ML19205A453

R. E. Ginna Nuclear Power Plant - Issuance of Relief Request Associated with Alternatives PR-01 and PR-02 for Sixth 10-Year Inservice Testing Program

ML19205A453
Person / Time
Site:	Ginna
Issue date:	08/05/2019
From:	James Danna Plant Licensing Branch 1
To:	Bryan Hanson Exelon Generation Co
Sreenivas V, NRR/DORL/LPL1, 415-2596
References
EPID L-2018-LLR-0381
Download: ML19205A453 (11)

Text

August 5, 2019 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

R. E. GINNA NUCLEAR POWER PLANT- ISSUANCE OF RELIEF REQUEST ASSOCIATED WITH ALTERNATIVES PR-01 AND PR-02 FOR THE SIXTH 10-YEAR INSERVICE TESTING PROGRAM (EPID L-2018-LLR-0381)

Dear Mr. Hanson:

By letter dated December 13, 2018 (Agencywide Documents Access and Management System Accession No. ML18347B036), Exelon Generation Company, LLC (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) associated with pump inservice testing for the R. E. Ginna Nuclear Power Plant.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), the licensee requested to use the proposed alternatives in requests PR-01 and PR-02 on the basis that the ASME OM Code requirements present an undue hardship, without a compensating increase in the level of quality or safety.

The U.S. Nuclear Regulatory Commission (NRC) staff has determined that compliance with the specified requirements would result in hardship or unusual difficulty, without a compensating increase in the level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(2).

Therefore, the NRC staff authorizes the use of these alternative requests for the sixth 10-year inservice testing program interval, which begins on January 1, 2020, and is scheduled to end on December 31, 2029.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable.

B Hanson If you have any questions, please contact the R. E. Ginna Nuclear Power Plant Project Manager, V. Sreenivas, at 301-415-2597 or V.Sreenivas@nrc.gov.

Sincerely,

/RA/

James G. Danna, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244

Enclosure:

Safety Evaluation cc: Listserv

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ALTERNATIVE REQUESTS PR-01 AND PR-02 FOR SIXTH 10-YEAR INTERVAL INSERVICE TESTING PROGRAM EXELON GENERATION COMPANY, LLC R. E. GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244

1.0 INTRODUCTION

By letter dated December 13, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18347B036), Exelon Generation Company, LLC (the licensee) submitted alternatives to the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) associated with pump inservice testing (IST) at R.E. Ginna Nuclear Power Plant (Ginna).

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), the licensee requested to use the proposed alternatives in requests PR-01 and PR-02 on the basis that the ASME OM Code requirements present an undue hardship, without a compensating increase in the level of quality or safety.

2.0 REGULATORY EVALUATION

The regulations in 10 CFR 50.55a(f), states, in part, that IST of certain ASME Code Class 1, 2, and 3 pumps and valves be performed in accordance with the specified ASME OM Code and applicable addenda incorporated by reference in the regulations.

The regulation in 10 CFR 50.55a(z) states that alternatives to the requirements of paragraph (f) of 10 CFR 50.55a may be used, when authorized by the U.S. Nuclear Regulatory Commission (NRC), if the licensee demonstrates (1) the proposed alternatives would provide an acceptable level of quality and safety or (2) compliance with the specified requirements would result in hardship or unusual difficulty, without a compensating increase in the level of quality and safety.

3.0 TECHNICAL EVALUATION

3.1 Licensees Alternative Request PR-01 The licensee requested an alternative to the pump testing requirements of the ASME OM Code.

Enclosure

ISTB-3550, Flow Rate, states, in part, When measuring flow rate, a rate or quantity meter shall be installed in the pump test circuit. If a meter does not indicate the flow rate directly, the record shall include the method used to reduce the data.

The licensee has requested to use the proposed alternative described below for the fuel oil transfer pumps listed in Table 1.

Table 1 Component Description ASME Code Class ASME OM Pump Category PDG02A Diesel Fuel Oil Transfer 3 B Pump A PDG02B Diesel Fuel Oil Transfer 3 B Pump B The Ginna sixth 10-year IST program interval begins on January 1, 2020, and is scheduled to end on December 31, 2029. The applicable ASME OM Code edition for the Ginna sixth 10-year IST program interval is the 2012 Edition.

Reason for Request

The licensee stated:

The diesel fuel oil transfer pumps are required to transfer fuel oil from the storage tank to the day tank. This function ensures a continuous fuel supply to support long term operation of the diesel during accident conditions.

There are no installed instruments on the diesel fuel oil transfer system that allow a direct measurement of the flow rate when testing the diesel oil fuel transfer pumps. The pump flow rate can be calculated by measuring the change in day tank level or volume and the pump operation time required to make that change.

The accuracy of this method is documented in design analysis Engineering Work Request (EWR) 4526-ME-20. This method determines a flow rate for a pump that can be used to evaluate the pump's hydraulic performance.

Proposed Alternative The licensee stated:

Ginnas diesel fuel oil transfer pumps, PDG02A & PDG02B, are positive displacement pumps. The flow rate for these pumps is determined by measuring the indicated level change in the diesel generator fuel oil day tank during a timed pump run and converting this data into fuel oil transfer pump flow rate for both the Group B and comprehensive pump tests.

Level gauges LG-2044 (A Emergency Diesel Generator) and LG-2045 (B Emergency Diesel Generator) are utilized to measure the change in indicated level while the fuel oil transfer pump is running and restoring fuel oil day tank level. Both LG-2044 and LG-2045 (sight glasses equipped with a reference

scale in inches of level) have a range of indicated level of 9 inches (2.5 inches to 11.5 inches).

The respective day tank is drained to an initial indicated level of 5.0 to 5.5 inches before initiating the fuel oil pump start. This level is logged as the initial level.

The pump is then started coincident with starting the stopwatch and the system allowed to stabilize. A minimum 2-minute stabilization period is observed for the comprehensive test.

Following a total minimum run time of 5 minutes (or exceeding an indicated tank level of 11 inches), the pump is stopped coincident with stopping the stopwatch and the day tank level is read in inches to the nearest 0.25 inch. This level is logged as the final level.

The change in day tank level is determined in inches and then converted to total gallons pumped using the constant conversion factor of 24.76 gallons per inch.

The constant of 24.76 gallons per inch of indicated level on the day tank sight glass was established by EWR 4526-ME-20 based on the tanks geometrical dimensions. The total gallons pumped is then divided by the total pump run time to arrive at the pump test flow rate in gallons per minute (gpm). This calculation is documented in the pump test procedures.

The test circuit for each pump is a fixed flow path from the storage tank (pump suction) to the day tank (pump discharge). Pump suction pressure is nearly constant because of the very small change in storage tank level. This change in suction pressure during pump operation is considered negligible. The normal rise in day tank level is approximately 5.5 inches, which corresponds to a quantity of approximately 136 gallons pumped during the 5 minutes of pump operation, resulting in a typical flow rate of approximately 27 gpm.

The small rise in day tank level during pump operation does not affect pump discharge pressure or flow rate. This conclusion is supported by the discussion in NUREG-1482, Revision 2, Section 5.5.2, Use of Tank Level to Calculate Flow Rate for Positive Displacement Pumps, where the NUREG states: Pump discharge pressure will match system pressure up to the shutoff head of the positive displacement pump. Because of the characteristics of a positive displacement pump, there should be virtually no change in pump discharge flow rate as a result of the rising tank level. Therefore, rising tank level will not have an impact on test results. By having approximately the same level in the tank at the beginning of each test, licensees can achieve repeatable results.

The accuracy of level gauges, LG-2044 and LG-2045, is determined using the 9-inch indicated range of level and the constant of 24.76 gallons per inch. This yields a total volume change of 222.84 gallons. Based on a readability uncertainty of +/-0.125 inch (0.25-inch scaling), which is equivalent to 3.10 gallons, divided by the total indicated volume of 222.84 gallons, the overall accuracy of the sight glass is +/- 1.39%.

In addition, the stopwatch used to measure the time the pump is operating and pumping fuel oil is now accurate to within +/-3 seconds per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (formerly

+/-0.6 second per minute) [the licensees submittal stated +/-0.6% second per

minute, which they have stated is incorrect] for a calibrated accuracy of +/-0.004%

(formerly +/-1.0%). Combining the accuracy of the stopwatch with the level gauge sight glass, using the square root of the sum of the squares method, results in an insignificant decrease with an overall indicated accuracy of +/-1.39% (formerly

+/-1.71%). This overall accuracy has been improved from that which was provided in the alternative previously authorized for use during the fifth 10-year interval IST program.

Therefore, the pump flow rate can be accurately calculated by measuring the change in day tank level or volume and the pump operation time required to make that change. This method determines a flow rate for these pumps that can be used to evaluate the pumps hydraulic performance and provide reasonable assurance of pump operational readiness. Therefore, relief is requested pursuant to 10 CFR 50.55a(z)(2) based on the determination that compliance with the Code pump testing requirements regarding pump flow rate cannot be achieved without resulting in a hardship or unusual difficulty without a compensating increase in the level of quality and safety; and the proposed alternative of using the tank level change vs. time to calculate the flow rate provides reasonable assurance of operational readiness and provides an acceptable level of quality and safety.

NRC Staff Evaluation

The licensee proposes alternative testing for the diesel fuel oil transfer pumps. The current configuration does not meet the requirements of ISTB-3550, which states that when measuring flow rate, a rate or quantity meter shall be installed in the pump test circuit. The licensees proposed alternative test shall determine the flow rate by calculation of day tank level versus time. The diesel fuel oil transfer pumps PDG02A and PDG02B are positive displacement pumps.

There are no installed instruments in the diesel fuel oil transfer system that allow a direct measurement of the flow rate when testing the diesel fuel oil transfer pumps. The pump flow rate can be calculated by measuring the change in day tank level or volume and the pump operation time required to make that change. The accuracy of this method is documented in the licensees design analysis EWR 4526-ME-20, Evaluation of Instrument Setpoints for EDG Fuel Oil System. This method determines a flow rate for a pump that can be used to evaluate the pump hydraulic performance.

The licensees alternative is consistent with NRC guidance in NUREG-1482, Revision 2, Guidelines for Inservice Testing at Nuclear Power Plants, Inservice Testing of Pumps and Valves and Inservice Examination and Testing of Dynamic Restraints (Snubbers) at Nuclear Power Plants, Final Report, Section 5.5.2, as an acceptable alternative for measuring positive displacement pump flow rate without using an installed flow rate instrument. The licensee has verified via design analysis EWR 4526-ME-20 that the alternative testing accuracy meets the requirements of ISTB-3510(a). The combined accuracy of the tank level gauge and the stopwatch is +/-1.39 percent, which is an improvement over the combined accuracy of

+/-1.71 percent that the licensee stated is the accuracy in the current Ginna fifth 10-year IST program interval. The NRC staff concludes that the proposed alternative of using the change in tank level to calculate the flow rate provides reasonable assurance of operational readiness of diesel fuel oil transfer pumps PDG02A and PDG02B, and provides an acceptable level of quality and safety.

It is noted that the NRC staff authorized the use of this alternative for the current Ginna fifth 10-year IST program interval.

3.2 Licensees Alternative Request PR-02 The licensee requested an alternative to the pump testing requirements of the ASME OM Code.

Table ISTB-3000-1, Inservice Test Parameters, provides the parameters for flow rate (Q) and differential pressure (P) for the Group A pump test and Q and P for the Group B pump test.

ISTB-3550, Flow Rate, states, in part, When measuring flow rate, a rate or quantity meter shall be installed in the pump test circuit. If a meter does not indicate the flow rate directly, the record shall indicate the method used to reduce the data.

ISTB-5121, Group A Test Procedure, states, in part, Group A tests shall be conducted with the pump operating as close as practical to a specified reference point and within the variances from the reference point as described in this paragraph. The test parameters shown in Table ISTB-3000-1 shall be determined and recorded as required by this paragraph.

ISTB-5121(c) states, Where it is not practical to vary system resistance, flow rate and pressure shall be determined and compared to their respective reference values.

ISTB-5122, Group B Test Procedure, states, in part, Group B tests shall be conducted with the pump operating as close as practical to a specified reference point and within the variances from the reference point as described in this paragraph. The test parameter value identified in Table ISTB-3000-1 shall be determined and recorded as required by this paragraph.

ISTB-5122(c) states, in part, System resistance may be varied as necessary to achieve a point as close as practical to the reference point. If the reference point is flow rate, the variance from the reference point shall not exceed +2% or -1%.

The licensee has requested to use the proposed alternative described below for the pumps listed in Table 2.

Table 2 Pump ID Pump Description ASME Code Class ASME OM Pump Group PAF01A A Preferred Motor 3 A Driven Auxiliary Feedwater (AFW) Pump PAF01B B Preferred Motor 3 A Driven AFW Pump PSF01A C Standby Motor Driven 3 B AFW Pump PSF01B D Standby Motor Driven 3 B AFW Pump

The Ginna sixth 10-year IST program interval begins on January 1, 2020 and is scheduled to end on December 31, 2029. The applicable ASME OM Code edition for the Ginna sixth 10-year IST program interval is the 2012 Edition.

Reason for Request

The licensee stated:

Pursuant to 10 CFR 50.55a, Codes and Standards, paragraph (z)(2), an alternative is proposed to the pump testing requirements regarding pump flow rate in the ASME OM-2012 Code. The basis of the request is that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The AFW pumps each have a minimum flow path that can be utilized for the respective Group A and Group B pump tests. The minimum flow lines provide a fixed resistance flow path from the pump discharge to the condensate storage or demineralized water storage tank, as applicable, then back to the suction of each pump. However, the minimum flow lines are not provided with flow instrumentation.

Compliance with the Code is an undue burden due to existing design limitations in that a flow rate measuring device is not installed in the associated pump minimum flow recirculation line being employed as the pump test circuit. Costly major hardware modifications would be required to provide a permanent flow measuring device in each affected line. It has been estimated that the cost would exceed $75,000 annually to install and maintain temporary flow measuring devices or more than $375,000 to install permanent flow measuring devices into the minimum flow recirculation lines in order to meet the ASME OM Code requirements and support the quarterly testing of the four AFW pumps.

Additionally, flow is not variable since an installed flow orifice establishes a 40 gpm flow rate when the pump is operated in the recirculation mode.

The flow path to the steam generators has flow instrumentation; however, this flow path has the potential for service water intrusion and requires a reactivity change. This flow path is used for the biennial comprehensive pump test.

Therefore, the instrumented flow path which has the potential for service water intrusion into the steam generators and requires a reactivity change, and the cost of installing either temporary or permanent flow instrumentation in the minimum flow recirculation lines imposes an undue burden without a compensating increase in the level of quality or safety.

Proposed Alternative The licensee stated:

The performance of pump tests using a fixed resistance flow path is an acceptable alternative to the Code requirements per NUREG-1482, Revision 2, Section 5.9, Pump Testing Using Minimum Flow Return Lines With or Without Flow Measuring Devices. During the performance of quarterly pump testing,

pump differential pressure will be measured and trended. This provides a reference value for differential pressure that can be duplicated during subsequent tests. This methodology provides for the acquisition of repeatable differential pressure, which is an adequate means of monitoring for pump degradation.

Concerns identified in NRC Bulletin 88-04, Potential Safety-Related Pump Loss, with regard to minimum recirculation flow line sizing were assessed and verified to not be of concern during pump testing.

Quarterly testing of the designated Group A AFW centrifugal pumps (PAF01A, PAF01B) will be performed on minimum flow recirculation measuring differential pressure across the pump and measuring vibration per ASME OM-2012 Code, paragraph ISTB-5121 and using NUREG-1482, Revision 2, Section 5.9 for guidance.

Quarterly testing of the designated Group B Standby AFW centrifugal pumps (PSF01A, PSF01B) will be performed on minimum flow recirculation measuring differential pressure across the pump per ASME OM-2012 Code, paragraph ISTB-5122 and using NUREG-1482, Revision 2, Section 5.9 for guidance.

Therefore, relief is requested pursuant to 10 CFR 50.55a(z)(2) based on the determination that compliance with the Code required Groups A and B centrifugal pump test requirements cannot be achieved without resulting in a hardship or unusual difficulty without a compensating increase in the level of quality and safety; and the proposed alternative testing provides reasonable assurance of the AFW pumps' operational readiness.

NRC Staff Evaluation

Motor-driven AFW pumps PAF01A and PAF01B are Group A centrifugal pumps. Inservice testing requirements for Group A centrifugal pumps are specified in ISTB-5121.

Motor-driven AFW pumps PSF01A and PSF01B are Group B centrifugal pumps. Inservice testing requirements for Group B centrifugal pumps are specified in ISTB-5122.

The licensee proposes alternative quarterly testing for the motor-driven auxiliary feedwater pumps. The current configuration does not meet ISTB-3550, which states that when measuring flow rate, a rate or quantity meter shall be installed in the pump test circuit. The licensee stated that the estimated cost to install and maintain temporary flow measuring devices in the pump minimum flow recirculation lines would exceed $75,000 annually, and the cost to install permanent flow measuring devices in the pump minimum flow recirculation lines would exceed

$375,000. The licensees proposed alternative quarterly test shall use the minimum flow path lines, which have a flow orifice installed. These minimum flow path lines provide a fixed resistance flow path without installed flow rate instrumentation. Measurements will include differential pressure across the pump in accordance with ISTB-5121 for the Group A pumps and ISTB-5122 for the Group B pumps, and vibration measurements in accordance with ISTB-5121 will be taken during the Group A pump tests.

The NRC staff has reviewed the licensees proposed alternative and has determined that the testing is consistent with the guidance in NUREG-1482, Revision 2, Section 5.9, Pump Testing Using Minimum Flow Return Lines With or Without Flow Measuring Devices, and Generic

Letter 89-04, Guidance on Developing Acceptable Inservice Testing Programs, Position 9.

The NRC staff finds that compliance with the ASME OM Code-required Group A and Group B pump test requirements cannot be achieved without major system modifications and would result in hardship or unusual difficulty. The NRC staff also finds that the alternative described in the licensees proposal provides reasonable assurance of pump operational readiness.

It is noted that the NRC staff authorized the use of this alternative for the current Ginna fifth 10-year IST program interval.

4.0 CONCLUSION

As set forth above, the NRC staff determined that for alternative requests PR-01 and PR-02 for Ginna, the proposed alternatives provide reasonable assurance that the pumps listed in Tables 1 and 2 are operationally ready. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2) for requests PR-01 and PR-02. Therefore, the NRC staff authorizes the use of the alternative requests PR-01 and PR-02 for Ginna for the sixth 10-year IST program interval, which begins on January 1, 2020, and is scheduled to end on December 31, 2029.

All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject requests remain applicable.

Principal Contributor: R. Wolfgang Date: August 5, 2019

ML19205A453 *by memorandum OFFICE DORL/LPL1/PM DORL/LPL1/LA DE/EMIB/BC* DORL/LPL1/BC DORL/LPL1/PM NAME VSreenivas KEntz; SBailey JDanna VSreenivas LRonewicz (MMarshall for)

DATE 07/26/2019 07/29/2019 07/18/2019 08/02/2019 08/05/2019