ML18047A036

2018/02/05 NRR E-mail Capture - Draft Request for Additional Information - Turkey Point 3 and 4 LAR 255 (CAC Nos MG0143 and MG0144; EPID L-2017-LLA-0272)

ML18047A036
Person / Time
Site:	Turkey Point
Issue date:	02/05/2018
From:	Wentzel M J Plant Licensing Branch II
To:	Czaya P F, Mihalakea S Florida Power & Light Co
References
L-2017-LLA-0272, MG0143, MG0144
Download: ML18047A036 (3)

Text

1NRR-DMPSPEm ResourceFrom:Wentzel, MichaelSent:Monday, February 05, 2018 10:17 AMTo:Czaya, Paul; Mihalakea, StavroulaCc:robert.hess@fpl.com; Mack, Jarrett; Hanek, OlgaSubject:Draft Request for Additional Information - Turkey Point 3 and 4 LAR 255 (CAC Nos MG0143 and MG0144; EPID L-2017-LLA-0272)Good morning Paul and Stavy, By application dated August 23, 2017, as supplemented by letter dated October 19, 2017 (Agencywide Documents and Access Management System (ADAMS) Accession Nos. ML17235B008 and ML17292A789, respectively), Florida Power & Light Company (FPL, the licensee) submitted License Amendment Request (LAR) No. 255 for Turkey Point Nuclear Generating Unit Nos. 3 and 4 (Turkey Point). The proposed amendments would revise the Technical Specifications (TSs) to relocate the Explosive Gas Monitoring Instrumentation, Explosive Gas Mixture, and Gas Decay Tanks System requirements to licensee-controlled documents and establish a Gas Decay Tank Explosive Gas and Radioactivity Monitoring Program. The proposed amendments also relocate the Standby Feedwater System requirements to licensee-controlled documents and modify related Auxiliary Feedwater (AFW) System requirements. The U.S. Nuclear Regulatory Commission's (NRC's) Containment and Plant Systems Branch (SCPB) staff reviewed the application and identified areas where it needs additional information to support its review. The draft request for additional information (RAI) is provided below. Please let me know by February 12, 2018, if a clarification call is needed and if the draft RAI contains any proprietary information. If a clarification call is not needed, please let me know if FPL can respond to the RAI by March 7, 2018.

Background

The requirements of Title 10 of the Code of Federal Regulations (10 CFR), Section 50.36, "Technical Specifications," specify that each Operating License issued by the Commission contain TSs that include limiting conditions for operation (LCOs), which are the lowest functional capability or performance levels of equipment required for safe operation of the facility. Section 50.36(c)(2)(ii) of 10 CFR provides the four criteria to define the scope of equipment and parameters to be included in the TS LCOs. Criterion 4 states, "A structure, system, or component which operating experience or probabilistic risk assessment has shown to be significant to public health and safety." NUREG-1431, Volume 2, "Standard Technical Specifications - Westinghouse Plants" identifies LCOs for the following systems as meeting Criterion 4:

• the remote shutdown systems for control room evacuation

• the reactor coolant system loops in Modes 4 and 5 for decay heat removal and boron mixing

• the residual heat removal system for coolant circulation in Mode 6 These systems support essential safety functions such as decay heat removal and reactivity management.

The Turkey Point TSs contain similar requirements for the reactor coolant system loops and the residual heat removal (RHR) system. For example, Turkey Point TS LCO 3.4.1.3, "Reactor Coolant System - Hot Shutdown," identifies five decay heat removal paths consisting of the three reactor coolant loops (i.e., the loop 2piping and the associated steam generator and reactor coolant pump) and the two RHR loops. The LCO specifies that at least two of these decay heat removal paths be operable and one be in operation.

The AFW system at Turkey Point consists of three turbine-driven pumps operated in two trains that are shared between the two units. Since the AFW pumps are all steam-driven and located in a single fire area, they could be susceptible to failure from a single cause.

As described in Section 9.11.2, "Auxiliary Feedwater Pumps," of the Turkey Point Updated Final Safety Analysis Report (UFSAR), the standby steam generator feedwater pumps (SSGFPs) consist of one motor-driven pump and one diesel-engine-driven pump with an integral fuel tank and electric starting system. The SSGFPs are used to supply feedwater to the steam generators during normal start-up, shutdown, and hot standby conditions. In case of loss of offsite power, the normal safety supply of feedwater to the steam generators is provided by the steam turbine-driven AFW pumps. However, feedwater can also be supplied by the diesel engine-driven SSGFP. In addition, the current standby feedwater system TS bases state the following, in part: "The function of the Standby Feedwater System for OPERABILITY determinations is that it can be used as a backup to the Auxiliary Feedwater (AFW) System in the event the AFW System does NOT function properly."

Section 9.3 of the Turkey Point UFSAR describes that the RHR system inlet from the reactor coolant system consists of a single line with two normally closed isolation valves in series. Therefore, a failure of one of the two isolation valves to open would prevent use of either RHR loop as a decay heat removal path.

SCPB RAI 1 As noted in LAR, the standby feedwater system is specifically credited for the AFW decay heat removal function for a fire in the AFW pump area. The system also could support the decay heat removal function above RHR entry conditions and below the reactor coolant system temperature necessary for adequate steam pressure to operate the turbine-driven AFW pumps. Neither the LAR, nor the supplement, provides a discussion of the safety-significance of these particular functions for the Turkey Point. This information is necessary for the staff to evaluate whether this item satisfies Criterion 4 of 10 CFR 50.36(c)(2)(ii). The standby feedwater system pumps could be necessary to support decay heat removal and coolant circulation when the reactor is in Mode 4, relying on the steam generators for decay heat removal, and the steam pressure is insufficient for the turbine-driven AFW pumps. Identify periods, as prescribed by procedures, during normal plant operations (i.e., heatup, startup, shutdown, and cooldown), abnormal operating conditions (e.g., valve failure to operate), and emergency operations where the standby feedwater system pumps would be part of the primary means of adding water to the steam generators for decay heat removal in Mode 4. Describe any Turkey Point-specific operating experience where the standby feedwater pumps were used for decay heat removal when the AFW pumps were not available and/or RHR entry conditions were not satisfied.

SCPB RAI 2 In the LAR supplement dated October 19, 2017, the licensee indicates for internal events and flooding events, a sensitivity analysis was done by increasing the failure probability of the SSGFPs by two orders of magnitude. The licensee further states that this results in the system's contribution to Turkey Point's core damage frequency (CDF) remaining below 1E-6 per year. Clarify whether the safety analysis includes any shutdown modes. Provide a comparison between the standby feedwater system pumps and other safety-related components that support similar decay heat removal functions using standard measures of safety significance.

Hearing Identifier: NRR_DMPS Email Number: 167 Mail Envelope Properties (Michael.Wentzel@nrc.gov20180205101700)

Subject:

Draft Request for Additional Information - Turkey Point 3 and 4 LAR 255 (CAC Nos MG0143 and MG0144; EPID L-2017-LLA-0272) Sent Date: 2/5/2018 10:17:04 AM Received Date: 2/5/2018 10:17:00 AM From: Wentzel, Michael Created By: Michael.Wentzel@nrc.gov Recipients: "robert.hess@fpl.com" <robert.hess@fpl.com> Tracking Status: None "Mack, Jarrett" <Jarrett.Mack@fpl.com> Tracking Status: None "Hanek, Olga" <Olga.Hanek@fpl.com>

Tracking Status: None "Czaya, Paul" <Paul.Czaya@fpl.com> Tracking Status: None "Mihalakea, Stavroula" <Stavroula.Mihalakea@fpl.com> Tracking Status: None Post Office: Files Size Date & Time MESSAGE 6802 2/5/2018 10:17:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received: