ML20236R463

Application for Amends to Licenses NPF-68 & NPF-81, Eliminating Periodic Response Time Testing Requirements on Selected Sensors & Selected Protection Channels

ML20236R463
Person / Time
Site:	Vogtle
Issue date:	07/13/1998
From:	Woodard J SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20236R465	List: ML20236R463 ML20236R466
References
LCV-1175, NUDOCS 9807220049
Download: ML20236R463 (11)

Text

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!~ J. D.Woodard Southern Nuclear

( Executive Vice President Operating Company. inc.

40 invemess Center Parkway Post Office Box 1295 -

Birmingham. /Jabama 35201 Tel 205.932.5086 SOUTHERNk h COMPANY Energy to Serve Your%rld*

l LCV-1175 July 13, 1998-Docket Nos. 50-424 50-425 U. S. Nuclear Regulatory Commission A'ITN: Document Control Desk Washington, D. C. 20555 Ladies and Gentlemen:

VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CHANNEL RESPONSE TIME TESTS In accordance with the provisions of 10 CFR 50.90, Southern h : clear Operating Company (SNC) proposes to revise the Vogtle Electric Generating Plant (VEGP) Unit I and Unit 2 Technical Specifications (TS) to eliminate periodic response time testing requirements on selected sensors and selected protection channels. The proposed amendment modines TS Section 1.1 De6nitions for " ENGINEERED SAFETY FEATURE (ESP) RESPONSE TIME" and " REACTOR TRIP SYSTEM (RTS) RESPONSE TIME" to provide for verincation of response time for selected components provided that the components and the methodology for serincation have been previously reviewed and approved by the NRC.

I The associated Bases revisions to Surveillance Requirements (SR) 3.3.1.15 and SR 3.3.2.8 clarify that allocations for sensor response times may be obtained from: 1) historical records based on acceptable response time tests; 2) in place, onsite, or ofTsite (e.g., vendor) test /

measurements; or 3) utilizing vendor engineering specincations. WCAP-13632-P-A, Revision 2

" Elimination of Pressure Sensor Response Time Testing Requirements," provides both the technical basis for deleting periodic pressure and differential pressure sensor response time testing and the methodology for verifying the total channel response time using an allocated h)I sensor response time. By letter dated September 5,1995, Bruce A. Boger (NRC) to Roger A.

Newton, Westinghouse Owners Group (WOG), the NRC approved WCAP-13632.

In addition, the Bases revision clari6es that allocations for signal processing and actuation logic response times may also be used in the verification of the overall protection system channel 9807220049 980713 PDR ADOCK 05000424 P PDR

U. S. Nuclear Regulatory Commission LCV-1175 Page 2 response times. WCAP-14036-P Revision 1," Elimination of Periodic Protection Channel Response Time Tests," provides the basis and methodology for using allocated signal processing and actuation logic response times in the overall verification of the protection system channel response times. WCAP-14036-P, Revision I was submitted to the NRC for review by WOG Letter OG-98-005 dated January 22, 1998. VEGP is the WOG lead plant for the review of WCAP-14036-P, Revision 1.

The elimination of periodic response time testing will result in reduced radiation exposure and maintenance testing man-hours. The expected savings are estimated to be $40,000 per unit per outage.

This results in total savings of $1.5 million over the remaining life of the plant.

Since the proposed change involves tests that are normally performed during refueling outages, SNC will implement the proposed change to support the upcoming refueling outages. The next scheduled refueling outage for Unit 1 is in the spring of 1999 and for Unit 2, the fall of 1999. Therefore, SNC requests approval of the proposed change by January 31,1999.

Enclosure 1 provides the basis for the proposed change. Pursuant to 10 CFR 50.92, Enclosure 2 demonstrates that the proposed change does not involve a significant hazard consideration, and Enclosure 3 is a mark-up of the affected pages from the VEGP Unit I and Unit 2 TS and the affected Bases pages.

Enclosure 3 also includes clean typed pages reflecting the proposed change.. Enclosure 4 contains a copy of the WOG letters that transmitted WCAP-13632-P-A, Revision 2, WCAP-13787-A, Revision 2, WCAP-14036-P, Revision 1, and WCAP-14037, Revision 1. As stated above, WCAP-13632-P-A and WCAP-13787-A were reviewed and approved by the NRC as part of a generic WOG program to eliminate response time testing requirements on pressure and differential pressure sensors. WCAP-14036-P and WCAP-14037-NP have been provided to the NRC in support of the WOG program to eliminate periodic response time testing on protection channels (excluding certain sensors and actuated devices). Enclosure 5 contains the VEGP responses to NRC bulletins 90-01, and 90-01 Supplement 1, pertinent to Rosemount transmitters as discussed in Enclosure 1.

Mr. J. D. Woodard states that he is Executive Vice President of Southern Nuclear Operating Company and is authorized to execute this oath on behalf of Southern Nuclear Operating Company and that, to the l

best of his knowledge and belief, the facts set forth in this letter are true.

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SOUTiiERN NUCLEAR OPERATING COMPANY l

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J. D. Woodard n md wbscribedbefore ne this lYday of _.

,1998.

l Notar' P blic (M W Myc sion expires: h$0l W/NJS 1

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U. S. Nuclect Regulatory Conunission LCV-1175 Page 3.

. Enclosure 1: Basis for Proposed Change Enclosure 2: Significant llazards Evaluation Enclosure 3: Technical Specification Mark-ups

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Enclosure 4: Owner's Group Letters

- Enclosure 5: Vogtle Responses to NRC Bulletins 90-01 and 90-01 Supplement 1 xc: Southern Nuclear Operating Company Mr. J. B. Beasley, Jr.

Mr. M. Sheibani

-NORMS ~

U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. D. II. Jaffe, Senior Project Manager, NRR Mr. John Zeiler, Senior Resident inspector, Vogtle L State of Georgia '

L. C. Barrett, Commissioner, Department of Natural Resources I

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l ENCLOSUREI VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CilANNEL RESPONSE TIME TESTS HASIS FOR PROPOSED CIIANGE

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Proposed Change I The current VEGP Technical Speci0 cations require periodic measurement of response times of reactor trip and engineered safety features instrumentation channels. The proposed change would eliminate the

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requirement to actually measure the response times. Instead, the response times would be verined by (

summing allocated times for sensors, the process protection system, the nuclear instrumentation system, I and the logic system. These allocated values will be added to the measured times for the actuated devices and compared to the overall analysis limits. The proposed change requires revising the TS deGnition for {

" Engineered Safety Features (ESF) Response Time" and " Reactor Trip System (RTS) Response Time" to provide for veri 0 cation of response time for selected components provided that the components and the methodology for verification have been previously reviewed and approved by the NRC. The TS requirements for response time verification will continue to be implemented by SRs 3.3.1.15 and 3.3.2.8.

The associated Bases for these SRs are revised to clarify that allocations for pressure and differential pressure sensor responses times may be derived from; (1) historical records based on acceptable response l time tests (hydraulic, noise, or power interrupt tests), (2) in place, onsite, or offsite (e.g. vendor) test measurements, or (3) utilizing vendor engineering speci0 cations. WCAP-13632-P-A, Revision 2,

" Elimination of Pressure Sensor Response Time Testing Requirements," provides both the technical basis j for deleting periodic pressure and differential pressure sensor response time testing and the methodology for verifying the total channel response time using an allocated sensor response time. WCAP-14036-P Revision 1. " Elimination of Periodic Protection Channel Response Time Tests," provides the basis and methodology for using allocated signal processing and actuation logic response times in the overall verification of the protection system channel response time. The allocations for sensor, signal conditioning and actuation logic response times must be veriGed prior to placing the component into operational service and re-verined following maintenance that may adversely affect the response time.

Basis for Proposed Change for Sensors WCAP-13632-P-A contains the technical basis and methodology for eliminating response time testing (RTT) requirements on sensors identified in the WCAP. The technical basis and methodology were approved by letter dated September 5,1995 from Bruce A. Boger (NRC) to Roger A. Newton (WOG).

The NRC safety evaluation for WCAP-13632-P-A requires confirmation by the licensee that the generic analysis in the WCAP is applicable to their plant, and that licensees take the following actions:

1. Perform a hydraulic response time test (RTT) prior to installation of a new transmitter / switch or following refurbishment of the transmitter / switch (e.g., sensor cell or variable damping components) to determine an initial sensor-specine response time value.

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2. For transmitters and switches that use capillary tubes, perform a RTT after initial installation and I after any maintenance or modification activity that could damage the capillary tubes.

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ENCLOSUREI VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECilNICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CIIANNEL RESPONSE TIME TESTS BASIS FOR PROPOSED CIIANGE

3. If variable damping is used, implement a method to assure that the potentiometer is at the required setting and cannot be inadvertently changed, or perform a hydraulic RlT of the sensor following each calibration.

4. Perform periodic drift monitoring of all Model 1151,1152,1153, and 1154 Rosemount pressure and differential pressure transmitters, for which RTT elimination is proposed, in accordance with the guidance contained in Rosemount Technical Bulletin No. 4 and continue to remain in full compliance with any prior commitments to Bulletin 90-01, Supplement 1, " Loss of Fill-Oil in Transmitters Manufactured by Rosemount." As an alternative to performing periodic drift monitoring of Rosemount transmitters, licensees may complete the following actions: (a) ensure that operators and technicians are aware of the Rosemount transmitter loss of fill-oil issue and make provisions to ensure that technicians monitor for sensor response time degradation during the performance of calibrations and functional tests of these transmitters, and (b) review and revise surveillance testing procedures, if necessary, to ensure that calibrations a being performed using equipment designed to provide a step function or fast ramp in the process variable and that calibrations and functional tests are being performed in a manner that allows l simultaneous monitoring of both the input and output response of the transmitter under test, thus

! l allowing, with reasonable assurance, the recognition of significant response time degradation.

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1 SNC has reviewed the plant data for VEGP Units 1 and 2. The following sensors installed at the units are those that are bounded by the generic analysis contained in WCAP-13632-P-A.

- Steam Generator Water Level Tobar 32DP, Veritrak 76DP, or Rosemount 1154Dl-1

- Pressurizer Pressure Veritrak 76Pil, Tobar 32PG, or Rosemount i154Sil 1 l - Steam line Pressure Tobar 32PA, Veritrak 76PG, Rosemount i 154Sil,

! or Rosemount ll53GB

- Containment Pressure Barton 764/351

- Reactor Coolant Flow Veritrak 76DP, Tobar 32DP, or Rosemount 115311B

- Refueling Water Storage Tank Level Veritrak 76DP, Tobar 32DP, or Rosemount  !

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ENCLOSURE 1 VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CIIANNEL RESPONSE TIME TESTS HASIS FOR PROPOSED CIIANGE To comply with the required actions of WCAP-13632-P-A, SNC commits to the following:

Response to item 1 Consistent with the proposed TS changes (including the associated Bases for SR 3.3.1.15 and SR 3.3.2.8) and EPRI Report NP-7243, Revision 1, the applicable plant procedures will include revisions which stipulate that pressure sensor response times must be verified by performance of an appropriate response time test prior to placing a sensor into operational service and re-verified following maintenance that may adversely affect sensor response time.

Response to Item 2 Plant procedure revisions (and/or other appropriate administrative controls) will stipulate that pressure sensors (transmitters and switches) utilizing capillary tubes, e.g., containment pressure, must be subjected to RTT after initial installation and following any maintenance or modification activity which could damage the transmitter capillary tubes.

Response to iten 3 VEGP has no pressure transmitters with variable damping installed in any RTS or ESFAS application for which RTT is required; therefore, no VEGP procedure changes or enhanced administrative controls are required. If VEGP replaces any transmitters in the future with I variable damping capability, then VEGP will implement proceduie changes and/or establish appropriate administrative controls to assure the variable damping potentiometer cannot be inadvertently changed. Examples of such administrative controls may include use of pressure transmitters that are factory set and hermetically sealed to prohibit tampering or in situ application of a tamper seal (or sealant) on the potentiometer to secure and give a visual indication of the potentiometer position.

Response to item 4 Georgia Power pro 5ided responses to NRC Bulletins 90-01, " Loss of Fill-Oil in Transmitters Manufactured by Rosemount" and 90-01, Supplement 1, " Loss of Fill-Oil in Transmitters Manufactured by Rosemount" by letters dated July 17,1990 and February 26,1993 respectively.

These letters are included in Enclosure 5 and address the actions that SNC is taking with respect to item 4 above.

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ENCLOSUREI VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECllNICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CHANNEL RESPONSE TIME TESTS BASIS FOR PROPOSED CHANGE Hasis for Proposed Change for Protection Channels WCAP-14036-P contains the technical basis and methodology for RTT requirements on protection channels identified in the WCAP. The basicjustiGcation for the elimination of periodic response time testing is based on a Failure Modes and Effects Analysis (FMEA) that: 1) determined that individual component degradation had no response time impact; or 2) identined components that may contribute to trip system response time degradation. Where potential response time impact was identined, testing was conducted to determine the magnitude of the response time degradation, or a bounding response time limit for the system or component was determined. As a result of the FMEA, the only components which were tested were the Westinghouse 7100 and 7300 Process Protection System circuit boards and modules. For the remainder of the hardware types shown in segments 2 and 3 of Figure 1 of the WCAP (e.g., NIS, Eagle 21, SSPS and relay logic), bounding response time allocations were determined. In these cases the bounding response time allocation is derived from design response time specifications for the component. .

For the 7100 and 7300 process protection system circuit boards and modules, the FMEA was performed I by having a circuit designer review the circuits and identify those components that may increase the response time if they degrade from their nominal value. The time response of dynamic function (i.e.,

lead-lag, etc.) cards is verified during periodic calibration testing and, therefore, these cards were not included in the program. Where it was necessary to provide a response time limit with component degradation, the conclusions of the FMEA were quantined by testing card and module response times with degraded components.

The FMEA does the following:

identines response time sensitive components on the cards and modules via circuit analysis; evaluates the impact on the response time if a component fails or degrades; identifies detectability of degraded component via calibration; and l

l identifies components that impact calibration but not response time.

The analysis identified capacitors and resistors as the dominant response time sensitive components.

l Other tested components included diodes, zener diodes, inductors, and potentiometers. Increased capacitance tends to lead to increased response time. Manufacturers of sensitive capacitors on the printed circuit cards identified the failure mechanism and the maximum change in capacitance which could be reached before the capacitor failed. One manufacturer stated that the capacitance will not increase beyond 25% of the nominal value. All of the responses of the manufacturers provided gross estimates El-4 L_______________________- -

ENCLOSURE 1 .

VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECilNICAL SPECIFICATIONS -

ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CllANNEL RESPONSE TIME TESTS HASIS FOR PROPOSED CilANGE that capacitors identified in the 7300 circuits do not have a failure mechanism that will double the nominal capacitance. Based on this information, a conservative increase of 50% in capacitance was used to determine the maximum change in response time for capacitor degradation. Resistors were assumed to degrade to as much as 200% of the nominal resistance, which is a conservative increase based on engineeringjudgement.

Actual testing was used to verify and further quantify the FMEA results. The test procedures were used to verify and/or determine actual response time of the card or module with a degraded capacitor or resistor. Compc.nents of different values were substituted to simulate various degrees of degradation.

The procedures required calibration checks on the card and module after each component change to detennine if the calibration could or could not detect the degraded component. If the post-component change calibration inaccuracy exceeded 0.5% of span, then the degradation was considered detectable.

An input step change was used to obtain step response traces. The response time was defined as the time to reach 63% of the final output. This time is equal to the time constant of a dynamic system with a characteristic first order lag. For the 7300 cards, a slightly more conservative limit of 67% was used. In summary, the tests: i i

1 measured the response time of calibrated production modules and provided response time l base-line data;

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verified the analysis by measuring response times and obtaining calibration data for the I

card or module when the component (s) identified by analysis as having an impact on response time were degraded; verified that similar results would be obtained if testing was done at a temperature that more closely modeled the rack environment; and measured the response time of a simulated protection channel from input to output with components degraded.

Sections 4.2 - 4.5 of the WCAP present the results of the FMEA and testing with degraded components.  ;

Testing verified that the FMEA was conservative and provided a baseline response time value for each l

card and module tested. Testing components with simulated degradations was deemed necessary to '

precisely quantify the increase in response time, because the Westinghouse 7100 and 7300 process )

l protection system FMEAs show that components can degrade and impact response time without a i j corresponding calibration or functional test failure. Because the degradation would be undetectable by ,

routine calibration testing, bounding response times with a degraded component were determined. In  !

cases where more than one component impacted the response time, the individual response time i degradation increments were summed to estimate the total response time degradation for the card. The i

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ENCLOSURE 1 VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CIIANNEL RESPONSE TIME TESTS BASIS FOR PROPOSED CIIANGE bounding response time isjustified because ofits small magnitude when compared to the total response time limit for the protection channel and because the simulated degradations were grossly exaggerated.

Sections 4.6 - 4.9 of the WCAP present the results of the FMEA for the NIS, EAGLE 21, SSPS and relay logic protection system. These systems did not require testing with degraded components. In some cases, the FMEA did not identify any response time sensitive components that are subject to degradation, and in other cases the effects of component degradation are accounted for in the overall response time allocation for the system.

In Section 8, the methodology to integrate the component response time results'inte Determination of the limit for protection channels is presented. This information is then combi-.a with t.:e . esults of the actuated component periodic response time tests to ensure that the Technical Specification res,.anse time limits are verified.

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ENCLOSURE 2 VOGTLE ELECTRIC GENERATING PLANT UNITS REQUEST TO REVISE TECllNICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND ELIMINATION OF PERIODIC PROTECTION CIIANNEL RESPONSE TIME TESTS SIGNIFICANT llAZARDS EVALUATION I

1 Description Of The Amendment Request As required by 10 CFR 50.91 (a)(1), an analysis is provided to demonstrate that the proposed license (

amendment to delete the requirement for certain response time testing does not involve a signi6 cant hazards consideration. The proposed amendment revises Section 1.1 Definitions for " ENGINEERED ]

i' SAFETY FEATURE (ESP) RESPONSE TIME" and " REACTOR TRIP SYSTEM (RTS) RESPONSE TIME" to provide for verification of response time for selected components provided that the components and the methodology for verification have been previously reviewed and approved by the NRC.

In addition, the Bases for surveillance SR 3.3.1.15 and SR 3.3.2.8, and the Bases References for Technical Specifications 3.3.1 and 3.3.2 would be revised clarify that allocations for pressure and differential pressure sensor responses times may be derived from;(1) historical records based on acceptable response time tests (hydraulic, noise, or power interrupt tests), (2) in place, onsite, or offsite (e.g. vendor) test measurements, or(3) utilizing vendor engineering speci6 cations. WCAP-13632-P-A,  !

Revision 2, " Elimination of Pressure Sensor Response Time Testing Requirements," provides both the  !

technical basis for deleting periodic pressure and differential pressure sensor response time testing and the methodology for verifying the total channel response time using an allocated sensor response time.

WCAP-14036-P Revision 1, " Elimination of Periodic Protection Channel Response Time Tests,"

provides the basis and methodology for using allocated signal processing and actuation logic response times in the overall verification of the protection system channel response time. The allocations for I sensor, signal conditioning and actuation logic response times must be verified prior to placing the component into operational service and re-verified following maintenance that may adversely affect the response time.

Evaluation Conformance of the proposed amendment to the standards for a determination of no significant hazards as defined in 10 CFR 50.92 is shown in the following:

1) The proposed license amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

This change to the Technical Specifications does not result in a condition where the design, material, and construction standards that were applicable prior to the change are altered. The same RTS and ESFAS instrumentation is being used; the time response allocations /modeling assumptions in the Chapter 15 analyses are still the same; only the method of verifying time response is changed. The proposed change will not modify any system interface and could not increase the likelihood of an accident since these events are independent of this change. The proposed activity will not change, degrade or prevent actions or alter any assumptions previously made in evaluating the radiological consequences of an accident described in the SAR.

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I ENCLOSURE 2

( VOGTLE ELECTRIC GENERATING PLANT UNITS l REQUEST TO REVISE TECIINICAL SPECIFICATIONS ELIMINATION OF PERIODIC PRESSURE SENSOR RESPONSE TIME TESTS AND l ELIMINATION OF PERIODIC PROTECTION CIIANNEL RESPONSE TIME TESTS l SIGNIFICANT IIAZARDS EVALUATION l

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

2) The proposed license amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

This change does not alter the performance of the pressure and differential pressure transmitters and switches, Process Protection racks, Nuclear Instrumentation, and Logic Systems used in the plant protection systems. Applicable sensors, Process Protection racks, Nuclear Instrumentation, and Logic Systems will still have response time verified by test before placing the equipment into operational service and after any maintenance that could affect the response time. Changing the method of periodically verifying instrument response times for certain equipment (assuring equipment operability) from time response testing to calibration and channel checks will not create any new accident initiators or scenarios. Periodic surveillance of these instruments will detect significant degradation in the equipment response time characteristics. Implementation of the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3) The proposed license amendment does not involve a significant reduction in margin of safety.

This change does not affect the total system response time assumed in the safety analysis. The periodic system response time verification method for selected pressure and differential pressure sensors and for Process Protection racks, Nuclear instrumentation, and Logic Systems is modified to allow use of actual test data or engineering data. The method of verification still provides assurance that the total system response time is within that assumed in the safety analysis, since calibration tests will detect any degradation which might significantly affect equipment response time. Based on the above, it is concluded that the proposed license amendment request does not result in a significant reduction in margin of safety.

Conclusion Based on the preceding analysis, it is concluded that elimination of periodic equipment response time testing is acceptable and the proposed license amendment does not involve a Significant Hazards i Consideration as defined in 10 CFR 50.92. l l

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