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Pirtle NRC PREP > EOP > Flashcards

EOP Flashcards

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1
Q

What are the methods of heat removal for a SBLOCA?

A

ECCS Flow / Breaker Flow

AFW / SGs

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2
Q

Why is a CL Break considered the worst scenario for a SBLOCA?

A

More mass is lost prior to ECCS flow equaling break flow. The cross under loop seal must be clear before steam can be vented from the break

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3
Q

What are indications of a faulted SG?

A

Tave lowers

Rx Power Rises

Possible turbine load lowering

SF > FF

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4
Q

What are indications of SGTR?

A

SJAE / GSLO Rad monitors high

SG Level rising uncontrollably

PRZ Pressure and Level Lowering

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5
Q

What are indications of a LOCA?

A

Containment Rad Monitor & Dew Point rising

PRZ Level and Pressure lowering

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6
Q

What does meeting your SI termination subcooling criteria tell you?

A

Adequate core cooling and secondary heat sink

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7
Q

What does meeting your heat sink SI termination criteria tell you?

A

Ensure subcooling will be maintained following termination

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8
Q

What does meeting your RCS Pressure SI Termination criteria tell you?

A

Ensures subcooling will be stable / rising and SI flow is effective in raising RCS Inventory

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9
Q

What does meeting your PRZ Level SI Termination Criteria tell you?

A

Sufficient RCS Inventory

Only valid if RC is subcooled

Ensures ability to maintain pressure following termination

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10
Q

Why do RCPs need to be tripped on a phase B?

A

Loss of CCW flow to RCP LO Coolers

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11
Q

In E-0, why do we lower AW to < 450K pph?

A

Limits overcooling the RCS

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12
Q

What removes most of the heat from the head on NC?

A

CRDMs

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13
Q

What are the benefits of restarting RCPs?

A

Enhances core heat removal

Improves RCS Pressure and Temp Control

Improves PRZ Level Control

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14
Q

Which RCP is the most effective?

A

3 bc it has the most dP

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15
Q

What are the 3 factors affecting spray flow?

A

Vessel and RCS piping DP

Coolant Velocity head at spray flow scoop located at spray flow penetration in CL

PRZ Level

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16
Q

What are the indications of NC?

A

Subcooling ? 40*F

Stable or Lowering:

  • SG Pressures
  • CETCs
  • RCS HL Temps

RCS CL Temps at saturation temp for SG Pressure

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17
Q

What should be done if NC cannot be verified?

A

Raise steam dump flow

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18
Q

For a SBLOCA, why is 1300# trip criteria?

A

Ensures RCPs are stopped before the break is uncovered so no additional mass is lost

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19
Q

Why is CCW to RHR adjusted to 5,000 gpm during CL Recirc?

A

Prevents pump Runout if 1 pump fails

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20
Q

When is RHR Spray placed in service?

A

50 mins (allows decay heat removal) - 70 mins (containment peak pressure)

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21
Q

What are the 10CFR100 Limits at the site boundary?

A

25 REM Whole Body, 300 REM Thyroid for 2 hours

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22
Q

For a Faulted SG, when will you have a SI?

Study These Flashcards
A

Upstream of the MSIVs for a steam break or downstream of check valve for a feed break.

23
Q

In E-2, faulted SG Isolation, why will AFW have to be periodically reduced to maintain SG Levels after RCS Temp is stabilized?

Study These Flashcards
A

Lowering Decay Heat Levels

24
Q

In E02, Faulted SG Isolation, why do we control AFW Flow?

Study These Flashcards
A

Prevent SG Dryout

Minimize RCS Cooldown

Prevent SG Overfill

Control RCS Temp after Cooldown is stopped

25
During E-3, SGTR, why do we want to terminate SI?
Helps control primary to secondary leakage
26
What could be a potential problem if the SG is overfilled during a SGTR?
Rupture of MS Line from weight of the water Damage to PORVs, Safeties and TDAFP
27
During a SGTR, what is the affected SG PORV set point changed to and why?
1040 psig to minimize the release
28
Why do we ensure the ruptured SG level reaches 13% before isolated AFW to it?
To ensure SG Tubes are covered, which will prevent depressurization
29
What does the UFSAR assume for a SGTR?
Operator actions are taken to isolate ruptured SG efficiently
30
What are the advantages and disadvantages of ES-3.1, Cooldown using backfill?
+ Minimizes radiological releases and allows processing of RCS - Potential boring dilution, secondary chemistry effects on RCS, Slow
31
What are the advantages and disadvantages of using ES-3.2, Cooldown using blowdown?
+ Minimizes radiological releases, NO boron dilutions or chemistry effects - storage / processing capabilities, spreads contamination, SLOW
32
What are the advantages / disadvantages of using ES-3.3, cooldown using steam dump method?
+ FAST - Contamination / radiation, potential water hammer on secondary components.
33
What is the purpose for tripping the turbine in FR-S.1?
Prevents excessive cooldown and conserves SG Water
34
Why do you NOT trip RCPs if power is >5%?
Provides core cooling and keeps fuel integrity in tact
35
Is an ATWS worse at BOL or EOL?
BOL due to less temperature feedback
36
Why is RCS pressure checked less than PRZ PORV setpoint in FR-S.1?
ensures ability to emergency borate
37
How could an unneeded SI complicate an ATWS?
FWI and MFPs will trip which will mean SGs could dryout
38
What are the possible ways to lose subcriticality during an ATWS?
Dilution Cooldown Rods do not fully insert
39
Why does ECA-1.1, Loss of emergency coolant recirc, direct depressurizing the SGs to 670 psig?
To prepare for a controlled accumulator injection to keep the core covered
40
What are the assumptions concerning the LBLOCA analysis?
Some zirc-water reaction is expected ECCS flow to the faulted loop and the accumulator injection for that loop spills to containment RHR pumps must not be aligned for spray prior to 50 mins after the onset to ensure decay heat levels are within the heat removal capability of 1 CCP and 1 SI pump Core safety could be challenged if RHR and CTS flow is interrupted for more than 5 mins while transferring over to CL Recirc
41
When should you not restart RCPs for ES-1.2, Post LOCA Cooldown and Depressurization?
When all seal cooling has been lost long enough that maximum RCP seal parameters have been exceeded. Instead, cool the RCS to reduce temp of the water flowing thru the pump seals This removes the potential thermal shock damage to the seals
42
What do CET temps of 757*F indicate?
Superheated core exit
43
Why is a 1” SBLOCA the worst scenario for FR-C.1?
Loop seal never clears, so steam mass loss rate out the break isn’t reduced.
44
What is indicative of superheated conditions?
High CETCs
45
What is indicative of core uncovery?
Low RVLIS
46
What is significant about 46% RVLIS level?
COre covered.... 3.5 ft from bottom of core
47
Why are RCPs stopped in FR-C.1 after SGs are Depressurize to 160 psi?
Loss of #1 seal requirements
48
Why are RCPs so important in FR-C.1?
They provide forced 2 phase flow to prevent inadequate core cooling
49
In FR-P.1, how long do you soak and when does the clock start?
1 hr when temps is stable
50
Is a cooldown or heatup more limiting for RCS Integrity and why?
Cooldown bc of tensile stress on the inner wall
51
What’s the worst case PTS accident and why?
3” SBLOCA when both RCS forced flow and NC are lost and cold RWST water streams to vessel belt line welds.
52
What are the benefits of feed and bleed?
Minimize core uncovery and prevent inadequate core cooling
53
When is an ATWS worse?
BOL due to less feedback from a smaller MTC

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