APP-MNT-01 — PS17: advice, selected intervention and return to use

The constructed case begins on 18 September 2026 with rising bearing-related vibration in PumpTrain-PS17-B, configuration C41. DistrictHeatingOperation-East supplies a qualified capacity result for the stated horizon: its agreed reduced-capacity operation can last four hours under the specified demand and fallback conditions. That operating contribution is the result exchange also identified as XRI-09.

The requested first result is a replacement recommendation. MNT.1 bounds the unit and use. MNT.3 and MNT.4 keep the supported failure and condition interpretation separate from an unproved long-term cause. MNT.6 compares the plausible responses and returns the recommendation from the evidence already adequate for it.

The replacement needs the case’s specialist applicability/certification return for the spare. MNT.5 identifies that unmet condition. The recommendation is complete, while actual replacement cannot start. The team may prepare compatible information, tools and available support without consuming the protected outage or pretending that the missing return exists.

In the extended branch, the specialist return arrives and the intervention is selected. MNT.7’s whole-outage calculation includes shutdown and isolation, the intervention, controlled testing, final restoration, return of control and explicit contingency. The resulting 225-minute plan fits the four-hour bound under the constructed estimates. Its calculation and delay branch are in MNT.7; the plan is not a time promise for an unknown pump.

MNT.8 establishes the applicable actual protection and permission. If an uncontrolled shared energy path is found, the protected work does not start and the arrangement returns for a competent revised decision. The earlier advice remains complete.

In the performed branch, MNT.9 records removal of bearing R551 and installation of compatible bearing R607. Configuration C42 identifies the resulting installed arrangement under the same approved design basis. MNT.12 preserves the connection between those events and the earlier C41 history.

MNT.10 then checks the immediate-duty claim under the constructed operating basis, using its stated measurements and limitations. MNT.11 reconciles the returned state, transfers control and obtains the operative resumed-use decision. A successful function test does not automatically establish that permission or an untested broader duty.

Long-horizon recurrence remains unresolved. MNT.13 can retain the current programme account, and MNT.16 can describe the team’s observed use only within the constructed case. A further investigation or practice intervention is selected for its worthwhile attainable contribution; it is not required to make the local recommendation or repair result true.