ML21062A195

Revised Written Examination (Parent Questions File) (Regional Audit Corrective Action)(Folder 2)

ML21062A195
Person / Time
Site:	Limerick
Issue date:	03/03/2021
From:	Brian Fuller Operations Branch I
To:	Byers T Exelon Nuclear Generation Corp
Shared Package
ML18116A036	List: IR 05000352/2018301 ML18116A054 ML20115E461 ML21040A471 ML21040A483 ML21050A181 ML21050A227 ML21062A195
References
CAC 000500
Download: ML21062A195 (14)

Text

Question 3 Parent Predict impact of DC power loss on CRD pump during ... Question Preview Question ID: 1097642 Points: 1.00 Unit 1 is operating at 100% power, with the following:

- Div 4 DC bus is de-energized due to ground fault

- '1 B' CRD Pump is in service

- No ECCS pumps are in service A LOCA results in reactor level lowering to -150".

N.Q operator action has been taken other than normal scram actions.

WHICH ONE of the following pumps will be running following the LOCA?

A. '18' CRD B. '1D' RHR C. 'OB' RHRSW D. '1D' Core Spray

!Answer A Answer Explanation With Div 4 DC de-energized, 4KV breakers on the D14 Bus will lose control power. This will prevent the breakers from being operated remotely or automatically. Since the 1 B CRD Pump breaker was already closed, it will remain closed after the LOCA since it will be unable to automatically trip. Any ECCS pumps powered from D14 (such as OB RHRSW, 1D RHR, and 1D Core Spray), which would start on a LOCA signal, will be unable to start without breaker control power available.

Answer: 1 B CAD, for the reasons above.

Distracters: OB RHRSW, 1D RHR, 1D Core Spray are wrong for the reasons above.

Question Information Predict impact of DC power loss on CRD pump during a LOCA I I Topic User ID MOD 2012 CERT-14 System ID 1097642 LM-OPS I I Project Status Active Point Value 11.00 Time (min) 13 Open or Closed Reference CLOSED Cognitive Level HIGH Operator Discipline LO-I Operator Type RO Question ID: 1097642 02/15/2021 2 of 4

Question 18 Parent High Off-site Release Rate - protection of the gen... Question Preview

!Question 1 ID: 1799237 Points: 1.00 I Plant conditions are as follows:

• Unit 1 is at 100%.

• Unit 2 is in OPCON 5 with refueling activities in progress with secondary containment set on the refuel floor.

• All, "REFUEL FLOOR/RX ENCL CNTMT ISO INTERLOCK" switches are in "NORMAL"

• A fuel handling accident results in Refuel Floor ventilation radiation levels of 13 mR/hr Regarding the reactor enclosure and the refuel floor, which of the following describes the Zones SBGT will maintain at a negative pressure and the reason for the initiation of SBGT?

Zones SBGT will maintain negative Reason for SBGT Initiation A. Refuel Floor ONLY Limit iodine and particulate concentration in gases, prior to discharge B. Refuel Floor ONLY Limit particulate concentration in gases ONLY, prior to discharge C. Unit 1 reactor enclosure and Refuel floor Limit iodine and particulate concentration in gases, prior to discharge D. Unit 1 reactor enclosure and Refuel floor Limit particulate concentration in gases ONLY, prior to discharge I Answer A Answer Explanation A Correct Refuel HVAC isolates at 2.00 mr/h. Although refuel floor containment and Unit 1 Reactor Containment are set, only when Zones are crosstied will a refuel HVAC isolation also isolate the Reactor enclosure. The purpose of the SBGT filters per the Design basis document L-S-32 is The SGTS/RERS filters iodine and particulate concentrations in gases potentially present within the Secondary Containment prior to discharge to the environment via the North Stack.

B Incorrect Limit particulate only is incorrect but plausible to the examinee who does not recall the purpose of the charcoal filters C incorrect plausible to the examinee who recognizes that the radiation levels are above the Reactor Enclosure setpoint, but either does not recall the crosstie logic or believe that hi refuel radiation will isolate the reactor enclosure as long as the zone is established D incorrect plausible to the examinee who recognizes that the radiation levels are above the Reactor Enclosure setpoint, but either does not recall the crosstie logic or believe that hi refuel radiation will isolate the reactor enclosure as long as the zone is established and does not recall the purpose of the charcoal filters Question ID: 1799237 02/15/2021 2 of 4

Question 28 Parent Examination Outline Cross-reference: Level RO SRO Tier# 2 Group# 1 KIA# 203000A4. 09 Importance Rating 4.1 A4.09 -Ability to manually operate and/or monitor in the control room: System flow (RHR/LPCI Injection Mode)

Proposed Question: Common 20 Unit 1 experienced a LOCA.

Current Unit 1 plant conditions are as follows:

Reactor level -160inches, down slow Reactor pressure 240psig,down slow Drywell pressure 5.7 psig, up slow One minute later, Unit 2 receives a spurious low-pressure ECCS initiation signal on low reactor level.

Current Unit 2plant conditions are as follows:

Reactor level +30inches, stable, controlled with RCIC and HPCI Reactor pressure 900psig, up slow,controlled with SRVs Drywell pressure 0.4psig, stable Which of the following describes the total approximate RHR system flow indicated on each unit?

Unit 1 Unit 2 A. 40,000gpm 2,000gpm B. 40,000gpm 0gpm C. 20,000gpm 2 ,000gpm D. 20,000gpm 0gpm

Question 44 Parent SGTS - Response to Process Rad Monitor Spikes... Question Preview lauestion 1 ID: 1798989 Points: 1.00 I Unit 1 is operating at 100% Power when the following process radiation monitors momentarily spike to the indicated values due to an electrical transient:

RISH-26-1K609C, REACTOR BLDG VENTILATION MON: 1.4 mR/hr and RISH-26-1K609D, REACTOR BLDG VENTILATION MON: 1.7 mR/hr WHICH ONE of the following identifies the status of the Standby Gas Treatment System (SGTS) for the above conditions:

A SGTS Fan B SGTS Fan A. NOT Running NOT Running B. NOT Running Running C. Running NOT Running D. Running Running I Answer B Answer Explanation From the stem the candidate determines that both process radiation monitors malfunctions took them above the isolation set point of 1.35 mR/hr. Based on this information the candidate concludes that the B SGTS fan is now in service.

From LGSOPS0076 Lesson Plan:

Question ID: 1798989 02/15/2021 2 of 5

SGTS - Response to Process Rad Monitor Spikes... Question Preview REACTOR ENCLOSURE ISOLATION SIGNALS SIGNAL DIVISION 1 DIVISION 2 SETPOINT MANUAL HS76-*78A HS76-*78B Arm & Depress EXH. HI A and B Inst. C and D Inst. *l.35mR/Hr RAD LOWRPV A and B Inst. C and D Inst. -38", 1.68#

LEVEUHIGH DW PRESSURE SGTS HV76-*96 HV76-*97 Not full closed DAl'vlPER OPEN LOWZONE A B -0.-r'H2O for 50 DP minutes (still a vacuum, but not enough vacuum)

REFUEL Any Div 1 Any Div 2 lsol.

• FLOOR lsol.

ISOLATION A Wrong - Plausible to the candidate that recalls the incorrect isolation set point (2.0 mR/hr for refuel ventilation exhaust).

B Correct for the above reasons C Wrong - Plausible to the candidate that recalls the incorrect Logic system association (i.e. they incorrectly recall that the OA Fan is associated with an Div 2 isolation)

D Wrong - plausible to the candidate the confuses the isolation logic with that of the CREFAS system where an upscale condition in the C detector would start the A Fan and an upscale on the D detector would start the B Fan.

Question Information Topic SGTS - Response to Process Rad Monitor Spikes User ID Q #12 I System ID 11798989 Project LM-OPS Active 11.00 13 Status I Point Value !rime (min)

Open or Closed Reference CLOSED Cognitive Level HIGH Operator Discipline LO-ct Operator Type RO References Provided None KIA Justification SRO-Only Justification Not applicable Additional Information Question ID: 1798989 02/15/2021 3 of 5

Question 67 Parent Refueling Administrative requirements... Question Preview lauestion 1 ID: 1845800 Points: 1.00 I Unit 2 is in OPCON 5 with Core Shuffle 2 in progress.

• The 2A SRM is bypassed

• The 2D SRM is INOP due to spiking WHICH ONE of the following identifies a core location where a fuel assembly may be inserted, if any, for the above conditions?

ATTACHMENT 1 SRM Quadrant Boundaries Page 1 of 1 0103050709 It 13 151719 ZI Z3Z5

A ,;

rn rzj 52 50 r?A 1§1 "4 11.§1 I 2

40 rzj 38 36

=

')0 28 28 Z6 f,

N N 22 2 zo co 18 mm If, 14 14 le' l?i,J le 10 10 08 OE>

04 D

fiJ1m C ::

lfiJl ffJ 04 oz 0c 010'3050709 ll 1'3 151719 2123c527Z '31'33'35 '37'39413"5"7 ..951'3 55 5759 o LPRM HIRM asRM A. 35-06 B. 27-56 C. 07-18 D. No locations Question ID: 1845800 02/19/2021 2 of 4

Refueling Administrative requirements... Question Preview I Answer A Answer Explanation From the stem the candidate determines that the 2A and 2D SRMs are INOP. Using this information, attachment 1 from NF-LG-310-2000 provided, and their knowledge of Tech Spec LCO 3.9.2 they determine that core alterations can continue in the B and C quadrants. Only 35-06 is in a quadrant where core alterations can continue.

REFUELING OPERATIONS 3/4.9.2 INSTRUMENTATION LIMITING CONDITION FOR OPERATION 3.9.2 At least two source range monitor <SRM) channels* shall be OPERABLE and inserted to the normal operating level with:

a. Continuous visual indication in the control room,

b. At least one with audible alarm in the control room,

c. One of the required SRM detectors located in the quadrant where CORE ALTERATIONS are being performed and the other required SRM detector located in an adjacent quadrant, and

d. Unless adequate SHUTDOWN MARGIN has been demonstrated, the "shorting links" shall be removed from the RPS circuitry prior to and during the time any control rod is withdrawn.**

A Correct for the above reasons B Wrong - plausible to the candidate that incorrectly uses attachment 1 (SRM Locations, Fuel Assembly coordinates, etc.)

C Wrong - plausible to the candidate that incorrectly uses attachment 1 (SRM Locations, Fuel Assembly coordinates, etc.)

D Wrong - plausible to the candidate the incorrectly applies Tech Spec 3.3.7.6.a where 3 SRMs are required to be operable for startup with IRMs on range 2 or below.

Question Information Topic Refueling Administrative requirements User ID 0#67 I System ID 11845800 Project LM-OPS Status Active I Point Value 11.00 I Time (min) 13 Open or Closed Reference CLOSED Cognitive Level HIGH Operator Discipline LO-ct Operator Type RO References Provided None KIA Justification Question ID: 1845800 02/19/2021 3 of 4

Question 81 Parent SRO action for loss of SOC ... Question Preview jauestion 1 ID: 1150607 Points: 1.00 I

• • • • • • • • • • • • • • • • • • • • SRO ONLY********************

Unit 2 is in OPCON 3 shutting down for a scheduled refueling outage:

- Reactor pressure is 68 psig.

- 2A AHR is in Shutdown Cooling The 2A AHR pump trips and cannot be restarted

- Reactor pressure is rising at 1 psig per minute

- The RO reports it will take 15 minutes to place 2B AHR in SOC (1) If no operator action is taken what is the earliest that an inboard isolation will occur?

(2) What actions should the CRS direct to allow 2B AHR to be started in shutdown cooling?

A. (1) When either A or B reactor pressure transmitter exceeds 75 psig (2) When reactor pressure exceeds 75 psig defeat the shutdown cooling isolation per ON-121 attachments 3 and 4 B. (1) When both A and B pressure transmitters exceeds 75 psig (2) Maintain Reactor pressure within SOC limits using bypass valves per ON-121 attachment 5 C. (1) When either A or B reactor pressure transmitter exceeds 75 psig (2) Maintain Reactor pressure within SOC limits using bypass valves per ON-121 attachment 5

0. (1) When both A and B reactor pressure transmitters exceeds 75 psig (2) When reactor pressure exceeds 75 psig defeat the shutdown cooling isolation per ON-121 attachments 3 and 4 JAnswer C Answer Explanation The NSSSS Group 2A isolation on reactor pressure is isolation signal V with a value of 75 psig. From GP-8.1 is can be seen that the closure of HV-51-2F009 is from channel Am B.

Question ID: 1150607 02/19/2021 2 of 6

SRO action for loss of SOC... Question Preview GP-8.1, Rev. 14 Page 53 of 61

• UNIT 2 ONLY *

• V V: REACTOR PRESSURE -HIGH (RHR VALVE PERMISSIVE} RESET - R1 Group IIA - RHR S/DCooling (Other Signal: A)

EQUIPMENT NAME POSITION CHANNEL BYPASS HV-51-2F009 "RHR SID Clg Suction" Close Aor B None (INBD)

HV-51-2F008 "RHR S/DClg Suction" Close C or D None (OUTBD) I HV-51-2F050A(B) "RHR S/DClg Rtn Ck" Close Aor B None  !

(INBDCHECK)

HV-51-251A(B) "RHR S/DClg Rtn Ck Equal" Close Aor B None (TEST )

HV-51-2F015A(B) "RHR S/DClg Rtn" (OUTBD) Close C or D None The correct ON-121 actions is to reduce Rx pressure to within the shutdown cooling pressure limits by performing Attachment 5. Attachment 5 has the operator lower RPV pressure using BPVs.

ON-121 Attachment 3 and Attachment 4 are for bypassing inadvertent Inboard and Outboard isolations, respectively. They are not for bypassing isolations.

For the above reasons, C is correct.

A, B, and D are plausible if the student fails to recall that these isolations are single channel isolations (most NSSSS isolations require multi channels to provide an isolation signal) and/or fails to recall that bypassing the isolations is only if they are inadvertent.

Question Information SRO action for loss of SOC I

Topic User ID LGSOPS0051.08C.01 System ID I 1150607 LM-OPS I

Project Status Active Point Value 11.00 I rime (min) 1 3

Open or Closed Reference CLOSED Cognitive Level HIGH Operator Discipline LO-R Operator Type SRO CFR: 43.5 Assessment of facility conditions and selection of appropriate procedures during normal, abnormal, and emergency situations.

1 0CFR55 Content References Provided I None Question ID: 1150607 02/19/2021 3 of 6

Question 86 Parent ID: S82 Points: 1.00 Source: NEW An ATWS has occurred and the Operating Shift is executing the EOPs. SLC Pump A was started at 12: 15 with a SLC tank level of 72 inches. The P603 operator observes that RWCU Isolates as required and SLC Tank level is trending down normally.

Assuming that the SLC system continues operating normally at time 12:45 which of the following EOP actions would be directed?

A. Shutdown SLC pumps B. Depressurize the RPV at< 90 ° F/hr C. Keep RPV water level between -25 inches and 114 inches D. Restore and keep RPV water level between 173 inches and 214 inches Answer: D ILO 2015 Written Page: 183 of 220 08 September 2015

Question 92 Parent Reactivity Addition - Low Power Accident... Question Preview lauestion 1 ID: 1845791 Points: 1.00 I Unit 1 is performing a startup:

Reactor Power is 4%

Control Rod 34-27 is being withdrawn to position 48.

Alarm 108 REACTOR F-5, ROD OVERTRAVEL is received.

WHICH ONE of the following identifies what postulated UFSAR Chapter 15 transient is of concern in this situation and a component that mitigates the effect of this transient?

UFSAR Chapter 15 transient Component that minimizes the transient A. Control Rod Drop Accident Velocity Limiter B. Control Rod Drop Accident Collet Fingers C. Control Rod Withdrawal Error Velocity Limiter D. Control Rod Withdrawal Error Collet Fingers

!Answer A Answer Explanation From the stem the candidate determines that Control Rod 34-27 is not coupled to the Control Rod Drive (CRD) and the control rod position is unknown (it could be anywhere between position 00 and 48). This is the situation of the Control Rod Drop Accident with the worst case being the control rod stuck at position 00 and dropping uncontrollably from 00 to 48. The analysis described in UFSAR 15.4.9.3.3 results in the assumed failure of 1200 fuel rods. This would result in radiation level requiring entry into The Emergency Action Plan, at a minimum for Threshold RU3 - 2 (Specific coolant activity> 4.0 micro curies per gram.)

The equipment credited in minimizing the impact of this accident are the Rod Worth Minimizer (which enforces a control rod sequence that minimizes local power peaks) and the velocity limiter (physical component on the Control Rod Blade that creates hydraulic drag to limit the speed of the control rod and the subsequent rate of reactivity insertion).

A Correct for the above reasons B Wrong - plausible if the candidate confuses the components of the CRD with the Control Rod Blade. The Collet Fingers are a component designed to prevent the CRD from withdrawing without a command signal, not the Control Rod Blade C Wrong - Plausible to the candidate that believes the Control Rod Withdrawal error transient is the concern in this situation due to the assumption that the control rod has not actually been withdrawn (due to it being uncoupled).

Question ID: 1845791 02/19/2021 2 of 4

Reactivity Addition - Low Power Accident... Question Preview D Wrong - Plausible to the candidate that believes the Control Rod Withdrawal error transient is the concern in this situation due to the assumption that the control rod has not actually been withdrawn (due to it being uncoupled) and plausible if the candidate confuses the components of the CRD with the Control Rod Blade. The Collet Fingers are a component designed to prevent the CRD from withdrawing without a command signal, not the Control Rod Blade Question Information Reactivity Addition - Low Power Accident I

Topic User ID 0#64 System ID 1 1845791 LM-OPS I I Project Status Active Point Value 1 1.00 Time (min) 12 Open or Closed Reference CLOSED Cognitive Level HIGH Operator Discipline LO-ct Operator Type RO References Provided None KIA Justification SRO- Only Justification Not applicable Additional Information General Data Level RO Tier 1 Group 2 KA# and Rating 295014 G2.4.9 RO Importance 3.8 295014 Inadvertent Reactivity Addition / 1 2.4.9 - Emergency Procedures I Plan: Knowledge of KA Statement low power I shutdown implications in accident (e.g.,

loss of coolant accident or loss of residual heat removal) mitiQation strateQies.

Cognitive level High Safety Function 1 - Reactivity Control I

41.10 I

10 CFR 55 UFSAR 15.4 08 Tech Spec Bases 3/4.1.1 Technical Reference with Revision No: Rev#:

Justification for Non SRO CFR Link: N/A Question Historv: (i.e. LGS NRC-05 OVS CERT-04) New Question Source: (i.e. New Bank Modified) New Low KA Justification (if reauired): N/A Revision History: Revision History: (i.e. Modified distractor "b" to make plausible based on OTPS review)

ILT Supplied Ref (If appropriate): (i.e. ABN-##) None LORT PRA: (i.e. Yes or No or#)

LORT Question Section: (i.e, A- Systems or B- Procedures)

Comments Question ID: 1845791 02/19/2021 3 of 4