Risk Integration Technical Element Module

Overview

The Risk Integration (RI) technical element aggregates PRA outputs into plant‑level risk metrics and insights. It consumes sequence/family frequencies and importance from Event Sequence Quantification (ESQ) and consequence metrics from Radiological Consequence Analysis (RC), applies risk significance criteria, performs screening/aggregation, and produces integrated risk metrics with uncertainty and feedback. It aligns with RG 1.247 expectations (HLR‑RI‑A…D) for establishing criteria, calculating overall risk, identifying significant contributors, and documenting/feedback.

Purpose

• Define and apply risk significance criteria to PRA elements (sequences, families, basics, systems, HFEs)
• Compute integrated risk metrics (e.g., CDF, LERF, application‑specific metrics) with uncertainty
• Identify significant contributors and screening dispositions with clear basis
• Provide feedback to upstream elements (ESQ, RC, systems/HRA via proxies) for model improvements
• Document methods, assumptions, thresholds, and acceptance criteria mapping

Structure

┌──────────────────────────────────────────────────────────────────────────────┐
│                            Risk Integration                                   │
│                                                                              │
│  ┌──────────────────────────────┐  ┌──────────────────────────────────────┐  │
│  │ Criteria & Screening         │  │ Inputs (via Proxies)                 │  │
│  │ - RiskSignificanceCriteria   │  │ - ESQ: RiskSignificantEventSequence  │  │
│  │ - RiskSignificanceEvaluation │  │ - RC : RiskSignificantConsequence    │  │
│  │ - ScreeningStatus/Criteria   │  │ - Mappings (Seq→Release Category)    │  │
│  └──────────────────────────────┘  └──────────────────────────────────────┘  │
│                                                                              │
│  ┌──────────────────────────────┐  ┌──────────────────────────────────────┐  │
│  │ Integration & Metrics        │  │ Contributors & Insights              │  │
│  │ - IntegratedRiskResults      │  │ - RiskContributor (importance, RAW)  │  │
│  │ - RiskMetric (value, unc.)   │  │ - SignificantContributor analyses    │  │
│  └──────────────────────────────┘  └──────────────────────────────────────┘  │
│                                                                              │
│  ┌──────────────────────────────┐  ┌──────────────────────────────────────┐  │
│  │ Documentation & Feedback     │  │ Dependency Hygiene                   │  │
│  │ - Process/peer review hooks  │  │ - Use ESQ/RC re‑exports; refs only   │  │
│  │ - Feedback to ESQ/RC         │  │ - String refs for upstream entities  │  │
│  └──────────────────────────────┘  └──────────────────────────────────────┘  │
└──────────────────────────────────────────────────────────────────────────────┘

Key Features

• Risk significance criteria with absolute/relative thresholds and intended applications
• Evaluation records per element with basis and insights
• Integrated risk metrics with units and uncertainty; optional acceptance criteria mapping
• Clean inputs via ESQ and RC proxy types (no direct upstream dependencies)
• Significant contributor identification with FV/RAW/RRW/Birnbaum and screening status
• Feedback channels to ESQ/RC capturing insights and recommended changes

Core Components

• RiskSignificanceCriteria, RiskSignificanceEvaluation
• IntegratedRiskResults, RiskMetric
• RiskContributor and significant contributor references
• Proxied input types: RiskSignificantEventSequence (ESQ) and RiskSignificantConsequence (RC)
• Mapping references: EventSequenceReference, EventSequenceFamilyReference, ReleaseCategoryReference, SourceTermDefinitionReference

Integration with Other Technical Elements

Element	Interaction
Event Sequence Quantification	Provides sequence/family frequencies, importance, and risk‑significant lists via proxy types
Radiological Consequence	Provides consequence metrics and risk‑significant consequences via proxy types
Mechanistic Source Term	Referenced indirectly via RC (release categories, source term IDs)
Systems/HRA/Data	Reflected indirectly through ESQ inputs (cut sets, HFEs, parameters)

Best Practices

• Use ESQ/RC re‑exports only; avoid direct upstream imports to preserve hierarchy
• Keep criteria explicit (metric, thresholds, justification, intended applications)
• Report both absolute and relative bases where applicable; state minimum reporting level
• Maintain clear screening status with rationale and traceability
• Surface actionable feedback to ESQ/RC when screening or metrics indicate modeling opportunities

Regulatory Alignment (RG 1.247)

Expectation / Requirement	Schema Support
HLR‑RI‑A (Criteria definition/application)	RiskSignificanceCriteria, RiskSignificanceEvaluation
HLR‑RI‑B (Overall risk calculation)	IntegratedRiskResults, RiskMetric with units/uncertainty
HLR‑RI‑C (Identification of contributors)	RiskContributor, importance metrics, screening status
HLR‑RI‑D (Documentation/feedback)	Documentation hooks in main interface and feedback channels to ESQ/RC

Usage Workflow

1. Define RiskSignificanceCriteria for target metrics (CDF, LERF, application‑specific)
2. Ingest ESQ and RC proxy inputs (risk‑significant sequences/consequences, mappings)
3. Aggregate to integrated metrics; compute uncertainty and compare to acceptance criteria
4. Apply criteria and produce RiskSignificanceEvaluation records; set screening statuses
5. Identify RiskContributors and capture importance and insights
6. Provide feedback objects back to ESQ/RC; document process, assumptions, and peer review

Example

See inline examples in risk-integration.ts for criteria, evaluations, and integrated metrics. Use ESQ/RCA proxy types for inputs (e.g., RiskSignificantEventSequence).

Additional Resources

• Source: risk-integration.ts
• Regulatory documentation: Risk Integration Documentation
• Integration patterns: integration-readme.md

Glossary (Selected)

• Risk Metric: Quantified plant risk measure (e.g., CDF) with units/uncertainty
• Risk Significance: Determination of contributors exceeding criteria thresholds
• Screening: Dispositioning contributors (retain/group/truncate) with basis

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This README summarizes the Risk Integration technical element and its RG 1.247 alignment, providing consistent interfaces and integration points within the OpenPRA MEF.