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AOPs > AOP-2 Excessive Load > Flashcards

AOP-2 Excessive Load Flashcards

1
Q

What is AOP-2 and its entry criteria?

A

AOP-2 Criteria

Excessive Load Procedure. Goal is to isolate the load.

Entry Criteria:

  1. EK-0968, “LOOP 1 TAVE/TREF GROSS DEVIATION” (5F)
  2. EK-0969, “LOOP 2 TAVE/TREF GROSS DEVIATION” (5F)
  3. EK-1362, “CONTAINMENT PRESSURE OFF NORMAL” with a steam leak in containment
  4. Turbine Governor Valve Control Malfunction (open)
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2
Q

What are the AOP-2 Exit Criteria?

A

AOP-2 Exit Criteria

  • An inappropriate procedure has been implemented. An inappropriate AOP may have been implemented if the event was misdiagnosed.
  • Once the event has been mitigated, and the plant is stable, the appropriate operating procedure should be used.
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3
Q

What happens with increased steam flow?

A

Feed Reg valves open to match increase in steam flow and maintain SG water level.

Secondary (SG) system pressure drops. Temperature drops.

SG Primary Side outlet temperature drops (Tcold). Tave drops.

Pressure level drops as PCS shrinks.

If negative MTC, reactor power rises.

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4
Q

Will the reactor trip during a increased steam demand event?

A

Depending on the magnitude of the increase in steam demand, a reactor trip
may not be activated.

Instead, the reactor system will reach a new steadystate
condition at a power level greater than the initial power level which is
consistent with the increased heat removal rate.

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5
Q

What is most likely to trip the reactor during an excess steam demand event?

A

TM/LP

Variable High Power

  • The limiting DNB case will typically trip on the variable overpower trip.
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6
Q

How does the VHP Trip function and what/why is decalibrated?

A

VHP auctioneers the highest of Delta-T or NI-Power.

  • Delta-T signal is decalibrated due to hot and cold leg RTD lag times.
  • NI-Power is decalibrated due to excore shadowing by cold water in the downcomer region.
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7
Q

What is the criteria for tripping the reactor during an excess steam demand event? Turbine?

A

Reactor

  • An un-isolable load rise which exceeds 1% change in HB Power Steady, NI or ΔT Power
  • A plant condition requiring a power reduction at a rate greater than 30%/hour
  • EK-1362, “CONTAINMENT PRESSURE OFF NORMAL” in alarm AND a steam leak inside containment
  • Reactor power greater than or equal to 15% AND Turbine Governor Valve Control in manual and not controlling

Turbine

  • Reactor power less than 15% AND Turbine Governor Valve Control in manual and not controlling
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8
Q

What AOP-2 Criteria would leak to an EI Plan entry?

A

Unusual Event

Any loss or any potential loss of Containment (Table F-1)

Containment Pressure greater than 55 psig

Contain pressure 4 psig with less than one full train of containment cooling system operating.

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9
Q

What MWe output on the generator equates to a 1% reactor power rise?

A

9 MW

Reactor Trip Criteria

  • An un-isolable load rise which exceeds 1% change in HB Power Steady, NI or ΔT Power
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10
Q

What events cause an excess load within AOP-2?

A
  • Turbine Governor Valve Control malfunction
  • Turbine Bypass Valve (CV-0511) open
  • Atmospheric Steam Dump Valve(s) open
  • High Energy Line Break or Steam Generator Code Safety stuck open
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11
Q

What are the actions for Governor Valve Malfunction?

A

Governor Valve Malfunction

  • PLACE Turbine Controls to MANUAL
  • VERIFY Turbine Governor Valve control restored.
  • CLOSE the Governor Valves using the Governor Close button to restore Reactor power to pre-event level or less as indicated by HB Power Steady, NI or ΔT Power.
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12
Q

What are the actions for a TBV Malfunction?

A

TBV Malfunction

CLOSE CV-0511 as follows:

  • DEPRESS the “M” pushbutton on PIC-0511, Turbine Bypass Valve Controller.
  • PLACE AND HOLD PIC-0511 manual lever to CLOSE until the valve position green closed light illuminates.
  • RELEASE PIC-0511 manual lever.

RNO

Isolate valve manually

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13
Q

What are the actions for an ASDV Malfunction?

A

ASDV Malfunction

CLOSE Atmospheric Steam Dump Valve(s) as follows:

  • DEPRESS the “M” pushbutton on HIC-0780A, Atmospheric Steam Dump Controller.
  • PLACE AND HOLD HIC-0780A manual lever to CLOSE until the valve position green closed light(s) illuminate.
  • RELEASE HIC-0780A manual lever.

RNO

Closed air supply valve for affected ASDV (preferred)

Manually isolate ASDV

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14
Q

What are the actions for a MS Code Safety?

A

MS Code Safety

If verified that a code safety is lifting then:

COMMENCE a power reduction at a rate of less than or equal to 30%/hour. Refer to
GOP-8, “Power Reduction and Plant Shutdown to Mode 2 or Mode 3 525F.”

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15
Q

What are the actions for a HELB?

A

HELB

VERIFY containment parameters normal.

  • IF indications of a steam leak inside Containment, AND EK-1362, “CONTAINMENT PRESSURE OFF NORMAL” is in alarm, THEN TRIP the Reactor.

LOCATE AND ISOLATE the High Energy Line break.

  • COMMENCE a power reduction at a rate of less than or equal to 30%/hour. Refer to GOP-8, “Power Reduction and Plant Shutdown to Mode 2 or Mode 3 <= 525F.”
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16
Q

At what setpoints do code safety valves lift? What T.S. applies?

A

1000, 1020 and 1040 psia (+ or - 3%)

T.S. 3.7.1

Twenty-three MSSVs shall be OPERABLE in Modes 1, 2 and 3

Beyond 3% of setpoint, valve is not operable.

17
Q

What is the ASDV T.S.?

A

ASDV T.S. 3.7.4

One ADV per steam generator shall be OPERABLE.

MODES 1, 2, and 3,
MODE 4 when steam generator is being relied upon for heat removal.

18
Q

Where are the SGCS and ASDV outlets?

A

B are East and North

A are West and South

19
Q

What are indications of stablity following AOP-2 actions?

A

Stable Indications

  • Pressurizer level is controlled and approaching normal programmed level. (42% - 57%).
  • Pressurizer pressure is controlled and approaching normal operating pressure of 2060 psia.
  • Both Steam Generator levels are controlled and approaching normal level (60% to 70%).
20
Q

What are the implications of Pressurizer pressure NOT greater than 2010 psi?

A

Pressurizer pressure NOT greater than 2010 psi

T.S. 3.4.1

PCS DNB parameters for pressurizer pressure, cold leg temperature, and PCS total flow rate shall be within the limits specified in the COLR in Mode 1.

21
Q

What is the Power Limit check per AOP-2?

A

Power Limit

VERIFY Reactor Power maintained less than or equal to 100.1%.

At 2565.4 MWt a 0.49% uncertainty is the difference to the 2580.6 safety analysis.

The intent of this step is to check that the licensed rated thermal power limit has been exceeded and if so, to make appropriate report to the NRC.

22
Q

What is the purpose of the Chemistry Check if power has changed greater than 15% MWt in any 1-hour period?

A

Chemistry Check

The intent of this step is to ensure surveillance requirements of T.S. SR 3.4.16.2 are met.

T.S. S.R. 3.4.16.2

  • Verify primary coolant DOSE EQUIVALENT I-131 specific activity ≤ 1.0 μCi/gm.
  • Performed every 14 days AND Once between 2 and 6 hours after THERMAL POWER change of ≥ 15% RTP within a 1 hour period
23
Q

What are the final two steps of AOP-2 and why?

A

AOP-2 Final

Inform RP to consider posting changes in Aux Building.

Ensure applicable steps are completed prior to exit.

CRS should review marked-up procedure to verify that all applicable steps have been completed prior to exiting procedure. If considered necessary, a crew brief may be conducted to assist in this determination.

24
Q

What is the mitigation strategy for an excess load event per AOP-2?

A
  1. Reduce turbine load to compensate for load increase.
  2. Add reactivity (borating and/or insert control rods) as necessary to maintain TAVE +-3F of TREF.
  3. Ensure systems are responding to stabilize plant conditions.
  4. Isolate/Terminate the excessive load condition.

AOPs (21 decks)

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