Decision Maker (ODM)
Role and Responsibilities
The Decision Maker (ODM) represents the Shift Supervisor / Senior Reactor Operator (SRO) within the nuclear plant control room simulation. The Decision Maker is responsible for:
- Directing all written procedure execution (e.g., Emergency Operating Procedures)
- Selecting high-level crew goals
- Initiating transitions between written procedures (e.g., between EOPs, or entry into functional recovery guidelines)
- Activating knowledge-based reasoning (KBR) problem-solving when the crew goal is set to "troubleshooting"
Key Distinction from the Action Taker
The Decision Maker does not directly manipulate control panel controls. All plant interactions are executed by the Action Taker (OAT). The Decision Maker directs the Action Taker to execute control manipulations and provide indicator readings. Because of this constraint, the Decision Maker cannot independently perform activities that require direct panel contact.
The Decision Maker's selection of high-level crew goals influences the overall problem-solving strategy. Only the Decision Maker can initiate procedure transitions and only the Decision Maker can activate knowledge-based reasoning (KBR) actions via KB_ODM_Diagnosis_Actions.txt. The Action Taker does not have this capability.
Input Files
The Decision Maker knowledge base consists of ten input files located in the Input/Crew/DecisionMaker/ project directory, plus the RM/ subdirectory (see below).
| ODM File | Equivalent OAT File | Notes |
|---|---|---|
DecisionMaker.txt | ActionTaker.txt | Identical format and content structure |
KB_ODM_Bias_Factors.txt | KB_OAT_Bias_Factors.txt | Identical format; replace OAT with ODM |
KB_ODM_Event_Matrix.txt | KB_OAT_Event_Matrix.txt | Identical format; replace OAT with ODM |
KB_ODM_HardWired_Diagnosis.txt | KB_OAT_HardWired_Diagnosis.txt | Identical format; replace OAT with ODM |
KB_ODM_Maneuver_Actions.txt | KB_OAT_Maneuver_Actions.txt | Deprecated legacy stub (set count to 0) |
KB_ODM_Safety_Parameters.txt | KB_OAT_Safety_Parameters.txt | Identical format; replace OAT with ODM |
KB_ODM_Scanned_Parameters.txt | KB_OAT_Scanned_Parameters.txt | Identical format; replace OAT with ODM |
KB_ODM_System_Decomposition.txt | KB_OAT_System_Decomposition.txt | Identical format; replace OAT with ODM |
KB_ODM_Time_Constrained_Input.txt | KB_OAT_Time_Constrained_Input.txt | Identical format; replace OAT with ODM |
KB_ODM_Diagnosis_Actions.txt | (no OAT equivalent) | Unique to the ODM. Fully documented in this section. |
File Naming Convention
With the exception of DecisionMaker.txt and KB_ODM_Diagnosis_Actions.txt, all ODM files have an identical format to their OAT counterparts. The only change required when adapting OAT files for the ODM is replacing the OAT acronym in the filename with ODM. Refer to the Action Taker input file descriptions for full format details on the shared files.
ReasonMachine Inputs (RM/ subdirectory)
Input/Crew/DecisionMaker/RM/ holds the knowledge inputs for the ReasonMachine — the Decision Maker's experimental reasoning module (concept base, semantic base, mental representations, investigator rules, and related files). Only the ODM constructs a ReasonMachine; these files are read at Decision Maker initialization, but the RM's snapshot/restore cycle is dormant unless the developer flag --enable-rm-cycle is passed. The file formats are covered in the developer documentation (ReasonMachine internals), not in this user section — copy the directory unchanged from the BV4 reference case unless you are working on the RM itself.
Knowledge-Based Reasoning Strategy
Only the Decision Maker implements a knowledge-based reasoning (KBR) problem-solving strategy. This strategy is activated when the crew goal is set to "troubleshooting". Under KBR, the ODM consults KB_ODM_Diagnosis_Actions.txt to select and execute corrective actions based on diagnosed functional imbalances.
The Action Taker does not have a KBR strategy; its KB_OAT_Diagnosis_Actions.txt file exists for structural completeness but is not used in simulation.
ODM-Unique File
KB_ODM_Diagnosis_Actions.txt is the only file in the Decision Maker knowledge base with no direct OAT counterpart in active use. It encodes the knowledge-based corrective actions the ODM takes when an imbalance is diagnosed during KBR problem solving. See the KB_ODM_Diagnosis_Actions page for full documentation.