ML15266A005
| ML15266A005 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/25/2015 |
| From: | Watford M M Plant Licensing Branch IV |
| To: | Edington R K Arizona Public Service Co |
| Watford M M | |
| References | |
| TAC MF6678 | |
| Download: ML15266A005 (17) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Randall K. Edington Executive Vice President Nuclear/ Chief Nuclear Officer Mail Station 7602 Arizona Public Service Company P.O. Box 52034 Phoenix, AZ 85072-2034 September 25, 2015
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNIT 2-ISSUANCE OF AMENDMENT TO AMEND TECHNICAL SPECIFICATION SURVEILLANCE REQUIREMENT TO ELIMINATE MOVEMENT OF CONTROL ELEMENT ASSEMBLY 88 FOR THE REMAINDER OF UNIT 2, OPERATING CYCLE 19 (EXIGENT CIRCUMSTANCES) (TAC NO. MF6678)
Dear Mr. Edington:
The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 196 to Renewed Facility Operating License No. NPF-51 for the Palo Verde Nuclear Generating Station, Unit 2. The amendment consists of changes to the Technical Specifications (TSs) in response to your application dated September 4, 2015, as supplemented by letter dated September 15, 2015. The amendment adds a Note to TS Surveillance Requirement (SR) 3.1.5.3, Control Element Assembly (CEA) freedom of movement surveillance, such that Unit 2, CEA 88 may be excluded from the remaining quarterly performance of the SR in Unit 2, Cycle 19 due to a degraded upper gripper coil. The amendment allows the licensee to delay exercising CEA 88 until after repairs can be made during the upcoming fall 2015 outage.
R. Edington A copy of the related Safety Evaluation is also enclosed.
The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice. Docket No. STN 50-529
Enclosures:
- 1. Amendment No. 196 to NPF-51 2. Safety Evaluation cc w/encls: Distribution via Listserv Sincere;Jk.y, ; . -t',,,_ fiL I Margaret M. Watford, Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ARIZONA PUBLIC SERVICE COMPANY. ET AL. DOCKET NO. STN 50-529 PALO VERDE NUCLEAR GENERATING STATION. UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 196 License No. NPF-51 1. The Nuclear Regulatory Commission (the Commission) has found that: A. The application for amendment by the Arizona Public Service Company (APS or the licensee) on behalf of itself and the Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Water and Power, and Southern California Public Power Authority dated September 4, 2015, as supplemented by letter dated September 15, 2015, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's regulations set forth in 1 O CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 1 O CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
Enclosure 2 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and Paragraph 2.C(2) of Renewed Facility Operating License No. NPF-51 is hereby amended to read as follows: (2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 196, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this license. APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.
- 3. This license amendment is effective as of the date of issuance and shall be implemented prior to the next required Surveillance Requirement (SR) 3.1.5.3 performance due date for Control Element Assembly (CEA) 88 in Unit 2, Cycle 19.
Attachment:
Changes to the Renewed Facility Operating License No. NPF-51 and Technical Specifications FOR THE NUCLEAR REGULATORY COMMISSION
/l:LJ --:. A'"?; Michael T. Markley, Chief Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance:
September 25, 2015 ATTACHMENT TO LICENSE AMENDMENT NO. 196 RENEWED FACILITY OPERATING LICENSE NO. NPF-51 DOCKET NO. STN 50-529 Replace the following pages of the Renewed Facility Operating License No. NPF-51, and Appendix A, Technical Specifications, with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change. Renewed Facility Operating License No. NPF-51 REMOVE INSERT 6 6 Technical Specifications REMOVE INSERT 3.1.5-3 3.1.5-3 (1) Maximum Power Level Arizona Public Service Company (APS) is authorized to operate the facility at reactor core power levels not in excess of 3990 megawatts thermal (100% power) in accordance with the conditions specified herein. (2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 196, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed operating license. APS shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan, except where otherwise stated in specific license conditions.
(3) Antitrust Conditions This renewed operating license is subject to the antitrust conditions delineated in Appendix C to this renewed operating license. (4) Operating Staff Experience Requirements (Section 13.1.2. SSER 9)* Deleted (5) Initial Test Program (Section 14, SER and SSER 2) Deleted (6) Fire Protection Program APS shall implement and maintain in effect all provisions of the approved fire protection program as described in the Final Safety Analysis Report for the facility, as supplemented and amended, and as approved in the SER through Supplement 11, subject to the following provision:
APS may make changes to the approved fire protection program without prior approval of the Commission only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire. (7) lnservice Inspection Program (Sections 5.2.4 and 6.6, SER and SSER 9) Deleted *The parenthetical notation following the title of many license conditions denotes the section of the Safety Evaluation Report and/or its supplements wherein the license condition is discussed.
Renewed Facility Operating License No. NPF-51 Amendment No. 196 SURVEILLANCE REQUIREMENTS SR 3 .1. 5 .1 SR 3 .1. 5. 2 SR 3 .1. 5. 3 SR 3 .1. 5. 4 SR 3 .1. 5. 5 SURVEILLANCE Verify the indicated position of each full strength and part strength CEA is within 6.6 inches of all other CEAs in its group. Verify that. for each CEA. its OPERABLE CEA position indicator channels indicate within 5.2 inches of each other. -------------------NOTE-------------------
Not required to be performed for Unit 2 CEA 88 for the remainder of Cycle 19. Verify full strength CEA freedom of movement Ctrippability) by moving each individual full strength CEA that is not fully inserted in the core at least 5 inches. Perform a CHANNEL FUNCTIONAL TEST of each reed switch position transmitter channel. Verify each full strength CEA drop time 4.0 seconds. CEA Alignment 3.1.5 FREQUENCY In accordance with the Surveillance Frequency Control Program In accordance with the Surveillance Frequency Control Program In accordance with the Surveillance Frequency Control Program In accordance with the Surveillance Frequency Control Program Prior to reactor criticality, after each removal of the reactor head PALO VERDE UNITS 1.2.3 3.1.5-3 AMENDMENT NO. +/-gg, 196 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 196 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-51 ARIZONA PUBLIC SERVICE COMPANY, ET AL. PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. STN 50-529
1.0 INTRODUCTION
By application dated September 4, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 15247A518), as supplemented by letter dated September 15, 2015 (ADAMS Accession No. ML 15258A848), Arizona Public Service Company (the licensee) requested a change to the Technical Specifications (TSs) for Palo Verde Nuclear Generating Station, Unit 2 (PVNGS-2).
The proposed amendment would add a Note to TS Surveillance Requirement (SR) 3.1.5.3, Control Element Assembly (CEA) freedom of movement surveillance, such that Unit 2, CEA 88 may be excluded from the remaining quarterly performance of the SR in Unit 2, Cycle 19 due to a degraded upper gripper coil (UGC). The proposed amendment would allow the licensee to delay exercising CEA 88 until after repairs can be made during the upcoming fall 2015 outage. The supplemental letter dated September 15, 2015, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the U.S. Nuclear Regulatory Commission (NRC) staff's original proposed no significant hazards consideration determination as published in the Arizona Republic on September 21 and 22, 2015. As discussed in its application dated September 4, 2015, the licensee requested that the proposed amendment be processed by the NRC on an exigent basis in accordance with the provisions in Title 10 of the Code of Federal Regulations (10 CFR) paragraph 50.91 (a)(6). The NRC's evaluation regarding the exigent circumstances is discussed in Section 4.0 of this safety evaluation (SE). Enclosure 2
2.0 REGULATORY EVALUATION
2.1 System Description The CEAs for PVNGS-2 are used for reactivity control. The CEAs are divided into nine groups, of which five are regulating groups designated by Groups 1 through 5. CEA 88 is in Regulating Group 4, Subgroup 22. The regulating groups are withdrawn during reactor startup in a predetermined sequence and position overlap after the shutdown groups are withdrawn.
During power operation, insertion limits are placed on the regulating groups to ensure that power distribution and reactivity limits are preserved.
While at power, the regulating groups are fully withdrawn except for limited insertion of the first regulating group in order to compensate for minor variations in moderator temperature and boron concentration as well as performing SRs. Since CEA 88 is within Regulating Group 4, this CEA usually remains fully withdrawn when the reactor is at power except during performance of SR 3.1.5.3. 2.2 Applicable Regulatory Requirements Section 182a of the Atomic Energy Act requires applicants for nuclear power plant operating licenses to include TSs as part of the license. The Commission's regulatory requirements related to the content of the TSs are contained in 10 CFR 50.36, "Technical specifications." The TS requirements in 10 CFR 50.36 include the following categories:
(1) safety limits, limiting safety systems settings and control settings, (2) limiting conditions for operation, (3) SRs, (4) design features, and (5) administrative controls.
Surveillance requirements in 10 CFR 50.36 are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met. The regulations in 10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants," include the following general design criteria (GDC) applicable to CEA design requirements:
GDC 23, "Protection system failure modes," states that "[t]he protection system shall be designed to fail into a safe state or into a state demonstrated to be acceptable on some other defined basis if conditions such as disconnection of the system, loss of energy (e.g., electric power, instrument air), or postulated adverse environments (e.g., extreme heat or cold, fire, pressure, steam, water, and radiation) are experienced." GDC 25, "Protection system requirements for reactivity control malfunctions," states that "[the protection system shall be designed to assure that specified acceptable fuel design limits are not exceeded for any single malfunction of the reactivity control systems, such as accidental withdrawal (not ejection or dropout) of control rods." GDC 26, "Reactivity control system redundancy and capability," states that "[t]wo independent reactivity control systems of different design principles shall be provided.
One of the systems shall use control rods, preferably including a positive means for inserting the rods, and shall be capable of reliably controlling reactivity changes to assure that under conditions of normal operation, including anticipated operational occurrences, and with appropriate margin for malfunctions such as stuck rods, specified acceptable fuel design limits are not exceeded.
The second reactivity control system shall be capable of reliably controlling the rate of reactivity changes resulting from planned, normal power changes (including xenon burnout) to assure acceptable fuel design limits are not exceeded.
One of the systems shall be capable of holding the reactor core subcritical under cold conditions." GDC 27, "Combined reactivity control systems capability," states that "[t]he reactivity control systems shall be designed to have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident conditions and with appropriate margin for stuck rods the capability to cool the core is maintained." GDC 28, "Reactivity limits," states that "[t]he reactivity control systems shall be designed with appropriate limits on the potential amount and rate of reactivity increase to assure that the effects of postulated reactivity accidents can neither (1) result in damage to the reactor coolant pressure boundary greater than limited local yielding nor (2) sufficiently disturb the core, its support structures or other reactor pressure vessel internals to impair significantly the capability to cool the core. These postulated reactivity accidents shall include consideration of rod ejection (unless prevented by positive means), rod dropout, steam line rupture, changes in reactor coolant temperature and pressure, and cold water addition." GDC 29, "Protection against anticipated operational occurrences," states that "[t]he protection and reactivity control systems shall be designed to assure an extremely high probability of accomplishing their safety functions in the event of anticipated operational occurrences." 3.0 TECHNICAL EVALUATION 3.1 Proposed TS Change Current SR 3.1.5.3 states: Verify full strength CEA freedom of movement (trippability) by moving each individual full strength CEA that is not fully inserted in the core at least 5-inches.
Revised SR 3.1.5.3 would state: --------------------------
NOTE ----------------------------
Not required to be performed for Unit 2 CEA 88 for the remainder of Cycle 19. Verify full strength CEA freedom of movement (trippability) by moving each individual full strength CEA that is not fully inserted in the core at least 5 inches. The current surveillance frequency of "In accordance with the Surveillance Frequency Control Program," would remain unchanged. 3.2 Summary of Technical Information Provided by Licensee The licensee requested to revise the PVNGS-2 TS. The proposed revision would eliminate exercising CEA 88 for the remainder of operating Cycle 19, currently scheduled to end on October 10, 2015. The proposed amendment would add a note to SR 3.1.5.3 such that CEA 88 may be excluded from SR performance for the remainder of Cycle 19. The licensee stated that during the August 27, 2015, performance of a monitoring program for all CEAs, CEA 88 had exceeded the monitoring threshold value for current noise and the holding function was transferred to the lower gripper coil. Upon transfer to the lower gripper coil, the UGC de-energized and remains de-energized.
The high current noise was considered an indication of UGC degradation.
The purpose of SR 3.1.5.3 is to verify that the CEAs are moveable and trippable (i.e., otherwise free from mechanical binding).
The licensee evaluated the degrading condition to avoid a rod drop accident or plant transient.
The licensee concluded that CEA 88 remains trippable and is expected to remain so. The reactor trip circuit breakers open upon an automatic or manual reactor trip signal which removes power from both control and holding circuitry.
All coils on each CEA de-energize, resulting in all CEAs inserting into the core by gravity. In an event of a loss of power, the CEAs will insert into the core regardless of a reactor trip signal because of the fail-safe design. Any postulated failure mechanism that could prevent rod insertion is not influenced or impacted by coil failure, or control or holding circuitry failures.
This was demonstrated in the Unit 2 CEA 15 drop event on November 6, 2014; see the licensee's letter dated December 30, 2014, regarding Licensee Event Report 2014-002-00 (ADAMS Accession No. ML 15005A045).
TS 3.1.2, "SHUTDOWN MARGIN (SOM) -Reactor Trip Breakers Closed," specifies that SOM shall be greater than or equal to that specified in the Core Operating Limits Report (COLR). The licensee stated that the Cycle 19 COLR SOM operating limit is 6.5 percent flk/k, where k is the reactivity, in Modes 3 through 5 with trip breakers closed. The licensee performed calculations at 450 effective full-power days through the remainder of Cycle 19 operation.
It was determined that a minimum SDM of 7.27 percent flk/k would exist following a reactor trip assuming both CEA 88 and the single CEA of highest reactivity worth fail to insert. The licensee concluded that this calculated minimum SOM would be above the 6.5 percent flk/k SOM requirement of the COLR. 3.3 NRC Staff Evaluation The NRC staff reviewed the application and determined that additional information was required regarding the evaluation of the request. In a letter dated September 15, 2015, the licensee responded to the NRC staff's request for additional information (RAI) dated November 11, 2014 (ADAMS Accession No. ML 15257A297), regarding PVNGS-2's elimination of movement of CEA 88 from SR 3.1.5.3 for the remainder of Cycle 19. The NRC staff requested that the licensee describe in detail what administrative controls were put in place to prevent energizing the UGC and causing further degradation.
In its letter dated September 15, 2015, the licensee stated that the administrative controls have been issued with instructions to not move any CEA that is currently on lower gripper without permission from the Unit 2 Operations Manager. The standing orders are reviewed at the start of each shift by the operating crews during turnover.
In addition, the mode select switch for the CEA drive mechanism control system (CEDMCS) has been flagged with an activities equipment status tag to reinforce the standing order and draw attention to the CEA 88 UGC condition.
Based on its review, the NRC staff determined that these administrative controls will help prevent accidentally energizing the UGC; therefore, the NRC staff concludes the proposed change is acceptable.
The NRC staff also requested that the licensee explain how the administrative controls address possible automatic motion of CEA 88 and what would cause automatic motion of CEA 88 for the remainder of Cycle 19. The licensee stated that the administrative controls do not address automatic motion. The administrative controls are only to address manual movement of CEA 88. The licensee then stated that there were two possible scenarios for CEA 88 automatic movement:
Reactor Power Cutback or a reactor trip. In both scenarios, Regulating Group 4 (which includes CEA 88) fully inserts into the core and the unit is taken offline. For any CEA movement to balance reactor power to secondary plant power, Regulating Group 5 would move first to bring power down at this point in core life. Power would have to reduce by 10 percent before Regulating Group 4 would have to move. Based on its review, the NRC staff determined that CEA 88's UGC will not energize in any foreseen power changes and, therefore, the NRC staff concludes that the proposed change is acceptable.
The NRC staff also requested that the licensee confirm that SOM calculations were performed using NRG-approved methodologies and are currently used by PVNGS-2 to perform the TS surveillances.
The licensee stated that the CASM0-4/SIMULATE-3 model was used to calculate the minimum SOM. The CASM0-4/SIMULATE-3 model was approved by the NRC Staff for use in SOM calculations in License Amendment No. 132 dated March 20, 2001 (ADAMS Accession No. ML010860187).
Thus, the NRC staff determined that the SOM calculation was performed using an NRG-approved method. Additionally, the NRC staff determined that the licensee's calculations assured adequate existing SOM assuming both CEA 88 and the single highest reactivity worth CEA failed to insert. These models and methods utilized for the SOM calculation are also used to perform the TS surveillances.
Based on the above, the NRC staff concludes that the licensee has adequately calculated the SOM available if CEA 88 fails to trip, and that the SOM available in that case would be greater than the SOM required by the COLR. The NRC staff reviewed the license amendment request, as supplemented by the RAI response, provided by the licensee to eliminate exercising CEA 88 for SR 3.1.5.3 for the remainder of operating Cycle 19 and determined that the licensee provided adequate information for its justification of excluding CEA 88 from SR performance for the remainder of Cycle 19. Based on its review, the NRC staff determined that any postulated failure mechanism that could prevent rod insertion is not influenced or impacted by coil failure, or control or holding circuitry failures.
The NRC staff also determined that the minimum SOM of 7.27% Llk/k is above the 6.5% Llk/k requirement of the COLR. Therefore, based on its review, the NRC staff concludes that the licensee has (1) identified the possible causes of the problems identified with CEA 88, (2) identified the failure modes, (3) established that CEA 88 will trip with reasonable certainty, and (4) shown there is adequate shutdown margin. Additionally, the NRC staff concludes that elimination of the exercising of CEA 88 will reduce the likelihood of a rod drop and a plant transient.
Therefore, the NRC staff concludes that the elimination of exercising CEA 88 for SR 3.1.5.3 for the remainder of Cycle 19 is acceptable and that there is reasonable assurance that the requirements of GDC 23, GDC 25, GDC 26, GDC 27, GDC 28, and GDC 29 will continue to be met.
4.0 EXIGENT CIRCUMSTANCES
4.1 Background As discussed in the licensee's application dated September 4, 2015, as supplemented by letter dated September 15, 2015, the licensee requested that the proposed amendment be processed by the NRC on an exigent basis. The Commission's regulations at 1 O CFR 50.91 (a)(6) describe the procedures for issuing amendments where exigent circumstances exist. Where the Commission finds that exigent circumstances exist, in that a licensee and the Commission must act quickly and that time does not permit the Commission to publish a Federal Register notice allowing 30 days for prior public comment, and it also determines that the amendment involves no significant hazards considerations, then the Commission will provide for a reasonable opportunity for the public to comment, using its best efforts to make available to the public whatever means of communication it can for the public to respond quickly, and, in the case of telephone comments, have these comments recorded or transcribed, as necessary and appropriate.
The Commission will also require the licensee to explain the exigency and why the licensee cannot avoid it, and use its normal public notice and comment procedures in 1 O CFR 50.91 (a)(2) if it determines that the licensee has failed to use its best efforts to make a timely application for the amendment in order to create the exigency and to take advantage of this procedure.
Under the provisions in 10 CFR 50.91 (a)(6)(i), the NRC notifies the public in one of two ways:
(1) by issuing a Federal Register notice providing an opportunity for hearing and allowing at least 2 weeks from the date of the notice for prior public comments; or (2) by using local media to provide reasonable notice to the public in the area surrounding the licensee's facility.
In this case, the NRC used the second approach and published a public notice in the Arizona Republic, located in Phoenix, Arizona 85001 (http://www.azcentral.com/), a newspaper local to the licensee's facility, from September 21 through September 22, 2015. 4.2 Licensee's Basis for Exigent Circumstances The licensee is basing exigent circumstances on the following:
On August 27, 2015, during the performance of a monitoring program for all CEAs, the licensee discovered the degraded condition of the UGC for CEA 88. CEA 88 exceeded the monitoring threshold value for current noise and the holding function was transferred to the lower gripper coil. The UGC was de-energized and remains de-energized.
Due to the recent discovery, the licensee requests that the amendment be considered for exigent circumstances because the degraded condition of the UGC was not discovered in sufficient time to permit the normal public noticing period. Furthermore, if APS were to perform SR 3.1.5.3, the UGC would re-energize to move CEA 88 and could further degrade the UGC during CEA movement.
The degraded CEA may drop into the core, resulting in a reactivity transient and subsequent power reduction, and would result in a plant shutdown if the CEA were deemed unrecoverable.
4.3 NRC Staff Conclusion
Based on the above, the NRC staff concludes that the licensee made a timely application for the proposed amendment following identification of the issue. In addition, the NRC staff determines that the licensee could not avoid the exigency because the degraded condition of the UGC for CEA 88 was not discovered in sufficient time to permit the normal public noticing period. Based on these findings, the NRC staff has determined that exigent circumstances exist and issuance of the license amendment using the exigent provisions of 10 CFR 50.91 (a)(6) is appropriate.
5.0 PUBLIC COMMENTS Under the provisions in 10 CFR 50.91 (a)(6), the NRC notifies the public in one of two ways: (1) by issuing a Federal Register notice providing an opportunity for hearing and allowing at least 2 weeks from the date of the notice for prior public comments; or (2) by using local media to provide reasonable notice to the public in the area surrounding the licensee's facility.
In this case, the NRC used the second approach and published a public notice in the Arizona Republic, located in Phoenix, Arizona 85001 (http://www.azcentral.com/), a newspaper local to the licensee's facility, from September 21 through September 22, 2015. The notice included the NRC staff's proposed no significant hazards consideration determination.
The notice also provided an opportunity for public comment until 4:15 p.m. Eastern Time on September 22, 2015, regarding the staff's proposed no significant hazards consideration determination.
No public comments were received regarding the proposed amendment.
6.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION The NRC's regulations in 10 CFR 50.92 state that the NRC may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility, in accordance with the amendment, would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated, or (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety. As required by 10 CFR 50.91 (a), in its application dated September 4, 2015, the licensee provided its analysis of the issue of no significant hazards consideration, which is presented below: 1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Operation of Palo Verde Nuclear Generating Station, Unit 2, in accordance with the proposed amendment, will not involve a significant increase in the probability or consequences of an accident evaluated previously.
The function of CEA 88 is to provide negative reactivity addition into the core upon receipt of a signal from the Reactor Protection System (RPS). CEA 88 remains trippable (free to move) as illustrated by the last performance of SR 3.1.5.3 and when it was placed on the lower gripper coil. Therefore, the function remains valid for CEA 88. The misoperation of a CEA, including a CEA drop event, has been evaluated previously in the Updated Final Safety Analysis and found acceptable.
The proposed change would minimize the potential for inadvertent insertion of CEA 88 into the core by maintaining the CEA in its place using the lower gripper. The proposed change would not affect the ability of CEA 88 to insert fully into the core upon receipt of a reactor trip signal. No modifications are proposed to the RPS or associated logic with regard to the ability of CEA 88 to remain available for immediate insertion into the core. Since CEA 88 remains trippable, no additional reactivity considerations need to be taken into consideration.
APS has evaluated the reactivity consequences associated with failure of CEA 88 to insert upon a reactor trip in accordance with TS and has determined that shutdown margin (SOM) requirements would be met should such an event occur at any time during the remainder of Unit 2, Cycle 19 operation.
The accident mitigation features of the plant are not affected by the proposed amendment.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident evaluated previously.
- 2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
The proposed amendment will not create the possibility of a new or different kind of accident from any analyzed previously.
CEA 88 was demonstrated to be moveable and trippable; therefore, the function remains valid for CEA 88. The proposed change will not introduce any new design changes or systems that can prevent the CEA from performing its specified safety function.
This change does not alter assumptions made in the safety analysis.
APS has evaluated the reactivity consequences associated with failure of CEA 88 to insert upon a reactor trip in accordance with TS and has determined that SOM requirements would be met should such an event occur at any time during the remainder of Unit 2, Cycle 19 operation.
Therefore, the proposed change will not create the possibility of a new or different kind of accident from any evaluated previously.
- 3. Does the proposed amendment involve a significant reduction in a margin of safety? The proposed amendment would not involve a significant reduction in a margin of safety. CEA 88 was demonstrated to be moveable and trippable during the last performance of SR 3.1.5.3 and when it was placed on the lower gripper coil. The physical and electrical design of the CEAs, and past operating experience, provides high confidence that CEAs remain trippable whether or not exercised during each SR interval.
Eliminating further exercise of CEA 88 for the remainder of Unit 2, Cycle 19 operation does not directly relate to the potential for CEA binding to occur. No mechanical binding has been experienced previously in Unit 2. APS has evaluated the reactivity consequences associated with failure of CEA 88 to insert upon a reactor trip in accordance with TS and has determined that SOM requirements would be met should such an event occur at any time during the remainder of Unit 2, Cycle 19 operation.
Therefore, the proposed change does not involve a significant reduction in the margin of safety. As explained above, the NRC published a public notice in the Arizona Republic, located in Phoenix, Arizona 85001 (http://www.azcentral.com/), a newspaper local to the licensee's facility, from September 21 through September 22, 2015. The notice included the NRC staff's proposed no significant hazards consideration determination.
The notice also provided an opportunity for public comment until 4:15 p.m. Eastern Time on September 22, 2015, regarding the staff's proposed no significant hazards consideration determination.
No public comments were received regarding the proposed amendment.
The NRC staff reviewed the licensee's no significant hazards consideration analysis.
Based on this review and on the NRC staff's evaluation of the underlying license amendment request as discussed above, the NRC staff concludes that the three standards of 10 CFR 50.92(c) are satisfied.
Therefore, the NRC staff has made a final determination that no significant hazards consideration is involved for the proposed amendment and that the amendment should be issued as allowed by the criteria contained in 10 CFR 50.91.
7.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Arizona State official was notified of the proposed issuance of the amendment.
The State official had no comments.
8.0 ENVIRONMENTAL CONSIDERATION The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant hazards consideration; that 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.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
9.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. Principal Contributor:
William I. MacFee, NRR/DSS/SRXB Date: September 25, 2015 R. Edington A copy of the related Safety Evaluation is also enclosed.
The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice. Docket No. STN 50-529
Enclosures:
- 1. Amendment No. 196 to NPF-51 2. Safety Evaluation cc w/encls: Distribution via Listserv DISTRIBUTION:
PUBLIC LPL4-1 r/f RidsAcrsAcnw MailCTR Resource RidsNrrDeEicb Resource RidsNrrDorlDpr Resource RidsNrrDorllp14-1 Resource RidsNrrDssSrxb Resource RidsNrrDssStsb Resource ADAMS Accession No. ML 15266A005 Sincerely, IRA JK/os For/ Margaret M. Watford, Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsNrrLAJBurkhardt Resource RidsNrrPMPaloVerde Resource RidsRgn4MailCenter Resource WMacFee, NRR/DSS/SRXB MHardgrove, NRR/DSS/SRXB HVu, NRR/DE/EICB MChernoff, NRR/DSS/STSB
- per SE memo **via email OFFICE NRR/DORL/LPL4-1
/PM NRR/DORL/LPL4-1
/LA N RR/DSS/SRXB/BC N RR/DSS/STSB/BC NAME MWatford JBurkhardt CJackson*
RElliott**
DATE 9/23/2015 9/23/15 9/18/15 9/23/15 OFFICE NRR/DE/EICB/BC OGC NLO NRR/DORL/LPL4-1
/BC N RR/DORL/LPL4-1
/PM NAME MWaters AGhosh MMarkley MWatford (J Klos for) DATE 9/24/15 9/24/15 9/25/15 9/25/15 OFFICIAL AGENCY RECORD