ML19081A151

NRR E-mail Capture - Draft Round 2 RAI - Sbdg Voltage and Frequency LAR (L-2018-LLA-0078)

ML19081A151
Person / Time
Site:	South Texas
Issue date:	03/21/2019
From:	Lisa Regner Plant Licensing Branch IV
To:	Brost W, Gonzales R, Richards D South Texas
References
L-2018-LLA-0078
Download: ML19081A151 (3)

Text

NRR-DMPSPEm Resource From: Regner, Lisa Sent: Thursday, March 21, 2019 4:19 PM To: Drew Richards (amrichards@STPEGS.COM); Brost, Wendy (webrost@STPEGS.COM);

Gonzales, Rafael Cc: Regner, Lisa

Subject:

DRAFT Round 2 RAI - SBDG Voltage and Frequency LAR (L-2018-LLA-0078)

Attachments: Rnd 2 RAI draft to licensee.docx

Drew, Attached is the DRAFT Round 2 RAI. Please let me know if this is clear.

I will add to ADAMS and let you know the ML no. when I get it.

Thanks, Lisa Lisa M. Regner Senior Project Manager Branch 4, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission OWFN 9E01

' 301-415-1906 Lisa.Regner@nrc.gov 1

Hearing Identifier: NRR_DMPS Email Number: 878 Mail Envelope Properties (BN6PR09MB149127E0F8D5EA02448E7998E5420)

Subject:

DRAFT Round 2 RAI - SBDG Voltage and Frequency LAR (L-2018-LLA-0078)

Sent Date: 3/21/2019 4:18:30 PM Received Date: 3/21/2019 4:18:31 PM From: Regner, Lisa Created By: Lisa.Regner@nrc.gov Recipients:

"Regner, Lisa" <Lisa.Regner@nrc.gov>

Tracking Status: None "Drew Richards (amrichards@STPEGS.COM)" <amrichards@STPEGS.COM>

Tracking Status: None "Brost, Wendy (webrost@STPEGS.COM)" <webrost@STPEGS.COM>

Tracking Status: None "Gonzales, Rafael" <rjgonzales@STPEGS.COM>

Tracking Status: None Post Office: BN6PR09MB1491.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 431 3/21/2019 4:18:31 PM Rnd 2 RAI draft to licensee.docx 21460 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATON FOR SOUTH TEXAS PROJECT NUCLEAR OPERATING COMPANY, UNITS 1 & 2, REVISE CERTAIN MINIMUM VOLTAGE AND FREQUENCY ACCEPTANCE CRITERIA FOR DIESEL GENERATOR SURVELLANCE REQUIREMENTS DOCKET NOS. 50-498 AND 50-499 (EPID L-2018-LLA-0078)

Follow-up STSB 1-1 In a March 27, 2018, license amendment request (LAR) (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18086B761), South Texas Project Nuclear Operating Company (STPNOC) proposed to modify the current Surveillance Requirement (SR) for Technical Specification (TS) 3/4.8.1 A.C. Sources to address a non-conservative TS. This non-conservatism was due to the difference between the required voltage and frequency band for the standby diesel generator (SBDG) and the assumptions in the transient model calculation supporting the sites design basis accident analyses. Thus, STPNOC proposed to change the steady-state voltage acceptance criteria to correct the non-conservatism.

As part of the LAR, STPNOC proposed a separate surveillance requirement [SR 4.8.1.1.2.a.5)]

to be performed on a less frequent basis, that is, every 6 months* using a new voltage and frequency bands calculated to ensure the SBDG would fulfill its specified function during design basis accidents. The licensee retained the existing monthly* surveillance requirement [SR 4.8.1.1.2.a.2)] without the new voltage and frequency band and retaining the existing / wider voltage and frequency band.

By letter dated December 6, 2018 (ADAMS Accession No. ML18340A206), the licensee responded to a NRC staff request for additional information, in which the NRC staff requested the licensee to explain how the SRs for the SBDGs would demonstrate that 10 CFR 50.36(c)(3)

Surveillance requirements, would be satisfied for South Texas Project, Units 1 and 2 (STP).

The licensee responded that only the steady-state voltage and frequency bands were determined to be non-conservative, more specifically, only the semi-annual SR acceptance criteria were non-conservative. The licensee also stated that the STP procedure for the non-steady-state, or monthly, SR does not require measurement of steady-state voltage and frequency.

The NRC staff reviewed the licensees response, but it did not provide sufficient information to allow the NRC staff to make an adequacy determination that the proposed STP technical specification (TS) changes comply with 10 CFR 50.36(c)(3).

As stated in STP SR 4.8.1.1.2, [e]ach standby diesel generator shall be demonstrated OPERABLE. In STP TS 1.20, it states [a] system, subsystem, train, component or device shall be OPERABLE or have OPERABLITY when it is capable of performing its specified function(s)

Explain how performance of the monthly SR 4.8.1.1.2.a.2 to a voltage and frequency band less restrictive than that assumed in the sites design basis accident analyses may be used to demonstrate continued operability of the DG.

• Or in accordance with the surveillance frequency control program