ML18275A012
| ML18275A012 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/04/2018 |
| From: | James Danna Plant Licensing Branch 1 |
| To: | Stoddard D Dominion Energy Nuclear Connecticut |
| Guzman R, NRR/DORL/LPL1 | |
| References | |
| EPID L-2018-LLR-0078 | |
| Download: ML18275A012 (10) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O.C. 20555-0001 October 4, 2018 Mr. Daniel G. Stoddard Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, VA 23060-6711
SUBJECT:
MILLSTONE POWER STATION, UNIT NO 3 -ALTERNATIVE REQUEST P-06 FOR 'C' CHARGING PUMP TEST FREQUENCY (EPID L-2018-LLR-0078)
Dear Mr. Stoddard:
By letter dated May 29, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18156A131), as supplemented by letter dated August 17, 2018 (ADAMS Accession No. ML18235A321 ), Dominion Energy Nuclear Connecticut, Inc. submitted an alternative 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 (1ST) for the Millstone Power Station, Unit No. 3 (Millstone 3) 'C' charging pump, 3CHS*P3C. The duration of the proposed alternative is requested for the remainder of the third 10-year 1ST program interval and for the fourth 10-year 1ST program interval.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (1 O CFR) 50.55a(z)(2), the licensee requested to use the proposed alternative in request P-06 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 reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that the licensee's proposed alternative P-06 for Millstone 3 provides reasonable assurance that charging pump 3CHS*P3C will remain 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 request P-06. Therefore, the NRC staff authorizes the use of the alternative request P-06 for Millstone 3 for the remainder of the third 10-year 1ST program interval and the entire fourth 10-year 1ST program interval that is scheduled to begin on December 2, 2018, and end on December 1, 2028.
D. Stoddard If you have any questions, please contact the Project Manager, Richard Guzman, at 301-415-1030 or by e-mail to Richard.Guzman@nrc.gov.
Sincerely,
~~::--
Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-423
Enclosure:
Safety Evaluation cc: Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ALTERNATIVE REQUEST P-06 FOR 'C' CHARGING PUMP TEST FREQUENCY MILLSTONE POWER STATION, UNIT NO. 3 DOMINION NUCLEAR CONNECTICUT, INC.
DOCKET NO. 50-423
1.0 INTRODUCTION
By letter dated May 29, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18156A131), as supplemented by letter dated August 17, 2018 (ADAMS Accession No. ML18235A321 ), Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee), submitted an alternative 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 (1ST) for the Millstone Power Station, Unit No. 3 (Millstone 3 or MPS3) 'C' charging pump, 3CHS*P3C. The duration of the proposed alternative is requested for the remainder of the third 10-year 1ST program interval and for the fourth 10-year 1ST program interval.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), the licensee requested to use the proposed alternative in request P-06 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 regulation in 10 CFR 50.55a(f), states, in part, that 1ST 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, in part, that alternatives to the requirements of paragraph (f) of 10 CFR 50.55a may be used, when authorized by the 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.
Based on the above, and subject to the following technical evaluation, the U.S. Nuclear Regulatory Commission (NRC) staff finds that regulatory authority exists for the licensee to request and the Commission to authorize the alternative requested by the licensee.
Enclosure
3.0 TECHNICAL EVALUATION
3.1 Licensee's Alternative Request P-06 The licensee is proposing an alternative to the pump testing requirements of the ASME OM Code. Specifically, the licensee requests to use the proposed alternative as described below for charging pump 3CHS*P3C. Charging pump 3CHS*P3C is classified as a Group A pump and is ASME Code Class 2. The applicable code requirement is described in ISTB-3400, "Frequency of lnservice Tests," which requires that a quarterly Group A test be performed on a Group A pump as specified in Table ISTB-3400-1, "lnservice Test Frequency."
The third 10-year 1ST program interval for Millstone 3 began on December 2, 2008, and is scheduled to end on December 1, 2018. The applicable ASME OM Code edition for the Millstone 3 third 10-year 1ST program interval is the 2001 Edition through the 2003 Addenda.
The fourth 10-year 1ST program interval for Millstone 3 is scheduled to begin on December 2, 2018, and end on December 1, 2028. The applicable ASME OM Code edition for the Millstone 3 fourth 10-year 1ST program interval is the 2012 Edition.
Reason for Request
Pursuant to 10 CFR 50.55a(z)(2), DENC is requesting NRC approval of a proposed alternative to the quarterly testing requirement of Table ISTB-3400-1 on the basis that the requirement to perform quarterly testing of 3CHS*P3C represents a hardship, without a compensating increase in quality or safety. Specifically, the licensee stated that approximately 20 percent of total high pressure safety injection (HPSI) unavailability is due to quarterly testing of 3CHS*P3C.
Quarterly testing of 3CHS*P3C requires that one train of HPSI be disabled to support electrically connecting 3CHS*P3C to a safety-related electrical bus for testing purposes. Unavailability is accrued for the HPSI safety function for the time the emergency core cooling system train is disabled. Additionally, the licensee considers the alignment of 3CHS*P3C for testing as a complex evolution involving the entry into a 72-hour shutdown technical specification (TS) action statement, as well as close coordination between the control room and field personnel, to execute the required breaker manipulations and realignment of cooling water to the charging pump oil cooler.
As the basis for the use of the P-06 alternative, the licensee provided the following:
The MPS3 charging system design includes three hydraulically similar pumps.
MPS3 TS require two independent emergency core cooling system (ECCS) trains. Charging pumps 3CHS*P3A and 3CHS*P3B are normally aligned and credited for maintaining the two independent trains. Pumps 3CHS*P3A and 3CHS*P3B are each electrically connected to an independent safety-related electrical bus backed by an emergency power source. Charging pump 3CHS*P3C serves as an installed spare pump that is not normally connected to any power source. There is a dedicated breaker cubicle on each of the safety related electrical buses that can be used to connect 3CHS*P3C to the associated bus. To connect 3CHS*P3C, either 3CHS*P3A or 3CHS*P3B must be electrically disconnected by racking out the appropriate breaker and physically removing, relocating and reinstalling the affected breaker in the 3CHS*P3C pump breaker cubicle. Kirk key interlocks are provided to prevent having two charging pumps capable of starting on the same electrical bus. Additionally, cooling water must be aligned to the 'C' charging pump oil cooler to support pump operation.
The process is then reversed to restore the system to its normal operational alignment. The time required to complete this evolution is approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
Aligning 3CHS*P3C for operation is not credited as the primary mitigation strategy for any Final Safety Analysis Report (FSAR) Chapter 15 accident analysis as the time required to place 3CHS*P3C in service exceeds the response time assumptions for functions credited for Chapter 15 accident mitigation. In its normal (spare) alignment, 3CHS*P3C is considered available for use but does not meet MPS3 TS requirements to be considered OPERABLE.
Should 3CHS*P3C be placed into service during normal plant operations (3CHS*P3A or B inoperable), it would become the credited component for FSAR Chapter 15 event mitigation and would be subject to all performance testing requirements specified in the Millstone 3 TS.
Alignment of 3CHS*P3C is listed as a contingency action in station Abnormal and Emergency Operating Procedures. A decision to use 3CHS*P3C while operating within the Abnormal and Emergency Operating Procedure network would be based on specific plant conditions and circumstances that exist at the time.
Should plant operators elect to align 3CHS*P3C during an abnormal or emergency event, performance of a quarterly test may be deferred until after plant conditions are stabilized.
Additionally, MPS3 TS Bases for entry into the 14-day allowed outage time (TS) 3.8.1.1.b ACTION for an emergency power source out of service require 3CHS*P3C be available to replace an inservice charging pump, if necessary.
The proposed alternate testing plan does not affect the availability of the spare pump to fulfill these functions. Charging pump 3CHS*P3C would be considered available provided a current satisfactory comprehensive test is documented.
Proposed Alternative The licensee is proposing to perform the quarterly Group A test on 3CHS*P3C for the time periods when the pump is required to be operable to support continued plant operation. If it becomes necessary to use 3CHS*P3C, a quarterly Group A test will be performed prior to declaring the pump operable. Testing on a quarterly frequency would be performed until 3CHS*P3C is returned to its normal (spare) alignment. A pump comprehensive test will continue to be performed on a refueling outage frequency. Charging pump 3CHS*P3C is considered available, provided a current satisfactory comprehensive test is documented.
Existing preventative maintenance activities are shown in Table 1.
In its proposed alternative request, the licensee stated that the requirement of ISTB-3400 and Table ISTB-3400-1 to perform a quarterly test on charging pump 3CHS*P3C results in an increased unavailability of the HPSI system and, therefore, presents a hardship, without a compensating increase in the level of quality and safety. DENC will continue to comply with all other aspects of the OM Code, such as comprehensive pump tests and post-maintenance tests.
The proposed alternative to perform the quarterly test prior to placing charging pump 3CHS*P3C into normal service with the existing preventative maintenance activities shown in Table 1 provide continued assurance of pump performance and an acceptable level of quality and safety, without increased HPSI system unavailability.
3.2 NRC Staff Evaluation Section ISTB-3400, "Frequency of lnservice Tests," of the 2012 Edition of the ASME Code requires that an inservice test shall be run on each pump as specified in Table ISTB-3400-1.
Table ISTB-3400-1 requires that a quarterly Group A test be performed on a Group A pump.
The licensee is proposing an alternative to this requirement for charging pump 3CHS*P3C.
As indicated above, the pump is an installed spare pump that is not normally connected to a power source. In order to perform the quarterly test, one train of HPSI has to be disabled in order to connect that train's power source to charging pump 3CHS*P3C. This process involves racking out the appropriate breaker and physically removing, relocating, and reinstalling it in the 3CHS*P3C pump breaker cubicle. In addition, cooling water must be aligned to the pump oil cooler. Unavailability is accrued for the HPSI safety function for the time the train is unavailable, and entry into a 72-hour TS action statement is required. Close coordination between the control room and field personnel is necessary to perform the required breaker manipulations and the realignment bf cooling water to the pump oil cooler.
The licensee is proposing to perform a Group A test only when it is necessary to use the pump.
After connecting the pump to a power source and aligning cooling water to the pump oil cooler, a Group A test will be performed prior to declaring the pump operable. In its proposed alternative request, the licensee stated that "should plant operators elect to align 3CHS*P3C during an abnormal or emergency event, performance of a quarterly test may be deferred until after plant conditions are stabilized." The licensee provided additional information to this statement in its response to RAI-P-06-4 in its letter dated August 17, 2018, stating that it was included in its submittal to recognize that there may be unanticipated emergency situations that are beyond the design basis of the plant (i.e., loss of two operable charging pumps) where operators may need to take immediate action and place the pump in service without testing in order to protect the health and safety of the public. In all other situations, DENG will perform the quarterly Group A test prior to declaring the pump operable.
In its response to the staff's RAI-P-06-2, the licensee stated that in accordance with the Millstone 3 TS Bases, the charging pump and charging pump cooling pump in operation are powered from the bus not associated with the out-of-service diesel generator. In addition, the spare charging pump will be available to replace an inservice charging pump, if necessary. The licensee further stated that it will perform the quarterly Group A test prior to declaring 3CHS*P3C operable when replacing an inservice charging pump that needs to be removed from service. If the charging pump associated with the operable diesel generator becomes inoperable, applicable TS actions will apply until the Group A test is performed and 3CHS*P3C is declared operable.
The NRC staff also noted that charging pump 3CHS*P3C has been referred to as both a swing pump and a spare pump in various licensing documents. In the proposed alternative request, pump 3CHS*P3C is designated as a spare pump, whereas in certain sections of the Millstone 3 FSAR, it is referred to as a swing pump. The staff requested the licensee in RAI-P-06-6 to address the difference. In its response to RAI-P-06-6, the licensee stated that the ASME OM Code Subsections ISTA-2000 and ISTB-2000 do not provide definitions for the terms "spare" or "swing" and that it has used both terms interchangeably to describe 3CHS*P3C in Millstone 3 licensing documents. The licensee has prepared an FSAR change to refer to the pump only as a spare pump. The licensee stated that the change is editorial in nature and has no effect on protecting the plant. As stated in the proposed alternative request, the spare charging pump 3CHS*P3C has no assigned FSAR Chapter 15 accident mitigation function, because the time
required to place the pump in service exceeds the response time assumptions for functions that are credited for accident mitigation in Chapter 15.
In its response to the staff's RAI-P-06-2, the licensee stated that the Group A test for charging pump 3CHS*P3C has a reference point flow rate of 67.2 gallons per minute (gpm). This reference point flow rate is limited by the capacity of the fixed resistance recirculation line that is used for the test. The comprehensive pump test reference point flow rate is 505.8 gpm. This lower flow rate for the Group A test is allowable because ISTB-3300(e)(2) in the 2012 Edition of the ASME OM Code states that, "Reference values shall be established at the comprehensive pump test flow rate for the Group A and Group B tests, if practicable. If not practicable, the reference point flow rate can be established at the highest practical flow rate." The Group A reference point flow rate of 67.2 gpm is on the flat portion of the pump curve. Because of this, pump degradation by flow rate and discharge pressure is difficult to detect with the Group A test. Pump degradation by flow rate and discharge pressure can be detected with the comprehensive pump test because the reference point flow rate is on the sloped portion of the pump curve. Vibration monitoring in both tests will be able to detect degradation.
As shown in Table 1 below, the licensee provided a list of the preventative maintenance tasks established to monitor for degradation of the lubricating oil through routine sampling and analysis for indicators of breakdown of the lubricant properties, as well as the presence of wear products. Pump vibration data is also collected and analyzed for indications of bearing wear or pump alignment problems whenever a pump is put in service and periodically while it remains in service.
Table 1 3CHS*P3C PREVENTATIVE MAINTENANCE STRATEGY PM Description Location Cycle Status RE94626 EEQ, 60A Pump Motor And Motor Main Lead M33CHS*P3C ACTIVE Replacement RE618954 PM, 1R- POMA (energized), health and condition M33CHS*P3C 3R20 ACTIVE monitoring of motor RE618902 PM, 2R - POMA (de-energized), health and M33CHS*P3C 3R22 ACTIVE condition monitoring of motor RE618669 PM, BR - Charging Pump Motor Overhaul M33CHS*P3C 3R29 ACTIVE RE614565 EEQ, 39A(J)- 5KV PWR Cable & Raychem Kit M33CHS*P3C ACTIVE Replacement RE613970 PM, 4R - Grease & Inspect Couplings - (Gear/ M33CHS*P3C ~R24 ACTIVE Pump & Motor I Gear)
RE610041 SI, 2R-- 3CHS*P3C (VT-2) Exam, VT-2 Exam of M33CHS*P3C 3R20 ACTIVE 3CHS*P3C & associated components.
RE609575 PM, 15R - Replace 0-Rings on Gear/ Pump M33CHS*P3C 3R36 lACTIVE Coupling, - Inspect 0-Rings on Motor I Gear Coupling
RE609004 PM, 1R - Motor Oil Change M33CHS*P3C 3R20 ACTIVE RE608085 RT, 6 Month - Seal Reservoir/Drain Line M33CHS*P3C ACTIVE Cleaning RE607891 PM, 1R- Gear Box & Reservoir Oil Sample M33CHS*P3C 3R19 ACTIVE RE607058 PM, 4.SA- 3CHS*P3C (34C22) Relay & Meter M33CHS*P3C ACTIVE Calibrations The licensee stated that extending the interval between tests will not degrade the performance of 3CHS*P3C. The three charging pumps (3CHS*P3A/B/C) are located in the controlled environment of the Millstone 3 auxiliary building and are constructed of materials specifically selected to be compatible with the chemistry of the pumped fluid (borated water). The charging system fluid chemistry is not expected to cause any degradation of the pump internals over time, as it is monitored and maintained to meet reactor coolant system water quality requirements. Additionally, the licensee stated that the pump bearings when sitting idle are not subjected to wear and, therefore, would not be expected to degrade. The staff requested additional information in RAI-P-06-3 as to what maintenance activities will be performed to prevent the development of flat spots on the pump bearings during the idle periods. In its response, the licensee confirmed in its review of the component design that both the motor and pump bearings are journal type bearings and not the roller type. Degradation from flat spots is not a significant concern on journal type bearings. DENC also stated that the preventative maintenance activities will be revised to include an annual requirement to manually rotate the pump and motor. The staff noted that the licensee has established the appropriate preventative maintenance tasks to monitor for degradation of the lubricating oil through routine sampling and analysis as shown in Table 1 above, which include activities such as health and condition monitoring of the motor, motor overhaul, grease and inspect couplings, and VT-2 visual exam of the pump and associated components.
In 2016, DENC submitted a formal Code Inquiry to ASME to clarify the intent of the 2001 Edition through 2003 Addenda of the OM Code in regard to testing of 3CHS*P3C. The response to the Code Inquiry, OM Code Interpretation No. OM-17-01, was issued on March 26, 2017. The licensee stated that while its alternative request references the 2012 Edition of the OM Code, the relevant Code requirements have not changed. Review by the Code Committee determined that it was not the intent of the Code to require testing of components (1) not connected to an emergency power source and (2) not required to be operable.
The NRC staff also notes that a proposed revision to Section ISTB-3420, "Pumps in Systems Out of Service," of the ASME OM Code has been submitted by the ASME OM Code Pump Committee. The proposed title of the revised section is "Pumps Out of Service." The NRC staff representative voted in the affirmative for this proposed change. The wording for the proposed revision is as follows:
For a pump declared inoperable or not required to be operable, the test schedule need not be followed. Within 3 months before the pump is placed in an operable status, the pump shall be tested and the test schedule followed in accordance with the requirements of this Subsection.
In accordance with the above evaluation, the NRC staff finds that compliance with the ASME OM Code required Group A pump test requirements would result in hardship or unusual difficulty. The NRC staff also finds that the alternative described in the licensee's proposal provides reasonable assurance of pump operational readiness and permits the detection of degradation, since (1) a Group A test will be conducted prior to declaring charging pump 3CHS*P3C operable, (2) preventative maintenance will be performed on the pump while it is inoperable, and (3) the comprehensive pump test will be performed at every refueling outage.
The NRC staff notes that when the proposed change to ISTB-3420 described above is incorporated into a future edition of the ASME OM Code, an alternative request such as P-06 submitted by DENC would not be necessary for a licensee that applies the future edition (or later) as its Code of Record.
4.0 CONCLUSION
As set forth above, the NRC staff has determined that the proposed alternative request P-06 provides reasonable assurance that the Millstone 3 charging pump 3CHS*P3C will remain 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 request P-06.
Therefore, the NRC staff authorizes the use of the alternative request P-06 for Millstone 3 for the remainder of the third 10-year 1ST program interval and for the entire fourth 10-year 1ST program interval, which begins on December 2, 2018, and is scheduled to end on December 1, 2028.
All other requirements of the ASME OM Code for which relief was not specifically requested and approved in the subject request remain applicable.
Principal Contributor: R. Wolfgang Date: October 4, 2018
D. Stoddard
SUBJECT:
MILLSTONE POWER STATION, UNIT NO 3 -ALTERNATIVE REQUEST P-06 FOR 'C' CHARGING PUMP TEST FREQUENCY (EPID L-2018-LLR-0078}
DATED OCTOBER 4, 2018 DISTRIBUTION:
PUBLIC PM Reading File RidsNrrDorlLpl1 Resource RidsNrrPMMillstone Resource RidsNrrLALRonewicz Resource RidsNrrDeEmib Resource RidsACRS_MailCTR Resource RidsRgn1 MailCenter Resource RWolfgang, NRR JBowen, OEDO LBurkhart, OEDO ADAMS A ccess1on No.: ML18275A012 *b1y e-ma1*1 OFFICE DORL/LPL 1/PM DORL/LPL 1/LA DE/EMIB/BC* DORL/LPL 1/BC DORL/LPL 1/PM NAME RGuzman LRonewicz SBailey JDanna RGuzman DATE 10/03/2018 10/03/2018 09/20/2018 10/04/2018 10/04/2018 OFFICIAL RECORD COPY