ML23013A136
| ML23013A136 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 12/08/2022 |
| From: | Joseph Demarshall NRC/RGN-I/DORS/OB |
| To: | Constellation Energy Generation |
| References | |
| EPID L-2022-OLL-0008 | |
| Download: ML23013A136 (1) | |
Text
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 1
The Facility submitted comments for two RO questions. Those comments and the associated NRC resolutions are provided below.
RO Question 37 Given the following plant conditions:
Plant is operating at 5% power HCO reports the following:
Annunciator B-27, RCS LOOP A LO FLOW CHANNEL ALERT, is LIT FI-411, 1A-1 RX COOLANT FLOW, indicates 0%
CLNT FLOW LOOP A FC411, Bistable Status Light is extinguished Which of the following correctly completes the statements below?
(1) FI-411 Low Flow Bistable IS / IS NOT in the tripped condition.
AND (2) The operating crew will enter to mitigate the event.
A. (1) IS (2) AP-RCS.2, LOSS OF REACTOR COOLANT FLOW B. (1) IS NOT (2) AP-RCS.2, LOSS OF REACTOR COOLANT FLOW C. (1) IS (2) ER-INST.1, REACTOR PROTECTION BISTABLE DEFEAT AFTER INSTRUMENTATION LOOP FAILURE D. (1) IS NOT (2) ER-INST.1, REACTOR PROTECTION BISTABLE DEFEAT AFTER INSTRUMENTATION LOOP FAILURE Answer: D References provided to NRC:
33013-1353, Sheet 14, LOGIC DIAGRAM REACTOR COOLANT SYSTEM TRIP SIGNALS (Rev. 5) 33013-2095, Sheet 27, LOW REACTOR COOLANT FLOW LOOP A TRAIN A (Rev. 4) 10905-367, ANNUNCIATOR PANEL B ELEMEMNTARY WIRING DIAGRAM, (Rev 5)
CPI-FLO-411, CALIBRATION OF REACTOR COOLANT FLOW CHANNEL 411 RACK INSTRUMENTATION, Attachment 6, Reactor Coolant Flow Loop 411, Page 24 of 25 (Rev. 12)
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 2
ER-INST.1, REACTOR PROTECTION BISTABLE DEFEAT AFTER INSTRUMENTATION LOOP FAILURE (Rev. 41)
Applicant 1 Comment:
Alarm B-27 is directly fed from the bistable. If B-27 is lit, then the Bistable Status Light has to be lit, or the bulbs burned out. (Reference 10905-0367 and 33013-2095 sh 27). No correct answer provided.
Applicant 2 Comment:
AR-B-27 is directly fed from Bistable 411. If B-27 is lit, Bistable Status Light must be lit or the bulbs are burnt out. (Reference 10905-0367 and 33013-2095 sh 27). No correct answer. CPI-FLO-411, pg 24 shows bistable directly fed from AR-B-27s input.
Discussion:
In the Stem of Question 37 it is stated that Annunciator B-27, RCS LOOP A LO FLOW CHANNEL ALERT, is illuminated and that the associated Bistable status light (FC411) is extinguished. The Bistable Status Light (FC411) being extinguished was intended to be the indication used to determine the Low Flow Bistable was not in a tripped condition. This is supported by ER-INST.1, Precaution 5.6.
Newly discovered technical information that was overlooked in the original answer explanation (Drawing 33013-1353 and CPI-FLO-411) shows that FT-411 Bistable Relay supplies the same input to both Annunciator B-27 and the FC411 Bistable Status Light (see attached mark up of DWG 33013-1353, Sheet 14 and CPI-FLO-411, Attachment 6). It is not possible to determine the status of the Bistable from the initial conditions given in the stem of the Question since the same input would be required to be tripped for the Annunciator to be LIT and not tripped for the Bistable Status Light to be extinguished. Therefore, the conditions provided in the stem of the question are unclear and not plausible.
Facility Position on Applicant Comments:
In accordance with ES-4.4, Section C.3.c, there is newly discovered technical information that supports a change in the answer key. Additionally, the information provided in the question stem was not operationally valid and resulted in the Applicants having to make assumptions to determine an answer. The station recommends the question be removed from the Exam.
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 3
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 4
NRC Evaluation/Resolution:
Recommendation accepted. RO Question 37, Part 1, tests the ability of the applicant to determine the trip status of Reactor Coolant System (RCS) Loop A Low Flow Bistable FC411, based on the following conditions:
Annunciator B-27, RCS LOOP A LO FLOW CHANNEL ALERT, is LIT FI-411, 1A-1 RX COOLANT FLOW, indicates 0%
CLNT FLOW LOOP A FC411, Bistable Status Light is extinguished The applicants contend that there is NO correct answer on the basis of confusing and unclear stem information that precludes the ability to reasonably determine, without having to make an assumption regarding Bistable FC411 Status Light Extinguished indication, whether the Bistable is actually tripped in Part 1 of the question.
The applicants assert that the only way for Annunciator B-27, RCS LOOP A LO FLO CHANNEL ALERT, to be LIT and Bistable FC411 Status Light to be Extinguished (i.e.,
Bistable NOT TRIPPED) as indicated in the stem, would be if the Bistable was actually tripped and the Bistable Status Light bulbs were burned out, which would require an assumption.
NUREG-1021 (Revision 12), ES-1.2, Guidelines For Taking NRC Examinations, Section B, Written Examination Guidelines, Paragraph 8, states:
When answering a question, do not make assumptions about conditions that are not specified in the question unless they occur as a consequence of other conditions that are stated in the stem.
The applicants further maintain that it would not be possible to determine the status of Bistable FC411 from the conditions provided in the stem because the output of the Bistable Relay is electrically the same as the inputs to both Annunciator B-27 and the Bistable Status Light (see above diagrams). Restated: (a) in order for Annunciator B-27 to be LIT, the Bistable would have to be in the TRIPPED condition, and (b) in order for Bistable FC411 Status Light to be Extinguished, the Bistable would have to be in the NOT TRIPPED condition. A review of the reference documents provided confirms the applicants assertion to be technically correct and the stem to be deficient in this regard.
Providing the Bistable Status Light Extinguished information was done with the intent to test applicant knowledge of Precaution and Limitation (P&L) 5.6 of ER-INST.1, as it pertains to the evaluation of Bistable trip status. P&L 5.6 states:
IF the bistable status light above is NOT lit, THEN the channel may NOT be in the tripped condition. Further investigation is necessary to ensure ITS requirements are met.
Implementation of this concept: (a) resulted in an unintended misapplication of P&L 5.6 guidance, which only applies when performing steps to defeat the Bistable after the Instrumentation Loop Failure (this was not the case), and (b) was done without the awareness of existing technical information that confirms the output of Bistable Relay FC411 to be electrically the same as the inputs to both Annunciator B-27 and the Bistable Status Light, making the question technically incorrect.
The NRC concludes that Choice D is incorrect and that there are no correct answers to RO
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 5
Question 37 based on the following:
- 1) the stem was unclear and confusing, resulting in a question that was not operationally valid in terms of being able to correctly determine the Trip Condition status of Bistable FC411 given the stated conditions,
- 2) stem deficiencies require assumptions to be made about conditions that (a) are not specified in the question, and (b) would not occur as a consequence of other conditions stated in the stem, with respect to Bistable FC411 Status Light Extinguished indication, and
- 3) newly discovered technical information confirmed the deficiencies in the stem, thereby supporting a change to the answer key.
As a result, Question 37 has been deleted. The deletion is reflected in the final written examination and answer key.
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 6
RO Question 40 Given the following plant conditions:
The plant is operating at 100% power Annunciator B-32, CONTAINMENT RECIRC FAN VIBRATION, is LIT Containment Recirc Fan SW flows are as follows:
o A - 1025 GPM and stable o B - 1150 GPM and stable o C - 1000 GPM and stable o D - 1075 GPM and stable FCV-4561, CNMT COOLERS SW OUTLET FLOW CONTROL AOV, status light is DIM FCV-4562, CNMT RECIRC FAN SW OUTLET BYPASS AOV, status light is DIM Which of the following correctly completes the statements below for the given plant conditions?
(1) Annunciator B-32 can be verified by checking the white VIBRATION Alarm light indication on the AND (2) Annunciator C-10, CONTAINMENT RECIRC CLRS WATER OUTLET LO FLOW 1050 GPM, ____________be in alarm.
A. (1) Main Control Board (2) will B. (1) Main Control Board (2) will NOT C. (1) Vibration Alarm Relay cabinet in the IB Clean Side (2) will D. (1) Vibration Alarm Relay cabinet in the IB Clean Side (2) will NOT Answer: B References provided to NRC:
AR-C-10, CONTAINMENT RECIRC CLRS WATER OUTLET LO FLOW 1050 GPM (Rev.
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 7
21946-0741, AOV-3343, 4561 & 4562 SAFEGUARD INDICATING LIGHTS 3343, 4561 &
4562 CONTROL SCHEMATIC (Rev. 2)
Applicant Comment:
(Docket # 55-76156): There is no correct answer. Valves actual position based on limit switch feeds into C-10 alarm. Valve indicating status lights are based off of solenoid valve position.
Valve actual position and indicating lights are not directly tied together. Based on information given in question, the valve can be full open and cause C-10 with dim status lights. C-10 Alarm Response has a note that states the status lights will not go bright if the SOV is not deenergized. During warm weather, these valves can be full open without bright status lights but will trigger alarm on actual position.
Discussion:
Annunciator C-10 requires SW flow from any Containment Recirc Fan less than 1050 gpm AND either FCV-4561 or FCV-4562 be FULL OPEN. Annunciator C-10 input from FCV-4561 or FCV-4562 comes from limit switches located on the valves (see 21946-0706). Safeguard status lights, indicated as DIM in the question stem, come from limit switches on local solenoids (see 21946-0741). Given that the solenoids are only manually actuated (locally) in an accident or open on an SI signal, they do not give the requisite information on valve position needed to determine if the limit switches mounted on the valve are closed, indicating the FCV(s) is/are full open, to give the C-10 alarm. There is insufficient information in the stem of the question for the Applicant to determine the actual position of either FCV-4561 or FCV-4562 given that the required limit switch position is unknown.
FCV-4561 throttles automatically based on Containment temperature and could be fully open even with DIM status light indications when no SI signal or local-manual actuation is present.
Without the status lights being bright, the only way to determine whether the FCVs are full open is by local position indication. Position indication is not given in the stem and therefore the actual position of FCV-4561, and subsequently, the status of Annunciator C-10 cannot be determined.
Additional Technical information:
A NOTE on AR-C-10 states Status light indication for FCV-4561 (FCV-4562) is generated from SOV-4561S (SOV-14400S) limit switch. When the solenoid is in the deenergized (Tripped) position, the White Status Light for FCV-4561 (FCV-4562) will be Bright.
Facility Position on Applicant Comment:
In accordance with ES-4.4, Section C.3c., there is newly discovered technical information that supports a change in the answer key. Additionally, there is not enough information provided in the question stem for the Applicants to determine the position of FCV-4561 and therefore, the status of Annunciator C-10. The station recommends the question be removed from the Exam.
NRC Evaluation/Resolution:
Recommendation accepted. RO Question 40, Part 1, tests the ability of the applicant to determine whether Annunciator C-10, CONTAINMENT RECIRC CLRS WATER OUTLET LO FLOW 1050 GPM, is in alarm based on the following conditions:
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 8
The plant is operating at 100% power Containment Recirc Fan SW flows are as follows:
o A - 1025 GPM and stable o B - 1150 GPM and stable o C - 1000 GPM and stable o D - 1075 GPM and stable FCV-4561, CNMT COOLERS SW OUTLET FLOW CONTROL AOV, status light is DIM FCV-4562, CNMT RECIRC FAN SW OUTLET BYPASS AOV, status light is DIM The applicant contends that there is NO correct answer on the basis that the question is technically flawed. Annunciator C-10 alarm condition requires Service Water (SW) flow from any Containment Recirculation Fan to be Less Than 1050 GPM AND either FCV-4561, CNMT COOLERS SW OUTLET FLOW CONTROL AOV, or FCV-4562, CNMT RECIRC FAN SW OUTLET BYPASS AOV, to be in the FULL OPEN position.
The question was written based on the premise that FCV-4561 and FCV-4562 valve positions could be determined from their respective Safeguard Status Light indications (which are provided in the stem), and that the input signals to these status lights also feed Annunciator C-
- 10. Hence: (a) if the valve status light is DIM, the actual valve position would be something other than Full Open, and (b) if the valve status light is BRIGHT, the actual valve position would be Full Open.
The applicant asserts that there is insufficient information in the stem of the question to be able to determine the actual position of either FCV-4561 or FCV-4562 and the position-dependent status of Annunciator C-10, because: (a) Safeguard Status Light indication for these valves is generated from the limit switches of Solenoid Operated Valves (SOVs) that are either manually actuated in the field during accident conditions only OR automatically actuated on a Safety Injection (SI) signal; NOT from the limit switches of the actual valves themselves, and (b)
Annunciator C-10 inputs for FCV-4561 and FCV-4562 come directly from the limit switches of the actual valves and NOT the limit switches of the associated SOVs. Annunciator C-10 Alarm Response Procedure (AR-C-10) contains the following NOTE:
Status light indication for FCV-4561 (FCV-4562) is generated from SOV-4561S (SOV-14400S) limit switch. When the solenoid is in the deenergized (Tripped) position, the White Status Light for FCV-4561 (FCV-4562) will be Bright.
The applicant further maintains that FCV-4561 throttles automatically based on Containment Temperature and could therefore be Fully Open with DIM Safeguard Status Light indication in the absence of an SI signal or conditions that resulted in local manual actuation of the associated SOVs (stem states that the Plant is at 100% power). Consequently, without BRIGHT Safeguards Status Light indication, the only way to ascertain the actual position of the FCVs and determine Annunciator C-10 alarm status, would be via local position indication, which has not been provided in this question.
A review of the reference documents provided confirms the applicants assertion to be technically correct and the developmental concept for this question to be technically flawed.
The NRC concludes that Choice B is incorrect and that there are no correct answers to RO
FACILITY POST-EXAM COMMENTS AND NRC RESOLUTIONS 9
Question 40 based on the following:
- 1) newly discovered technical information provides confirmation that the alarm status of Annunciator C-10 cannot be determined under the conditions specified because: (a)
FCV-4561 and FCV-4562 valve positions are unable to be determined from their respective Safeguard Status Lights, given that the input signals which serve to provide these indications are not generated from the limit switches of the actual valves but rather from the limit switches of associated SOVs which are only actuated under certain accident conditions, and (b) FCV-4561 and FCV-4562 valve position signal inputs to Annunciator C-10 are only generated from the limit switches of the actual valves.
As a result, Question 40 has been deleted. The deletion is reflected in the final written examination and answer key.