In-outage diagnostic · Execution and Return to Service
Find the configuration conflict before the slice starts.
Outage schedules shift every shift. A deterministic checker like PRISM tests each upcoming schedule slice against tech specs, protected equipment and plant conditions. WIMS turns those findings into readiness evidence that leadership, work control and the PRA group can act on early.
Why this problem is real
Main drivers: configuration control, procedure use and mode-change issues. Source: INL-EXT-19-55308, DOE LWRS program (2019).
The in-outage gap
One SRO, many requirement lists, a schedule that keeps moving.
Before each work authorization, the work-control SRO must check tech specs, shutdown risk, mode-change checklists, clearance orders, concurrent work and plant conditions. Each lives in its own tracking method. When the schedule shifts, conflicts often surface only when the slice is already live.
For major component work such as RCP replacement, steam generator replacement or turbine centerline work, a late conflict means a hold, a resequence or an LCO entry, and it lands on the critical path.
What PRISM checked in the 2019 pilot
- Tech spec LCOs per slice, with the reason for any failure. Example: TS 3.8.2 AC Sources–Shutdown fails when one train's offsite breaker and the other train's EDG are out of service together.
- Protected-equipment rules against each slice and every out-of-service change
- Risk Management Action Level (RMAL) notifications
- System alignment and flow paths, including support-system dependencies
- Plant conditions: SFP level, time to boil, RCS inventory, containment integrity
- Live and Preview modes to see the current state or any future slice
Pilot scope covered the safety injection and AC power systems only. PRISM is deterministic; it does not produce PRA results.
Where it fits
Four layers, one decision owner.
PRISM answers whether a slice is allowed. The licensee's risk monitor, such as EPRI Phoenix, shows how much risk the slice carries. WIMS asks whether the organization is ready to execute into it and whether the evidence is current. The SRO still decides.
WIMS stays read-only and advisory. It does not control plant equipment, compute PRA, or replace licensee authority.
Benefits by role
Earlier signals for everyone who carries the outage.
Work-control SRO
Conflicts appear hours ahead in Preview, not at the moment of authorization. Less manual cross-checking across lists.
Outage manager
Resequence while margin still exists. Track whether look-ahead conflicts are being cleared before their slice starts.
PRA group
See deterministic conflicts next to risk-monitor results on the same slice timeline, including where the two disagree.
Project owner
RCP, steam generator and turbine scopes get configuration evidence tied to WIMS dimensions and gates, not just a date.
Mapped to the canonical WIMS dimensions
PRISM strengthens six dimensions. The other six need other evidence.
PRISM feeds existing dimensions as a separate diagnostic agent. No new dimension is added.
| WIMS dimension | PRISM evidence | What it contributes |
|---|---|---|
| Configuration Certainty | Primary | Tech spec, protected-equipment and alignment checks per slice; re-checks after changes |
| Schedule Margin | Primary | Look-ahead conflicts found and cleared before slice start |
| Procedure / Work Package | Secondary | Packages released into slices that later failed a check; open checklist items |
| Testing / Commissioning | Secondary | Mode-change prerequisites ahead of the planned mode change |
| Interface Maturity | Secondary | Cross-system dependency conflicts, such as AC power supporting SI trains |
| OE / Repetition | Secondary | Recurring conflict types carried into the next outage's scope definition |
| Design Maturity · Constructability · Supply Chain · Workforce Readiness · Tooling / Mock-up · Logistics / Lift | None | Outside PRISM's demonstrated scope. WIMS draws these from engineering, planning, procurement, crew and field sources. |
Proposed leading indicator
Look-ahead configuration conflict clearance.
The share of Preview conflicts in the look-ahead window that are resolved before their slice starts, plus the count first found live. A falling clearance rate warns that schedule margin is being consumed before any date moves.
Status: proposed. No threshold, baseline or calibration exists yet.
Applies across the three scenarios
- RCP replacement · High relevance
Reduced-inventory windows, protected shutdown cooling, AC sources during pump and motor work - Steam generator replacement · High relevance
Containment construction opening, SFP cooling protection, restoration checklists - Existing turbine centerline · Moderate to low
Mostly non-TS work. The value is in offsite power and backfeed alignments and return-to-service prerequisites.
Boundaries
What this briefing does not claim.
Not a forecast
All scenario values are synthetic. There is no calibrated WIMS engine run and no P50, P80 or P90 result.
Not plant control
WIMS reads diagnostic output and advises. Configuration authority stays with the licensee's SRO and shift management.
Not an endorsement
PRISM's current product status, ownership and software QA classification are unconfirmed. Phoenix is an EPRI product. No regulatory acceptability is asserted.