MNS-18-001, Application to Revise Technical Specifications to Adopt TSTF-234-A Revision 1, Add Action for More than One Dpri Inoperable
| ML18159A035 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/31/2018 |
| From: | Teresa Ray Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| MNS-18-0014 | |
| Download: ML18159A035 (22) | |
Text
(_~ DUKE ENERGY May 31, 2018 Serial: MNS-18-0014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 Thomas D. Ray, P.E.
Site Vice President McGuire Nuclear Station Duke Energy MGOl VP I 12700 Hagers Ferry Road Huntersville, NC 28078 O: 980.875.4805 f: 980.875.4809 Tom.Ray@duke-energy.com 10 CFR 50.90 DOCKET NOS. 50-369 AND 50-370 / RENEWED LICENSE NOS. NPF-9 AND NPF-17
SUBJECT:
APPLICATION TO REVISE TECHNICAL SPECIFICATIONS TO ADOPT TSTF-234-A REVISION 1, "ADD ACTION FOR MORE THAN ONE DRPI INOPERABLE" Pursuant to 10 CFR 50.90, Duke Energy Carolinas, LLC, referred to henceforth as "Duke Energy," is submitting a request for an amendment to the Technical Specifications (TS) for McGuire Nuclear Station (MNS), Units 1 and 2.
The proposed amendment would modify TS requirements in Section 3.1.7, "Rod Position Indication", to add a Condition for more than one inoperable digital rod position indication (DRPI) per group, revise the Action Note and to clarify the wording of current Required Actions A.1 and B.1. This change is consistent with NRG-approved Technical Specification Task Force (TSTF) Traveler TSTF-234-A, "Add Action for More Than One DRPI Inoperable," Revision 1. provides a description and assessment of the proposed changes. Attachment 2 provides the existing TS pages marked up to show the proposed changes. Attachment 3 provides existing TS Bases pages marked up to show the proposed changes. Changes to the existing TS Bases will be implemented under the Technical Specification Bases Control Program and are provided in Attachment 3 for information only. Attachment 4 provides the retyped TS pages.
The proposed changes have been evaluated in accordance with 10 CFR 50.91 (a)(1) using criteria in 10 CFR 50. 92( c ), and it has been determined that the proposed changes involve no significant hazards consideration. The bases for these determinations are included in.
This submittal contains no regulatory commitments.
Approval of the proposed amendment is requested within six months of NRC acceptance.
Duke Energy is requesting a six month approval of the proposed changes to better align with www.duke-energy.com
U.S. Nuclear Regulatory Commission MNS-18-0014 Page 2 NUREG-1431 and avoid unnecessary unit shutdowns.
Once approved, the amendments will be implemented within 30 days.
In accordance with 10 CFR 50.91, a copy of this application, with Attachments, is being provided to the designated North Carolina official.
If you have any questions regarding this submittal, or require additional information, please contact Joseph Hussey at (980)875-5045.
I declare under penalty of perjury that the foregoing is true and correct. Executed on May 31, 2018.
Sincerely, j),
Thomas D. Ray, P.E.
Vice President - McGuire Attachments: 1. Description and Assessment
- 2. Proposed Technical Specification Changes (Mark-up)
- 3. Proposed Technical Specification Bases Changes (Mark-up for information only)
- 4. Retyped Technical Specification Pages
U.S. Nuclear Regulatory Commission MNS-18-0014 Page 3 cc (with Attachments):
C. Haney Region II Administrator U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, GA 30303-1257 M. Mahoney Project Manager (MNS)
U.S. Nuclear Regulatory Commission Michael.Mahoney@nrc.gov G.A. Hutto NRC Senior Resident Inspector McGuire Nuclear Station W. L. Cox, 111, Section Chief North Carolina Department of Environmental and Natural Resources lee.cox@dhhs.nc.gov to MNS-18-0014 Page 1 of 3 DESCRIPTION AND ASSESSMENT 1.0
SUMMARY
DESCRIPTION This evaluation supports a request to amend Renewed Facility Operating Licenses NPF-9 and NPF-17 McGuire Nuclear Station, Units 1 and 2, Docket Nos. 50-369 and 50-370.
The proposed amendment would revise the Operating Licenses by modifying Technical Specification (TS) 3.1. 7, "Rod Position Indication," in accordance with TSTF-234-A, "Add Action for More Than One [D]RPI Inoperable," Revision 1. The amendment adds a Condition for more than one inoperable digital rod position indication (DRPI) per group, revises the Action Note to reflect the change, and clarifies the wording of current Required Actions A.1 and B.1. The amendment better aligns McGuire TS 3.1. 7 with NUREG-1431, Revision 4. Duke Energy is requesting a six month completion timeframe to avoid unnecessary unit Shutdowns.
2.0 ASSESSMENT
2.1 Summary of the Approved Traveler Justification The proposed change adds a new Condition B, which applies when more than one DRPI per group is inoperable. The proposed Required Actions allow 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore all but one DRPI per group. The additional time to restore an inoperable DRPI is appropriate because the proposed Actions would require that the control rods be under manual control, that Reactor Coolant System average temperature be monitored and recorded hourly, and that rod position be verified indirectly every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> using the movable incore detectors, thereby assuring that the rod alignment and rod insertion LCOs are met.
Therefore, the required shutdown margin will be maintained. Given the alternate position monitoring requirement, and other indirect means of monitoring changes in rod position (e.g., alarms on Reactor Coolant System average temperature deviation), a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time to restore all but one DRPI per group provides sufficient time to restore operability while minimizing shutdown transients during the time that the position indication system is degraded.
2.2 Differences Between the Proposed Change and the Approved Traveler The McGuire TS Section 3.1 specification numbers are different from the ISTS Section 3.1 specification numbers when TSTF-234-A, Rev. 1, was approved by the NRC in 1999. McGuire Specification 3.1. 7, "Rod Position Indication," is analogous to Specification 3.1.8 in the TSTF ISTS mark-up.
TSTF-234-A contains the bracketed text"[, or B.1, as applicable]" in the Bases discussion for Condition C. This change is not adopted because it is not necessary to provide direction in the Bases that all applicable Conditions must be entered.
These variations do not affect the applicability of TSTF-234-A or the TSTF justification as approved by the NRC staff.
to MNS-18-0014 Page 2 of 3 2.3 Differences Between the Plant-Specific Justification and the Approved Traveler Justification None.
2.4 Licensee Commitments Required to Adopt this Change None.
2.5 NRC Approval The NRC documented their approval of TSTF-234-A, Revision 1, in a letter from William D. Beckner (NRC) to James Davis (NEI) dated January 13, 1999 (ML9901210038). The NRC approved TSTF-234-A, Revision 1, for Vogtle Electric Generating Plant (VEGP), Units 1 and 2, amendment No. 180 and Amendment No. 161 dated June 9, 2016 (ML15132A569).
3.0 REGULATORY ANALYSIS
3.1 Applicable Regulatory Requirements/Criteria Title 10 of the Code of Federal Regulations (10 CFR), 50.36(c)(2), states: Limiting conditions for operation. (i) Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility.
When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.
10 CFR 50.36(c)(2) allows licensees to follow remedial actions permitted by the Technical Specifications until the (limiting) condition for plant operation can be met. The ISTS for Westinghouse Plants (NUREG-1431) provides remedial actions for more than one DPRI inoperable in a group. The proposed amendment is consistent with NUREG-1431.
In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the approval of the proposed change will not be inimical to the common defense and security or to the health and safety of the public.
3.2 No Significant Hazards Consideration Analysis Duke Energy has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
- 1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The proposed amendment provides a Condition and Required Actions for more than one inoperable digital rod position indications (DRPI) per rod group. The DRPls are not an initiator of any accident previously evaluated. The DRPls are one indication used by operators to verify control rod insertion following an accident; however other to MNS-18-0014 Page 3 of 3 indications are available. Therefore, allowing a finite period of time to correct more than one inoperable DRPI prior to requiring a plant shutdown will not result in an increase in the consequences of any accident previously evaluated. The proposed amendment does not involve an increase in the probability or consequences of any accident previously evaluated.
- 2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No.
The proposed amendment does not involve a physical alteration to the plant (i.e., no new or different type of equipment will be installed) or a change to the methods governing normal plant operation. The changes do not alter the assumptions made in the safety analysis. Therefore, the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed amendment involve a significant reduction in a margin of safety?
Response: No.
The proposed amendment provides time to correct the condition of more than one DRPI inoperable in a rod group. Compensatory measures are required to verify that the rods monitored by the inoperable DRPls are not moved to ensure that there is no effect on core reactivity. Requiring a plant shutdown with inoperable rod position indications introduces plant risk and should not be initiated unless the rod position indication cannot be repaired in a reasonable period. As a result, the safety benefit provided by the proposed Condition offsets the small decrease in safety resulting from continued operation with more than one inoperable DRPI. Therefore, the proposed amendment does not involve a reduction in a margin of safety.
Based on the above, Duke Energy concludes that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and accordingly, a finding of "no significant hazards consideration" is justified.
4.0 ENVIRONMENTAL EVALUATION Duke Energy has reviewed the proposed changes pursuant to 10 CFR 50.92 and determined that it does not involve a significant hazards consideration. In addition, there is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite, and there is no significant increase in individual or cumulative occupational radiation exposure. Consequently, the proposed Technical Specifications changes have no significant effect on the human environment and satisfy the criteria of 10 CFR 51.22 for categorical exclusion from the requirements for an environmental assessment.
to MNS-18-0014 Page 1 of 4 Proposed Technical Specification Changes (Mark-up)
3.1 REACTIVITY CONTROL SYSTEMS 3.1.7 Rod Position Indication Rod Position Indication 3.1.7 LCO 3.1.7 The Digital Rod Position Indication (DRPI) System and the Demand Position Indication System shall be OPERABLE.
APPLICABILITY:
MODES 1 and 2.
ACTIONS
NOTE----------------------------------------------------------
Separate Condition entry is allowed for each inoperable rod position indicator per group and each demand position indicator per bank.
CONDITION REQUIRED ACTION COMPLETION TIME A
One DRPI per group A.1 Verify the position of the Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable for one or rods with inoperable more groups.
position indicators indirectly by using movable incore detectors.
OR A.2 Reduce THERMAL 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> POWER to~ 50% RTP.
B.
More than one DRPI per B.1 Place the control rods Immediately group inoperable.
under manual control.
AND B.2 Monitor and Record RCS Once per 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Tavg*
AND (continued)
McGuire Units 1 and 2 3.1. 7-1 Amendment Nos. 184/166
CONDITION B. (continued)
B:-C.
One or more rods with inoperable position indicators have been moved in excess of 24 steps in one direction since the last determination of the rod's position.
G,.D.
One demand position indicator per bank inoperable for one or more banks.
McGuire Units 1 and 2 REQUIRED ACTION B.3 Verify the position of the rods with inoperable position indicators indirectly by using the moveable incore detectors.
AND B.4 Restore inoperable position indicators to OPERABLE status such that a maximum of one DRPI per group is inoperable.
B:-C. 1 Verify the position of the rods with inoperable position indicators indirectly by using movable incore detectors.
OR B:-C.2 Reduce THERMAL POWER to ~ 50% RTP.
G,.D. 1.1 Verify by administrative means all DRPls for the affected banks are OPERABLE.
AND G,.D.1.2 Verify the most withdrawn rod and the least withdrawn rod of the affected banks are
~ 12 steps apart.
OR G,.D.2 Reduce THERMAL POWER to~ 50% RTP.
Rod Position Indication 3.1.7 COMPLETION TIME Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 24 hours 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 8 hours Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 hours
( continued) 3.1.7-2 Amendment Nos. 184/166
CONDITION 1*E.
Required Action and associated Completion Time not met.
REQUIRED ACTION 1*E.1 Be in MODE 3.
SURVEILLANCE REQUIREMENTS SURVEILLANCE Rod Position Indication 3.1.7 COMPLETION TIME 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> FREQUENCY SR 3.1. 7.1 Verify each DRPI agrees within 12 steps of the group demand position for the full indicated range of rod travel.
Once prior to criticality after each removal of the reactor head McGuire Units 1 and 2 3.1.7-3 Amendment Nos. 184/166 to MNS-18-0014 Page 1 of 7 Proposed Technical Specification Bases Changes (Mark-up)
(For Information Only)
Rod Position Indication B 3.1.7 B 3.1 REACTIVITY CONTROL SYSTEM B 3.1.7 Rod Position Indication BASES BACKGROUND According to GDC 13 (Ref. 1 ), instrumentation to monitor variables and systems over their operating ranges during normal operation, anticipated operational occurrences, and accident conditions must be OPERABLE.
LCO 3.1. 7 is required to ensure OPERABILITY of the control rod position indicators to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits.
The OPERABILITY, including position indication, of the shutdown and control rods is an initial assumption in all safety analyses that assume rod insertion upon reactor trip. Maximum rod misalignment is an initial assumption in the safety analysis that directly affects core power distributions and assumptions of available SOM. Rod position indication is required to assess OPERABILITY and misalignment.
Mechanical or electrical failures may cause a control rod to become inoperable or to become misaligned from its group. Control rod inoperability or misalignment may cause increased power peaking, due to the asymmetric reactivity distribution and a reduction in the total available rod worth for reactor shutdown. Therefore, control rod alignment and OPERABILITY are related to core operation in design power peaking limits and the core design requirement of a minimum SOM.
Limits on control rod alignment and OPERABILITY are established in LCO 3.1.4, "Rod Group Alignment Limits," and all rod positions are monitored and controlled during power operation to ensure that the power distribution and reactivity limits defined by the design power peaking and SOM limits are preserved.
Rod cluster control assemblies (RCCAs), or rods, are moved out of the core (up or withdrawn) or into the core (down or inserted) by their control rod drive mechanisms. The RCCAs are divided among control banks and shutdown banks. Each bank may be further subdivided into two groups to provide for precise reactivity control.
The axial position of shutdown rods and control rods are determined by two separate and independent systems: the Bank Demand Position Indication System (commonly called group step counters) and the Digital Rod Position Indication (DRPI) System.
McGuire Units 1 and 2 B 3.1.7-1 Revision No. ~
BASES Rod Position Indication B 3.1.7 BACKGROUND (continued)
The Bank Demand Position Indication System counts the pulses from the Rod Control System that move the rods. There is one step counter for each group of rods. Individual rods in a group all receive the same signal to move and should, therefore, all be at the same position indicated by the group step counter for that group. The Bank Demand Position Indication System is considered highly precise(+/- 1 step or+/- 5/8 inch). If a rod does not move one step for each demand pulse, the step counter will still count the pulse and incorrectly reflect the position of the rod.
The DRPI System provides a highly accurate indication of actual control rod position, but at a lower precision than the step counters. This system is based on inductive analog signals from a series of coils spaced along a hollow tube with a center to center distance of 3. 75 inches, which is 6 steps. To increase the reliability of the system, the inductive coils are connected alternately to data channel A or B. Thus creating two separate and independent channels (Data A and Data B). Also, the coils are not placed at the reflected six step increments starting at rod bottom.
Because of this arrangement, the nominal accuracy of the system is +/- 3 steps indicated versus true rod position. Due to mechanical positioning of the coils on the rod position detector and expansion in containment atmosphere, another +/- 1 step is added to system accuracy making it +/-
4 steps.
If one channel fails, the DRPI will go to half accuracy. The accuracy will be - 10, + 4 steps when either channel fails. Therefore, the maximum deviation between the group demand counters and DRPI could be 10 steps, or 6.25 inches.
Gray code (A & B data from the data cabinets in containment) is sent to the DRPI equipment in the control room. The gray code is processed by the DRPI equipment and the rod position is displayed on the control board. The gray code is also sent from the DRPI equipment to the Operator Aid Computer (OAC), where it is processed by the OAC and the rod position is displayed on the OAC. The processing of the gray code by the DRPI equipment and the OAC are completely independent.
Therefore, both the DRPI display and the OAC DRPI indication are considered valid indications of control rod position.
APPLICABLE Control and shutdown rod position accuracy is essential during SAFETY ANALYSES power operation. Power peaking, ejected rod worth, or SOM limits may be violated in the event of a Design Basis Accident (Ref. 2), with control or shutdown rods operating outside their limits undetected. Therefore, the acceptance criteria for rod position indication is that rod positions must be known with sufficient accuracy in order to verify McGuire Units 1 and 2 B 3.1.7-2 Revision No. ~
BASES Rod Position Indication B 3.1.7 APPLICABLE SAFETY ANALYSES (continued)
LCO the core is operating within the group sequence, overlap, design peaking limits, ejected rod worth, and with at least minimum SOM (LCO 3.1.5, "Shutdown Bank Insertion Limits," and LCO 3.1.6, "Control Bank Insertion Limits"). The rod positions must also be known in order to verify the alignment limits are preserved (LCO 3.1.4, "Rod Group Alignment Limits"). Control rod positions are continuously monitored to provide operators with information that ensures the plant is operating within the bounds of the accident analysis assumptions.
The control rod position indicator channels satisfy Criterion 2 of 10 CFR 50.36 (Ref. 3). The control rod position indicators monitor control rod position, which is an initial condition of the accident.
LCO 3.1. 7 specifies that one DRPI System ( either A or B Channel) and one Bank Demand Position Indication System be OPERABLE for each control rod. For the control rod position indicators to be OPERABLE requires meeting the SR of the LCO and the following :
- a.
The DRPI System indicates within 12 steps of the group step counter demand position as required by LCO 3.1.4, "Rod Group Alignment Limits";
- b.
For the DRPI System either Data A or Data B is operable for each rod; and
- c.
The Bank Demand Indication System has been calibrated either in the fully inserted position or to the DRPI System.
The 12 step agreement limit between the Bank Demand Position Indication System and the DRPI System indicates that the Bank Demand Position Indication System is adequately calibrated, and can be used for indication of the measurement of control rod bank position.
A deviation of less than the allowable limit, given in LCO 3.1.4, in position indication for a single control rod, ensures high confidence that the position uncertainty of the corresponding control rod group is within the assumed values used in the analysis (that specified control rod group insertion limits).
These requirements ensure that control rod position indication during power operation and PHYSICS TESTS is accurate, and that design assumptions are not challenged.
McGuire Units 1 and 2 B 3.1.7-3 Revision No. e8
BASES LCO (continued)
APPLICABILITY ACTIONS Rod Position Indication B 3.1.7 OPERABILITY of the position indicator systems ensures that inoperable, misaligned, or mispositioned control rods can be detected. Therefore, power peaking, ejected rod worth, and SOM can be controlled within acceptable limits.
The requirements on the DRPI and step counters are only applicable in MODES 1 and 2 (consistent with LCO 3.1.4, LCO 3.1.5, and LCO 3.1.6),
because these are the only MODES in which power is generated, and the OPERABILITY and alignment of rods have the potential to affect the safety of the plant. In the shutdown MODES, the OPERABILITY of the shutdown and control banks has the potential to affect the required SOM, but this effect can be compensated for by an increase in the boron concentration of the Reactor Coolant System.
The ACTIONS table is modified by a Note indicating that a separate Condition entry is allowed for each inoperable rod position indicator f)ef
~
and each demand position indicator per bank. This is acceptable because the Required Actions for each Condition provide appropriate compensatory actions for each inoperable position indicator.
When the DRPI channels (Data A and Data B) for one rod per group, for one or more groups fails, the position of the rods GaR may still be determined indirectly by use of the movable incore detectors. The Required Action may also be satisfied by ensuring at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> that Fa satisfies LCO 3.2.1, F aH satisfies LCO 3.2.2, and SHUTDOWN MARGIN is within the limits provided in the COLR, provided the non-indicating rods have not been moved. Based on experience, normal power operation does not require excessive movement of banks.
If a bank has been significantly moved, the Required Action of B.1 or B.2 C.1 or C.2 below is required. Therefore, verification of RCCA position within the Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is adequate for allowing continued full power operation, since the probability of simultaneously having a rod significantly out of position and an event sensitive to that rod position is small.
Reduction of THERMAL POWER to ~ 50% RTP puts the core into a condition where rod position is not significantly affecting core peaking factors (Ref. 4 ). The allowed Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is reasonable, based on operating experience, for reducing power to ~ 50% RTP from full power conditions without challenging plant systems and allowing for rod position determination by Required Action A.1 above.
McGuire Units 1 and 2 B 3.1.7-4 Revision No. a8
BASES Rod Position Indication B 3.1.7 ACTIONS ( continued)
When more than one DRPI per group fails, (Data A and Data B),
additional actions are necessary to ensure that acceptable power distribution limits are maintained, minimum SOM is maintained, and the potential effects of rod misalignment on associated accident analyses are limited. Placing the Rod Control System in manual assures unplanned rod motion will not occur. Placing the Rod Control System in manual together with the indirect position determination available via movable incore detectors will minimize the potential for rod misalignment. The immediate Completion Time for placing the Rod Control System in manual reflects the urgency with which unplanned rod motion must be prevented while in this Condition.
8.2 Monitoring and recording reactor coolant Tavg help assure that significant changes in power distribution and SOM are avoided. The once per hour Completion Time is acceptable because only minor fluctuations in RCS temperature are expected at steady state plant operating conditions.
The position of the rods may be determined indirectly by use of the movable incore detectors. The Required Action may also be satisfied by ensuring at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> that Fa satisfies LCO 3.2.1, FN e.H satisfies LCO 3.2.2, and SHUTDOWN MARGIN is within the limits provided in the COLR, provided the non-indicating rods have not been moved. Verification of RCCA position once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is adequate for allowing continued full power operation for a limited, 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, since the probability of simultaneously having a rod significantly out of position and an event sensitive to that rod position is small.
8.4 The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time provides sufficient time to troubleshoot and restore the DRPI system to operation while avoiding the plant challenges associated with a shutdown without full rod position indication (Ref. 4 ).
Based on operating experience, normal power operation does not require excessive rod movement. If one or more rods has been significantly moved, the Required Action of C.1 or C.2 below is required.
McGuire Units 1 and 2 B 3.1.7-5 Revision No. a8
BASES Rod Position Indication B 3.1.7 ACTIONS (continued)
BC.1 and BC.2 These Required Actions clarify that when one or more rods with inoperable position indicators have been moved in excess of 24 steps in one direction, since the position was last determined, the Required Actions to determine the position of the rods indirectly by use of the movable incore detectors of l\\..1 and l\\..2 are still appropriate but must be initiated promptly under Required Action BC.1 to begin verifying that these rods are still properly positioned, relative to their group positions using the movable incore detectors.
If, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, the rod positions have not been determined, THERMAL POWER must be reduced to ~ 50% RTP within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to avoid undesirable power distributions that could result from continued operation at > 50% RTP, if one or more rods are misaligned by more than 24 steps.
The allowed Completion Time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> provides an acceptable period of time to verify the rod positions.
GD.1.1 and GD.1.2 With one demand position indicator per bank inoperable, the rod positions can be determined by the DRPI System. Since normal power operation does not require excessive movement of rods, verification by administrative means (e.g., observation of appropriate DRPI status indications) that the rod position indicators are OPERABLE and the most withdrawn rod and the least withdrawn rod are ~ 12 steps apart within the allowed Completion Time of once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is adequate. Since DRPI is the only operable rod position indication, administrative means are actions taken by the control room SRO to assure that the DRPI for the affected bank remains operable at all times. These administrative means would prevent any maintenance or testing of the operable DRPI for the affected bank until the inoperable demand position indicator is returned to operable status.
Reduction of THERMAL POWER to ~ 50% RTP puts the core into a condition where rod position is not significantly affecting core peaking factor limits (Ref. 4). The allowed Completion Time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> provides an acceptable period of time to verify the rod positions per Required Actions C.1.1 and C.1.2 or reduce power to ~ 50% RTP.
McGuire Units 1 and 2 B 3.1.7-6 Revision No. a8
BASES Rod Position Indication B 3.1.7 ACTIONS (continued)
SURVEILLANCE REQUIREMENTS REFERENCES If the Required Actions cannot be completed within the associated Completion Time, the plant must be brought to a MODE in which the requirement does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The allowed Completion Time is reasonable, based on operating experience, for reaching the required MODE from full power conditions in an orderly manner and without challenging plant systems.
SR 3.1.7.1 Verification that the DRPI agrees with the demand position within 12 steps ensures that the DRPI is operating correctly.
This Surveillance is performed prior to reactor criticality after each removal of the reactor head as there is the potential for unnecessary plant transients if the SR were performed with the reactor at power.
- 1.
10 CFR 50, Appendix A, GDC 13.
- 2.
UFSAR, Section 15.0.
- 3.
10 CFR 50.36, Technical Specifications, (c)(2)(ii).
- 4.
UFSAR, Section 15.4 McGuire Units 1 and 2 B 3.1.7-7 Revision No. W to MNS-18-0014 Page 1 of 4 Technical Specification Pages (Retyped)
3.1 REACTIVITY CONTROL SYSTEMS 3.1.7 Rod Position Indication Rod Position Indication 3.1.7 LCO 3.1. 7 The Digital Rod Position Indication (DRPI) System and the Demand Position Indication System shall be OPERABLE.
APPLICABILITY:
MODES 1 and 2.
ACTIONS
NOTE----------------------------------------------------------
Separate Condition entry is allowed for each inoperable rod position indicator and each demand position indicator.
CONDITION REQUIRED ACTION COMPLETION TIME A.
One DRPI per group A.1 Verify the position of the Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable for one or rods with inoperable more groups.
position indicators indirectly by using movable incore detectors.
OR A.2 Reduce THERMAL 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> POWER to~ 50% RTP.
B.
More than one DRPI per B.1 Place the control rods Immediately group inoperable.
under manual control.
AND B.2 Monitor and Record RCS Once per 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Tavg*
AND (continued)
McGuire Units 1 and 2 3.1.7-9 Amendment Nos. 184/166
CONDITION B. (continued)
C.
One or more rods with inoperable position indicators have been moved in excess of 24 steps in one direction since the last determination of the rod's position.
D.
One demand position indicator per bank inoperable for one or more banks.
McGuire Units 1 and 2 REQUIRED ACTION B.3 Verify the position of the rods with inoperable position indicators indirectly by using the moveable incore detectors.
AND B.4 Restore inoperable position indicators to OPERABLE status such that a maximum of one DRPI per group is inoperable.
C. 1 Verify the position of the rods with inoperable position indicators indirectly by using movable incore detectors.
OR C.2 Reduce THERMAL POWER to.'.5. 50% RTP.
D.1.1 Verify by administrative means all DRPls for the affected banks are OPERABLE.
AND D.1.2 Verify the most withdrawn rod and the least withdrawn rod of the affected banks are
.:5. 12 steps apart.
OR D.2 Reduce THERMAL POWER to.'.5. 50% RTP.
Rod Position Indication 3.1.7 COMPLETION TIME Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 24 hours 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 8 hours Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 hours (continued) 3.1.7-10 Amendment Nos. 184/166
E.
CONDITION Required Action and associated Completion Time not met.
SURVEILLANCE REQUIREMENTS REQUIRED ACTION E.1 Be in MODE 3.
SURVEILLANCE Rod Position Indication 3.1.7 COMPLETION TIME 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> FREQUENCY SR 3.1. 7.1 Verify each DRPI agrees within 12 steps of the group demand position for the full indicated range of rod travel.
Once prior to criticality after each removal of the reactor head McGuire Units 1 and 2 3.1.7-11 Amendment Nos. 184/166