ML18145A303

License Amendment Request to Revise Technical Specifications Regarding Response Time Testing of Pressure Transmitters

ML18145A303
Person / Time
Site:	Palo Verde
Issue date:	05/25/2018
From:	Lacal M Arizona Public Service Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
102-07703-MLL/MDD
Download: ML18145A303 (26)

Text

10 CFR 50.90 Oaps MARIA L. LACAL Senior Vice President, Nuclear Regulatory & Oversight Palo Verde Nuclear Generating Station P.O. Box 52034 Phoenix, AZ 85072 102-07703-MLL/MDD Mail Station 7605 May 25, 2018 Tel 623.393.6491 U. S. Nuclear Regulatory Commission ATTN: Pocument Control Desk Washington, DC 20555-0001

Subject:

Palo Verde Nuclear Generating Station Units 1, 2, and 3 Docket Nos. STN 50-528, 50-529, and 50-530 Renewed Operating License Nos. NPF-41, NPF-51, NPF-74 License Amendment Request to Revise Technical Specifications Regarding Response Time Testing of Pressure Transmitters In accordance with the provisions of Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), Arizona Public Service Company (APS) is submitting a license amendment request (LAR) to revise the Technical Specifications (TSs) for Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2, and 3. The LAR would revise TS requirements regarding response time testing of pressure transmitters.

The PVNGS TSs currently authorize the elimination of periodic response time testing for specific transmitter models that have been reviewed and approved by the NRC staff. The specific vendor transmitter models approved by the NRC staff that are exempt from periodic response time testing have become obsolete and are being replaced by a new model of similar design and construction. This LAR seeks NRC staff approval of the engineering evaluation methodology for eliminating periodic response time testing. This would provide that if vendor transmitter models become obsolete in the future, appropriate engineering evaluations can be performed to preserve the authorization for elimination of periodic response time testing.

The enclosure to this letter provides a description and assessment of the proposed changes including a summary of the technical evaluation, a regulatory evaluation, a no significant hazards consideration, and an environmental consideration. The enclosure also contains three attachments. Attachment 1 provides the marked-up existing TS pages. Attachment 2 provides the revised (clean) TS pages. Attachment 3 provides the marked-up TS Bases pages to show the conforming changes, for information.

No new commitments are being made in this submittal. In accordance with the PVNGS Quality Assurance Program Description, the Plant Review Board has reviewed and approved the LAR.

A member of the STARS Alliance LLC Callaway

• Diablo Canyon

• Palo Verde

• Wolf Creek

102-07703-MLL/MDD ATTN: Document Control Desk U. S. Nuclear Regulatory Commission LAR to Revise TS Regarding Response Time Testing of Pressure Transmitters Page 2 By copy of this letter, this LAR is being forwarded to the Arizona Department of Health Services in accordance with 10 CFR 50.91(b)(1).

APS requests approval of the LAR prior to March 1, 2019, in support of the Unit 1 Spring refueling outage, and will implement the TS amendment within 30 days following NRC approval.

Should you have any questions concerning the content of this letter, please contact Matthew S. Cox, Licensing Section Leader, Nuclear Regulatory Affairs, at (623) 393-5753.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on ; Mav 25. 2018 (Date)

Sincerely,

\\fVoLrC\

MLL/MDD/CJS/sma

Enclosure:

Description and Assessment of Proposed License Amendment cc: K. M. Kennedy NRC Region IV Regional Administrator M. D. Orenak NRC NRR Project Manager for PVNGS C. A. Peabody NRC Senior Resident Inspector for PVNGS T. Morales Arizona Department of Health Services (ADHS)

Enclosure Description and Assessment of Proposed License Amendment

TABLE OF CONTENTS 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION 2.1 Proposed Changes to the Technical Specifications 2.2 Need for Proposed Changes

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements 4.2 Precedent 4.3 No Significant Hazards Consideration 4.4 Conclusion

6.0 REFERENCES

ATTACHMENTS

1. Marked-up Technical Specifications Pages

2. Revised Technical Specifications Pages (Clean Copy)

3. Marked-up Technical Specification Bases Pages

LIST OF ACRONYMS APS Arizona Public Service Company CFR Code of Federal Regulations DC Direct Current ESF Engineered Safety Feature FMEA Failure Modes and Effects Analysis LAR License Amendment Request LCO Limiting Condition for Operation PVNGS Palo Verde Nuclear Generating Station RTT Response Time Testing SR Surveillance Requirement TS Technical Specification UFSAR Updated Final Safety Analysis Report

Enclosure Description and Assessnnent of Proposed License Amendment 1.0

SUMMARY

DESCRIPTION In accordance with the provisions of Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), Arizona Public Service Company (APS) is submitting a license amendment request (LAR) to revise the Technical Specifications (TSs) for Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2, and 3. The LAR would revise TS requirements regarding response time testing of pressure transmitters, also referred to as pressure sensors.

The PVNGS TSs currently authorize the elimination of periodic response time testing for specific transmitter models that have been reviewed and approved by the NRG staff. The specific vendor transmitter models approved by the NRG staff that are exempt from periodic response time testing have become obsolete and are being replaced by a new model of similar design and construction. This LAR seeks NRG staff approval of the engineering evaluation methodology for eliminating periodic response time testing. This would provide that if vendor transmitter models become obsolete in the future, appropriate engineering evaluations can be performed to preserve the authorization for elimination of periodic response time testing.

This enclosure provides a description and assessment of the proposed changes including a summary of the technical evaluation, a regulatory evaluation, a no significant hazards consideration, and an environmental consideration. This enclosure also contains three attachments. Attachment 1 provides the marked-up existing TS pages. Attachment 2 provides the revised (clean copy) TS pages. Attachment 3 provides the marked-up TS Bases pages to show the conforming changes, for information.

2.0 DETAILED DESCRIPTION 2.1 Proposed Changes to the Technical Specifications The following specific TS changes are proposed to address elimination of periodic response time testing of pressure transmitters.

• TS Section 1.1, Definitions, ENGINEERED SAFETY FEATURE (ESF) RESPONSE TIME, is proposed to be revised as indicated below:

The ESF RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ESF actuation setpoint at the channel sensor until the ESF equipment is capable of performing its safety function (i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.).

Times shall include diesel generator starting and sequence loading delays, where applicable. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured.

In lieu of measurement, response time may be verified for selected components provided that the componcnt-and methodology for verification have has been previously reviewed and approved by the NRC.

• TS Section 1.1, Definitions, REACTOR PROTECTIVE SYSTEM (RPS) RESPONSE TIME, is proposed to be revised as indicated below:

Enclosure Description and Assessment of Proposed License Amendment The RPS RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its RPS trip setpoint at the channel sensor until electrical power to the CEAs drive mechanism is interrupted. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured. In lieu of measurement, response time may be verified for selected components provided that the components and methodology for verification have has been previously reviewed and approved by the NRC.

The proposed changes in the TS definitions impact response time testing described in TS surveillance requirements (SR) 3.3.1.13, 3.3.2.5, and 3.3.5.4. Marked-up TS pages are provided in Attachment 1 and revised TS pages (clean copy) are provided in Attachment 2.

The TS Bases will also be revised for consistency with the proposed TS changes. A markup of the TS Bases pages reflecting these conforming changes is provided in Attachment 3 for information. The proposed TS Bases changes will be implemented in accordance with TS 5.5.14, Technical Specifications (TS) Bases Control Program, at the same time that the TS changes in the approved license amendment are implemented.

2.2 Need for Proposed Changes Summary Description Consistent with NUREG-1432, Standard Technical Specifications - Combustion Engineering Plants, the PVNGS TSs contain definitions for Engineered Safety Feature (ESF) Response Time and Reactor Protective System (RPS) Response Time, that are referenced in Surveillance Requirements (SRs), hereafter referred to as Response Time Testing (RTT).

These definitions allow the response times for specific NRC-approved pressure transmitters to be verified using an approved methodology in lieu of being measured. The proposed change revises the definitions to eliminate the requirement for prior NRC review and approval of the response time verification of similar pressure transmitters, while retaining the requirement for the verification to be performed using an NRC-approved methodology.

The proposed change will permit APS to evaluate response time testing provisions of similar pressure transmitters using an NRC approved methodology, without the need for prior NRC staff approval of subsequent components when approved components become obsolete.

Reason for the Proposed Change Periodic response time testing is resource intensive, which is why the industry owners groups pursued its elimination through TSTF-368 and TSTF-111. The RTT is generally performed in discrete steps that include components of the total protection system including the sensor and the final actuated device response times. The RTT of instrument channels that include pressure sensors requires procedures and techniques to be used for measuring the response time of the pressure sensor device(s) in those instrument channels. As such, pressure sensor RTT takes additional time and effort and often involves the use of specialized contractor services. This prompted the industry efforts to develop alternatives to periodically measuring the response time of selected components.

As components become obsolete, replacement components must be installed to support continued operation. The replacement components are not identical to the originally selected components and, therefore, are not specifically listed in the NRC-approved topical reports that justified the application of an alternative to measuring response times. Because

Enclosure Description and Assessment of Proposed License Amendment the replacement components are not listed in the NRC-approved topical reports, the TS definitions require prior NRC review and approval to use bounding response times for the replacement components. Therefore, absent this proposed change, RTT is required to be performed on the replacement pressure transmitters in the RPS and ESF system. APS has installed a number of replacement transmitters and none have failed the installation RTT.

3.0 TECHNICAL EVALUATION

Verification Methods Related to Response Time Testing Response time testing of RPS and ESF system instrumentation has been required by TS since about 1970. The purpose of periodic RTT was to demonstrate that the instrumentation channels met the response time performance requirements assumed in the plant safety analyses.

In 1991, the Electric Power Research Institute (EPRI) published Report NP-7243, Investigation of Response Time Testing Requirements (Reference 6.1), which established the basis for justifying the elimination of the periodic response time testing required by plant TS for certain pressure sensors. The EPRI report concluded that response time testing was redundant to other TS required testing (i.e., Channel Checks and Channel Calibrations) for the pressure sensors evaluated.

Based on the results of EPRI Report NP-7243, Westinghouse created WCAP-13632-P-A, Elimination of Pressure Sensor Response Time Testing Requirements, (approved by the NRC in 1995 for Westinghouse plants) and the Combustion Engineering Owners Group created NPSD-1167-A, Elimination of Pressure Sensor Response Time Testing Requirements (approved by the NRC in 2000 for Combustion Engineering plants)(Reference 6.2).

These reports provided the justification for eliminating the periodic response time testing requirement for specific pressure and differential pressure transmitters in Westinghouse and Combustion Engineering plant TS. The Westinghouse and Combustion Engineering Owners Group reports also provided model TS changes that eliminated the requirements for response time testing the specified pressure sensors, which APS adopted in License Amendment 135, dated April 19, 2001 (Reference 6.3).

Approved Methodology The aforementioned industry documents capture the current NRC approved methodology that can be used to evaluate similar components to determine if the component response time can be verified in lieu of measured. The methodology is a combination of failure modes and effects analysis (FMEA), similarity review, field history and experience. For each component type, the analysis steps were:

Definition of the transmitter to be analyzed.

Description of the operation of the transmitter.

Definition of the analysis boundary and level of detail.

Identification of the failure categories.

Completion of the FMEA worksheet, and Summary discussion of the FMEA results.

Enclosure Description and Assessment of Proposed License Amendment The FMEA method of systems analysis is selected for the response time investigation because it provides a valid, systematic approach for identifying failure modes. FMEAs are a semi-quantitative technique to the extent that they are not supported by explicit calculations or testing for particular failure modes. Fill fluid viscosity effects, frictional linkage forces, and capillary effects are addressed on a generic basis. The failure modes included each physical boundary and force transmitting element, regardless of the probability for a failure mechanism.

Since the quality of each FMEA is directly related to the quantity and quality level of information regarding transmitter design, component materials, and operational characteristics, the transmitter vendors have been and will continue to be requested to provide technical documentation and design expertise needed to perform the analysis.

The FMEAs allow for the identification and analysis of failure modes associated with each principal design element of the pressure transmitters that could affect response time.

Tables can be developed for each transmitter type specifying component, failure modes, symptoms and local effects, methods of failure detection, effects on transmitter response time, and other effects on the transmitter.

Recent Rosemount Pressure Transmitter Verifications to Support Elimination of RTT Among the specific pressure transmitters currently approved for RTT elimination was the Rosemount 1150 series of pressure and differential pressure transmitters. At PVNGS the 1150 series pressure transmitters are currently used in safety-related applications for level, flow, and pressure process measurements. In 2012, Rosemount Nuclear Instruments announced that the Rosemount 1150 series pressure and differential pressure transmitters are being replaced by the 3150 series.

As an example of implementing the NRC approved methodology for verification, Emerson Electric Company (the Rosemount transmitter vendor) provided a report (Reference 6.4) based on FMEA, similarity review, field history, and experience to conclude that the new Rosemount 3150 series of pressure and differential pressure transmitters can be considered for elimination of the periodic TS response time testing requirement.

Specificaliy, based on FMEA, field history, and experience, this report concluded that no new plausible failure modes exist with the Rosemount 3150 series that would alter the response time of the product without first being detected by other changes in performance characteristics such as channel monitoring with redundant instruments, functional checks, or both.

Model Differences and Similarities The 3150 Series and 1150 Series pressure transmitter designs both utilize capacitance sensing technology coupled with analog electronics to produce a 4 mA to 20 mA signal proportional to pressure input. The pressure sensors are physically mounted in the sensor module for both designs, which is a hermetically sealed assembly also containing selected electronics. Both 3150 Series and 1150 Series designs utilize stainless steel process wetted material as the standard offering; however, there are differences in the design architecture of the flanged interface.

Enclosure Description and Assessnnent of Proposed License Amendment The 1150 Series utilizes a conventional architecture; with the pressure sensing diaphragms on separate planes. This architecture is based on the Rosemount 1151 design. The 3150 Series utilizes a "coplanar" architecture; with both pressure sensing diaphragms on the same plane. This architecture, which is based on the Rosemount 3051 design released for commercial applications in 1989, enables the use of more advanced sensor technology for improved performance. The coplanar architecture used on the 3150 Series has been in use on the Rosemount 3051C commercial pressure transmitter for approximately twenty-five years and also on the 3051N nuclear safety transmitter for approximately fifteen years.

A major benefit of the "coplanar" architecture is that the sensor is isolated from flange and welding stresses within the module. For the 1150 Series, however, the capacitive sensing element (sensor) experiences stresses due to process flange bolting. The large stresses on the 1153 and 1154 sensor was the root cause of oil loss issues experienced in the late 1980 time frame, and resulted in the issuance of four Rosemount Technical Bulletins. On the other hand, the 3150 Series, in addition to isolating the sensor from stresses, also utilizes a process c-ring that requires a much lower seating load, imparting less stress to the isolation diaphragms. Because of this design similarity between the 3150 Series and the Rosemount Model 3051 (with its long-term reliability of over 3.5 million units shipped), any failures related to oil loss are, therefore, expected to be rare for 3150 Series.

The oil-filled system for 3150 Series and 1150 Series both contain the same oil types, similar isolation diaphragms, fill tubes, and similar materials of construction. The sensor designs for both 3150 Series and 1150 Series are primarily of metal and glass construction.

For both the 3150 Series and 1150 Series, the capacitive sensor is excited by an AC voltage, which is rectified and conditioned to provide a DC sensor current output, which is then amplified and adjusted to provide a 4mA to 20mA DC output for the intended pressure measurement.

The electrical designs of both products are based on bipolar semiconductor technology and purely analog circuitry. No microprocessors or digital electronics are employed on either platform. The 3150 Series electronics employ the same basic architecture of the 1150 Series, yet have improved accuracy, linearity, EMC performance, scalability (range down),

and ease of calibration. To optimize the performance of the 3150 Series sensor, the oscillator frequency has an increased value of 110 kFIz, and a temperature stable E-core transformer has replaced the toroidal core transformer used in the 1150 Series. The 3150 Series electronics provide improvements in stability, reliability, and qualified life over the 1150 Series.

The 3150 Series electronics circuitry is partitioned onto three circuit boards, whereas the 1150 Series circuitry requires five. This reduction in circuit boards reduces number of interconnects and risk of interconnect failure. The 3150 also utilizes surface-mount packaging which performs better in shock and vibration.

FMEA Results The theory of operation for 3150 Series is identical to 1150 Series. The process pressure introduced to the transmitter's pressure chambers produces a displacement of the sensing diaphragm which is measured via capacitance measurements between the sensing diaphragm and the metallized surfaces on either side of the sensing diaphragm. The sensor is protected in overpressure conditions by the glassed regions which also provide electrical

Enclosure Description and Assessment of Proposed License Amendment insulation. The sensor capacitance is processed by the transmitter eiectronics to provide a iinearized signal through the 4 mA to 20 mA current.

Like the 1150 Series transmitters, the 3150 Series transmitters isoiate the process fiuid from the capacitive sensing element via dual isolation diaphragms that contain an incompressible fill fluid. For 3150 Series, the fiuid is contained in geometries that are different from the 1150 Series, but the design concept is identicai with the fill fluid acting as the medium that transfers pressure from the process fiuid to the capacitive sensing element. The oil-fiiied system aiso creates the dielectric for the capacitance signai between sensing diaphragm and metaliized surfaces.

Electrical component failures are considered in the FMEA. Based on experience, electrical component failures annunciate as highiy detectable changes such as large off-set, erratic output, off-scaie failure, or non-linearity. Based on experience with both 1150 and 3150 series pressure transmitters, electricai component failure is random in nature, not common mode, and does not adversely affect time response without being detectable through typical channel monitoring or functional checks.

Like the 1150 Series, transmitter time response of 3150 Series can be affected by a small leak within the oil-filled system. A small leak can originate at one of several points within the system including fill tube leaks, isolating diaphragms, and glass-to-metal seals. If leaks occur within either side of the oil-filled system, the isolating diaphragm (on the leaking side) will contract proportionally to the leak, and will eventually contract to a point at which the isolating diaphragm contacts and rests against the convolution plate. At that point, the fill fluid leak would be detectable during calibration. Prior to that point, a leak would not result in a degraded response time.

Like the 1150 Series, the viscosity of the oil also affects 3150 transmitter response time. If viscosity increases, so will the transmitter response time. Oil viscosity will change with ambient temperature, therefore published time constants are specified at 100°F (37.8°C).

The 3150 Series has undergone numerous qualification test programs and no discernable changes in transmitter response time have been noted, suggesting that the viscosity of the oil is largely unaffected by aging or radiation at levels achieved in the various 3150 series qualifications.

Operating Experience of Rosemount 3150 Series and 3051N Series The FMEA summarized above establishes an analytical assessment of failure modes associated with the Rosemount 3150 Series design that could affect pressure transmitter response time. It is appropriate to discuss operating experience for the 3150 Series design to determine if there is any inconsistency between the analytical approach and what has been experienced in actual service. As such, a summary of the field return history of the 3150 Series pressure transmitter and the observed field failure rate for all known field failures; specifically, for field failures that could affect response time, is provided.

A summary of the field return history of the Rosemount 3051N product and an estimate of field failure rate of this product is also provided in the same manner. Analysis of the 3051N operating history is relevant for assessment of failure modes related to the sensor design (such as oil loss), since the 3051N has been shipped for mild environment nuclear safety applications since 2001, and the sensor and oil fill system designs are consistent between Rosemount 3150 series and 3051N.

Enclosure Description and Assessment of Proposed License Amendment For the purpose of this assessment, estimated failure rate is calculated using the following formula:

Estimated Failure Rate = Returned Field Failures / Estimated Cumulative Service Flours Table 1 summarizes estimated failure rates for both Rosemount 3150 Series and 3051N Series pressure transmitters. In this evaluation, three failure rates are calculated:

• Total Failure Rate: Uses all units returned for failure analysis, whether confirmed or not confirmed in the factory. This is a highly conservative method to established estimated failure rate.

• In-Service Failure Rate: Uses only units that failed in service. If it was not reported whether or not a unit failed in service, it will be conservatively assumed that it failed in service.

• Oil Loss Failure Rate-. Uses failures related to oil loss. This failure mode is specifically presented due to legacy industry concerns with 1150 Series failures and to highlight that there have been no reported field failures in nuclear safety applications due to oil loss for either the Rosemount 3150 Series or 3051N Series coplanar platforms.

The data outlined in Table 1 provide high confidence that the overall failure rate of coplanar pressure transmitters used in nuclear safety applications is low and that failure modes found in service or that may impact response time are rare or have not been observed in the field.

Table 1 - Estimated Failure Rates for 3150 Series and 3051N Series 3150 3051N Year Launched 2009 2001 Units Shipped 12,117 2,767 Estimated Cumulative Service Flours 3.82x10^ 5.03x10^

Total Return Failures 15 15 Total Failure Rate (Failure/Flour) 3.93 X 10'^ 2.98 X 10'^

Observed In-Service Failures 3 12 In-Service Failure Rate (Failure/Flour) 7.85 X 10 2.39 X 10'^

Observed Oil Loss Failures 0 0 Oil Loss Failure Rate (Failures/Hour) 0 0 Conclusions Based on the evaluation performed for the Rosemount 3150 Series pressure transmitters, it has been concluded that no new failure modes exist for the 3150 Series design which would alter the applicability of the conclusions for the 1150 Series pressure transmitters contained in the EPRI, Westinghouse, or Combustion Engineering Owners Group reports discussed above.

In addition to following the approved methodology developed above, the associated EPRI recommendations will also be retained:

Enclosure Description and Assessment of Proposed License Amendment

• Perform hydraulic RTT before installation of new transmitters and/or switches or after refurbishment.

• Transmitters and/or switches that utilize capillary tubes have RTT performed after initial installation and after each maintenance or modification that has the potential to damage the capillary tubes.

• If variable damping is used, implement a method to assure that the potentiometer is at the required setting and cannot be inadvertently changed.

This method also continues to use "allocated response time" for the specified pressure sensors. Since the response time assumed in the safety analyses is the summation of all response times of components with the protective function, some assumed value for the transmitter response time value must be used in lieu of an actual measured value. In accordance with Section 3.1 of the NRC Safety Evaluation for the CEOG report (Reference 6.2), the allocated response times are obtained from two sources: either from the original equipment manufacturer specification or from a statistical analysis of the results of previous RTTs.

The APS modification process will evaluate similar replacement pressure transmitters that are not listed in the NRC-approved topical reports to ensure the proper application of the NRC-approved methodology to the replacement components. This limits the scope of similar replacement component types to pressure and differential pressure transmitters.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements Regulatory Guide (RG) 1.118, Periodic Testing of Electric Power and Protection Systems, describes a method acceptable to the NRC staff for complying with the NRC's regulations with respect to the periodic testing of the electric power and protection systems. This RG endorses the use of IEEE Std. 338-1987, Criteria for the Periodic Surveillance Testing of Nuclear Power Generating Station Safety Systems. The standard provides design and operational criteria for the performance of periodic testing as part of the surveillance program of nuclear power plant safety systems. The periodic testing consists of functional tests and checks, calibration verification, and time response measurements, as required, to verify that the safety system performs to meet its defined safety functions. Clause 6.3.4 of IEEE 338-1987 states response time testing shall be required only on safety systems or subsystems to verify that the response times are within the limits given in the Safety Analysis Report, including Technical Specifications. Response time testing of all safety-related equipment is not required if the response time of safety system equipment is verified by functional testing, calibration checks, other tests, or both. This is acceptable if it can be demonstrated that changes in response time beyond acceptable limits are accompanied by changes in performance characteristics that are detectable during routine periodic tests.

The proposed change will allow certain replacement pressure transmitters to be evaluated to determine whether response time verification can be implemented in lieu of the measurement of response times. This is consistent with Clause 6.3.4 of IEEE 338-1987, in that the evaluation would confirm whether or not it can be demonstrated that changes in response time beyond acceptable limits are accompanied by changes in performance characteristics that are detectable during other routine periodic tests. The replacement pressure transmitters will continue to perform the same function as the original equipment.

8

Enclosure Description and Assessment of Proposed License Amendment As such, the system operation, design basis, and capability for testing will remain unchanged.

4.2 Precedent The proposed license amendment was developed using relevant information from NRC approved TSTF-111, TSTF-368, and industry technical reports.

4.3 No Significant Hazards Consideration As required by 10 CFR 50.91(a), Notice for Public Comment, an analysis of the issue of no significant hazards consideration, using the standards in 10 CFR 50.92, Issuance of Amendment, is presented below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change revises the Technical Specification (TS) Definition of Reactor Protective System (RPS) and Engineered Safety Features (ESF) system instrumentation response time to permit Arizona Public Service Company (APS) to evaluate using an NRC-approved methodology and apply a bounding response time for pressure transmitters in lieu of measurement. The requirement for the instrumentation to actuate within the response time assumed in the accident analysis is unaffected.

The response time associated with the RPS and ESF instrumentation is not an initiator of any accident. Therefore, the proposed change has no significant effect on the probability of any accident previously evaluated.

The affected RPS and ESF instrumentation are assumed to actuate their respective components within the required response time to mitigate accidents previously evaluated. Revising the TS definition for RPS and ESF instrumentation response times to allow an NRC-approved methodology for verifying response time for pressure transmitters does not alter the surveillance requirements that verify the RPS and ESF instrumentation response times are within the required limits. As such, the TS will continue to assure that the RPS and ESF instrumentation actuate their associated components within the specified response time to accomplish the required safety functions assumed in the accident analyses. Therefore, the assumptions used in any accidents previously evaluated are unchanged and there is no significant increase in the consequences.

Therefore, the proposed amendment does not involve a significant increase in the probability or consequences of an 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.

Enclosure Description and Assessment of Proposed License Amendment The proposed change revises the TS Definition of RPS and ESF instrumentation response time to permit APS to evaluate using an NRC-approved methodology and apply a bounding response time for pressure transmitters in lieu of measurement. The proposed change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed). The proposed change does not alter any assumptions made in the safety analyses. The proposed change does not alter the limiting conditions for operation for the RPS or ESF instrumentation, nor does it change the Surveillance Requirement to verify the RPS and ESF instrumentation response times are within the required limits. As such, the proposed change does not alter the operability requirements for the RPS and ESF instrumentation, and therefore, does not introduce any new failure modes.

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 change revises the TS Definition of RPS and ESF instrumentation response time to permit APS to evaluate using an NRC-approved methodology and apply a bounding response time for pressure transmitters in lieu of measurement. The proposed change has no effect on the required RPS and ESF instrumentation response times or setpoints assumed in the safety analyses and the TS requirements to verify those response times and setpoints.

The proposed change does not alter any Safety Limits or analytical limits in the safety analysis. The proposed change does not alter the TS operability requirements for the RPS and ESF instrumentation. The RPS and ESF instrumentation actuation of the required systems and components at the required setpoints and within the specified response times will continue to accomplish the design basis safety functions of the associated systems and components in the same manner as before. As such, the RPS and ESF instrumentation will continue to perform the required safety functions as assumed in the safety analyses for all previously evaluated accidents.

Therefore, the proposed amendment does not involve a significant reduction in the '

margin of safety.

4.4 Conclusion APS concludes that operation of the facility in accordance with 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.

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 issuance of the amendment will not be inimical to the common defense and security or the health and safety of the public.

Enclosure Description and Assessment of Proposed License Amendment

5.0 ENVIRONMENTAL CONSIDERATION

The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, Standards for Protection Against Radiation, or would change an inspection or surveillance requirement.

However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.

6.0 REFERENCES

6.1 EPRI Report NP-7243, Revision 1, Investigation of Response Time Testing Requirements, May 1991 6.2 CEOG NPSD-1167-A, Revision 2, Eiimination of Pressure Sensor Response Time Testing Requirements, January 2001, and NRC Letter (Stuart A. Richards - NRC to Richard Bernier - CEOG), Correction of Safety Evaluation for Combustion Engineering Owners Group Topical Report CE NPSD-1167, Revision 2, Elimination of Pressure Sensor Response Time Testing Requirements, December 5, 2000 6.3 NRC letter to Arizona Public Service Company dated April 19, 2001, Palo Verde Nuclear Generating Station Units 1, 2, and 3 - Issuance of Amendments on Response Time Testing for Engineered Safety Feature and Reactor Pressure System Pressure Sensors (ADAMS Accession number ML011130056) ^License Amendment 135) 6.4 Emerson Report, 3150 Series Pressure Transmitter FMEA and Evaluation Related to Elimination of Pressure Sensor Response Time Testing, Document Number D2015006, Revision A, dated November 7, 2017

Enclosure Description and Assessment of Proposed License Amendment ATTACHMENT 1 Marked-up Technical Specifications Pages 1.1- 4 1.1-6

Definitions 1.1 1.1 Definitions DOSE EQUIVALENT XE-133 be performed using effective dose conversion (continued) factors for air submersion listed in Table B-1 of Regulatory Guide 1.109, Rev. 1, NRC, 1977.

ENGINEERED SAFETY The ESF RESPONSE TIME shall be that time interval FEATURE (ESF) RESPONSE from when the monitored parameter exceeds its ESF TIME actuation setpoint at the channel sensor until the ESF equipment is capable of performing its safety function (i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.). Times shall include diesel generator starting and sequence loading delays, where applicable. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured. In lieu of measurement, response time may be verified for selected components provided that the component ef^d-methodology for verification have has been previously reviewed and approved by the NRC.

Kn-l Kn-iis the K effective calculated by considering the actual CEA configuration and assuming that the fully or partially inserted full strength CEA of highest worth is fully withdrawn.

LEAKAGE LEAKAGE shall be:

a. Identified LEAKAGE

1. LEAKAGE, such as that from pump seals or valve packing (except reactor coolant pump (RCP) seal water injection or leakoff),

that is captured and conducted to collection systems or a sump or collecting tank:

2. LEAKAGE into the containment atmosphere from sources that are both specifically located and known either not to interfere with the operation of leakage detection systems or not to be pressure boundary LEAKAGE: or (continued)

PALO VERDE UNITS 1,2.3 1.1-4 AMENDMENT NO. i92.

Definitions 1.1 1.1 Definitions PHYSICS TESTS b. Authorized under the provisions of (continued) 10 CFR 50.59: or

c. Otherwise approved by the Nuclear Regulatory Conmission.

PRESSURE AND The PTLR is the site specific document that TEMPERATURE LIMITS provides the reactor vessel pressure and REPORT (PTLR) temperature limits, including heatup and cooldown rates, for the current reactor vessel fluence period. These pressure and temperature limits shall be determined for each fluence period in accordance with Specification 5.6.9.

RATED THERMAL POWER RTP shall be a total reactor core heat transfer (RTP) rate to the reactor coolant of 3990 MWt.

REACTOR PROTECTIVE The RPS RESPONSE TIME shall be that time interval SYSTEM (RPS) RESPONSE from when the monitored parameter exceeds its RPS TIME trip setpoint at the channel sensor until electrical power to the CEAs drive mechanism is interrupted. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured. In lieu of measurement, response time may be verified for selected components provided that the components and methodology for verification have has been previously reviewed and approved by the NRCT SHUTDOWN MARGIN (SOM) SDM shall be the instantaneous amount of reactivity by which the reactor is subcritical or would be subcritical from its present condition assuming:

a. All full strength CEAs (shutdown and regulating) are fully inserted except for the single CEA of highest reactivity worth, which is assumed to be fully withdrawn. With any full strength CEAs not capable of being fully inserted, the withdrawn reactivity worth of these CEAs must be accounted for in the determination of SDM and

b. There is no change in part strength CEA position.

PALO VERDE UNITS 1,2,3 1.1-6 AMENDMENT NO. 492,

Enclosure Description and Assessment of Proposed License Amendment ATTACHMENT 2 Revised Technical Specifications Pages (Clean Copy) 1.1-4 1.1-6

Definitions 1.1 1.1 Definitions DOSE EQUIVALENT XE-133 be performed using effective dose conversion (continued) factors for air submersion listed in Table B-1 Regulatory Guide 1.109, Rev. 1, NRC. 1977.

ENGINEERED SAFETY The ESF RESPONSE TIME shall be that time interval FEATURE (ESF) RESPONSE from when the monitored parameter exceeds its ESF TIME actuation setpoint at the channel sensor until the ESF equipment is capable of performing its safety function (i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.). Times shall include diesel generator starting and sequence loading delays, where applicable. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured. In lieu of measurement, response time may be verified for selected components provided that the methodology for verification has been previously reviewed and approved by the NRC.

Kn-l Kn-iis the K effective calculated by considering the actual CEA configuration and assuming that the fully or partially inserted full strength CEA of highest worth is fully withdrawn.

LEAKAGE LEAKAGE shall be:

a. Identified LEAKAGE

1. LEAKAGE, such as that from pump seals or valve packing (except reactor coolant pump (RCP) seal water injection or leakoff),

that is captured and conducted to collection systems or a sump or collecting tank:

2. LEAKAGE into the containment atmosphere from sources that are both specifically located and known either not to interfere with the operation of leakage detection systems or not to be pressure boundary LEAKAGE: or (continued)

PALO VERDE UNITS 1,2,3 1.1-4 AMENDMENT NO. 49^.

Definitions 1.1 1.1 Definitions PHYSICS TESTS b. Authorized under the provisions of (continued) 10 CFR 50.59: or

c. Otherwise approved by the Nuclear Regulatory Commission.

PRESSURE AND The PTLR is the site specific document that TEMPERATURE LIMITS provides the reactor vessel pressure and REPORT (PTLR) temperature limits, including heatup and cooldown rates, for the current reactor vessel fluence period. These pressure and temperature limits shall be determined for each fluence period in accordance with Specification 5.6.9.

RATED THERMAL POWER RTP shall be a total reactor core heat transfer (RTP) rate to the reactor coolant of 3990 MWt.

REACTOR PROTECTIVE The RPS RESPONSE TIME shall be that time interval SYSTEM (RPS) RESPONSE from when the monitored parameter exceeds its RPS TIME trip setpoint at the channel sensor until electrical power to the CEAs drive mechanism is interrupted. The response time may be measured by means of any series of sequential, overlapping, or total steps so that the entire response time is measured. In lieu of measurement, response time may be verified for selected components provided that the methodology for verification has been previously reviewed and approved by the NRC.

SHUTDOWN MARGIN (SDM) SDM shall be the instantaneous amount of reactivity by which the reactor is subcritical or would be subcritical from its present condition assuming;

a. All full strength CEAs (shutdown and regulating) are fully inserted except for the single CEA of highest reactivity worth, which is assumed to be fully withdrawn. With any full strength CEAs not capable of being fully inserted, the withdrawn reactivity worth of these CEAs must be accounted for in the determination of SDM and

b. There is no change in part strength CEA position.

PALO VERDE UNITS 1.2.3 1.1-6 AMENDMENT NO. 4^.

Enclosure Description and Assessment of Proposed License Amendment ATTACHMENT 3 Marked-up Technical Specification Bases Pages B 3.3.1-50 B 3.3.2-17 B 3.3.5-29

RPS Instrumentation - Operating B 3.3.1 BASES SURVEILLANCE SR 3.3.1.13 (continued)

REQUIREMENTS Response time may be verified by any series of sequential, overlapping or total channel measurements, Including allocated sensor response time, such that the response time is verified.

Allocations for sensor response times may be obtained from the records of test results, vendor test data, or vendor engineering specifications. Topical Report CE NPSD-1167-A, "Elimination of Pressure Sensor Response Time Testing Requirements."

(Ref. 12) provides the basis and methodology for using allocated sensor response times in the overall verification of the channel in accordance with the methodology contained in the Topical Report. Response time verification for other sensor types must be demonstrated by test. The allocation of sensor response times must be verified prior to placing a new component in operation and reverified after maintenance that may adversely affect the sensor response time.

A Note is added to indicate that the neutron detectors are excluded from RPS RESPONSE TIME testing because they are passive devices with minimal drift and because of the difficulty of simulating a meaningful signal. Slow changes in detector sensitivity are compensated for by performing the daily calorimetric calibration (SR 3.3.1.4)

REFERENCES 1. 10 CFR 50, Appendix A, GDC 21

2. 10 CFR 100.

3. NRC Safety Evaluation Report, July 15, 1994.

4. UFSAR, Chapter 7

5. UFSAR, Chapters 6 and 15.

6. 10 CFR 50.49.

7. "Calculation of Trip Setpoint Values, Plant Protection System". CEN-286(v), or Calculation 13-JC-SG-203 for the Low Steam Generator Pressure Trip function.

8. UFSAR, Section 7.2, Tables 7.2-1 and 7.3-11 A.

PALO VERDE UNITS 1,2,3 B 3.3.1-50 REVISION §3

RPS Instrumentation - Shutdown B 3.3.2 BASES SURVEILLANCE SR 3.3.2.4 (continued)

REQUIREMENTS because of the difficulty of simulating a meaningful signal.

Slow changes in detector sensitivity are compensated for by performing the daily calorimetric calibration (SR 3.3.1.4).

SR 3.3.2.5 This SR ensures that the RPS RESPONSE TIMES are verified to be less than or equal to the maximum values assumed in the safety analysis. Individual component response times are not modeled in the analyses. The analyses model the overall or total elapsed time, from the point at which the parameter exceeds the trip setpoint value at the sensor to the point at which the RTCBs open. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

Response time may be verified by any series of sequential, overlapping or total channel measurements, including allocated sensor response time, such that the response time is verified. Allocations for sensor response times may be obtained from records of test results, vendor test data, or vendor engineering specifications. Topical Report CE NPSD-1167-A, "Elimination of Pressure Sensor Response Time Testing Requirements." (Ref. 7) provides the basis and methodology for using allocated sensor response times in the overall verification of the channel response time for specific-thesensors- identified in types evaluated in accordance with TFie methodology contained in the lopical Report. Response time verification for other sensor types must be demonstrated by test. The allocation of sensor response times must be verified prior to placing a new component in operation and reverified after maintenance that may adversely affect the sensor response time.

(continued)

PALO VERDE UNITS 1,2.3 B 3.3.2-17 REVISION 56

ESFAS Instrumentation B 3.3.5 BASES SURVEILLANCE SR 3.3.5.4 (continued)

REQUIREMENTS Testing Requirements." (Ref. 10) provides the basis and methodology for using allocated sensor response times in the overall verification of the channel response time for spec-IT-l-c-the sensors- identified in types evaluated In accordance with the methodology contained in the Topical Report. Response time verification for other sensor types must be demonstrated by test. The allocation of sensor response times must be verified prior to placing a new component in operation and re-verified after maintenance that may adversely affect the sensor response time.

The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

SR 3.3.5.5 SR 3.3.5.5 is a CHANNEL FUNCTIONAL TEST similar to SR 3.3.5.2. except SR 3.3.5.5 is performed within 92 days prior to startup and is only applicable to operating bypass functions. Since the Pressurizer Pressure - Low operating bypass is identical for both the RPS and ESFAS, this is the same Surveillance performed for the RPS in SR 3.3.1.13.

The CHANNEL FUNCTIONAL TEST for proper operation of the operating bypass permissives is critical during plant heatups because the bypasses may be in place prior to entering MODE 3 but must be removed at the appropriate points during plant startup to enable the ESFAS Function.

Consequently, just prior to startup is the appropriate time to verify operating bypass function OPERABILITY. Once the operating bypasses are removed, the bypasses must not fail in such a way that the associated ESFAS Function is inappropriately bypassed. This feature is verified by SR 3.3.5.2.

The allowance to conduct this test with 92 days of startup is based on the reliability analysis presented in topical report CEN-327, "RPS/ESFAS Extended Test Interval Evaluation" (Ref. 9).

(continued)

PALO VERDE UNITS 1,2,3 B 3.3.5-29 REVISION