System

Radiochemistry Laboratory for a UK Nuclear Dockyard v2, continuing decomposition of analytical measurement subsystems. Prior sessions completed 7 of 13 subsystems (ventilation, radiation protection, effluent treatment, safety, waste management, sample receipt, and separations). This session tackled the two highest-priority analytical suites: {{entity:Gamma Spectrometry Suite}} and {{entity:Alpha Spectrometry Laboratory}}, both core to the laboratory’s primary mission of characterising radioactive materials from submarine refit and decommissioning operations.

Decomposition

The {{entity:Gamma Spectrometry Suite}} was decomposed into 5 components following the signal chain from photon detection to certified result: {{entity:HPGe Detector Array}} ({{hex:D6E51018}}), {{entity:Lead Shielding and Counting Chambers}} ({{hex:CE851018}}), {{entity:Detector Cryogenic Cooling System}} ({{hex:D5D71018}}), {{entity:Digital MCA and Signal Processing System}} ({{hex:54F77218}}), and {{entity:Gamma Spectroscopy Analysis and QA Workstation}} ({{hex:50A53058}}). The architecture decision {{stk:ARC-REQ-012}} records the rationale for electric cryocoolers over LN2 dewars — nuclear safety (eliminating cryogen handling near active samples) and operational availability (unattended 24/7 operation during refit campaigns) outweigh the slightly higher microphonic noise floor.

The {{entity:Alpha Spectrometry Laboratory}} was decomposed into 4 components: {{entity:Alpha Detector Chamber Array}} ({{hex:D6C51018}}), {{entity:Electrodeposition and Source Preparation Station}} ({{hex:54D53219}}), {{entity:Alpha Spectrometry Vacuum System}} ({{hex:D4F71018}}), and {{entity:Alpha MCA and Spectral Processing Unit}} ({{hex:54F53018}}). Architecture decision {{stk:ARC-REQ-013}} documents the retention of dual source preparation methods (electrodeposition and NdF3 microprecipitation) to cover both routine and urgent analysis turnaround requirements.

flowchart TB
    subgraph GS[Gamma Spectrometry Suite]
        CC[Cryogenic Cooling] -->|85K cooling| HPGe[HPGe Detector Array]
        HPGe -->|Mounted in| LS[Lead Shielding Chambers]
        HPGe -->|Pulses| MCA[Digital MCA System]
        MCA -->|Spectra| QA[Analysis and QA Workstation]
    end
    subgraph AS[Alpha Spectrometry Laboratory]
        ED[Electrodeposition Station] -->|Disc sources| ADC[Alpha Detector Chambers]
        VS[Vacuum System] -->|Below 5 Pa| ADC
        ADC -->|Alpha pulses| AMCA[Alpha MCA Unit]
    end
    QA -->|Results| LIMS[LIMS]
    AMCA -->|Results| LIMS

Analysis

Cross-domain entity search for {{entity:Alpha Detector Chamber Array}} identified structural similarity with the {{entity:Optical Payload Subsystem}} from earth observation satellite decompositions — both are precision measurement instruments requiring cryogenic or thermally controlled environments, shielded enclosures, and high signal-to-noise ratio electronics. The {{trait:Powered}}, {{trait:Observable}}, and {{trait:Intentionally Designed}} traits dominate both measurement instrument clusters. A {{entity:Pulse-Tube Cryocooler}} from space applications shares the same engineering pattern as the gamma spec cryogenic system, reinforcing the architecture decision rationale.

Lint identified 5 pre-existing ontological mismatch findings (chemical treatment plant, criticality warning system, liquid waste conditioning system, active drain system, continuous air monitor network classified without Physical Object trait despite physical constraints in requirements). These are from prior sessions and will need QC attention. A likely duplicate exists between ARC-REQ-011 and {{stk:ARC-REQ-012}} (both addressing Gamma Spec cryocooler selection) — flagged for QC cleanup.

Requirements

Created 12 subsystem requirements ({{sub:SUB-REQ-065}} through {{sub:SUB-REQ-076}}), 5 interface requirements ({{ifc:IFC-REQ-036}} through {{ifc:IFC-REQ-040}}), 7 verification entries (VER-REQ-040 through VER-REQ-046), and 2 architecture decisions ({{stk:ARC-REQ-012}}, {{stk:ARC-REQ-013}}). Key requirements include: HPGe energy resolution of 2.0 keV FWHM at 1332 keV ({{sub:SUB-REQ-065}}), shielding background below 1 cps ({{sub:SUB-REQ-067}}), alpha detector resolution of 25 keV FWHM ({{sub:SUB-REQ-072}}), and electrodeposition source thickness below 50 micrograms per cm2 ({{sub:SUB-REQ-073}}). All subsystem requirements trace to {{sys:SYS-REQ-001}} (gamma MDA) or {{sys:SYS-REQ-004}} (alpha detection limits). System-level end-to-end verification tests (VER-REQ-043, VER-REQ-046) exercise the full measurement chains. Project totals: 190 requirements, 62 PART_OF facts, 9 of 13 subsystems decomposed.

Next

Four subsystems remain: {{entity:Liquid Scintillation Counting Facility}}, {{entity:ICP-MS and Elemental Analysis Suite}}, {{entity:Laboratory Information Management System}}, and {{entity:Laboratory Utilities and Building Services}}. Next session should prioritise LSC and ICP-MS to complete the analytical suite decomposition. LIMS will require careful interface definition as it connects to all analytical subsystems. ARC-REQ-011 duplicate needs QC cleanup. First-pass completion likely achievable within 2 more sessions.