Chapter 1: IAEA GSG-1 Classification

Radioactive waste classification links the characteristics of a waste inventory to its management requirements. The International Atomic Energy Agency (IAEA) publication GSG-1, Classification of Radioactive Waste, divides waste into six classes: exempt waste, very short lived waste, very low level waste, low level waste, intermediate level waste and high level waste. The classes are distinguished by the activity concentration of the radionuclides present, radioactive decay, heat generation, and the level of containment and isolation needed for disposal.

WIA-ENE-026 v1.0 defines waste categories, waste package records, storage information, monitoring and traceability. The standard consists of a main text and four phase documents: PHASE-1 (Foundation & Classification), PHASE-2 (Storage & Containment), PHASE-3 (Monitoring & Tracking) and PHASE-4 (Future Technologies). This book refers to them as the ‘main text’ and ‘PHASE-n’ respectively. PHASE-1, Foundation & Classification, establishes the basis for classification, radioactive decay assessment, regulatory review and waste tracking information systems. The numbered package categories of the standard and the extended classification terms of PHASE-1 describe related characteristics on different bases. IAEA classes are a conceptual framework describing the management and disposal route to which waste is directed, whereas WIA package codes are values that identify a package’s category in record-keeping and tracking systems. The actual disposal route is decided by the regulatory body through the licensing process, so a class or a code value alone does not settle how waste is disposed of.

How This Book Is Organized and How to Read It

This book explains WIA-ENE-026 v1.0 in eight chapters. Chapter 1 covers waste classification, Chapter 2 spent nuclear fuel management, Chapter 3 the safety case for geological disposal, Chapter 4 the transport of radioactive material, Chapter 5 the decommissioning of nuclear facilities, Chapter 6 stakeholder engagement, Chapter 7 radiological protection and Chapter 8 long-term stewardship. First-time readers should become familiar with the classification concepts in Chapter 1 and then turn to the chapters of interest. The data record and interface sections of each chapter are written for practitioners who implement information systems; readers responsible for policy or regulation can skip them without losing the thread.

Places where the standard gives different values for the same item in different documents are collected in the Standard Reading Notes at the end of Section 1.3; other chapters simply refer to these notes. The complete list of interfaces is in Section 2.8, and security requirements such as authentication, encryption and audit logs are collected in Section 4.8.1. Detailed definitions of radiation units and doses are given in Section 7.2.1.

Section numbers are written in three ways. Sections of this book are written as ‘Section 1.4.2’, sections of the main text as ‘standard §6.2’ or ‘WIA-ENE-026 v1.0 §6.2’, and sections of the phase documents as ‘PHASE-1 §2.3’. Example records are shown in JSON (JavaScript Object Notation), a data interchange format, and the calling conventions between systems are referred to as APIs (Application Programming Interfaces).

Basic units used in this book

• Bq (becquerel): the unit of activity; 1 Bq corresponds to one radioactive decay per second.
• Bq/g: activity per gram of mass, that is, activity concentration.
• Sv, mSv, µSv (sievert): units of dose received by people. 1 Sv = 1,000 mSv and 1 mSv = 1,000 µSv.
• mSv/h, µSv/h: dose per hour, that is, dose rate.

The distinctions between measured quantities are discussed in Section 1.4.1, and detailed definitions of effective dose and dose rate in Section 7.2.1.

1.1 The Six IAEA Waste Classes

IAEA Safety Standards Series No. GSG-1, Classification of Radioactive Waste (2009), divides solid radioactive waste into six classes. The six classes express the management requirements for the waste rather than steps defined uniformly by activity values alone. Classification takes into account the origin of the waste, the external dose rate and the total activity, together with the radionuclide composition and the intended management route. Filters or metal components of the same type may be managed differently if they differ in contamination, activation or radionuclide inventory. The classification of a waste and its acceptability at a particular facility are assessed separately.

1.1.1 Exempt Waste (EW)

Exempt waste is waste that meets the criteria for clearance, exemption or exclusion from regulatory control for purposes of radiation protection. Exemption is a determination of whether specific regulatory requirements apply to a source or practice, whereas clearance releases material already under regulatory control from that control. Exclusion places outside the scope of regulation, from the outset, exposures that are not amenable to control through regulation. Authorization of discharges of liquid or gaseous effluents to the environment is a separate regulatory decision.

GSG-1 cites IAEA Safety Standards No. RS-G-1.7 (2004) as the basis for exemption and clearance concentration values; the main radiological basis for the values for artificial radionuclides is an individual effective dose of the order of 10 µSv or less per year. Waste that has been cleared is no longer regarded as radioactive waste. The assessment applies the relevant criteria, including radionuclide-specific limits and provisions for mixtures. PHASE-1 describes the typical activity concentration of EW as below 1 Bq/g. Whether exemption or clearance actually applies is decided against the criteria for the radionuclides concerned. Even after radiological control has been removed, chemical hazards and other non-radiological hazards remain subject to their own management requirements.

1.1.2 Very Short Lived Waste (VSLW)

Very short lived waste can be managed by decay storage followed by an assessment of whether it meets the applicable clearance criteria. GSG-1 describes this class as waste that can be stored for decay over a limited period of up to a few years and then cleared in accordance with arrangements approved by the regulatory body, citing waste from Ir-192 and Tc-99m sources as examples. This management approach can be applied to medical and research waste containing short-lived radionuclides. PHASE-1 uses a half-life of less than 100 days as the screening condition for VSLW.

The inventory to be assessed includes longer-lived contaminant radionuclides and radioactive decay products as well as the radionuclide originally used. The storage period forms the basis of the clearance assessment, and authorization depends on the remaining inventory and the applicable criteria. Section 1.4.2 uses an I-131 decay calculation to illustrate the relationship between storage period and clearance decisions.

1.1.3 Very Low Level Waste (VLLW)

Very low level waste does not necessarily meet the criteria for exempt waste (EW), but because it does not need a high level of containment and isolation, it may be suitable for disposal in near-surface landfill-type facilities with limited regulatory control. The typical examples given in GSG-1 are soil and rubble with low levels of activity concentration; concrete and other materials arising from decommissioning may also fall into this class.

The suitability of a disposal route depends on the radionuclide inventory, the facility design and the facility’s waste acceptance criteria. Activity limits, disposal depth and institutional control arrangements are set by the applicable regulatory framework and the safety assessment for the facility.

1.1.4 Low Level Waste (LLW)

Low level waste is waste above clearance levels but with limited amounts of long-lived radionuclides. According to GSG-1, it requires robust isolation and containment for periods of up to a few hundred years and is suitable for disposal in engineered near-surface facilities. The limit on long-lived radionuclide content is the key criterion distinguishing LLW from ILW. The assessment considers heat generation together with long-lived alpha-emitting radionuclides and other long-lived radionuclides that affect disposal safety.

Operational waste such as contaminated clothing, tools, filters and resins may belong to this class, and the specific classification is confirmed through characterization. LLW may also require shielding during handling. The need for shielding and the disposal class are therefore each judged by assessing the relevant physical characteristics and safety factors.

1.1.5 Intermediate Level Waste (ILW)

Intermediate level waste requires a greater degree of containment and isolation than near-surface disposal can provide, particularly because of its inventory of long-lived radionuclides. Heat generation is generally not the main factor governing disposal design, but significant shielding may be needed during handling.

Examples of waste that may require this approach include activated components, fuel cladding, and certain process residues such as sludges. Their class is determined from measured or assessed characteristics. GSG-1 describes the disposal depth for this class as being on the scale of tens to hundreds of metres; the specific disposal depth and barriers are set by the waste inventory, the facility design and the safety assessment.

1.1.6 High Level Waste (HLW)

High level waste includes waste whose decay heat strongly influences storage and disposal design, and waste whose large inventory of long-lived radionuclides calls for a high level of isolation. Typical examples are spent nuclear fuel that has been declared as waste and high level vitrified waste from reprocessing. GSG-1 describes disposal in stable geological formations, usually several hundred metres or more below the surface, as the generally recognized option for HLW.

Heat removal requirements depend on the waste characteristics, the time since generation, the cooling history, the package design and the storage conditions. Cooling may be active or passive. WIA-ENE-026 v1.0 §6.2 describes dry storage using natural convection. Whichever approach is used, sufficient heat removal capacity must be ensured together with adequate shielding and containment.

1.2 Interpreting the PHASE-1 Decision Tree

WIA-ENE-026 PHASE-1 §2.3 defines the following screening sequence. The numerical conditions and branch order in the table apply to the PHASE-1 classification scheme. The broader IAEA management concepts are described in Section 1.1.

For screening assessments to be reproducible, the clearance criteria applied must be stated. The assessment record should also document how the activity and half-life conditions are applied to mixtures, which radionuclides contribute to the TRU activity, and how measurement uncertainty affects the decision. The condition “slightly above the clearance level” is qualitative, so its interpretation must be defined explicitly before it can be used for quantitative decisions.

Boundary cases that need interpretation during implementation—values exactly equal to a threshold, overlaps between category descriptions and tree conditions, and the scope of different thresholds—are collected as implementation notes in Section 1.9.

The branch order affects the classification result. If waste is classified as VSLW or TRU at an earlier step, the result may be fixed before heat generation is assessed. Even then, heat removal and shielding remain management requirements to be considered. Because LLW may also require shielding, the shielding branch is interpreted together with the broader classification principles in Section 1.1. Before screening results are used as the final classification, the way the system handles overlapping conditions must be documented.

1.3 Classification Terminologies and Package Fields

WIA-ENE-026 v1.0 distinguishes the broad IAEA classes, the numbered WIA categories and the PHASE-1 subcategories. The following table summarizes the role of each classification scheme.

The standard does not define a complete mapping between the numbered categories and the PHASE-1 extended terminology. Classification records should therefore state, along with each code, the classification scheme to which the code belongs.

The waste package model in WIA-ENE-026 v1.0 §4.1 identifies a package by packageId and records its classification in wasteClass. Classification codes appear in four places in the standard, each with a different scope. The following table sets out these layers at a glance.

The package record examples in this book use the codes from the standard’s §2 classification table. The relationship between top-level filters and subcodes, and the correspondence with PHASE-1 codes, are set in the implementation conventions, and the basis for them is recorded alongside. In a JSON record, wasteClass holds the single selected code as a literal string.

For example, LLW-2 combines an activity concentration band of 100–10,000 Bq/g with a half-life range of 5–30 years. The PHASE-1 description of LLW-B uses a contact dose rate range of 0.5–2 mSv/h. Activity concentration and external dose rate are different physical quantities, so converting between the two codes requires a separately established classification basis.

§2 of the standard uses the name “very low level” for LLW-1. This name is interpreted according to the criteria of that numbered category, whereas IAEA VLLW is interpreted according to the broad management scheme in Section 1.1. The IAEA terminology also includes EW and VSLW. Because the numbered classification table has overlapping concentration bands and combines several physical criteria, the classification of some waste may be ambiguous. Assessment records should state how overlapping conditions were handled.

National classifications follow the regulatory basis of the country concerned. The example value Special_Nuclear_Material in regulatory.classification indicates the regulatory status of the material, whereas wasteClass records the waste classification. Additional jurisdiction-specific classifications and their source documents can be linked by documenting an agreement on how the record is extended.

Machine-processed values remain unchanged in multilingual records. Human-readable descriptions may be translated, while exchanged identifiers and enumerated values follow the notation that defines them. For example, even if the display name is translated, the data value LLW-3 stays as it is. Converting codes requires an agreed mapping, separate from language translation.

Standard Reading Notes — Where Values Differ Within WIA-ENE-026 v1.0

The main text and the PHASE documents of WIA-ENE-026 v1.0 sometimes give different values or names for the same item. These notes collect those places in one location and set out, for each item, the value this book adopts and what should be recorded in practice. Other chapters refer to these notes by number.

Standard Reading Notes: items whose values differ between documents and sections

No.	Item	Main text	PHASE document or other section	Choice in this book and practical action
1	Cs-137 half-life	§3.1 table and §4.1 package example: 30.17 years	PHASE-1 §3.3: 30.07 years	The examples in this book use 30.17 years, consistent with the standard’s JSON. In actual calculations, record the half-life adopted together with the name and version of the nuclear data from which it was taken.
2	Range of wasteClass codes	§2 classification table: 14 codes	§4.1 example: 4 values; §10.1.1 filter: HLW, ILW, LLW; PHASE-1 §2.2: 7 codes	Records use the §2 codes. The relationship between filters and subcodes is written into the implementation conventions (see the code layer table above).
3	Spent nuclear fuel code	§2.1.3: HLW-1	PHASE-1 §2.2.5: HLW-SF	The examples in this book use HLW-1. Because the two codes belong to different schemes, keep each with the name of its scheme, and where a project maps one to the other, record the basis.
4	Wet storage and cooling period	§2.1.3 HLW-1: wet storage 40–60 years	PHASE-1 §2.2.5 HLW-SF: decay-heat cooling 30–50 years	Cite each only as a value describing its own classification. The actual transfer time is set by a heat-load assessment of the loading and its approval (Section 2.3.2).
5	Onkalo schedule	§6.3: depth 430 m, planned operating period 2025–2120	§9.2: status at the time the standard was written, ‘under construction’	The former is a planned schedule and the latter the status at a particular time. Check project status against the operator’s official sources, with a reference date (Section 3.4.2).
6	KBS-3 buffer thickness	§6.3 KBS-3 example: 350 mm	§4.2 facility record example: 500 mm	Both are example values. The design basis should record the dimensions actually applied and their source (Section 3.4.1).
7	Dose limit for the lens of the eye	§5.1.1 table: 150 mSv/year	Current international recommendations (ICRP Publication 118 (2012), IAEA GSR Part 3): 20 mSv/year averaged over 5 years, 50 mSv in any single year	Review against the current international recommendations and confirm the national legislation that applies to the facility (Section 7.2.2).
8	Storage location field path	§4.1: storage.storageLocation	§11 SDK example: storage.location	Exchanged records follow storage.storageLocation, and the conversion rule between the two paths is stated explicitly (Section 2.6).
9	LLW-B dose rate condition	Not applicable	PHASE-1 §2.2.2 description: 0.5–2 mSv/h; PHASE-1 §2.3 tree: above 0.5 mSv/h (no upper bound)	Keep the stated comparison operators unchanged and record the interpretation applied (Section 1.9).

These notes reproduce the standard’s values as given and state which value the book’s examples follow. Readers can use them as the reference point without rechecking the same differences in each chapter.

1.4 Characterization, Decay and the Basis for Clearance

1.4.1 Distinguishing Measured Quantities

Activity, activity concentration, dose rate and thermal output each convey different information. Activity, expressed in Bq, is the number of nuclear transformations per unit time. Activity concentration, expressed in Bq/g, is the activity per unit of the reference mass. Dose rate describes the radiation field under stated measurement conditions. Thermal output is the amount of heat generated per unit time.

The package model of the standard stores the total activity in radiologicalData.totalActivity and the activity of individual radionuclides in the radiologicalData.isotopes array. If the concentration C is in Bq/g and the corresponding waste mass m is in g, the activity is A = C × m. Which mass is used as the basis matters. The container mass, the mass of conditioned waste and the mass of waste before conditioning are different denominators in a concentration calculation. The per-isotope mass is the mass of that radionuclide, whereas concentration conversions use the mass of the waste that the concentration represents. Applying a sample concentration to an entire package also requires evidence that the sample is representative.

The radiologicalData.doseRate structure distinguishes contact measurements from measurements at 1 m. Dose rate depends on radionuclide composition, distance and shielding. The package example in WIA-ENE-026 v1.0 uses Sv/h, while the PHASE-1 conditions for LLW subcategories use mSv/h. Comparing the two requires bringing the units and measurement conditions onto a comparable basis.

radiologicalData.thermalOutput represents the total output in kW, whereas the PHASE-1 heat generation test is based on output per unit volume. Converting total output to kW/m³ requires a clearly defined volume and consistent units. The volume occupied by the waste used in the assessment may differ from the nominal capacity or external volume of the container.

Measurements and calculations also need a reference date and a stated basis for estimating uncertainty. Activities measured at different times are converted to a common reference time before being summed, taking account of decay and, where necessary, daughter ingrowth. The standard’s model includes radiologicalData.totalActivity.referenceDate and uncertainty fields. The package timestamp indicates when the record was made, whereas the activity reference date indicates the time to which the radiological values apply. The assessment record should state how individual activities and their uncertainties were brought onto the same basis.

1.4.2 Decay Storage

The activity of a radionuclide that decays without further production follows the equation below.

A(t) = A₀ × 2^−t/T_½

Here A₀ is the initial activity, t is the elapsed time, and T_½ is the half-life expressed in the same time unit as t. This book writes the half-life as T_½ (T_half in code blocks) and the decay constant as λ (lambda in code blocks). Since λ = ln 2 / T_½, the same equation can be written A(t) = A₀ × e^−λt. All decay calculations in other chapters follow this equation. After ten half-lives, the activity of the parent radionuclide falls to 1/1,024 of its initial value, about 0.0977%.

For example, using the I-131 half-life of 8.02 days given in WIA-ENE-026 v1.0, ten half-lives correspond to 80.2 days. Assuming an illustrative initial activity of 1,024,000 Bq, 1,000 Bq of I-131 remains after this period. A clearance assessment considers this remaining activity together with the applicable criteria, the basis of the assessment and the authorization requirements.

A complete assessment of a decay chain must also consider radioactive daughters that can grow in while the parent decays. Even after the initially dominant radionuclides have largely decayed, longer-lived contaminant radionuclides may determine the final management route.

The main text and PHASE-1 give different values for the half-life of Cs-137 (Standard Reading Notes, item 1, in Section 1.3). The half-life used in a calculation should be chosen explicitly, and a reproducible calculation record should state the selected half-life, the nuclear data used as its basis and the version of those data, so that the same result can be produced again.

WIA-ENE-026 v1.0 §3.3 gives the half-life of C-14 as 5,730 years. Because C-14 persists for a long time, it is a long-lived component that must be considered when assessing mixed inventories, including inventories initially dominated by short-lived radionuclides.

1.4.3 Mixtures and Clearance Decisions

Where the applicable regulations set criteria for mixtures, a determination for the mixture as a whole is needed in addition to radionuclide-by-radionuclide checks. One commonly used test is the sum of the fractions obtained by dividing the concentration of each radionuclide by its limit.

S = Σ_i C_i/L_i

In this equation, C_i is the concentration of radionuclide i and L_i is the limit applicable to that radionuclide. Whether this test applies, which radionuclides it includes and the acceptable threshold are set by the relevant regulations. The assessment record should retain the calculation result together with the clearance limits and the mixture rule applied.

The initial activity, measurement uncertainty, detection limits, completeness of the inventory and physical state of the material can all affect the assessment. Radionuclides that are not detected are treated in accordance with the measurement method and the applicable criteria. A time predicted by decay calculation is a basis for planning; actual clearance requires an assessment that the inventory meets the relevant conditions.

1.4.4 Classification and Facility Acceptance

The waste class expresses management requirements. Judging whether a particular facility can accept the waste also involves the inventory limits set in the facility licence, package requirements, characteristics specific to the waste form and the waste acceptance criteria. Even when a package has been assigned a classification code, additional evidence may be needed for acceptance.

In the Republic of Korea, too, classification, clearance and facility acceptance follow the applicable laws and regulations and the conditions of the facility. The management system keeps the applicable criteria and the basis for decisions together with the classification record. IAEA classes and WIA codes represent one part of the assessment; regulatory decisions are made in accordance with the applicable requirements.

1.5 Waste Package Record Examples and Activity Consistency Checks

1.5.1 Content Mass from Container Weights

All conditions and values in the following example are hypothetical. Consider a drum containing 0.2 m³ of conditioned waste. In this example, the empty container has a mass of 20 kg and the loaded container a mass of 220 kg. The net mass of the contents is therefore 200 kg, or 200,000 g. All concentrations in the table refer to the same contents on the example reference date of 15 May 2026. The example illustrates data representation and arithmetic.

The concentrations total 2,484 Bq/g. This arithmetic example assumes that the four entries in the table make up the entire inventory reported on the reference date. Before this total is used as the total activity in an actual operational assessment, it must first be confirmed that the inventory has been fully identified, including the relevant decay products.

The following is part of a JSON record using field names defined in the package model of WIA-ENE-026 v1.0 §4.1. It shows how to represent package identification, container weights, the activity of each radionuclide and physical properties. Formal registration of the package and its acceptance at a facility require further information and decisions.

{
  "packageId": "RW-2026-KR-00000001",
  "timestamp": "2026-05-15T09:14:33Z",
  "containerInfo": {
    "weight": {
      "empty": 20,
      "loaded": 220,
      "unit": "kg"
    }
  },
  "radiologicalData": {
    "totalActivity": {
      "value": 496800000,
      "unit": "Bq",
      "referenceDate": "2026-05-15"
    },
    "isotopes": [
      {
        "isotope": "Cs-137",
        "activity": {
          "value": 236000000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "Co-60",
        "activity": {
          "value": 4800000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "Sr-90",
        "activity": {
          "value": 172000000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "H-3",
        "activity": {
          "value": 84000000,
          "unit": "Bq"
        }
      }
    ]
  },
  "physicalProperties": {
    "form": "solid",
    "matrix": "concrete",
    "volume": {
      "value": 0.2,
      "unit": "m3"
    }
  }
}

The table records concentrations, and the isotope array in the JSON records the corresponding activities in Bq. The reference date applies to the entire example inventory.

1.5.2 Content Mass from Volume and Density

The second hypothetical example shows how to obtain the content mass from volume and density. Assume homogeneous solid waste in a concrete matrix with a content volume of 0.2 m³ and a density of 1,500 kg/m³. The content mass is 0.2 × 1,500 = 300 kg, or 300,000 g. The same content mass is applied to all concentrations, and the reference date is 25 December 2025. The calculation includes the following four radionuclides.

The activity of each radionuclide is its concentration multiplied by the content mass. The concentrations listed in the table total 2,484 Bq/g, and the corresponding activities total 7.452 × 10⁸ Bq. The following is part of a JSON record expressing these measurement inputs with the fields of WIA-ENE-026 v1.0 §4.1.

{
  "packageId": "RW-2025-KR-00000001",
  "timestamp": "2025-12-25T10:30:00Z",
  "radiologicalData": {
    "totalActivity": {
      "value": 745200000,
      "unit": "Bq",
      "referenceDate": "2025-12-25"
    },
    "isotopes": [
      {
        "isotope": "Cs-137",
        "activity": {
          "value": 354000000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "Co-60",
        "activity": {
          "value": 7200000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "Sr-90",
        "activity": {
          "value": 258000000,
          "unit": "Bq"
        }
      },
      {
        "isotope": "H-3",
        "activity": {
          "value": 126000000,
          "unit": "Bq"
        }
      }
    ]
  },
  "physicalProperties": {
    "form": "solid",
    "matrix": "concrete",
    "volume": {
      "value": 0.2,
      "unit": "m3"
    },
    "density": {
      "value": 1500,
      "unit": "kg/m3"
    }
  }
}

solid and concrete are the values that identify the physical form and the matrix respectively. The unit strings m3 and kg/m3 use the notation defined in the standard as they are. Each example uses a complete hypothetical packageId. The identifier rules for actual operation are set in the agreed data exchange conventions.

1.5.3 Interpreting the Examples

The two record examples focus on representing measurement inputs; classification is assessed separately. Whether wasteClass is mandatory or optional is a matter for the agreed package data conventions. The total activity concentration falls within the LLW-2 concentration band, but the half-life of Cs-137 exceeds the 30-year upper half-life bound of the LLW-2 entry whichever document’s value is used (Standard Reading Notes, item 1, in Section 1.3). The classification assessment must therefore state how the criteria are applied to the mixed inventory and which classification terminology has been selected.

The completeness of the inventory, thermal output, dose rate and the criteria of the relevant jurisdiction also affect the assessment. The two examples show how units and arithmetic are applied consistently. Even at the same concentration, the total activity changes if a different waste mass is applied. Clearance and acceptance at a disposal facility each require evidence supporting the decision concerned.

1.6 Classification History and Chain of Custody

A classification record should state both the decision and the inventory on which it was based. Later measurements, conditioning operations and data corrections can change the basis of the assessment. If the assessment history is kept in sequence, reviewers can distinguish cases where understanding of the waste changed from cases where the contents physically changed.

WIA-ENE-026 v1.0 defines traceability.chainOfCustody for the chain of custody (hand-over and acceptance records), and each entry includes timestamp, event, location and responsible. These fields indicate what happened during hand-over and acceptance and who was responsible. The time of occurrence and the activity reference date serve different roles here: the former marks when an action took place in the management history, while the latter sets the time basis for the radiological quantities.

As an implementation example, assessment reports and classification history can be stored linked to the packageId. Useful evidence includes the classification codes before and after a change, the inventory reference date, analytical results, the classification scheme and its version, the criteria applied, the reasons for the decision and the results of review. Implementation agreements can set how these related records are stored and how they are linked to the package.

Authentication and security requirements, including audit log retention periods and digital signatures for IAEA reporting, are explained together in Section 4.8.1. In the classification history, it must be possible to confirm from these authentication records who recorded and who approved each decision. Signature verification uses established procedures and trusted key information. The package identifier links the inventory to the related evidence, and the authentication and approval records provide the basis for confirming who performed or authorized an action.

Data representation, technical classification review and regulatory decisions each verify different things. Consistent JSON and units show that the physical quantities in a record are expressed without contradiction. The processing.qualityControl.qcPassed field records the result of processing quality control. Classification, facility acceptance and clearance are decided according to their own assessment criteria and evidence.

1.7 Information System Design and Data Exchange

A radioactive waste management information system can organize the inventory, location, measurements and chain of custody records for each package around the identifiers defined in WIA-ENE-026 v1.0. The following is an example of a system design that uses these records.

A package record represents a unit of waste under management. Facility and storage references identify where that unit originated or is held. Monitoring records hold observations, and chain of custody entries represent movements and responsibility. Keeping the role of each record distinct preserves the clear meaning of sensor measurements, package identification, location changes and disposal facility acceptance decisions.

WIA-ENE-026 v1.0 defines interfaces that support these records. The interfaces follow the REST style, in which records are retrieved, registered and updated using web address paths and HTTP methods (GET, POST, PUT); each path that receives requests is called an endpoint. This chapter covers only the interfaces directly related to package records; the complete list is collected in Section 2.8. OAuth 2.0, the authorization delegation protocol, and TLS (Transport Layer Security), the protocol for encrypting data in transit, are covered in Section 4.8.1, and webhooks, which automatically notify other systems when an event occurs, in Section 4.9.1.

Package registration returns 201 Created with the packageId. A package query returns 200 OK with the package object. A location update takes a StorageLocation object and returns 200 OK. The meaning of each response is interpreted according to the purpose of the operation.

In an example data exchange procedure, characterization results are first organized by package, the classification basis is documented and the interpretation of codes is agreed. After the completed registration object is submitted, it is retrieved again using the returned identifier, and the stored classification, per-radionuclide activities, units and reference date are compared with the record that was meant to be registered. When a package moves, the chain of custody history, which is managed separately from the current location, is reviewed as well.

In this procedure, monitoring results can prompt a review of classification or storage conditions. When an alarm occurs, the measurement conditions and package characteristics are assessed, and any resulting classification decision is recorded separately. This keeps observed facts distinct from the conclusions drawn from them.

The wasteClass filter of GET /packages uses top-level values, while package records use numbered codes (code layer table in Section 1.3). Agreements on system integration set the relationship between filters and detailed codes, including prefix matching, expansion to subcategories and the handling of SRW queries. The meaning and behaviour of these filters are matters to be made explicit in the data exchange conventions.

Integration with external systems requires the correspondence between identifiers, classification codes, units and reference times to be stated explicitly. As an example of an exchange test, the same package can be retrieved from two systems and the per-radionuclide activities and the meaning of the classification compared. This comparison confirms how the data exchange under test behaves. Institutional approval and reporting arrangements require separate agreements.

Reporting also needs a basis for calculating the inventory. The current inventory and the cumulative amount generated over a period are different indicators. Repeated chain of custody entries for the same package represent that package’s management history and are counted separately from newly generated waste. When material is split, combined or repackaged, the relationship between the new records and the original inventory is preserved in accordance with the system’s data lineage rules.

1.8 Applying Classification by Waste Source

1.8.1 Operation and Decommissioning of Nuclear Facilities

Operational waste and activated components can have different radionuclide mixes even when they arise at the same facility. Establishing the full inventory requires characterization evidence that identifies the relevant radionuclides, in addition to external gamma measurements. This evidence is especially important where long-lived radionuclides affect disposal requirements. Classification records should therefore preserve, together with the waste origin or component name, the characterization evidence that supports the class determination.

In decommissioning, too, it is important to be clear about the mass basis and the material being assessed. Concrete, metal and other materials may be assessed separately, and later conditioning changes the mass or volume attributable to a package. Converting a concentration based on one material to a basis of another requires the calculation to be documented.

1.8.2 Medical Waste

Decay storage records distinguish batches and the activity reference date of each batch. Adding newly generated material to an existing batch changes the inventory, and a clearance prediction based on the original contents may no longer be valid. Longer-lived sources and contaminant radionuclides also continue to be managed separately from waste suitable for short-term decay storage.

1.8.3 Research Waste and Mixed Waste

Research waste may contain several radionuclides together with hazardous chemicals. WIA-ENE-026 v1.0 classifies mixed waste as SRW-2. Recording radiological and chemical characteristics separately allows each hazard to be reflected in management decisions. External dose rate represents one aspect of the waste; assessments of clearance and treatment routes also consider the relevant inventory and material properties.

1.8.4 Industrial Sealed Sources

Even for the same radionuclide activity, the external dose rate measured can vary greatly depending on the shielding and housing of the source. Source identification, radionuclide inventory, activity reference date and containment condition are therefore recorded as important management information. WIA-ENE-026 v1.0 includes sealed sources in SRW-3. Classifying a source within the six broad IAEA classes requires an assessment of its inventory and management requirements.

1.9 Introducing a Classification Record System

Introducing a classification record system begins by identifying the classification scheme and version applied to each existing record. The numbered categories, based on activity concentration and other characteristics, use different classification criteria from the PHASE-1 categories, which are based on dose rate. Even when both codes contain “LLW”, each is interpreted according to the criteria of the scheme to which it belongs. Code mappings awaiting interpretation by an authorized party are managed so that their status remains visible throughout the review process.

The next step is to check the consistency of physical quantities. Existing concentration results need a mass basis, per-isotope activities need comparable reference dates, and assessments of heat generation per unit volume need a clearly defined volume. Trial conversions make these relationships explicit, as in Section 1.5, and confirm that the meaning of physical quantities is preserved between systems.

During introduction, rules are also set for interpreting the thresholds and overlapping conditions of the PHASE-1 tree. The following are boundary cases to check when implementing the screening sequence in Section 1.2.

Applying the PHASE-1 thresholds requires separate interpretation for some classification outcomes. Heat generation of exactly 2 kW/m³ is excluded both by the tree’s “greater than 2 kW/m³” condition and by the “less than 2 kW/m³” condition in the ILW description. The ILW subtype branch covers half-lives of less than and greater than 30 years, so a half-life of exactly 30 years needs interpretation to determine the subtype. In the LLW subtype branch, assigning a type at exactly 0.5 mSv/h likewise needs separate interpretation. The range given in the LLW-B description is 0.5–2 mSv/h, whereas the tree uses the condition “greater than 0.5 mSv/h” with no upper bound. When interpreting these differences, the stated comparison operators must be kept unchanged.

The ILW-LL category description in PHASE-1 §2.2 covers waste with a half-life greater than 30 years or containing alpha-emitting radionuclides. The tree’s ILW subtype branch uses half-life alone. Because alpha emission and a long half-life are different characteristics, the assessment record should state how each of the two conditions was applied.

The TRU threshold and the threshold for the numbered ILW-3 entry have different scopes. Converted, 100 nCi/g equals 3,700 Bq/g. WIA-ENE-026 v1.0 §2.1.2 gives the alpha activity concentration criterion for ILW-3 as greater than 400 Bq/g. Each threshold is applied according to the range of radionuclides and the classification purpose defined for its classification. The activity concentration band for LLW-3 is 10,000–100,000 Bq/g and is given together with descriptions of half-life and management characteristics. The concentration value is therefore interpreted together with the other criteria of that category.

Data review addresses the classification ambiguities described in Section 1.2 and in the boundary cases above. The main items for review are the boundaries of stated thresholds, mixtures of short-lived and long-lived radionuclides, inventories that satisfy two or more branch conditions, and differences between the sum of per-isotope activities and the reported total activity. Classification assessments that need further judgement can be held in an under-review status in the workflow, while the exchanged WIA values keep their defined meanings.

Before records are exchanged, the participating systems agree on the selected terminology, schema requirements, supported filters and the handling of related evidence. Test records can then be compared with existing inventory and reporting records. Software verification confirms the consistency of the data, whereas regulatory classification, clearance and facility acceptance each require their own basis for decision.

1.10 Standards and Reference Frameworks

The following standards and guides address classification, waste management, disposal safety and radiation protection. Each serves its own purpose and supports assessment in a different way. Classification thresholds and compliance requirements are set by the applicable technical standards, laws and regulations.

• WIA-ENE-026: Radioactive Waste Management Standard, Version 1.0. Defines the numbered waste categories, package and facility models, monitoring information and management interfaces.
• WIA-ENE-026 PHASE-1: Foundation & Classification, Version 1.0.0. Establishes the foundational concepts, the extended classification terminology and the screening tree described in Section 1.2.
• IAEA Safety Standards Series No. GSG-1, Classification of Radioactive Waste, 2009. The reference framework for the six broad waste classes.
• IAEA Safety Standards Series No. RS-G-1.7, Application of the Concepts of Exclusion, Exemption and Clearance, 2004. The guide that GSG-1 cites as the basis for exemption and clearance concentration values.
• IAEA Safety Standards Series No. GSR Part 5, Predisposal Management of Radioactive Waste, 2009. Addresses safety requirements for the management of waste before disposal.
• IAEA Safety Standards Series No. SSR-5, Disposal of Radioactive Waste, 2011. Addresses safety requirements for disposal.
• IAEA Safety Standards Series No. SSG-23, The Safety Case and Safety Assessment for the Disposal of Radioactive Waste, 2012. Addresses safety assessment and the safety case, which demonstrates safety with supporting evidence on the basis of the waste inventory and disposal design.
• ICRP Publication 122, Radiological Protection in Geological Disposal of Long-lived Solid Radioactive Waste, 2013. Radiological protection guidance from the International Commission on Radiological Protection for the geological disposal of long-lived solid radioactive waste.

Chapter Summary

• IAEA GSG-1 describes six broad waste classes according to management and disposal requirements. WIA-ENE-026 v1.0 records package identification in packageId and waste classification in wasteClass.
• The numbered WIA categories and the PHASE-1 extended names use different criteria. Records and data exchange agreements state the classification terminology and the basis for any code mapping.
• Classification codes fall into four layers: the standard’s §2 classification table, the §4.1 example, the §10.1.1 list filter and the PHASE-1 extended classification. The record examples in this book use the §2 codes, and items whose values differ within the standard are collected in the Standard Reading Notes in Section 1.3.
• The PHASE-1 tree uses a TRU threshold of greater than 100 nCi/g and a heat generation condition of strictly greater than 2 kW/m³. Qualitative conditions, overlapping criteria and values exactly equal to a threshold need explicit interpretation.
• The limit on long-lived radionuclide content distinguishes LLW from ILW. HLW heat removal can use active or passive systems depending on the waste characteristics and storage design; natural convection is a passive approach.
• After ten half-lives, 1/1,024 of the initial parent activity remains. For I-131, with a half-life of 8.02 days, this period is 80.2 days; whether clearance is possible depends on the remaining inventory and the applicable criteria.
• The example concentrations total 2,484 Bq/g. This corresponds to 496,800,000 Bq for 200 kg of contents and 745,200,000 Bq for 300 kg. Each result depends on its stated waste-mass basis.
• Reproducible decay calculations require the underlying nuclear data to be identified. For half-lives that differ between documents, such as that of Cs-137, record the adopted value and its source as described in item 1 of the Standard Reading Notes. The standard gives the half-life of C-14 as 5,730 years.
• Package registration, monitoring, processing quality control, chain of custody history, classification and facility acceptance each have their own meaning. Related evidence links decisions to the package.

References

WIA Standards — WIA-ENE-026 — Chapter 1. Hongik Ingan (弘益人間) — Benefit All Humanity.