ML23159A080
| ML23159A080 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/08/2023 |
| From: | NRC/RGN-II |
| To: | Southern Nuclear Operating Co |
| References | |
| 50-424/23-301, 50-425/23-301 50-424/OL-23, 50-425/OL-23 | |
| Download: ML23159A080 (1) | |
Text
Comment from Applicant RO Question #67 KIA G2.4.16 Initial Conditions:
Unit 1 reactor trip and SI occur due to a LOCA RWST level is 26% and lowering 19013-1, "Transfer to Cold Leg Recirculation," is in progress.
Current Conditions Crew is at Step 3 of 19013-1 "Initiate ATTACHMENT -1 to align ECCS Pumps to the Cold Leg Recirculation flowpath" ST A reports a valid RED path exists on Core Cooling Neither Train of ECCS has been aligned for Cold Leg Recirculation Which one of the following completes the following statement?
Based on the conditions given, the crew_ (1) _ required to immediately transfer to procedure 19221-1, "Response to Inadequate Core Cooling,"
And Once procedure 19221-1 has been entered, the OATC _ (2)_ permitted to continue with subsequent steps of 19013-1 concurrently.
(1)_
_(2)_
is NOT is is NOT is NOT is is is is NOT The first part of the question asks, based on current plant conditions, if a transition to the "Response to Inadequate Core Cooling" procedure is required. The current conditions state the crew is at step #3 of 19013-1, "Transfer to Cold Leg Recirculation".
A note prior to step #1 of the "Transfer to Cold Leg Recirculation" procedure states "FRPs should not be implemented until at least one flow path exists from the CNMT sumps to the RCS Cold Legs and the completion of step #13." Per the bases of 19013-1, the intent of this note is to ensure the operation is done to align the Safety Injection systems to cold leg recirculation in a rapid manner to ensure core cooling is maintained.
The safety injection systems include Residual Heat Removal, Safety Injection, and Charging. These steps ensure adequate core cooling through cold leg recirculation, no Critical Safety Functions (FRPs) could be successful until this evolution is complete. A transition to 19221-1, "Response to Inadequate Core Cooling" would not occur at this step. The answer to the first part of this question is "IS NOT".
The second half of this question states, "Once procedure 19221-1 has been entered, the OATC _ (2) _ permitted to continue with subsequent steps of 19013-1 concurrently."
Per the Transient Response Procedure User's Guide, NMP-AP-005-004, "There are cases where guidance provided in other procedures (AOPs, SOPs, ARPs, etc.) may be useful to enhance the EOP procedure performance. This usage may be directed by referencing steps in the controlling EOPs. In addition, operator judgment may be used to identify appropriate performance of other procedures in conjunction with an EOP to enhance equipment and personnel emergency response. EOP actions take priority.
Other procedures may be performed in parallel with EOPs as long as their actions do not conflict with the EOP steps. In cases where conflicts are present, the operator should use the guidance contained in the EOPs, as well as their knowledge of the overall recovery strategy to determine the correct course of action.
The SS shall determine how many procedures (including AOPs and EOPs) will be implemented at a time, and their priority based on manpower availability and the particular event in progress. NLO's may be given the responsibility, commensurate with their qualifications, to implement the lower priority procedure when procedures are being performed concurrently."
During an event such as "Response to Inadequate Core Cooling", there are subsequent actions in 19013-1 which would be required to ensure all possible efforts are made to protect accident mitigating equipment as well as ensure adequate make up attempts are being made to the Refueling Water Storage Tank (RWST), as required.
Once 19013-1 is exited, the crew would "Return to procedure step in effect". Based on the initial conditions of a Safety Injection and LOCA, this would return the crew to 19010-1 "E-1 Loss of Reactor or Secondary Coolant". Once in 19010-1 (E-1 ), the crew can implement FRPs such as 19221-1 "Response to Inadequate Core Cooling".
However, the crew would continue to monitor RWST level for <8% to ensure the containment spray pumps are swapped to recirculation mode in 19013-1 "Transfer to Cold Leg Recirculation". This action would prevent cavitation of the Containment Spray pumps.
This action would be crucial in a scenario where containment pressure is high and the containment spray system could be used to mitigate the accident and prevent challenging containment integrity, the third barrier for release to the public. Additionally, actions isolating AHR from the RWST to prevent air entrainment in the system and disabling to VCT Low Level RWST swap over from the shutdown panels are still required in 19013-1. Instead of delaying further actions out of 19221-1, the shift supervisor, based on resources and competing priorities, can make the decision to implement both procedures concurrently based on NMP-AP-005-004, Transient Response Users. Therefore, "IS" is the correct answer for the second part of question
- 67.
The recommended change to the answer is "A". IS NOT, IS.
Licensee Recommendation RO Question #67 KIA G2.4.16 The question provides that the crew has entered procedure 19013-1 due to RWST level lowering below 29%. It also states that neither Train of ECCS has been aligned to Cold Leg Recirculation. A note in 19013-1 states "FRPs should not be implemented until at least one flow path exists from the CNMT Sump to the RCS Cold Legs and the completion of Step 13." The question states a valid RED path exists for Core Cooling.
Due to the note in 19013-1, entry to FRP 19221-1 is not permitted at this time and the crew should continue actions to align cold leg recirculation.
There are no issues with the first part of the question.
EOP usage is controlled by procedure NMP-AP-005-004, 1/4Transient Response Procedure User's Guide." Procedure 19200-1, "F-0 Critical Safety Function Status Tree," requires the crew "immediately go to FRP" in the case of a valid RED path. The above-mentioned note prevents the crew from "going to" procedure 19221-1. Once the transition is permitted 19013-1 step #14 and the above-mentioned note state that "FRP implementation may resume at this time" NMP-AP-005-004 states that "Implement" is to "begin another guideline or procedure and follow it to completion (may be concurrent with procedure/task in progress)".
The completion of step #13 would be expected to occur prior to the RWST level going
<8%. This would require performing the remaining steps of 19013-1 to prevent the Containment Spray Pumps from losing suction and adding an additional challenge to Containment integrity. NMP-AP-005-004 provides guidance for Operators to address the RWST Empty (8%) annunciator if it actuates. This annunciator is addressed in 17006-1, which states, "Actions for RWST empty level during SI are governed by 19013-1, "ES-1.3 Transfer to Cold Leg Recirculation."
NMP-AP-005-004 would permit Operators to perform the steps of 19013-1 to realign the Containment Spray Pump suction source from the RWST to the Recirculation Sump concurrent with the steps of 19221-1 as long as the steps do not impede the performance of or conflict with the actions of 19221-1.
Recommend changing the answer to "A" for this question.
Comment from Applicant SRO Question #8 KIA 050G2.2.45 Initial conditions:
- Both Units are at 100% reactor power.
- Unit 2 'B' Train CREFS is tagged out.
Current conditions:
- Unit 1 'A' Train CREFS is deemed inoperable due to breaker malfunction.
- OATC reports that the Control Room Temperature is 78F and slowly rising at a rate of 2F per hour.
Which one of the following completes the following statement?
Per Tech Spec 3.7.10, "Control Room Emergency Filtration System (CREFS) - Both Units Operating," the operating crew is required to _(1 )_ when required completion time of Condition B is not met, and Control Room Tech Spec air temperature limit will first be exceeded in _(2)_ hours.
_(1)_
_(2)_
A.
Be in Mode 3 4
B.
Be in Mode 3 6
C.
Start 2 CREFS Units 4 D.
Start 2 CREFS Units 6 The question stem provides a condition in which one CREFS on each Unit is declared inoperable with both units at 100% power. Based on these conditions, Tech Spec 3.7.10 Condition Bis entered with a completion time of 7 days.
The first part of the question asks what the operating crew is required to do when the completion time of Condition B is not met. The answers provided are "Be in Mode 3" or "Start 2 CREFS Units." When the 7 day completion time expires on 3.7.10 Condition B, 3.7.10 Condition Fis entered which requires action to be initiated to place the unit in Mode 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. The required action is NOT to "Be in Mode 3" as soon as 3. 7. 10 Condition B is not met. Per the Use and Application Chapter, Completion Time Section, of Technical Specifications, an example is provided (TS Example 1.3-2, shown below) in which it is demonstrated that when a required action is not met and another condition
subsequently entered, the required actions of the first condition are still required to be completed even after the first condition's required action completion time is not met.
Applying this example to 3.7.10 and the question asked if the actions of 3. 7.10 Condition B are completed (Start 2 CREFS Units) AFTER the 3.7.10 Condition B completion time has expired but before the 3.7.1 O Condition F completion time is exceeded, 3.7.10 Condition F would be exited. The action to continue shutting down the units to Mode 3 would be terminated.
Furthermore, the bases of 3. 7.10 Condition F state, "The allowed Completion Times are reasonable, based on operating experience, to perform the Required Actions and to reach the required unit conditions from full power conditions in an orderly manner without challenging unit systems" indicating that an immediate shutdown to Mode 3 is NOT the intent.
Therefore, per the Bases and Tech Specs rules of usage, "Start 2 CREFS Units" is still a required action and is more correct than immediately placing the units in Mode 3 following 3. 7.10 Condition B being not met. The correct answer to the first part of this question is "Start 2 CREFS Units".
The second part of this question asks the length of time before the control room Tech Spec temperature limit of 85F would first be exceeded. The answers provided are "4" or "6" hours. Based on the given information with temperature rising 2F per hour and an initial temperature of 78F, after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, the temperature would have risen to 86F which exceeds the control room temperature limit. The correct answer to the second part of this question is "4" hours.
It is recommended the answer to SRO Question #8 be changed from the incorrect answer "A" to the correct answer "C".
Licensee Recommendation SRO Question #8 K/A 050G2.2.45 The question tests the applicant's knowledge of greater than 1-hour Technical Specification pertaining to the Control Room Ventilation System.
Tech Spec 3.7.10, "Control Room Emergency Filtration System (CREFS) - Both Units Operating states that Four CREFS trains shall be operable in Modes 1-4. Condition 'A' is one CREFS train inoperable for reasons other than Condition 'D'. Condition 'B' is one CREFS train inoperable in each unit for other than Condition 'D'. Condition 'C' is two CREFS trains in inoperable in one unit for reasons other than Condition 'D'. Condition
'D' is one or more CREFS trains inoperable due to inoperable CRE boundary. Based on provided information, Condition 'B' applies. Condition 'E' also applies, and that is Control Room air temperature not within limit.
Condition 'B' requires the crew to place two Operable trains in the emergency mode within 7 days. If condition B is not met within 7 days, Condition 'F' must be entered.
Condition 'F' requires the Units be placed in MODE 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />.
The first part of the question asks, "Per Tech Spec 3.7.10, "Control Room Emergency Filtration System (CREFS) - Both Units Operating," the operating crew is required to_
(1) _ when required completion time of Condition B is not met."
The keyed answer is "be in MODE 3".
When the completion time for Condition 'B' (7 days) is not met the unit has 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> to be in MODE 3. The answer implies that the unit is to be in MODE 3 when the 7-day clock for Condition 'B' expires. This is not true. The plant is given a reasonable amount of time (7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />) to perform an orderly plant shutdown. Based on the given plant conditions the option of placing the 2 Operable CREFS Trains in service, to avoid going to MODE 3 does exist.
There are no issues with the second part of the question.
Recommend changing the answer to "C" for this question.