ML12292A344
| ML12292A344 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/26/2012 |
| From: | David Reeser Operations Branch III |
| To: | Exelon Generation Co |
| Shared Package | |
| ML11354A119 | List: |
| References | |
| Download: ML12292A344 (9) | |
Text
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS I.
Question #7 The high pressure sensing line for the core plate D/P instrumentation has a fitting leak of 10 gpm at the transmitter.
An ATWS event occurs and SBLC is started.
Which of the following describes the response of the SBLC system?
The SBLC system will inject__________.
A.
all of the boron into the RPV above the core plate B.
all of the boron into the RPV below the core plate C.
most of the boron into the RPV above the core plate, the rest outside the RPV D.
most of the boron into the RPV below the core plate, the rest outside the RPV Answer:
D Candidate Feedback:
Knowledge of high side and low side for core plate D/P, reference needed.
Facility Response:
Objective DRE211LN001.03 requires from memory to be able to discuss the operation of SBLC components under normal operating conditions including support required from other plant systems and local indications, operations or override capability.
No reference required for this question.
NRC Resolution The SBLC injection line taps into the below core plate pressure sensing line, used by the core plate differential pressure (D/P) instrument, before the line penetrates the reactor pressure vessel (RPV) so that the boron solution is injected at the core inlet. This is system level knowledge (i.e., physical connections and cause/effect relationships with interfacing systems/structures/components) that is required to be memorized. The candidate statement implies that a reference is needed to determine whether the high or low side of the core plate D/P instrument is associated with the below core plate sensing line. With fundamental knowledge of the operation of a differential pressure instrument and of the flow paths through the RPV, the applicant would, without reference material, be able to conclude that the below core plate pressure sensing line is associated with the high side tap of the D/P instrument.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS The knowledge needed to answer the question - the physical connection, between the Standby Liquid Control system and the below core plate pressure sensing line, and differential pressure instrument operation relative to the flow paths internal to the RPV -
is fundamental knowledge. Therefore, the NRC agrees with the facility that reference material was not needed for answering the question. No changes were made to the question.
II.
Question #15 Unit 2 is at 10% of rated thermal power, with APRM 1 having eight (8) of its input LPRMs bypassed, when the following occurs:
An LPRM input to APRM 1 fails DOWNSCALE.
APRM 1 indicates 1%.
The ___(1)___ light(s) will be illuminated and the Operator is required to bypass the failed LPRM ___(2)___.
A.
(1) APRM 1 DOWNSCALE ONLY; (2) ONLY B.
(1) APRM 1 DOWNSCALE ONLY; (2) AND APRM 1.
C.
(1) APRM 1 DOWNSCALE AND INOP; (2) ONLY D.
(1) APRM 1 DOWNSCALE AND INOP; (2) AND APRM 1 Answer:
B Candidate Feedback:
Question does not indicate where lights are illuminated. INOP and DOWNSCALE light are the same tile on 902(3)-5 panel.
Facility Response:
Question is acceptable as written for this exam. Facility will evaluate possible enhancement to include corresponding back panel number for APRM stated in question stem.
NRC Resolution The applicant is correct in stating that the question does not specify the location of the light(s) referred to by the stem, however, the bold upper case formatting of the word AND in answer choices C and D indicates that the DOWNSCALE and INOP lights are two separate lights. There are four status lights located on the apron section of panel 902(3)-5 for each APRM channel; HI-HI (red), HIGH (amber), DWNSCL OR INOP
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS (white), and BYPASS (white). For each of the APRM instruments, located on back panel 902(3)-37, there are individual status (alarm) lights, one for each alarm function; BYPASS (white), INOP (white), DNSCL (white), HI (amber), and HI-HI (red). There are not separate DWNSCL and INOP lights on panel 902(3)-5. Given the information provided in the question stem, the DWNSCL OR INOP status light on panel 902-5 will be illuminated, but this particular status light was not one of the choices. To determine whether the 902-5 DWNSCL OR INOP status light is due to a DOWNSCALE or INOP condition requires the operator to view the associated status lights on back-panel 902-
- 37. This is system level knowledge that the candidate is expected to know. Since only 8 LPRMs are bypassed, the INOP status light on 902-37 will not be illuminated. Only the DWNSCL status light will be illuminated. Bypassing the failed ninth LPRM will then render APRM 1 inoperable requiring that channel to also be bypassed. Choice B is the only possible answer. None of the applicants asked, during administration of the examination, for any clarification on the location of the status lights.
The NRC agrees with the facility that the question is acceptable as written. No changes were made to the question.
III.
Question #43 A transient has occurred resulting in the following conditions:
Drywell pressure 42 psig and stable.
Torus bottom pressure is 55 psig and stable.
Primary containment water level is 27 feet and slowly increasing.
RPV level -173" and slowly decreasing.
The Unit Supervisor has directed venting of the primary containment to lower pressure.
Which of the following vent paths should the NSO align first?
A.
torus via the APCV system B.
torus via the SBGT system C.
drywell via the APCV system D.
drywell via the SBGT system Answer:
B Candidate Feedback:
Knowledge of procedure steps and level limit for venting. Should have been provided a reference 27' and rising is close to 30' and will rise faster. Replace 27' with a number between 20' - 25'. Do not feel this is a memory level question.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS Facility Response:
Question is acceptable as written for this exam. Objective 29502LK063 requires from memory: When venting from the containment, discuss why the operator is directed to vent from the torus whenever possible and state the limitations placed on venting from the torus. No reference required. Facility will evaluate possible enhancement to initial primary containment level in the stem of the question.
NRC Resolution As stated in the facility response, the applicants are required to know from memory, the limitations placed on venting from the Torus. Attachment 1, Primary Containment Pressure Control, of DEOP 0500-04, Containment Venting, specifies that if Torus water level is less than 30 feet, that the containment be vented from the Torus via the SBGT system. Only if Torus water level is greater than or equal to 30 feet is venting from the Drywell specified. The question states that Primary Containment water level (and therefore Torus water level) is 27 feet which is clearly less than 30 feet. It is immaterial whether Torus water level is 20 - 25 feet or 27 feet since the procedure clearly defines the vent transition point at 30 feet.
The Augmented Primary Containment Vent (APCV), or hardened vent, is utilized only if unable to control and maintain Torus Bottom Pressure below the Primary Containment Pressure Limit (60 psig with Primary Containment water level greater than 15 feet).
The NRC agrees with the facility that the question is acceptable as written and does not require any reference material to answer. No changes were made to the question.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS IV.
Question #46 Unit 2 and Unit 3 are operating at near rated power when Transmission Systems Operations (TSO) notifies the Control Room that the predicted post Unit trip with LOCA switchyard voltages are:
Unit 2: 325 KV Unit 3: 350 KV What are the required actions from the Operating team AND the reason for these actions?
A.
Adjust TR 32 Tap Changer; to restore system operability B.
Adjust TR 32 Tap Changer; to reduce circulating currents C.
Adjust TR 86 Tap Changer; to restore system operability D.
Adjust TR 86 Tap Changer; to reduce circulating currents Answer:
C Candidate Feedback:
Do not feel this is a memory level question. Provide reference.
Facility Response:
Question is acceptable as written for this exam. These are entry conditions for DOA 6500-12. Objective DRE262LN003.12 requires from memory: State the effect: A total loss or malfunction of various plant systems has on the Switchyards. A total loss or malfunction of Switchyards has on the plant. No reference required.
NRC Resolution The above question can be broken down into three parts in order to answer the question. The first part requires the applicant to evaluate the provided voltage predictions to determine if they fall outside of operation limitations. As stated in the Facility Response the Unit 2 predicted voltage falls below the entry condition (less than 328.5 kV) for DOA 6500-12, Low Switchyard Voltage. The second part requires the applicant to know that Unit 2 is fed from TR 86 and Unit 3 is fed from TR 32. The third part, necessary to answer the question, is an understanding of the reason for the tap changer adjustment. The purpose of adjusting the tap changer is to raise output voltage, and since TR 86(TR 32) are not in parallel with any other voltage source there will not be circulating currents. The answer, to each of these parts, is based on basic system knowledge or knowledge of electrical fundamentals which fall within the range of knowledge expected to be memorized by applicants.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS The NRC agrees with the facility response that the question is acceptable as written and does not require any reference material to answer. No changes were made to the question.
V.
Question #67 Given the following conditions:
There is a fire in the Aux Electric Equipment Room and Control Room evacuation is required The Unit 2 NSO has been directed to SCRAM the plant All procedural means to SCRAM the plant have failed Action is immediately needed to protect Public Health and Safety What is the lowest level of authority needed to approve action to SCRAM the plant that is NOT covered by a procedure or technical specification?
A.
Any licensed Reactor Operator (RO)
B.
Any licensed Senior Reactor Operator (SRO)
C.
The Shift Manager (SM)
D.
The Shift Operations Superintendent (SOS)
Answer:
B Candidate Feedback:
OP-DR-108-101-1003 and DSSP 100-CR disagree as to the level of authority required to authorize actions outside of procedures and tech specs.
Facility Response:
DSSP 100-CR states: Certain steps or conditions within this procedure may contradict normal license conditions or Technical Specification requirements, as stated in 10 CFR 50.54x: "A licensee may take reasonable action that departs from a license condition or Technical Specification requirements in an emergency when this action is immediately needed to protect the public health and safety and no action consistent with the license conditions and Technical Specifications that can provide adequate or equivalent protection is immediately apparent." This action "shall be approved, as a minimum, by a licensed Senior Reactor Operator (SRO) prior to taking the action."
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS OP-DR-108-101-1003 states: TRANSIENT CONDITIONS: It is recognized that it is possible that circumstances will arise that are not foreseen in the procedures. If such a circumstance arises and presents imminent personal injury, equipment damage, injury to the public or similar consequence, then actions outside of procedures may be taken, provided those actions are approved by the Shift Manager.
Accept B and C as two correct answers. Issue number 01403313 has been entered into the facilitys corrective action program to correct the disagreement between the two procedures.
NRC Resolution The question describes a fire scenario requiring evacuation of the Main Control Room, where all procedurally specified means for completing a reactor SCRAM have failed, and asks the minimum level of approval required to approve action(s), that is(are) not covered by a procedure or Technical Specifications, to be taken in an attempt to complete the SCRAM.
The identified correct answer - Any licensed Senior Reactor Operator (SRO) - is based on a limitation (F.5.) in DSSP 100-CR, Hot Shutdown Procedure - Control Room Evacuation, which is based on 10 CFR 50.54 (x) and (y). In part, 10 CFR 50.54 (x) and (y), state: reasonable action that departs from a license condition or Technical Specification requirements in an emergency when this action is immediately needed to protect the public health and safety and no action consistent with the license conditions and Technical Specifications that can provide adequate or equivalent protection is immediately apparent, "shall be approved, as a minimum, by a licensed Senior Reactor Operator (SRO) prior to taking the action."
The candidate feedback states that the guidance, specified in DSSP 100-CR Limitation F.5., is inconsistent with the guidance stated in OP-DR-108-101-1003, Operations Craft Capability Activities. The guidance, from OP-DR-108-101-1003, is stated in the definition of the term TRANSIENT CONDITION found in that procedure. This definition is based on guidance found in Exelon Nuclear corporate procedure HU-AA-104-101, Procedure Use and Adherence, which specifies how approved procedures, including work instructions within a work package, are to be used and adhered to by company and contractor personnel while conducting activities at Exelon Nuclear facilities. Section 4.8, Transient Conditions, of that procedure states, in step 4.8.1, that IF unforeseen circumstances arise that present imminent personal injury, equipment damage, injury to the public or similar consequence, THEN actions outside of procedures may be taken, provided those actions are approved by the Shift Manager. Step 4.8.4, also a part of Section 4.8, Transient Condition, also restates the guidance from 10 CFR 50.54 (x) and (y), and is nearly identical to Limitation F.5. found in DSSP 100-CR. When compared with the upper tier corporate procedure (HU-AA-104-101), the definition of Transient Conditions found in OP-DR-108-101-1003 appears to be taken out of context and is not complete.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS 10 CFR 50.54, Conditions of licenses, specifies conditions which are part of every nuclear power reactor operating license issued under 10 CFR 50. While not specifically stated in 10 CFR 50.54 (y), the other conditions specified in 10 CFR 50.54 imply that the licensed Senior Reactor Operator (SRO) specified must be a member of the on shift crew, and not just any licensed SRO. The only answer choice that matches these conditions is C The Shift Manager (SM), however, the Shift Manager is not the lowest level of authority on an operating crew with a SRO license. This responsibility would normally rest with the Unit Supervisor, but could fall under the responsibility of any on shift licensed SRO.
Based on the above discussion there does not appear to be any correct answer, and therefore the question will be deleted.
VI.
Question #69 Unit 2 is operating at 50% power and expected to pick up load early next shift.
'D' Lift pump is being prepared to start after maintenance on the motor has been completed.
The NSO in the control room attempts to start the 'D' Lift pump.
The EO at the Lift Station reports no observable change in status locally.
Based on these events, in regards to the 'D' Lift pump, the operating crew should A.
leave the pump as is to support troubleshooting activities B.
attempt to restart the pump ONE more time ONLY C.
attempt to restart the pump a MAXIMUM of TWO more times D.
place the control switch in PULL TO LOCK at the local control panel in the Lift Station Answer:
A Candidate Feedback:
Clarification of question needed. Capitalize 'after' in the stem of the question.
Facility Response:
Question is acceptable as written for this exam. Facility will evaluate possible enhancement to the stem of the question.
DRESDEN 2012-301 NRC WRITTEN EXAM POST EXAM COMMENTS AND RESOLUTIONS NRC Resolution Candidate feedback stated that clarification was needed, however, there were no questions, asking for clarification, during the exam administration. DOP 6500-19, Racking a Lift Station 4160 Volt Manually Operated Circuit Breaker, contains a Limitation stating IF a breaker fails to operate AND plant conditions permit, THEN leave conditions as-is in order to quarantine the affected equipment. The stem of the question indicates that the breaker failed to operate (i.e., No observable change in pump status on the attempted start) and since the pump was already out of service for maintenance, there is no reason to believe that plant conditions would preclude leaving the affected equipment as-is to support troubleshooting. Per conversation with the exam author, the Lift Station Pump breakers have had a history of problems associated with operation, and therefore the limitation is expected to be common knowledge The NRC agrees with the facility response that the question is acceptable as written and since applicants are responsible for knowing the reason for procedural operating limitations, does not require any reference material to answer. No changes were made to the question.