Chapter 1: IAEA GSG-1 Classification

1.1 IAEA GSG-1 Six-Class System in Depth

The IAEA Safety Standards Series General Safety Guide No. 1 (GSG-1, published 2009) classifies radioactive waste into six classes from a disposal-decision perspective. This section reconciles each class with IAEA GSG-1 Tables 2 and 3 by listing the defining variables (activity concentration, half-life, heat generation, fissile content, and physical-chemical form) and the canonical disposal pathway. The five-variable decision space determines both the depth of geological isolation and the duration of institutional control required at disposal time. The WIA-ENE-026 envelope's class field carries exactly this six-value enumeration: EW, VSLW, VLLW, LLW, ILW, HLW.

1.1.1 Exempt Waste (EW)

Waste with activity concentration below the IAEA RS-G-1.7 exemption levels, which can be released into conventional industrial waste streams. The exemption levels are nuclide-specific, with representative values of 0.1 Bq/g for Co-60, 0.1 Bq/g for Cs-137, and 0.01 Bq/g for Pu-239. Korea codifies its national exemption levels in Annex 1 of the Enforcement Decree of the Nuclear Safety Act, with the Nuclear Safety and Security Commission (NSSC) operating the clearance procedure under Notice 2017-31. The EW envelope carries the activity_concentration field as an array of nuclide-specific Bq/g values and the exempt_reference field pointing to the applicable exemption document (either RS-G-1.7 or NSSC 2017-31).

1.1.2 Very Short-Lived Waste (VSLW)

Waste dominated by nuclides with half-lives below 100 days, typically managed through decay storage of several years until the activity drops below the EW exemption level. Medical isotope waste streams from Tc-99m (T½ 6 h), F-18 (110 min), I-131 (8 d), and I-123 (13 h) are the dominant sources. The Korean Ministry of Food and Drug Safety (MFDS) and the NSSC jointly publish the medical-facility waste management guideline, permitting I-131 to be released as clearance waste after 80 days of decay storage (roughly 10 half-lives). The WIA envelope's decay_storage_days field is computed from the IAEA-recommended 10 × T½ rule.

1.1.3 Very Low Level Waste (VLLW)

Waste with very low long-lived activity concentrations that can be isolated using simple near-surface trench disposal. Decommissioning concrete rubble, contaminated soil, and metal scrap form the bulk of VLLW. France's ANDRA CIRES facility at Morvilliers is the IAEA's canonical reference VLLW disposal site. Korea accepts VLLW at the Gyeongju Low- and Intermediate-Level Radioactive Waste Disposal Facility (operated by KORAD - the Korea Radioactive Waste Agency), specifically in the near-surface disposal section. The institutional control period is assumed to be 300 years.

1.1.4 Low Level Waste (LLW)

Waste with activity concentration above the exemption levels but with negligible heat generation (typically less than 2 kW/m³), permitting near-surface disposal or shallow cavern disposal. The Gyeongju cavern disposal facility in Korea (KORAD-1, Phase 1) is constructed at 80 m below ground in granite host rock, comprising six silos with a combined inventory capacity of 100,000 drums. Operation began in 2014. The LLW envelope adds the specific_activity_alpha_long_lived field to separately track alpha-emitting long-lived nuclides such as Pu-239 and Am-241, which are bounded by stricter near-surface concentration limits.

1.1.5 Intermediate Level Waste (ILW)

Waste with long-lived nuclide concentrations too high for near-surface disposal but with sufficiently low heat generation that active cooling is not required. Reactor internals such as core shrouds and control-rod guide tubes, steam generator tubes, and cut sections of reactor pressure vessel surfaces are typical ILW. ILW typically requires disposal at depths of several hundred meters or in intermediate-depth disposal facilities. Korea plans to receive ILW in dedicated silos as part of the Phase 2 cavern expansion at Gyeongju, with the Korea Atomic Energy Research Institute (KAERI) leading R&D on long-term behavior of cemented ILW waste forms under the 2024-2028 KAERI-MOTIE programme.

1.1.6 High Level Waste (HLW)

Waste with very high fission-product concentrations and heat generation at or above 2 kW/m³, requiring active cooling and substantial shielding. Once-through-cycle spent nuclear fuel and vitrified raffinate from reprocessing both fall into HLW. Korea enacted the Special Act on the Management of High-Level Radioactive Waste in January 2024 to launch the formal siting procedure, operating under the High-Level Radioactive Waste Management Basic Plan (2021-2060) administered by the Ministry of Trade, Industry and Energy (MOTIE). The baseline 37-year roadmap allocates 13 years for siting + 7 years for site characterization + 7 years for interim storage construction + 10 years for permanent disposal facility construction.

1.2 Classification Decision Algorithm and Envelope Binding

The WIA-ENE-026 Phase 1 envelope's standard classify() function follows a five-step decision tree.

1. Exemption check: If for every nuclide i the activity concentration a_i is below the RS-G-1.7 exemption level e_i, classify as EW and terminate.
2. Half-life check: If every detected nuclide has T½ less than 100 days, classify as VSLW (eligible for reclassification to EW after decay storage).
3. Long-lived alpha check: If the aggregate alpha-emitting long-lived (T½ > 30 y) nuclide concentration is at most 400 Bq/g and beta/gamma concentrations are also low, classify as VLLW.
4. Heat-generation check: If volumetric heat generation P is less than 2 kW/m³, classify as LLW or ILW, branching on the long-lived alpha threshold.
5. HLW assignment: If P is at least 2 kW/m³ or aggregate fission-product concentration is at least 10⁴ Bq/g, classify as HLW.

This decision tree can be demonstrated against measured data in the reference simulator panel 0. The simulator accepts a nuclide-concentration array, a half-life table, and a heat-generation input, then returns the six-value enum. The Radioactive Waste Management Information System (RWMIS) operated by the Korea Institute of Nuclear Safety (KINS) implements the same decision tree as a validated database, aggregating waste arisings across all Korean nuclear facilities by nuclide and class.

1.3 Korean Classification Mapping

Korea does not adopt the IAEA six-class system verbatim. Instead, the NSSC operates a five-class system under Notice 2021-19 (Regulation on the Classification and Clearance of Radioactive Waste): clearance waste / very-low-level / low-level / intermediate-level / high-level. The IAEA EW and VSLW classes collapse into the Korean clearance class, while VLLW is retained as a separate class. This section provides the reconciliation table between IAEA and Korean classes.

• IAEA EW ↔ Korean clearance waste (NSSC Notice 2017-31)
• IAEA VSLW ↔ Korean clearance waste after decay storage (NSSC Notice 2021-19, Annex 3)
• IAEA VLLW ↔ Korean very-low-level (NSSC Notice 2021-19, Annex 1, ≤ 100 Bq/g)
• IAEA LLW ↔ Korean low-level (Annex 1, ≤ 4 × 10⁵ Bq/g beta/gamma)
• IAEA ILW ↔ Korean intermediate-level (Annex 1, alpha long-lived ≤ 4 × 10⁶ Bq/g)
• IAEA HLW ↔ Korean high-level (Annex 1, heat generation ≥ 2 kW/m³ or spent nuclear fuel)

The WIA envelope's jurisdiction_class_korea field carries the Korean five-value enum separately so that the arisings statistics reported to KINS and KORAD remain consistent with the IAEA Joint Convention national report.

1.4 Korea Radioactive Waste Infrastructure Mapping

This section maps the IAEA GSG-1 classification to the Korean radioactive waste management infrastructure across eight categories of institutions, laws, and facilities.

• Regulator: Nuclear Safety and Security Commission (NSSC) - a deliberative administrative commission under the Office of the Prime Minister, issuing classification notices and granting final licenses. Korea Institute of Nuclear Safety (KINS) - the technical support organization for NSSC, performing classification conformance review and operating the RWMIS database.
• Disposal operator: Korea Radioactive Waste Agency (KORAD) - operates the Gyeongju low- and intermediate-level disposal facility (KORAD-1) and serves as the secretariat for the high-level waste siting process; an affiliated public institution under MOTIE.
• Generators (nuclear facility operators): Korea Hydro & Nuclear Power (KHNP) - operates Korea's 24 operating reactors at Kori, Saeul, Wolsong, New Wolsong, Hanul, New Hanul, and Hanbit. Korea Institute of Radiological and Medical Sciences (KIRAMS), National Cancer Center, and MFDS-licensed radiology facilities are the dominant non-power generators.
• R&D and technical support: Korea Atomic Energy Research Institute (KAERI, Daejeon) - R&D on ILW cementation, HLW site characterization, and isotope production. Korea Institute of Nuclear Non-proliferation and Control (KINAC) - nuclear material accountancy.
• Statutes: Nuclear Safety Act (regulatory framework), Radioactive Waste Management Act (KORAD enabling statute and generator-fee structure), Atomic Energy Promotion Act (MOTIE promotion function), Special Act on the Management of High-Level Radioactive Waste (enacted January 2024 - legal basis for the siting process and interim storage construction).
• Disposal facilities: Gyeongju low- and intermediate-level disposal facility (KORAD-1, Yangbuk-myeon, Gyeongju, North Gyeongsang Province, in operation since 2014) - six cavern-disposal silos with capacity for 100,000 drums plus a near-surface disposal Phase 2 with 125,000-drum capacity planned. Korea has not yet selected a high-level disposal site; the 37-year roadmap is now active following the 2024 Special Act.
• Adjacent R&D facilities: KAERI Advanced Radiation Research Institute in Jeongup (neutron activation analysis), Korea Nuclear Fuel (KNF, Daejeon) - fuel fabrication waste generator.
• International cooperation: Korea is a party to the IAEA Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management, submitting a National Report every three years. The most recent submission was at the 8th Review Meeting in 2023.

1.5 Envelope Example: KORAD-1 Near-Surface LLW Drum

The following operational example presents the WIA-ENE-026 Phase 1 envelope for a 200 L LLW steel drum accepted at the Gyeongju near-surface disposal facility. This envelope reconciles the standard surface that KORAD reports quarterly to NSSC for waste acceptance records.

{
  "version": "1.0",
  "host_id": "korad.kr.korad1.silo04",
  "tenant_id": "khnp.kori-unit-3",
  "envelope_class": "WIA-ENE-026.LLW",
  "envelope_id": "ulid:01HK7VNZQE9X8K2Y5T...",
  "package_serial": "KORAD-LLW-200L-2026-014773",
  "classification": {
    "iaea_class": "LLW",
    "jurisdiction_class_korea": "low-level",
    "rationale": "activity 1.2e3 Bq/g (Cs-137 dominant), heat 0.04 W/m^3",
    "regulator_decision_ref": "KINS-RWMIS-2026-Q1-08442"
  },
  "activity_concentration_bqg": {
    "Cs-137": 1.18e3, "Co-60": 2.4e1, "Sr-90": 8.6e2, "H-3": 4.2e2
  },
  "physical_form": "homogeneous cement matrix",
  "container": "carbon steel drum 200L, painted, lid bolted",
  "audit": {
    "timestamp": "2026-05-15T09:14:33Z",
    "traceparent": "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01"
  }
}

This envelope makes the KINS RWMIS nuclide-by-nuclide inventory record, the KORAD disposal conformance review, and the NSSC licensing audit traceable end-to-end through the same identifier (envelope_id and package_serial).

1.6 Audit Posture and Cross-Standard Composition

Beyond the radioactive-waste-specific fields, every Phase 1 envelope inherits the WIA Standards family's cross-cutting audit posture. The audit.timestamp field follows RFC 3339 / ISO 8601 with UTC offset zero. The audit.traceparent field follows the W3C Trace Context specification version 1.0, with a 16-byte trace identifier and an 8-byte span identifier in hexadecimal. The audit.tracestate optional field carries vendor-specific context such as the KORAD internal tracking number, in compliance with RFC 9560 (Tracestate Encoding).

The Phase 2 REST surface exposes the same trace identifier in the X-WIA-Trace-Id response header, allowing operators to correlate an envelope record from the database back to the originating HTTP request log without bespoke parsing. Phase 3 federation envelopes carry the trace identifier in the federation.trace_chain field as an ordered list of (host_id, trace_id, span_id) tuples, so that a record federated through three or four institutional boundaries (for example, from KHNP Kori Unit 3 - KINS RWMIS - KORAD-1 disposal records - IAEA Joint Convention reporting line) preserves a complete provenance chain.

The cross-standard identity binding through WIA-OMNI-API carries the host certificate and the tenant token. The runtime trust list under WIA-AIR-SHIELD anchors the per-host certificate chain to the WIA root, so that a KORAD audit record can be cryptographically verified by an IAEA reviewer without bilateral key exchange. The workload-intent declaration under WIA-INTENT lets the host declare the data-flow purpose - "submit-classification", "amend-classification", "withdraw-classification" - so that NSSC inspectors can derive intent from the envelope payload itself rather than from out-of-band documentation.