ML22116A192
| ML22116A192 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 03/30/2022 |
| From: | Joseph Demarshall Operations Branch I |
| To: | Public Service Enterprise Group |
| Shared Package | |
| ML21020A061 | List: |
| References | |
| EPID: L-2022-OLL-0002 | |
| Download: ML22116A192 (8) | |
Text
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 1
The Facility submitted comments for two SRO questions. Those comments and the associated NRC resolutions are provided below.
SRO Question 84 Given:
Unit 2 reactor tripped due to loss of all offsite power.
The crew has verified natural circulation flow and is cooling down the plant per 2-EOP-TRIP-4, Natural Circulation Cooldown.
Train A RVLIS is out of service for Maintenance.
The Shift Manager directs the crew to perform a rapid cooldown and depressurization due to secondary inventory concerns.
Current plant conditions are:
RCS Pressure is 1840 psig and stable.
RCS Hot Leg temperatures are 540 °F and lowering.
2PT-405 Wide Range RCS Pressure has failed.
Based on the above conditions, what procedure will the CRS implement and what is the MAXIMUM allowable RCS cooldown rate in the procedure entered?
A.
2-EOP-TRIP-5, Natural Circulation Cooldown with Steam Voids in Vessel (with RVLIS); 100 °F/hr.
B.
2-EOP-TRIP-5, Natural Circulation Cooldown with Steam Voids in Vessel (with RVLIS); 50 °F/hr.
C.
2-EOP-TRIP-6, Natural Circulation Cooldown with Steam Voids in Vessel (without RVLIS); 50
°F/hr.
D.
2-EOP-TRIP-6, Natural Circulation Cooldown with Steam Voids in Vessel (without RVLIS); 100
°F/hr.
Answer: C References provided to NRC:
2-EOP-TRIP-6, Sheet 1 (Rev. 40)
Applicants Exam Sheet for SRO Q84 Applicants Comment Sheet for SRO Q84
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 2
Applicant Comment:
In accordance with NUREG 1021, Appendix E (Part B.7, Written Exam Guidelines), the applicant submitted a question in writing to the exam proctor that asked the following concerning Part 2 of the question:
The question asks: MAXIMUM CDR (cooldown rate) in the procedure entered. Does this mean, MAX CDR given the plant conditions (540 °F) OR the MAX CDR in the entire procedure?
The response provided to the applicant from the exam proctor, after consulting the NRC Chief Examiner, was as follows; All the information you need is provided in the stem.
The applicant requested clarification because they were unsure if part 2 of the question was to be answered using the same conditions as in the stem (i.e., 540 °F) or was a standalone question not related to current plant conditions but only to the procedure guidance itself. The highest or maximum cooldown rate allowed anywhere in the procedure entered is 100 °F/hr.
This assessment would result in Answer D.
The applicant notes on their exam answer sheet that shows choice C was originally selected, but then changed to answer choice D since they were left to make an assumption based on the proctor response to their question.
Determination:
A clarifying response to the applicant question such as, Yes the maximum cooldown rate in the procedure entered is based on the conditions of the stem would have provided the applicant the necessary information to stay with his original answer choice of C. In addition, providing such a clarification, as stated, would not have provided a cue or leading information that would have given unfair advantage to answering the question. The applicant still needed to assess the plant conditions and determine the maximum cooldown rate based on T-Hot.
Facility Position on Applicant Comment:
The licensee agrees with the applicants comments. Per the licensee, the applicant followed NUREG 1021, Appendix E (Part B.7, Written Exam Guidelines), when he was confronted with an unclear question and submitted his question for clarification to the exam proctor. Based on the guidelines in NUREG 1021, Rev. 11, ES-403 D.1.b, a question with an unclear stem that confused the applicants or did not provide all the necessary information, can be considered for an answer change. Therefore, the Licensee recommends accepting both answers C and D.
NRC Evaluation/Resolution:
Recommendation not accepted. SRO Question 84 tests the ability of the applicant to: a) select the correct EOP TRIP procedure based on determining the availability of Train B Reactor Vessel Level Indication System (RVLIS) instrumentation, and b) determine the maximum allowable Reactor Coolant System (RCS) cooldown rate based on evaluation of the stem conditions (emphasis added) against the maximum RCS cooldown rate guidance provided in 2-EOP-TRIP-6, Natural Circulation Cooldown with Steam Void in Vessel (without RVLIS). Part 2 of correct answer C, requires the applicant to know that the maximum allowable RCS cooldown rate is 50°F/hr until RCS T-Hots are less the 450°F, at which point the
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 3
allowable RCS cooldown rate changes to a maximum of 100°F/hr. One of the plant conditions provided in the stem of the question is RCS Hot Leg Temperatures are 540°F and Lowering.
The applicant contends that the stem contains insufficient information to ascertain whether Part 2 of the question, for determining the maximum allowable RCS cooldown rate, is to be answered: a) using the plant conditions specified in the stem, or b) as a stand-alone question (not related to the stem conditions) that only requires identifying the highest RCS cooldown rate allowed anywhere in the 2-EOP-TRIP-6 procedure (i.e., 100 °F/hr).
The applicant, in support of this contention, states that he submitted a question in writing to the exam proctor requesting clarification of this item, in accordance with NUREG-1021, Operator Licensing Examination Standards for Power Reactor (Rev. 11), Appendix E, Policies and Guidelines for Taking NRC Examination, Subsection B, Written Examination Guidelines, Paragraph B.7. The referenced section of NUREG-1021, in part, states: If you have any questions concerning the intent or the initial conditions of a question, do not hesitate to ask them before answering the question. The question posed by the applicant during administration of the Written Examination, as documented verbatim by the proctor and provided as a reference in the post-exam submittal, reads:
The stem states: MAXIMUM CDR in procedure entered. Does this mean, MAX CDR given in the plant conditions (540 °F), OR the MAX CDR in entire procedure?
The applicant also offers an after-the-fact example of what would be considered, in their opinion, a clarifying response that would have provided the information necessary to select the correct answer; noting that such a clarification, as stated, would not have provided a cue or leading information that would have given unfair advantage to answering the question. In doing so, the applicant is implying that the response given by the proctor and approved by the NRC was less than adequate.
The applicant, in their challenge comments, and the Licensee, in their supporting position comments, both omit any mention of the fact that the words Based on the above conditions, are specified at the front end of the question statement, which immediately succeeds the bulleted information provided in the stem. The actual question statement reads as follows:
Based on the above conditions, what procedure will the CRS implement and what is the MAXIMUM allowable RCS cooldown rate in the procedure entered?
While Question 84 is comprised of two components, there is clearly only one question statement, as indicated above. Accordingly, the qualifier Based on the above conditions, applies to both the Procedural (Part 1) and the Cooldown Rate (Part 2) aspects of the question statement, which are conceptually linked/joined by the conjunction word and, directly refuting the applicants contention that: a) the stem contains insufficient information to answer the question correctly, and b) the Part 2 component can reasonably be interpreted as a stand-alone question that is completely unrelated to the stem. The NRC maintains the following regarding the response provided to the applicant:
- 1) the proctors response, i.e., All the information you need is provided in the stem, was appropriate and adequate, given the construction of the question statement as described above, and the information item provided in the stem that states RCS Hot Leg Temperatures are 540°F and Lowering,
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 4
- 2) the proctors response and applicant example response are similar in that both statements convey that the cooldown component of the question relies upon evaluation of the conditions/information contained in the stem to be answered correctly.
Lastly, the Licensee, in their supporting position comments, recommends accepting both answers C and D, citing the following guidance in NUREG-1021, Operator Licensing Examination Standards for Power Reactor (Rev. 11), ES-403, Grading Initial Site-Specific Written Examinations, Section D.1.b, which pertains to questions that can be considered for an answer change, as a basis.
a question with an unclear stem that confused the applicants or did not provide all the necessary information.
Note that the Licensees position regarding this statement, as it relates to an unclear stem, directly conflicts with the FORM 9 - EXAM ITEM ANALYSIS document submitted as part of the post-exam submittal package. While the Licensee appears to agree with the applicant that the stem is unclear, the Licensee has also concluded that Question 84 is acceptable as written, with no required corrective action, as evidenced by assignment of the G Type Code Item which has been formally documented in Section A of the FORM 9.
Separately, the Licensees recommendation that answers C and D both be accepted, is in direct conflict with and is not supported by NUREG-1021, Operator Licensing Examination Standards for Power Reactor (Rev. 11), ES-403, Grading Initial Site-Specific Written Examinations, Section D.1.c, because the Part 2 answers for C and D contain conflicting information; i.e., 50°F/hr and 100°F/hr respectively. The referenced Section D.1.c of NUREG-1021, Rev.11, states in part:
If a question is determined to have two correct answers, both answers will be accepted as correct. If however, both answers contain conflicting information, the question will likely be deleted.
In summary, the NRC concludes that the stem is sufficiently clear and provides all of the information necessary to correctly answer Part 2 of Question 84, regarding determination of the maximum allowable RCS cooldown rate. Accordingly, Question 84 is considered acceptable as written and administered, and that choice C, as annotated on the As-Administered Exam Answer Key, is the only correct answer.
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 5
SRO Question 88 Given:
Unit 1 is at 100% Power.
11 Charging Pump is in service.
A Loss of All Control Air has occurred.
The crew enters S1.OP-AB.CA-0001, Loss of Control Air.
The CRS directs manually tripping the reactor and entering 1-EOP-TRIP-1, Reactor Trip or Safety Injection.
Operators are locally controlling AFW valves to maintain post trip SG Narrow Range levels.
Which ONE of the following completes both statements?
- 1. What will be the subsequent impact on PZR level?
- 2. What is the preferred course of action?
A.
- 1) PZR level will rise
- 2) Locally control charging flow by adjusting the 1CV54, CENT CHG PUMP FLOW CONT VLV.
B.
- 1) PZR level will rise
- 2) Transfer to 13 Charging Pump and locally control the speed changer.
C.
- 1) PZR level will lower
- 2) Transfer to 13 Charging Pump and locally control the speed changer.
D.
- 1) PZR level will lower
- 2) Locally control charging flow by adjusting the 1CV54, CENT CHG PUMP FLOW CONT VLV.
Answer: B References provided to NRC:
S1.OP-AB.CA-0001, Loss of Control Air (Rev. 25)
Simplified Drawing CV-1, Chemical & Volume Control System (Rev. 2)
P&ID Drawing 205228, Sheet 2, Chemical & Volume Control System (Rev. 85)
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 6
Applicant Comment:
The challenge to the question pertains to part 2 of the question, and whether the necessary information was provided in the question stem to determine whether local operation of the centrifugal charging pump discharge valve or the local operation of the PDP speed changer is the preferred course of action.
The question stem does not specify what plant conditions exist at the time for the CRS to determine which section of S1.OP-AB.CA-0001 is correct to maintain pressurizer level. The procedure provides three sections that discuss pressurizer level control; (1) Selected CAS Items, (2) Attachment 1 CAS (Continuous Action Summary), and (3) Attachment 8, CRS Decision. The first section to be implemented would be the CAS sections when the procedure is entered.
Prior to being asked the preferred course of action, the applicant is provided with current plant conditions, which indicate that the Loss of All Control Air will cause the pressurizer level to rise slowly. This is a result of the loss of all control air causing the isolation of letdown and charging flow, the 1CV55 failed open, and all charging flow being supplied only to the RCP seals. In addition, the applicant has been told that the 11 charging (centrifugal) pump is in service prior to the event. With the 1CV55 failed open and the 11 charging pump in service, seal injection flow to the RCPs will be higher than normal. The 13 charging (Positive Displacement Pump-PDP) pump was not in service and is not impacted from the effects from the loss of control air at this time, unless it was in service. If 13 charging pump was running at the time, then its speed changer would fail to its low speed stop or minimum charging flow.
Per S1.OP-AB.CA-0001, Selected CAS Items, Step 1.2, states the following; 1.2 SEND Operators to maintain Pressurizer level between 24 and 90% while maintaining RCP seal Injection flow 6-12 gpm/pump, NOT to exceed 40 gpm total, by local operation of appropriate components:
1CV73, CHG HDR PCV BYP VALVE Speed Changer on 13 Charging Pump 1CV54, CENT CHG PUMP FLOW CONT VALVE The question stem does not state whether Attachment 8, CRS Decision, is being implemented at the time. The stem states that the crew enters S1.OP-AB.CA-0001, and the CRS directs manually tripping the reactor. Upon entering the procedure, the crew would first implement the CAS. The CAS allows for the CRS to maintain pressurizer level by either locally controlling the charging flow using the 1CV54 and/or 1CV73 or locally controlling the 13 charging pump speed changer, if it was in service. Since the stem stated that 11 charging pump was in service, then the CRS would logically dispatch operators to locally control charging flow by using 1CV54 and/or 1CV73 as necessary to maintain pressurizer level.
, CRS decision, is not implemented until later in the procedure at step 3.42. Step 3.42 states the following:
NOTIFY CRS/SM to refer to Attachment 8 for guidance on the following:
RCP operation RCS cooldown decision Centrifugal Charging Pump recirc flowpath
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 7
Pressurizer Spray options Service Water operations Control Area Ventilation (CAV)
Excerpt from Attachment 8, CRS Decisions, states the following:
Charging Pump Decisions With 1CV55 failed open and 1CV71 failed closed, operating a Centrifugal Charging Pump (CCP), will result in higher flow and pressure to the RCP seals. This will result in higher flow into the RCS and thus raise Pressurizer level faster. It is recommended to operate 13 Charging Pump (if available), since its speed controller is failed at the low speed stop (minimum RCP seal flow). If a CCP must be operated, its discharge valve, (1CV48/1CV53) can be throttled to control RCP seal flow. If the PDP can supply seals and makeup for cooldown contraction, it should be left in service during the cooldown also. The reason for this is explained below.
Determination:
Based on predicting that pressurizer level will subsequently rise and a centrifugal charging pump is running resulting in high charging flows to the RCP seals, it is reasonable to conclude that the appropriate action at the time would be to take local control of the 1CV54 to reduce charging flow to the RCP seals until such time later that Attachment 8 would be implemented and the CRS would determine taking additional actions to transfer from the centrifugal charging pump to the 13 PDP.
Facility Position on Applicant Comment:
The licensee agrees with the applicants comments. Per the licensee, the applicant correctly determined that the preferred action, given the stated conditions, was to control Pressurizer level locally by controlling charging flow using 1CV54 (CENT CHG PMP FLOW CONT VALVE INLET) with the 11 Charging Pump in service, in accordance with the procedure CAS. The licensee states that local operation of the PDP speed changed is also correct when Attachment 8 is implemented later in the procedure. The Licensee recommends that both answers A and B be accepted as correct.
NRC Evaluation/Resolution:
Recommendation accepted. SRO Question 88 tests the ability of the applicant to determine: a) the impact of a Loss of All Control Air on Pressurizer Level, and b) the preferred course of action to control Pressurizer level, in accordance with S1.OP-AB.CA-0001, Loss of Control Air, following a manual reactor trip with a Centrifugal Charging pump (CCP) in service and operators locally controlling AFW valves to maintain post-trip SG Narrow Range levels.
The applicant contends that there are two correct answers, A and B, on the basis that the stem does not provide sufficient information for the applicant to reasonably conclude which section of S1.OP-AB.CA-0001 is appropriate/correct for use in determining whether local operation of the Centrifugal Charging Pump or local operation of the Positive Displacement Pump (PDP) is the preferred course of action for controlling Pressurizer level in Part 2 of the question.
On a complete Loss of Control Air, Letdown isolates, 1CV55 (CENT CHG PMP FLOW CONT
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 8
VALVE) fails open, and 1CV71 (SEAL INJ PRESS VALVE) fails closed. Operating in this configuration with a Centrifugal Charging pump in service will result in higher flow and pressure to the RCP seals, which increases flow to the RCS and raises Pressurizer level faster. The basis for Transferring to 13 Charging Pump and locally controlling the speed changer, as the preferred course of action in Part 2 of correct Answer B in the As-Administered Exam Key, assumes implementation of the guidance contained in the Charging Pump Decisions section of Attachment 8, CRS Decisions, which states:
It is recommended to operate 13 Charging Pump (if available), since its speed controller is failed at the low speed stop (minimum RCP seal flow). If a CCP must be operated, its discharge valve (1CV48/1CV53), can be throttled to control RCP seal flow.
The applicant asserts that S1.OP-AB.CA-0001 contains three sections that provide guidance for controlling Pressurizer level; 1) Selected Continuous Action Summary (CAS) Items, 2) Attachment 1 Continuous Action Summary, and 3) Attachment 8, CRS Decisions. The applicant further maintains that the first section to be implemented by the CRS when entering the procedure would be either of the CAS sections identified in Items 1 and 2 above, both of which state:
SEND Operators to maintain Pressurizer level between 24 and 90% while maintaining RCP seal Injection flow 6-12 gpm/pump, NOT to exceed 40 gpm total, by local operation of appropriate components:
1CV73, CHG HDR PCV BYP VALVE Speed Changer on 13 Charging Pump 1CV54, CENT CHG PUMP FLOW CONT VALVE INLET The NRC concludes that answers A and B are both correct on the basis that:
- 1) the actions to control Pressurizer level would be taken in accordance with either of the aforementioned CAS sections upon initial entry into S1.OP-AB.CA-0001,
- 2) the CAS actions to control Pressurizer level are bulleted items, indicating that local operation of either 1CV54 or the PDP Speed Changer would be appropriate and acceptable given the conditions specified in the stem,
- 3) local operation of 1CV54 as the preferred course of action is a viable option considering that CCP 11 was already in service, and
- 4) local operation of the PDP Speed Changer as the preferred course of action using, CRS Decisions, is a viable option because a) the associated guidance contained therein and cited above, recommends operation of the PDP, and b) the Selected CAS Items section of S1.OP-AB.CA-0001 provides direction to reference the Exhibit 1 Briefing Sheet, which in turn provides direction to reference Attachment 8.
In summary, insufficient information resulted in an unclear stem that confused three of the four SRO applicants and the subsequent determination that Question 88, as administered, had two correct answers, both of which have been accepted by the NRC. Accordingly, the final written examination and answer key have been revised to reflect the fact that answers A and B are both correct.