System

{{entity:Radiochemistry Laboratory for a UK Nuclear Dockyard v2}} — new project se-radiochem-lab-v2 scaffolded as a re-decomposition of the completed v1 (se-radiochem-lab). The v1 had 12 subsystems and 278 requirements but was analytically focused — subsystems covered instruments (gamma spec, alpha spec, LSC, ICP-MS) and LIMS in depth but lacked explicit treatment of the facility safety envelope: ventilation containment, radiation protection monitoring, active effluent treatment, waste management, criticality safety, and building utilities. This v2 addresses those gaps while retaining the analytical capability decomposition.

Decomposition

The system was decomposed into 13 subsystems reflecting the real functional architecture of a UK nuclear dockyard radiochemistry laboratory. The decomposition is driven by independent functional boundaries, distinct regulatory regimes, and separate failure modes rather than symmetric templating:

• Analytical core (6 subsystems): {{entity:Sample Receipt, Registration and Preparation Facility}}, {{entity:Gamma Spectrometry Suite}}, {{entity:Alpha Spectrometry Laboratory}}, {{entity:Liquid Scintillation Counting Facility}}, {{entity:ICP-MS and Elemental Analysis Suite}}, {{entity:Radiochemical Separations Laboratory}}
• Safety and containment (3 subsystems): {{entity:Active Ventilation and Containment System}}, {{entity:Radiation Protection and Health Physics Monitoring System}}, {{entity:Facility Safety and Emergency Response System}}
• Environmental compliance (2 subsystems): {{entity:Active Effluent Treatment and Discharge System}}, {{entity:Radioactive Waste Management Facility}}
• Support (2 subsystems): {{entity:Laboratory Information Management System}}, {{entity:Laboratory Utilities and Building Services}}

System entity classified as {{hex:40853859}} — Synthetic, Intentionally Designed, System-Integrated, System-Essential, Rule-Governed, Compositional, Normative, Institutionally Defined, Regulated, Economically Significant, Ethically Significant. All 13 subsystems classified with rich context descriptions in namespace SE:radiochem-lab-v2.

flowchart TB
  RL["Radiochemistry Laboratory"]
  SRP["Sample Receipt and Preparation"]
  GS["Gamma Spectrometry Suite"]
  AS["Alpha Spectrometry Laboratory"]
  LSC["Liquid Scintillation Counting"]
  ICP["ICP-MS and Elemental Analysis"]
  RCS["Radiochemical Separations Lab"]
  AVC["Active Ventilation and Containment"]
  RPM["Radiation Protection Monitoring"]
  AET["Active Effluent Treatment"]
  LIMS["LIMS and Data Management"]
  RWM["Radioactive Waste Management"]
  FSE["Facility Safety and Emergency"]
  UBS["Utilities and Building Services"]
  RL --> SRP
  RL --> GS
  RL --> AS
  RL --> LSC
  RL --> ICP
  RL --> RCS
  RL --> AVC
  RL --> RPM
  RL --> AET
  RL --> LIMS
  RL --> RWM
  RL --> FSE
  RL --> UBS

Analysis

The context diagram captures six external interfaces: {{entity:Dockyard Health Physics}} (dose records), ONR (licence compliance), EA/SEPA (discharge permits), Reactor Operations (sample supply), Waste Management Organisation (waste consignment), and Nuclear Material Accountancy (assay data). These drive the stakeholder requirements and represent genuine contractual/regulatory boundaries rather than convenience groupings.

Requirements

Five stakeholder requirements capture the distinct stakeholder perspectives: reactor operations turnaround ({{stk:STK-REQ-001}}), ONR licence compliance ({{stk:STK-REQ-002}}), EA/SEPA discharge limits ({{stk:STK-REQ-003}}), ALARP dose management ({{stk:STK-REQ-004}}), and nuclear material accountancy ({{stk:STK-REQ-005}}). Ten system requirements derive from these with quantified performance thresholds: gamma spec MDA at 0.5 Bq/L Cs-137 in 1 hour ({{sys:SYS-REQ-001}}), depression cascade at 15 Pa per zone ({{sys:SYS-REQ-002}}), batch effluent monitoring with 0.1 Bq/L alpha detection ({{sys:SYS-REQ-003}}), alpha spec 0.5 mBq Pu detection at 25 keV resolution ({{sys:SYS-REQ-004}}), LIMS audit trail ({{sys:SYS-REQ-005}}), CAM alarm within 60 seconds ({{sys:SYS-REQ-006}}), ICP-MS Tc-99 at 0.05 Bq/L ({{sys:SYS-REQ-007}}), twin-bank HEPA at DF 1000 per bank ({{sys:SYS-REQ-008}}), criticality safety with two independent barriers ({{sys:SYS-REQ-009}}), and LSC tritium at 1 Bq/L in 120 minutes ({{sys:SYS-REQ-010}}). All 10 trace links include rationale explaining the derivation mechanism.

Next

The scaffold is complete with 15 requirements (5 STK, 10 SYS) and 10 trace links across 13 classified subsystems. Next session should begin first-pass subsystem requirements, starting with the safety-critical subsystems: Active Ventilation and Containment (highest consequence — loss of depression cascade), Radiation Protection Monitoring (highest exposure pathway — airborne alpha), and Facility Safety (criticality controls). Interface requirements between the analytical subsystems and LIMS should follow. The v2 target is improved rationale depth and verification coverage compared to the v1’s 278 requirements.