Junior Operator Grade I cheat sheet

Reactor coolant pump seal staging: No. 1 seal takes the full RCS-to-letdown differential; No. 2 seal sees a controlled leakoff backpressure; No. 3 seal is the final barrier to containment atmosphere.

Pressurizer level program is temperature-compensated: indicated level varies with RCS average temperature at constant inventory, so level alone cannot confirm inventory during cooldown or heatup.

Instrument channel failure modes: an upscale failure drives alarms and automatic actions high; a downscale failure drives them low; a failed channel is placed in the tripped or bypassed condition per technical specification direction.

Two-out-of-four logic: a trip requires any two channels in the same protection group; a single failed channel does not spuriously trip but defeats the redundancy required for the second.

Steam generator water level is measured by narrow-range and wide-range instruments; narrow range covers normal operation, wide range covers startup, shutdown, and post-accident conditions.

Differential pressure transmitters across an orifice give flow as the square root of dP; a 4x dP increase is a 2x flow increase, so flow errors are amplified at low dP.

Containment hydrogen recombiners and post-accident hydrogen monitors are part of the engineered safety features; hydrogen above roughly 4 percent by volume in air is flammable.

Instrument air loss fails pneumatic valve actuators to their designed failure position (fail-open, fail-closed, or fail-as-is), so the failure position must be known for each valve before declaring air loss.

Reactor startup sequence: criticality by rod withdrawal with boron held constant, then heatup on nuclear heat, then turbine roll and generator synchronization, then power escalation to the target with rod and boron control.

Criticality approach uses the inverse-count-rate plot (1/CR versus rod position or time); a straight line predicts the critical rod position at the extrapolated 1/CR = 0 intercept.

Shutdown margin must remain positive at all times, including during refueling; it equals the reactivity worth of all rods assumed fully inserted minus the reactivity of the core at that condition.

Boron dilution rate is set by charging flow and blended boron concentration; the reactivity addition rate is limited by administrative controls on dilution volume per hour.

Turbine generator synchronization requires matching voltage, frequency, and phase; the breaker is closed when the synchroscope passes slowly through the 12 o'clock position.

During power ascension the axial flux difference and quadrant power tilt are checked against limits at each hold point before further rod withdrawal.

Main steam line drains and turbine bypass valves control steam pressure during low-power operation before the turbine is on line.

A plant heatup rate limit protects vessel and piping from thermal stress; the limit is stated in degrees per hour and applies to the RCS average temperature.

Emergency classification levels escalate: Notification of Unusual Event, Alert, Site Area Emergency, General Emergency; each has specific entry criteria and required notifications.

Loss of reactor coolant accident response: trip the reactor, start safety injection, isolate letdown, and monitor subcooling margin; subcooling margin is the difference between saturation temperature at RCS pressure and the hottest RCS temperature.

Steam generator tube rupture: identify the affected generator by rising level and radiation, isolate it, and control RCS cooldown rate to limit primary-to-secondary leakage.

Station blackout: loss of offsite power plus loss of emergency diesel generators; response relies on battery-backed instrumentation and alternate AC sources if available.

Anticipated transient without scram: if the reactor does not trip on demand, manual trip, then emergency boration and, if needed, containment isolation and injection paths per the emergency procedure.

Loss of feedwater: reactor trip, turbine trip, and auxiliary feedwater start; if AFW fails, steam generator inventory and RCS heat removal become the limiting parameters.

Emergency operating procedures are symptom-based, not event-based; the operator works from the critical safety function status trees: reactivity, core cooling, heat removal, RCS integrity, containment, and inventory.

A small-break LOCA can mask itself: pressurizer level may stay normal while RCS inventory is lost, so subcooling margin and containment radiation are the earlier indicators.

Technical specifications define limiting conditions for operation; an LCO violation requires entry into the applicable action statement within the stated completion time or a plant shutdown.

The three technical specification bases categories: safety limits, limiting safety system settings, and limiting conditions for operation; each action time is derived from the analyzed consequence of continued operation.

Annual effluent and environmental limits are set in the plant's radioactive effluent release permit; releases are monitored and reported, and any unplanned release above limits is reportable.

Reportable events include those in 10 CFR 50.72 (immediate notification) and 10 CFR 50.73 (written report within 60 days); the immediate notification is by telephone to the NRC operations center.

The design basis accident for a light-water reactor is the large-break loss-of-coolant accident; the emergency core cooling system is analyzed against it with acceptance criteria on peak clad temperature, clad oxidation, and hydrogen generation.

ALARA is a regulatory requirement, not an aspiration: exposures must be kept as low as reasonably achievable, with dose limits as the ceiling and ALARA as the operating target below it.

Fitness-for-duty and access authorization programs control who may enter the protected area; the protected area boundary and vital area boundary are distinct security zones.

Surveillance test deferrals require technical specification allowance; a missed surveillance is an LCO issue, not an administrative footnote, and may require a report.

Clearance and tagout: the equipment is de-energized or isolated, locked, tagged, and verified; the operator verifies zero energy before work begins, and only the tag owner removes the tag.

Surveillance frequency basis: a test interval is set so that the probability of an undetected failure between tests stays within the analyzed value; extending an interval requires a technical specification change.

Diesel generator surveillance includes start time, load acceptance, and continuous run at rated load; the monthly and quarterly tests have different acceptance criteria.

Containment integrated leak rate test is performed at reduced pressure and periodic intervals; the acceptance criterion is a maximum leakage rate as a fraction of containment volume per day.

Pump and valve inservice testing verifies required flow, differential pressure, and stroke time; the results are compared with the acceptance criteria in the inservice testing program.

Calibration traceability: instruments are calibrated against standards traceable to a national standard, and calibration records are retained for the required period.

Post-maintenance testing confirms the component performs its safety function before return to service; a functional test is not the same as a calibration check.

Equipment important to safety is classified and its maintenance is controlled by the plant's maintenance rule program, which tracks functional failures and unavailability.

Dose equivalent formulas: dose (rem) = exposure (R) x quality factor for the radiation type; 1 rem = 0.01 sievert; 1 rad = 0.01 gray.

Inverse square law: dose rate falls with the square of distance from a point source; doubling distance cuts the dose rate to one quarter.

ALARA dose control hierarchy: time, distance, shielding; halving time in the field halves the dose, and shielding is chosen by radiation type (lead for gamma, plastic or water for beta, hydrogenous material for neutron).

Contamination control: protective clothing, step-off pads, and survey of personnel and tools at the boundary; contamination is measured in counts per minute and converted to disintegrations per minute by detector efficiency.

Primary chemistry control: pH is maintained with lithium hydroxide, boron concentration is adjusted for reactivity, and dissolved oxygen is controlled with hydrogen overpressure to limit corrosion.

Chloride and fluoride limits in the primary system are tight because halide stress corrosion cracking of stainless steel and Inconel is a known failure mode.

Dose rate from a gamma source is halved by about 1 cm of lead for a 1 MeV photon (half-value layer); the half-value layer depends strongly on photon energy.

Airborne radioactivity control: high-efficiency particulate air filters and charcoal filters are used for particulate and iodine; the ventilation flow path must be verified before entry into a posted area.

Three-way communication: sender states the message, receiver repeats it back, sender confirms the repeat is correct; used for any command that changes plant configuration.

Procedure use and adherence: place the place-keeping marker at the current step, read the step before acting, and never work from memory when a procedure exists.

Self-check (STAR): Stop, Think, Act, Review; applied before operating a component or opening a valve.

Peer check: a second qualified person independently verifies the component, the position, and the action before the operation is performed.

Turnover must include current plant configuration, out-of-service equipment, active clearances, and any abnormal conditions; incomplete turnover is a leading cause of configuration errors.

Human performance error precursors include time pressure, fatigue, distraction, vague procedures, and first-time performance; recognizing the precursor allows a defensive action.

Log entries are contemporaneous and factual: time, equipment identifier, action taken, and result; subjective interpretation is separated from observation.

Operating experience is documented and reviewed so that a known failure mode at one plant is checked at another before it recurs.

Ohm's law and power: V = I x R, P = V x I; for three-phase power, P = sqrt(3) x V(line) x I(line) x power factor.

Motor current at reduced voltage: torque varies with the square of applied voltage, so a 10 percent voltage drop cuts starting torque by about 19 percent.

Transformer relation: V1/V2 = N1/N2 and I1/I2 = N2/N1; a step-down transformer raises current in the same ratio it lowers voltage.

AC induction motor slip: synchronous speed = 120 x frequency / number of poles; rotor speed is slightly less than synchronous speed, and slip increases with load.

Diesel generator rating is stated in kW and power factor; the kVA rating is kW divided by power factor, and the engine must carry the kVA load at that power factor.

Pump affinity laws: flow varies with speed, head with speed squared, and power with speed cubed; a 10 percent speed reduction cuts power by about 27 percent.

Pump cavitation occurs when local pressure drops below vapor pressure; net positive suction head available must exceed net positive suction head required to avoid it.

Heat exchanger effectiveness: heat transferred Q = U x A x LMTD; fouling raises the overall resistance and reduces U, so the same duty needs a larger temperature difference.

Reactor coolant pump seal staging: No. 1 seal takes the full RCS-to-letdown differential; No. 2 seal sees a controlled leakoff backpressure; No. 3 seal is the final barrier to containment atmosphere.

Pressurizer level program is temperature-compensated: indicated level varies with RCS average temperature at constant inventory, so level alone cannot confirm inventory during cooldown or heatup.

Instrument channel failure modes: an upscale failure drives alarms and automatic actions high; a downscale failure drives them low; a failed channel is placed in the tripped or bypassed condition per technical specification direction.

Two-out-of-four logic: a trip requires any two channels in the same protection group; a single failed channel does not spuriously trip but defeats the redundancy required for the second.

Steam generator water level is measured by narrow-range and wide-range instruments; narrow range covers normal operation, wide range covers startup, shutdown, and post-accident conditions.

Differential pressure transmitters across an orifice give flow as the square root of dP; a 4x dP increase is a 2x flow increase, so flow errors are amplified at low dP.

Containment hydrogen recombiners and post-accident hydrogen monitors are part of the engineered safety features; hydrogen above roughly 4 percent by volume in air is flammable.

Instrument air loss fails pneumatic valve actuators to their designed failure position (fail-open, fail-closed, or fail-as-is), so the failure position must be known for each valve before declaring air loss.

Reactor startup sequence: criticality by rod withdrawal with boron held constant, then heatup on nuclear heat, then turbine roll and generator synchronization, then power escalation to the target with rod and boron control.

Criticality approach uses the inverse-count-rate plot (1/CR versus rod position or time); a straight line predicts the critical rod position at the extrapolated 1/CR = 0 intercept.

Shutdown margin must remain positive at all times, including during refueling; it equals the reactivity worth of all rods assumed fully inserted minus the reactivity of the core at that condition.

Boron dilution rate is set by charging flow and blended boron concentration; the reactivity addition rate is limited by administrative controls on dilution volume per hour.

Turbine generator synchronization requires matching voltage, frequency, and phase; the breaker is closed when the synchroscope passes slowly through the 12 o'clock position.

During power ascension the axial flux difference and quadrant power tilt are checked against limits at each hold point before further rod withdrawal.

Main steam line drains and turbine bypass valves control steam pressure during low-power operation before the turbine is on line.

A plant heatup rate limit protects vessel and piping from thermal stress; the limit is stated in degrees per hour and applies to the RCS average temperature.

Emergency classification levels escalate: Notification of Unusual Event, Alert, Site Area Emergency, General Emergency; each has specific entry criteria and required notifications.

Loss of reactor coolant accident response: trip the reactor, start safety injection, isolate letdown, and monitor subcooling margin; subcooling margin is the difference between saturation temperature at RCS pressure and the hottest RCS temperature.

Steam generator tube rupture: identify the affected generator by rising level and radiation, isolate it, and control RCS cooldown rate to limit primary-to-secondary leakage.

Station blackout: loss of offsite power plus loss of emergency diesel generators; response relies on battery-backed instrumentation and alternate AC sources if available.

Anticipated transient without scram: if the reactor does not trip on demand, manual trip, then emergency boration and, if needed, containment isolation and injection paths per the emergency procedure.

Loss of feedwater: reactor trip, turbine trip, and auxiliary feedwater start; if AFW fails, steam generator inventory and RCS heat removal become the limiting parameters.

Emergency operating procedures are symptom-based, not event-based; the operator works from the critical safety function status trees: reactivity, core cooling, heat removal, RCS integrity, containment, and inventory.

A small-break LOCA can mask itself: pressurizer level may stay normal while RCS inventory is lost, so subcooling margin and containment radiation are the earlier indicators.

Technical specifications define limiting conditions for operation; an LCO violation requires entry into the applicable action statement within the stated completion time or a plant shutdown.

The three technical specification bases categories: safety limits, limiting safety system settings, and limiting conditions for operation; each action time is derived from the analyzed consequence of continued operation.

Annual effluent and environmental limits are set in the plant's radioactive effluent release permit; releases are monitored and reported, and any unplanned release above limits is reportable.

Reportable events include those in 10 CFR 50.72 (immediate notification) and 10 CFR 50.73 (written report within 60 days); the immediate notification is by telephone to the NRC operations center.

The design basis accident for a light-water reactor is the large-break loss-of-coolant accident; the emergency core cooling system is analyzed against it with acceptance criteria on peak clad temperature, clad oxidation, and hydrogen generation.

ALARA is a regulatory requirement, not an aspiration: exposures must be kept as low as reasonably achievable, with dose limits as the ceiling and ALARA as the operating target below it.

Fitness-for-duty and access authorization programs control who may enter the protected area; the protected area boundary and vital area boundary are distinct security zones.

Surveillance test deferrals require technical specification allowance; a missed surveillance is an LCO issue, not an administrative footnote, and may require a report.

Clearance and tagout: the equipment is de-energized or isolated, locked, tagged, and verified; the operator verifies zero energy before work begins, and only the tag owner removes the tag.

Surveillance frequency basis: a test interval is set so that the probability of an undetected failure between tests stays within the analyzed value; extending an interval requires a technical specification change.

Diesel generator surveillance includes start time, load acceptance, and continuous run at rated load; the monthly and quarterly tests have different acceptance criteria.

Containment integrated leak rate test is performed at reduced pressure and periodic intervals; the acceptance criterion is a maximum leakage rate as a fraction of containment volume per day.

Pump and valve inservice testing verifies required flow, differential pressure, and stroke time; the results are compared with the acceptance criteria in the inservice testing program.

Calibration traceability: instruments are calibrated against standards traceable to a national standard, and calibration records are retained for the required period.

Post-maintenance testing confirms the component performs its safety function before return to service; a functional test is not the same as a calibration check.

Equipment important to safety is classified and its maintenance is controlled by the plant's maintenance rule program, which tracks functional failures and unavailability.

Dose equivalent formulas: dose (rem) = exposure (R) x quality factor for the radiation type; 1 rem = 0.01 sievert; 1 rad = 0.01 gray.

Inverse square law: dose rate falls with the square of distance from a point source; doubling distance cuts the dose rate to one quarter.

ALARA dose control hierarchy: time, distance, shielding; halving time in the field halves the dose, and shielding is chosen by radiation type (lead for gamma, plastic or water for beta, hydrogenous material for neutron).

Contamination control: protective clothing, step-off pads, and survey of personnel and tools at the boundary; contamination is measured in counts per minute and converted to disintegrations per minute by detector efficiency.

Primary chemistry control: pH is maintained with lithium hydroxide, boron concentration is adjusted for reactivity, and dissolved oxygen is controlled with hydrogen overpressure to limit corrosion.

Chloride and fluoride limits in the primary system are tight because halide stress corrosion cracking of stainless steel and Inconel is a known failure mode.

Dose rate from a gamma source is halved by about 1 cm of lead for a 1 MeV photon (half-value layer); the half-value layer depends strongly on photon energy.

Airborne radioactivity control: high-efficiency particulate air filters and charcoal filters are used for particulate and iodine; the ventilation flow path must be verified before entry into a posted area.

Three-way communication: sender states the message, receiver repeats it back, sender confirms the repeat is correct; used for any command that changes plant configuration.

Procedure use and adherence: place the place-keeping marker at the current step, read the step before acting, and never work from memory when a procedure exists.

Self-check (STAR): Stop, Think, Act, Review; applied before operating a component or opening a valve.

Peer check: a second qualified person independently verifies the component, the position, and the action before the operation is performed.

Turnover must include current plant configuration, out-of-service equipment, active clearances, and any abnormal conditions; incomplete turnover is a leading cause of configuration errors.

Human performance error precursors include time pressure, fatigue, distraction, vague procedures, and first-time performance; recognizing the precursor allows a defensive action.

Log entries are contemporaneous and factual: time, equipment identifier, action taken, and result; subjective interpretation is separated from observation.

Operating experience is documented and reviewed so that a known failure mode at one plant is checked at another before it recurs.

Ohm's law and power: V = I x R, P = V x I; for three-phase power, P = sqrt(3) x V(line) x I(line) x power factor.

Motor current at reduced voltage: torque varies with the square of applied voltage, so a 10 percent voltage drop cuts starting torque by about 19 percent.

Transformer relation: V1/V2 = N1/N2 and I1/I2 = N2/N1; a step-down transformer raises current in the same ratio it lowers voltage.

AC induction motor slip: synchronous speed = 120 x frequency / number of poles; rotor speed is slightly less than synchronous speed, and slip increases with load.

Diesel generator rating is stated in kW and power factor; the kVA rating is kW divided by power factor, and the engine must carry the kVA load at that power factor.

Pump affinity laws: flow varies with speed, head with speed squared, and power with speed cubed; a 10 percent speed reduction cuts power by about 27 percent.

Pump cavitation occurs when local pressure drops below vapor pressure; net positive suction head available must exceed net positive suction head required to avoid it.

Heat exchanger effectiveness: heat transferred Q = U x A x LMTD; fouling raises the overall resistance and reduces U, so the same duty needs a larger temperature difference.

Reactor coolant pump seal staging: No. 1 seal takes the full RCS-to-letdown differential; No. 2 seal sees a controlled leakoff backpressure; No. 3 seal is the final barrier to containment atmosphere.

Pressurizer level program is temperature-compensated: indicated level varies with RCS average temperature at constant inventory, so level alone cannot confirm inventory during cooldown or heatup.

Instrument channel failure modes: an upscale failure drives alarms and automatic actions high; a downscale failure drives them low; a failed channel is placed in the tripped or bypassed condition per technical specification direction.

Two-out-of-four logic: a trip requires any two channels in the same protection group; a single failed channel does not spuriously trip but defeats the redundancy required for the second.

Steam generator water level is measured by narrow-range and wide-range instruments; narrow range covers normal operation, wide range covers startup, shutdown, and post-accident conditions.

Differential pressure transmitters across an orifice give flow as the square root of dP; a 4x dP increase is a 2x flow increase, so flow errors are amplified at low dP.

Containment hydrogen recombiners and post-accident hydrogen monitors are part of the engineered safety features; hydrogen above roughly 4 percent by volume in air is flammable.

Instrument air loss fails pneumatic valve actuators to their designed failure position (fail-open, fail-closed, or fail-as-is), so the failure position must be known for each valve before declaring air loss.

Reactor startup sequence: criticality by rod withdrawal with boron held constant, then heatup on nuclear heat, then turbine roll and generator synchronization, then power escalation to the target with rod and boron control.

Criticality approach uses the inverse-count-rate plot (1/CR versus rod position or time); a straight line predicts the critical rod position at the extrapolated 1/CR = 0 intercept.

Shutdown margin must remain positive at all times, including during refueling; it equals the reactivity worth of all rods assumed fully inserted minus the reactivity of the core at that condition.

Boron dilution rate is set by charging flow and blended boron concentration; the reactivity addition rate is limited by administrative controls on dilution volume per hour.

Turbine generator synchronization requires matching voltage, frequency, and phase; the breaker is closed when the synchroscope passes slowly through the 12 o'clock position.

During power ascension the axial flux difference and quadrant power tilt are checked against limits at each hold point before further rod withdrawal.

Main steam line drains and turbine bypass valves control steam pressure during low-power operation before the turbine is on line.

A plant heatup rate limit protects vessel and piping from thermal stress; the limit is stated in degrees per hour and applies to the RCS average temperature.

Emergency classification levels escalate: Notification of Unusual Event, Alert, Site Area Emergency, General Emergency; each has specific entry criteria and required notifications.

Loss of reactor coolant accident response: trip the reactor, start safety injection, isolate letdown, and monitor subcooling margin; subcooling margin is the difference between saturation temperature at RCS pressure and the hottest RCS temperature.

Steam generator tube rupture: identify the affected generator by rising level and radiation, isolate it, and control RCS cooldown rate to limit primary-to-secondary leakage.

Station blackout: loss of offsite power plus loss of emergency diesel generators; response relies on battery-backed instrumentation and alternate AC sources if available.

Anticipated transient without scram: if the reactor does not trip on demand, manual trip, then emergency boration and, if needed, containment isolation and injection paths per the emergency procedure.

Loss of feedwater: reactor trip, turbine trip, and auxiliary feedwater start; if AFW fails, steam generator inventory and RCS heat removal become the limiting parameters.

Emergency operating procedures are symptom-based, not event-based; the operator works from the critical safety function status trees: reactivity, core cooling, heat removal, RCS integrity, containment, and inventory.

A small-break LOCA can mask itself: pressurizer level may stay normal while RCS inventory is lost, so subcooling margin and containment radiation are the earlier indicators.

Technical specifications define limiting conditions for operation; an LCO violation requires entry into the applicable action statement within the stated completion time or a plant shutdown.

The three technical specification bases categories: safety limits, limiting safety system settings, and limiting conditions for operation; each action time is derived from the analyzed consequence of continued operation.

Annual effluent and environmental limits are set in the plant's radioactive effluent release permit; releases are monitored and reported, and any unplanned release above limits is reportable.

Reportable events include those in 10 CFR 50.72 (immediate notification) and 10 CFR 50.73 (written report within 60 days); the immediate notification is by telephone to the NRC operations center.

The design basis accident for a light-water reactor is the large-break loss-of-coolant accident; the emergency core cooling system is analyzed against it with acceptance criteria on peak clad temperature, clad oxidation, and hydrogen generation.

ALARA is a regulatory requirement, not an aspiration: exposures must be kept as low as reasonably achievable, with dose limits as the ceiling and ALARA as the operating target below it.

Fitness-for-duty and access authorization programs control who may enter the protected area; the protected area boundary and vital area boundary are distinct security zones.

Surveillance test deferrals require technical specification allowance; a missed surveillance is an LCO issue, not an administrative footnote, and may require a report.

Clearance and tagout: the equipment is de-energized or isolated, locked, tagged, and verified; the operator verifies zero energy before work begins, and only the tag owner removes the tag.

Surveillance frequency basis: a test interval is set so that the probability of an undetected failure between tests stays within the analyzed value; extending an interval requires a technical specification change.

Diesel generator surveillance includes start time, load acceptance, and continuous run at rated load; the monthly and quarterly tests have different acceptance criteria.

Containment integrated leak rate test is performed at reduced pressure and periodic intervals; the acceptance criterion is a maximum leakage rate as a fraction of containment volume per day.

Pump and valve inservice testing verifies required flow, differential pressure, and stroke time; the results are compared with the acceptance criteria in the inservice testing program.

Calibration traceability: instruments are calibrated against standards traceable to a national standard, and calibration records are retained for the required period.

Post-maintenance testing confirms the component performs its safety function before return to service; a functional test is not the same as a calibration check.

Equipment important to safety is classified and its maintenance is controlled by the plant's maintenance rule program, which tracks functional failures and unavailability.

Dose equivalent formulas: dose (rem) = exposure (R) x quality factor for the radiation type; 1 rem = 0.01 sievert; 1 rad = 0.01 gray.

Inverse square law: dose rate falls with the square of distance from a point source; doubling distance cuts the dose rate to one quarter.

ALARA dose control hierarchy: time, distance, shielding; halving time in the field halves the dose, and shielding is chosen by radiation type (lead for gamma, plastic or water for beta, hydrogenous material for neutron).

Contamination control: protective clothing, step-off pads, and survey of personnel and tools at the boundary; contamination is measured in counts per minute and converted to disintegrations per minute by detector efficiency.

Primary chemistry control: pH is maintained with lithium hydroxide, boron concentration is adjusted for reactivity, and dissolved oxygen is controlled with hydrogen overpressure to limit corrosion.

Chloride and fluoride limits in the primary system are tight because halide stress corrosion cracking of stainless steel and Inconel is a known failure mode.

Dose rate from a gamma source is halved by about 1 cm of lead for a 1 MeV photon (half-value layer); the half-value layer depends strongly on photon energy.

Airborne radioactivity control: high-efficiency particulate air filters and charcoal filters are used for particulate and iodine; the ventilation flow path must be verified before entry into a posted area.

Three-way communication: sender states the message, receiver repeats it back, sender confirms the repeat is correct; used for any command that changes plant configuration.

Procedure use and adherence: place the place-keeping marker at the current step, read the step before acting, and never work from memory when a procedure exists.

Self-check (STAR): Stop, Think, Act, Review; applied before operating a component or opening a valve.

Peer check: a second qualified person independently verifies the component, the position, and the action before the operation is performed.

Turnover must include current plant configuration, out-of-service equipment, active clearances, and any abnormal conditions; incomplete turnover is a leading cause of configuration errors.

Human performance error precursors include time pressure, fatigue, distraction, vague procedures, and first-time performance; recognizing the precursor allows a defensive action.

Log entries are contemporaneous and factual: time, equipment identifier, action taken, and result; subjective interpretation is separated from observation.

Operating experience is documented and reviewed so that a known failure mode at one plant is checked at another before it recurs.

Ohm's law and power: V = I x R, P = V x I; for three-phase power, P = sqrt(3) x V(line) x I(line) x power factor.

Motor current at reduced voltage: torque varies with the square of applied voltage, so a 10 percent voltage drop cuts starting torque by about 19 percent.

Transformer relation: V1/V2 = N1/N2 and I1/I2 = N2/N1; a step-down transformer raises current in the same ratio it lowers voltage.

AC induction motor slip: synchronous speed = 120 x frequency / number of poles; rotor speed is slightly less than synchronous speed, and slip increases with load.

Diesel generator rating is stated in kW and power factor; the kVA rating is kW divided by power factor, and the engine must carry the kVA load at that power factor.

Pump affinity laws: flow varies with speed, head with speed squared, and power with speed cubed; a 10 percent speed reduction cuts power by about 27 percent.

Pump cavitation occurs when local pressure drops below vapor pressure; net positive suction head available must exceed net positive suction head required to avoid it.

Heat exchanger effectiveness: heat transferred Q = U x A x LMTD; fouling raises the overall resistance and reduces U, so the same duty needs a larger temperature difference.

Reactor coolant pump seal staging: No. 1 seal takes the full RCS-to-letdown differential; No. 2 seal sees a controlled leakoff backpressure; No. 3 seal is the final barrier to containment atmosphere.

Pressurizer level program is temperature-compensated: indicated level varies with RCS average temperature at constant inventory, so level alone cannot confirm inventory during cooldown or heatup.

Instrument channel failure modes: an upscale failure drives alarms and automatic actions high; a downscale failure drives them low; a failed channel is placed in the tripped or bypassed condition per technical specification direction.

Two-out-of-four logic: a trip requires any two channels in the same protection group; a single failed channel does not spuriously trip but defeats the redundancy required for the second.

Steam generator water level is measured by narrow-range and wide-range instruments; narrow range covers normal operation, wide range covers startup, shutdown, and post-accident conditions.

Differential pressure transmitters across an orifice give flow as the square root of dP; a 4x dP increase is a 2x flow increase, so flow errors are amplified at low dP.

Containment hydrogen recombiners and post-accident hydrogen monitors are part of the engineered safety features; hydrogen above roughly 4 percent by volume in air is flammable.

Instrument air loss fails pneumatic valve actuators to their designed failure position (fail-open, fail-closed, or fail-as-is), so the failure position must be known for each valve before declaring air loss.

Reactor startup sequence: criticality by rod withdrawal with boron held constant, then heatup on nuclear heat, then turbine roll and generator synchronization, then power escalation to the target with rod and boron control.

Criticality approach uses the inverse-count-rate plot (1/CR versus rod position or time); a straight line predicts the critical rod position at the extrapolated 1/CR = 0 intercept.

Shutdown margin must remain positive at all times, including during refueling; it equals the reactivity worth of all rods assumed fully inserted minus the reactivity of the core at that condition.

Boron dilution rate is set by charging flow and blended boron concentration; the reactivity addition rate is limited by administrative controls on dilution volume per hour.

Turbine generator synchronization requires matching voltage, frequency, and phase; the breaker is closed when the synchroscope passes slowly through the 12 o'clock position.

During power ascension the axial flux difference and quadrant power tilt are checked against limits at each hold point before further rod withdrawal.

Main steam line drains and turbine bypass valves control steam pressure during low-power operation before the turbine is on line.

A plant heatup rate limit protects vessel and piping from thermal stress; the limit is stated in degrees per hour and applies to the RCS average temperature.

Emergency classification levels escalate: Notification of Unusual Event, Alert, Site Area Emergency, General Emergency; each has specific entry criteria and required notifications.

Loss of reactor coolant accident response: trip the reactor, start safety injection, isolate letdown, and monitor subcooling margin; subcooling margin is the difference between saturation temperature at RCS pressure and the hottest RCS temperature.

Steam generator tube rupture: identify the affected generator by rising level and radiation, isolate it, and control RCS cooldown rate to limit primary-to-secondary leakage.

Station blackout: loss of offsite power plus loss of emergency diesel generators; response relies on battery-backed instrumentation and alternate AC sources if available.

Anticipated transient without scram: if the reactor does not trip on demand, manual trip, then emergency boration and, if needed, containment isolation and injection paths per the emergency procedure.

Loss of feedwater: reactor trip, turbine trip, and auxiliary feedwater start; if AFW fails, steam generator inventory and RCS heat removal become the limiting parameters.

Emergency operating procedures are symptom-based, not event-based; the operator works from the critical safety function status trees: reactivity, core cooling, heat removal, RCS integrity, containment, and inventory.

A small-break LOCA can mask itself: pressurizer level may stay normal while RCS inventory is lost, so subcooling margin and containment radiation are the earlier indicators.

Technical specifications define limiting conditions for operation; an LCO violation requires entry into the applicable action statement within the stated completion time or a plant shutdown.

The three technical specification bases categories: safety limits, limiting safety system settings, and limiting conditions for operation; each action time is derived from the analyzed consequence of continued operation.

Annual effluent and environmental limits are set in the plant's radioactive effluent release permit; releases are monitored and reported, and any unplanned release above limits is reportable.

Reportable events include those in 10 CFR 50.72 (immediate notification) and 10 CFR 50.73 (written report within 60 days); the immediate notification is by telephone to the NRC operations center.

The design basis accident for a light-water reactor is the large-break loss-of-coolant accident; the emergency core cooling system is analyzed against it with acceptance criteria on peak clad temperature, clad oxidation, and hydrogen generation.

ALARA is a regulatory requirement, not an aspiration: exposures must be kept as low as reasonably achievable, with dose limits as the ceiling and ALARA as the operating target below it.

Fitness-for-duty and access authorization programs control who may enter the protected area; the protected area boundary and vital area boundary are distinct security zones.

Surveillance test deferrals require technical specification allowance; a missed surveillance is an LCO issue, not an administrative footnote, and may require a report.

Clearance and tagout: the equipment is de-energized or isolated, locked, tagged, and verified; the operator verifies zero energy before work begins, and only the tag owner removes the tag.

Surveillance frequency basis: a test interval is set so that the probability of an undetected failure between tests stays within the analyzed value; extending an interval requires a technical specification change.

Diesel generator surveillance includes start time, load acceptance, and continuous run at rated load; the monthly and quarterly tests have different acceptance criteria.

Containment integrated leak rate test is performed at reduced pressure and periodic intervals; the acceptance criterion is a maximum leakage rate as a fraction of containment volume per day.

Pump and valve inservice testing verifies required flow, differential pressure, and stroke time; the results are compared with the acceptance criteria in the inservice testing program.

Calibration traceability: instruments are calibrated against standards traceable to a national standard, and calibration records are retained for the required period.

Post-maintenance testing confirms the component performs its safety function before return to service; a functional test is not the same as a calibration check.

Equipment important to safety is classified and its maintenance is controlled by the plant's maintenance rule program, which tracks functional failures and unavailability.

Dose equivalent formulas: dose (rem) = exposure (R) x quality factor for the radiation type; 1 rem = 0.01 sievert; 1 rad = 0.01 gray.

Inverse square law: dose rate falls with the square of distance from a point source; doubling distance cuts the dose rate to one quarter.

ALARA dose control hierarchy: time, distance, shielding; halving time in the field halves the dose, and shielding is chosen by radiation type (lead for gamma, plastic or water for beta, hydrogenous material for neutron).

Contamination control: protective clothing, step-off pads, and survey of personnel and tools at the boundary; contamination is measured in counts per minute and converted to disintegrations per minute by detector efficiency.

Primary chemistry control: pH is maintained with lithium hydroxide, boron concentration is adjusted for reactivity, and dissolved oxygen is controlled with hydrogen overpressure to limit corrosion.

Chloride and fluoride limits in the primary system are tight because halide stress corrosion cracking of stainless steel and Inconel is a known failure mode.

Dose rate from a gamma source is halved by about 1 cm of lead for a 1 MeV photon (half-value layer); the half-value layer depends strongly on photon energy.

Airborne radioactivity control: high-efficiency particulate air filters and charcoal filters are used for particulate and iodine; the ventilation flow path must be verified before entry into a posted area.

Three-way communication: sender states the message, receiver repeats it back, sender confirms the repeat is correct; used for any command that changes plant configuration.

Procedure use and adherence: place the place-keeping marker at the current step, read the step before acting, and never work from memory when a procedure exists.

Self-check (STAR): Stop, Think, Act, Review; applied before operating a component or opening a valve.

Peer check: a second qualified person independently verifies the component, the position, and the action before the operation is performed.

Turnover must include current plant configuration, out-of-service equipment, active clearances, and any abnormal conditions; incomplete turnover is a leading cause of configuration errors.

Human performance error precursors include time pressure, fatigue, distraction, vague procedures, and first-time performance; recognizing the precursor allows a defensive action.

Log entries are contemporaneous and factual: time, equipment identifier, action taken, and result; subjective interpretation is separated from observation.

Operating experience is documented and reviewed so that a known failure mode at one plant is checked at another before it recurs.

Ohm's law and power: V = I x R, P = V x I; for three-phase power, P = sqrt(3) x V(line) x I(line) x power factor.

Motor current at reduced voltage: torque varies with the square of applied voltage, so a 10 percent voltage drop cuts starting torque by about 19 percent.

Transformer relation: V1/V2 = N1/N2 and I1/I2 = N2/N1; a step-down transformer raises current in the same ratio it lowers voltage.

AC induction motor slip: synchronous speed = 120 x frequency / number of poles; rotor speed is slightly less than synchronous speed, and slip increases with load.

Diesel generator rating is stated in kW and power factor; the kVA rating is kW divided by power factor, and the engine must carry the kVA load at that power factor.

Pump affinity laws: flow varies with speed, head with speed squared, and power with speed cubed; a 10 percent speed reduction cuts power by about 27 percent.

Pump cavitation occurs when local pressure drops below vapor pressure; net positive suction head available must exceed net positive suction head required to avoid it.

Heat exchanger effectiveness: heat transferred Q = U x A x LMTD; fouling raises the overall resistance and reduces U, so the same duty needs a larger temperature difference.