnuclear fuel Final stage of a nuclear-fuel cycleFinal stage of a nuclear-fuel cycle Includes operations and activities associated with Includes operations and activities associated with

processing, storing and interment of exhausted nuclear processing, storing and interment of exhausted nuclear fuelfuel


4.4.2 Intermediate storing of exhausted nuclear fuel


Intermediate storing is an operation associated with

The following are used for the purposes of intermediate storing

- depositories for exhausted nuclear fuel with wet storing

depositing of exhausted nuclear fuel in extra-reactor nuclear operations for storing prior to its successive treatment (delayed treatment) and/or interment

- depositories for exhausted nuclear fuel with dry storing


Wet storing of exhausted nuclear fuel


Wet storing consists in depositing of exhausted nuclear fuel in depositories where the exhausted fuel is stored in a poll filled with a liquid (most commonly water)

The water along with the construction of the pools ensures:

- reliable heat abstraction from the residual heat release of the exhausted nuclear fuel

- protection against radiation - guaranteeing subcriticality with normal operation and

likely external effects


Dry storing of exhausted nuclear fuel


Dry storing consists in depositing of exhausted nuclear fuel in depositories where the exhausted fuel is stored in gas environment, for example air or inert gases.

Dry depositories include facilities for storing exhausted fuel in containers, bunkers or chambers.


Diagram of a container for dry storage of exhausted nuclear fuel


Cycle of operation typical of dry storage of exhausted nuclear fuel

Documents

2 TECHNOLOGIES FOR NUCLEAR FACILITIES DECOMMISSIONING “SAFE DECOMMISSIONING OF POWER PLANTS” Project BG/04/B/F/PP-166005, Leonardo da Vinci Programme Module