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newSchoolWorks.com › VoTechWorks › Building & Construction › Nuclear Power Plant Technician / Operator Prep › Nuclear Plant Maintenance: Procedures, Equipment, and Reliability › Lesson 12
BLD-NUCL84-08 · Lesson 12 · 45 clock hours · lab

Integrated Maintenance Evolution: Full Work Package Execution on a Plant System Mock-Up

Objective. Students will execute a complete maintenance work package—from pre-job briefing through post-maintenance testing and closeout—on a multi-component plant system training mock-up, demonstrating all competencies developed in the course.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Integrated Maintenance Evolution: Full Work Package Execution

A maintenance evolution is not a collection of separate tasks—it is a single, controlled event that begins before anyone touches a tool and ends only when a supervisor accepts a complete, accurate work package. This lab brings together every skill practiced in this course and asks you to perform them in the correct sequence, under procedure control, as a team. Nuclear plant employers hire technicians who can do exactly this.

The Work Package as a Governing Document

The maintenance work order (MWO) package is your authority and your record. It contains the approved procedure, the scope of work, the isolation boundary, acceptance criteria, post-maintenance test (PMT) instructions, and the data sheets on which you record every measurement and observation. Nothing in the package is optional. If a step does not apply, you write N/A and your initials—you do not skip it silently. Uncontrolled changes to procedure steps require a formal revision through your supervisor; you never mark through a step and proceed without authorization.

Pre-Job Briefing

The pre-job briefing (PJB) is a mandatory human performance tool, not a suggestion. Before any hands-on work begins, the team assembles and covers: the full scope of the task, all known hazards (electrical, mechanical, radiological, thermal), the radiological work permit (RWP) requirements and dose-rate controls, each LOTO step and who owns which lock, stop-work authority (every team member has it, and using it is never wrong), and the expected duration with hold points identified. The PJB is documented—each attendee signs the briefing sheet, which becomes part of the closed package. During this lab your instructor will listen and score the briefing; an incomplete PJB is the single most common reason teams fail the first attempt.

Lockout/Tagout Execution

Lockout/tagout (LOTO) is governed by OSHA standards and reinforced by plant procedures. On this mock-up the energy sources include electrical power to the motor, system pressure, and stored mechanical energy in the valve actuators. Your procedure lists every energy isolation point. Work in order: notify affected workers, de-energize at the disconnect, apply your personal lock and tag, bleed down pressure, verify zero energy state with a test instrument before you touch any component. Each team member working on the equipment applies their own lock. Nobody removes another worker's lock. After LOTO is confirmed, record the verified zero-energy state on the appropriate form—this entry is required for the package to close.

Disassembly, Repair, and Reassembly

On the mock-up you will remove pump packing or a seal, inspect the shaft for wear, install replacement packing or seals, and reassemble to the torque values specified in the procedure. Use a calibrated torque wrench and record the actual torque achieved—not just a check mark. Calibrated means the instrument has a current calibration tag; if the tag is expired, stop work and get a calibrated tool. Use a dial indicator to verify shaft runout if the procedure requires it, and record the reading. Calipers measure seal dimensions; compare measured values to the drawing tolerance and record both. Human performance tools—two-person verification on critical torque steps, place-keeping with a finger on each step, flagging for re-read after an interruption—are observed by the instructor throughout.

Radiological Controls During Maintenance

Even on a training mock-up, you practice radiological discipline. In a real plant, the RWP specifies the dose-rate zone, required dosimetry, and any contamination controls. During this lab you wear assigned PPE consistent with the simulated RWP. You do not bring food, drinks, or personal items into the simulated radiologically controlled area. You perform a contamination survey of tools and surfaces as directed. Radiological control compliance is a scored category; one procedural skip earns a deficiency.

Post-Maintenance Testing

When reassembly is complete and energy is restored under procedure control, the team performs the PMT exactly as written. On this mock-up the PMT includes: verifying motor current draw with a clamp-on ammeter and recording the value against the acceptance band, checking bearing temperature with an infrared thermometer after a specified run time, confirming system pressure at the instrumentation tap is within range, and verifying no packing leakoff exceeds the allowable rate. All readings go on the PMT data sheet with the time, the technician's initials, and a pass/fail notation against each acceptance criterion. A reading outside the band is not automatically a failure of the lab—it is a condition that must be documented on a condition report (CR) and dispositioned before you write the operability determination.

Operability Determination and Package Closeout

The operability determination is a written statement by the maintenance team (reviewed by supervision in the plant) that the component or system is operable per its design basis following maintenance. For this lab you write: what work was done, what the PMT results showed, whether all acceptance criteria were met, whether any open CRs exist and their status, and your conclusion about operability. This statement must be specific—not "the pump is fine" but a reference to data values and criteria. Once written, the entire package—PJB sign-in sheet, LOTO records, procedure with data entries, PMT data sheet, any CRs, and the operability determination—is assembled in order and submitted to the instructor. Any missing document or unresolved deficiency results in the package being returned for correction before a passing grade is awarded.

Safety Throughout the Evolution

Stop-work authority applies at every moment. If a team member identifies an unexpected hazard, an unclear step, or a condition outside the procedure's bounds, work stops, the team reassembles, and the situation is resolved before proceeding. This is not a sign of weakness; it is the standard expected of every licensed and non-licensed operator in the US nuclear industry.

Key terms10

Maintenance Work Order (MWO) PackageThe complete set of governing documents for a maintenance task, including the approved procedure, isolation requirements, acceptance criteria, data sheets, and closeout records; the package must be fully complete and accurate before work is considered finished.
Pre-Job Briefing (PJB)A documented team meeting held before any hands-on work begins that covers task scope, hazards, LOTO steps, radiological controls, hold points, and each worker's stop-work authority; all attendees sign the briefing sheet.
Lockout/Tagout (LOTO)An energy-control procedure requiring that every energy source (electrical, pressure, mechanical, thermal) be isolated, locked, and verified at zero energy before maintenance work begins; each worker applies their own personal lock.
Zero Energy VerificationThe confirmed and documented state in which all energy sources have been isolated, released, or restrained and tested with an instrument to prove no hazardous energy remains before a worker contacts equipment.
Post-Maintenance Test (PMT)A written test procedure performed after reassembly and energy restoration to confirm that the repaired component or system meets all performance and safety acceptance criteria before it is returned to service.
Operability DeterminationA written conclusion, supported by PMT data and procedure results, stating whether a component or system is capable of performing its design-basis function following maintenance.
Condition Report (CR)A formal plant document used to record any equipment deficiency, procedure deviation, or out-of-specification finding so it can be evaluated, tracked, and resolved under the corrective action program.
Human Performance Tools (HP Tools)Structured behaviors—such as two-person verification, place-keeping, flagging, and questioning attitude—that reduce the likelihood of human error during critical maintenance steps.
Calibrated Torque WrenchA torque-applying tool that has been tested against a traceable standard within its required calibration interval; only a currently calibrated tool produces legally defensible torque records for a work package.
Stop-Work AuthorityThe right and responsibility of any worker on a nuclear site to halt work immediately when an unsafe condition, an unclear procedure step, or an unexpected hazard is identified, without fear of reprisal.

Worked examples4

1. The procedure requires pump packing gland bolts to be torqued to 35 ft-lb. You apply the torque wrench and the indicator stops at 32 ft-lb on the first pass. What do you record, and what do you do next?
  1. Record 32 ft-lb in the 'First-Pass Torque' column on the data sheet with your initials and the time—never leave a data field blank or estimate.
  2. Continue tightening in small increments and re-check until the wrench clicks or the indicator reaches 35 ft-lb.
  3. Record the final achieved torque of 35 ft-lb in the 'Final Torque' column and initial the step.
  4. If the bolt reaches 35 ft-lb but the gland is uneven, note the condition and consult the procedure for guidance on sequential torquing patterns before proceeding.
Answer: Record the first-pass reading of 32 ft-lb, continue tightening to the specified 35 ft-lb, then record 35 ft-lb as the final achieved torque. Both data entries remain in the package; nothing is erased.
2. The PMT acceptance criterion for motor running current is 18.0 A ± 2.0 A (acceptable range: 16.0 A to 20.0 A). Your clamp-on ammeter reads 21.3 A. What is your next action?
  1. Confirm the ammeter is on the correct range and the jaws are fully closed around a single conductor; re-take the reading to rule out instrument error.
  2. If the second reading is still 21.3 A, the value exceeds the upper acceptance limit of 20.0 A—record 21.3 A on the PMT data sheet and mark the criterion 'FAIL'.
  3. Do not declare the system operable; initiate a Condition Report describing the out-of-specification current reading, the acceptance criterion, and the observed value.
  4. Notify the instructor (who represents supervision) before making any additional adjustments; wait for disposition of the CR before writing the operability determination.
Answer: 21.3 A exceeds the 20.0 A upper limit by 1.3 A. Record the actual reading, mark the PMT step failed, open a Condition Report, and stop work pending supervisory disposition. The operability determination cannot be written as 'operable' until the deficiency is resolved.
3. Shaft runout is specified as 0.003 inch (3 mils) maximum total indicator reading (TIR). Your dial indicator shows 0.0018 inch on one side and 0.0012 inch on the opposite side of the shaft rotation. What is the TIR and does it pass?
  1. TIR is the total swing of the indicator needle over a full 360-degree rotation: TIR = highest reading − lowest reading.
  2. Identify the highest reading: 0.0018 inch. Identify the lowest reading: the indicator reads 0.0012 inch on the opposite side, but for TIR you need the algebraic range. If the indicator zeroed at start, the full swing is 0.0018 + 0.0012 = 0.0030 inch.
  3. Compare to the acceptance criterion: 0.0030 inch ≤ 0.003 inch (the limit).
  4. Record TIR = 0.0030 inch on the data sheet and mark the criterion 'PASS' (exactly at the limit is acceptable unless the procedure states 'less than').
Answer: TIR = 0.0030 inch, which equals the 0.003 inch maximum allowed. The step passes. Record the exact measured value—not just a check—and initial the data sheet.
4. Your infrared thermometer reads 147 °F on the pump bearing housing after the required run time. The PMT acceptance criterion is ≤ 160 °F and ≥ 20 °F above ambient. Ambient temperature in the room is 72 °F. Does the bearing temperature pass both criteria?
  1. Check the upper limit: 147 °F ≤ 160 °F — PASS.
  2. Calculate the minimum rise above ambient: 72 °F + 20 °F = 92 °F minimum bearing temperature.
  3. Check the lower limit: 147 °F ≥ 92 °F — PASS.
  4. Record 147 °F bearing temperature and 72 °F ambient on the data sheet, note both criteria checked, and mark the step 'PASS'.
Answer: 147 °F satisfies both criteria: it is below the 160 °F ceiling and at least 20 °F above the 72 °F ambient (minimum required value: 92 °F). Record all three values and mark the PMT step passed.
In class: Each student team receives a complete maintenance work order package for a corrective maintenance task on the training mock-up (which incorporates a pump, two valves, motor, and instrumentation); teams conduct a pre-job briefing covering scope, hazards, radiological controls, LOTO steps, and stop-work authority before any hands-on work begins. · Teams execute the maintenance task step-by-step under procedure control, performing LOTO, disassembly, repair or replacement, reassembly to torque specification, and restoration in correct sequence while the instructor observes and evaluates human performance tool use, documentation accuracy, and team communication throughout. · Teams complete the post-maintenance test per the written procedure, record all data on the test data sheet, write the operability determination, and present the closed work order package to the instructor for a final review; any deficiency identified during the review must be corrected and the documentation resubmitted before the team receives a passing grade.
Materials: Multi-component plant system training mock-up (pump, valves, motor, instrumentation), complete maintenance work order package (training version), LOTO equipment, calibrated torque wrench, dial indicator set, calipers, replacement packing and seals, clamp-on ammeter, infrared thermometer, pressure gauges, all required PPE, condition report forms, post-maintenance test data sheets
Check: Instructor uses a standardized evaluation rubric covering 10 categories: pre-job briefing completeness, LOTO application correctness, procedure adherence (no skipped steps), torque values documented, human performance tool use observed, radiological control compliance, post-maintenance test data complete and within acceptance bands, operability determination written, work order package complete, no unresolved deficiencies; student must score satisfactory in at least 8 of 10 categories to pass.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NRC Non-Licensed Operator Prep — human performance and procedure use
1. During the pre-job briefing, a team member realizes the procedure does not address a small secondary drain valve on the mock-up that could trap pressure. What is the correct action?
OSHA 10 — lockout/tagout
2. A technician's personal lock is on the motor disconnect. A supervisor tells the technician to remove the lock so the motor can be tested while the technician is away from the equipment. What should the technician do?
NUCP Uniform Curriculum (NEI) — work package closeout
3. After reassembly, the PMT data sheet shows all readings within acceptance bands. Before writing the operability determination, what must the team verify about the work order package?
NRC Reactor Operator (RO) License — maintenance and operability
4. Which of the following best describes what the operability determination must include?
NUCP Uniform Curriculum (NEI) — electrical measurement
5. A clamp-on ammeter is used during the PMT to measure motor running current. What is the correct technique for obtaining an accurate reading?
NRC Non-Licensed Operator Prep — corrective action program
6. During disassembly the team discovers the pump shaft has visible scoring not described in the incoming condition. What is the correct first action?
NUCP Uniform Curriculum (NEI) — human performance tools
7. What is the purpose of the two-person verification human performance tool when applied to a critical torque step?
NRRPT Radiation Protection Tech — contamination control
8. The NRRPT body of knowledge emphasizes that during maintenance in a radiologically controlled area, tools and materials must be surveyed before removal from the area. Why is this step critical?
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