ML18213A115

Request for Additional Information Alternative Request P-06 'C' Charging Pump (08/01/2018 E-mail from R. Guzman to M. Whitlock)

ML18213A115
Person / Time
Site:	Millstone
Issue date:	08/01/2018
From:	Richard Guzman Plant Licensing Branch 1
To:	Whitlock M Dominion Energy Nuclear Connecticut
Guzman R
References
EPID L-2018-LLR-0078
Download: ML18213A115 (2)

Text

From: Guzman, Richard To: "Michael.Whitlock@Dominionenergy.com"

Subject:

Millstone Unit 3 - Request For Additional Information - Alternative Request P-06 "C" Charging Pump (EPID: L-2018-LLR-0078)

Date: Wednesday, August 01, 2018 10:23:08 AM

Michael, On July 16, 2018, the U.S. Nuclear Regulatory Commission (NRC) staff sent Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) the subject Request for Additional Information (RAI) as a draft (via e-mail shown below). This RAI relates to the relief request proposing an alternative to the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) 2012 Edition, ISTB-3400, for Millstone Power Station, Unit 3 (MPS3) for the 'C' charging pump, 3CHS*P3C. .

On July 31, 2018, the NRC staff conducted a conference call with the licensee staff to clarify the request. Following the discussion, Ms. Wanda Craft indicated that DENC will provide a response to this RAI by August 20, 2018. Updated below is the official (final) RAI. A publicly available version of this e-mail and RAI will be placed in the NRCs ADAMS system. Please contact me should you have any questions in regard to this request.

Thanks, Rich

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Rich Guzman Sr. PM, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-9C07 l Phone: 301-415-1030 From: Guzman, Richard Sent: Monday, July 16, 2018 10:08 AM To: 'Wanda D Craft' <wanda.d.craft@dominionenergy.com>

Subject:

Millstone Unit 3 - DRAFT Request For Additional Information - Alternative Request P-06 'C' Charging Pump

Wanda, By letter dated May 29, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18156A131), Dominion Energy Nuclear Connecticut, Inc. (Dominion, the licensee) submitted a relief request proposing an alternative to the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) 2012 Edition, ISTB-3400, for Millstone Power Station, Unit 3 (MPS3) for the 'C' charging pump, 3CHS*P3C. The Nuclear Regulatory Commission (NRC) staff has determined that additional information is needed to complete its review, as described in the request for additional information (RAI) shown below.

This RAI is identified as draft at this time to confirm your understanding of the information that the NRC staff needs to complete the evaluation. Please contact me if you would like to set up a conference call to clarify this request for information.

Thanks,

~~~~~~~~~

Rich Guzman Sr. PM, Division Operator Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-9C7 l Phone: (301) 415-1030 Richard.Guzman@nrc.gov

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REQUEST FOR ADDITIONAL INFORMATION (RAI)

DOMINION ENERGY NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION, UNIT 3 THIRD AND FOURTH 10-YEAR INTERVAL INSERVICE TESTING PROGRAMS ALTERNATIVE REQUEST P-06 DOCKET NO. 50-423 EPID: L-2018-LLR-0078 By letter dated May 29, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18156A131), Dominion Energy Nuclear Connecticut, Inc. (Dominion, the licensee) submitted a relief request proposing an alternative to the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) 2012 Edition, ISTB-3400, "Frequency of lnservice Tests," for Millstone Power Station, Unit 3 (MPS3) for the 'C' charging pump, 3CHS*P3C. The following requests for additional information (RAIs) outline the information needed to support the completion of the NRC staffs review:

RAI-P-06-1 The letter for proposed alternative request P-06 states, in part:

Realignment of the charging pumps to support required quarterly testing results in pressure, temperature and flow transients on the reactor coolant pump (RCP) seals, which have been identified as contributors to RCP seal degradation. DENC recently identified a shift in the RCP seal differential temperature trend, which is a precursor to seal degradation. The RCP seals remain capable of performing their safety function. RCP seal replacement is planned at the next refueling outage. However, to minimize challenges to the RCP seals and to support continued plant operation, DENC requests expedited review of this proposed alternative by October 18, 2018.

It is the NRC staffs understanding that the new RCP seals will not be degraded by the realignment of the charging pumps. Explain why this alternative request is required for the entire fourth 10-year IST interval instead of until the new RCP seals are installed on all RCPs.

RAI P-06-2 It is stated in the proposed alternative request that, if it becomes necessary to use 3CHS*P3C, a quarterly Group A test will be performed prior to declaring the pump OPERABLE.

ISTB-3300(e)(2) in the 2001 Edition of the ASME OM Code states that, reference values shall be established within +/- 20% of pump design flow for the Group A and Group B tests, if practicable. If not practicable, the reference point flow rate shall be established at the highest practical flow rate. 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. State whether the Group A test is performed at the comprehensive pump test flow rate. If it is not, explain why not and provide the Group A test flow rate and the pump curve for 3CHS*P3C.

RAI P-06-3 It is stated in the proposed alternative request that, when idle, the pump bearings will not be subjected to wear and therefore would not be expected to degrade.

Pump 3CHS*P3C can sit idle for up to two years between comprehensive pump tests if it is not connected to a bus and tested during that two year time period. During that idle time, pump bearings can develop flat spots from inactivity. Describe what maintenance activities will be performed to prevent bearing flat spots from developing.

RAI-P-06-4 It is stated in the alternative request, 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.

Explain how 3CHS*P3C can be aligned during an abnormal or emergency event without the performance of a quarterly test, when it is stated in the alternative request that a quarterly test is required to be performed prior to declaring the pump OPERABLE.

RAI-P-06-5 It is stated in the alternative request:

Additionally, MPS3 TS Bases for entry into the 14-day allowed outage time (TS 3.8.1.1b 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.

TS 3.8.1.1b ACTION states, in part, that all required systems, subsystems, trains, components and devices that depend on the remaining OPERABLE diesel generator as a source of emergency power are OPERABLE Discuss whether or not a Group A test will be performed on 3CHS*P3C prior to it replacing an inservice charging pump, in order to declare it OPERABLE. If not, explain why not.

RAI-P-06-6 In the alternative request, pump 3CHS*P3C is designated as a spare pump. Currently in licensee documents, pump 3CHS*P3C is designated as a swing pump.

Discuss the differences between a swing pump and a spare pump, and any effect on protecting the plant if the pump is changed from a swing pump to a spare pump.

References:

Letter from Gerald T. Bischof of Dominion Energy Nuclear Connecticut, Inc. to NRC, Proposed Alternative Request P-06 for C Charging Pump Test Frequency, dated May 29, 2018 (Agencywide Document Access and Management System (ADAMS) Accession Number ML18156A131).

GDC 35, Emergency core cooling, states that a system to provide abundant emergency core cooling shall be provided. The system safety function shall be to transfer heat from the reactor core following any loss of reactor coolant at a rate such that (1) fuel and clad damage that could interfere with continued effective core cooling is prevented and (2) clad metal-water reaction is limited to negligible amounts. The GDC also requires that suitable redundancy in components and features, and suitable interconnections, leak detection, isolation, and containment capabilities shall be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished, assuming a single failure.

GDC 37, Testing of emergency core cooling system, states that the emergency core cooling system shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leaktight integrity of its components, (2) the operability and performance of the active components of the system, and (3) the operability of the system as a whole and, under conditions as close to design as practical, the performance of the full operational sequence that brings the system into operation, including operation of applicable portions of the protection system, the transfer between normal and emergency power sources, and the operation of the associated cooling water system.