RA-22-0245, Response to Request for Additional Information (RAI) Regarding Removal of 4.160 Kilovolt Bus 2 from Surveillance Requirement 3.8.1.16

Response to Request for Additional Information (RAI) Regarding Removal of 4.160 Kilovolt Bus 2 from Surveillance Requirement 3.8.1.16

ML22251A117
Person / Time
Site:	Robinson
Issue date:	09/08/2022
From:	Flippin N Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-22-0245
Download: ML22251A117 (5)

Text

Nicole L. Flippin H. B. Robinson Steam Electric Plant Unit 2 Site Vice President Duke Energy 3581 West Entrance Road Hartsville, SC 29550 O: 843 951 1701 F: 843 951 1319 Nicole.Flippin@duke-energy.com Serial: RA-22-0245 10 CFR 50.90 September 8, 2022 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23

SUBJECT:

Response to Request for Additional Information (RAI) Regarding Removal of 4.160 kilovolt Bus 2 from Surveillance Requirement 3.8.1.16

REFERENCES:

1. Duke Energy letter, Remove 4.160 kilovolt Bus 2 from Surveillance Requirement 3.8.1.16 (Automatic Transfer Capability from Unit Auxiliary Transformer to Startup Transformer), dated April 28, 2022 (ADAMS Accession No. ML22118A367)

2. NRC letter, Request for Additional Information Regarding Duke's Request to Remove 4.160 kV Bus 2 from Surveillance Requirement 3.8.1.16 (EPID L-2022-LLA-0064), dated August 10, 2022 (ADAMS Accession No. ML2222A108)

Ladies and Gentlemen:

In Reference 1, Duke Energy Progress, LLC (Duke Energy) submitted a license amendment request (LAR) to the Technical Specifications (TS) for H. B. Robinson Steam Electric Plant (RNP), Unit No. 2. The proposed amendment would revise a Surveillance Requirement (SR) for TS 3.8.1, AC Sources - Operating. Specifically, SR 3.8.1.16 would be revised to remove 4.160 kilovolt (kV) bus 2 from the requirement to verify automatic transfer capability from the unit auxiliary transformer to a startup transformer. In Reference 2, the Nuclear Regulatory Commission (NRC) staff requested additional information regarding Reference 1.

The Enclosure provides Duke Energys response to the Reference 2 RAI. The conclusions of the No Significant Hazards Consideration and Environmental Consideration in the original LAR are unaffected by this RAI response.

This submittal contains no new regulatory commitments.

Duke Energy is notifying the state of South Carolina by transmitting a copy of this letter to the state official.

Should you have any questions concerning this letter, or require additional information, please contact Ryan Treadway, Manager - Nuclear Fleet Licensing, at 980-373-5873.

U.S. Nuclear Regulatory Commission RA-22-0245 Page 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed on September 8, 2022.

Sincerely, vV\j~ i. ~~)pwiv Nicole L. Flippin Site Vice President

Enclosure:

Response to Request for Additional Information cc: (all with Enclosure)

L. Dudes, Regional Administrator USNRC Region II J. Zeiler, NRC Senior Resident Inspector T. Hood, NRR Project Manager L. Haeg, NRR Project Manager A. Wilson, Attorney General (SC)

A. Nair, Director, Division of Environmental Response (SC)

L. Garner, Manager, Radioactive and Infectious Waste Management Section (SC)

Enclosure RA-22-0245 Enclosure Response to Request for Additional Information

Enclosure RA-22-0245 Page 1 of 2 NRC RAI INTRODUCTION By letter dated April 28, 2022, (Agency wide Document Access Management System (ADAMS)

Accession No. ML22118A367), Duke Energy Progress, LLC (the licensee), requested an amendment to Facility Operating License No. DPR-23 for the H. B. Robinson Steam Electric Plant, Unit No. 2 (Robinson). The proposed amendment would revise Surveillance Requirement (SR) 3.8.1.16 for Technical Specification (TS) 3.8.1, AC Sources - Operating to remove 4.160 kilovolt (kV) bus 2 from the requirement to verify automatic transfer capability from the unit auxiliary transformer (UAT) to a startup transformer (SUT).

The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee. The staff finds that the following additional information is required to complete the review of the license amendment request (LAR).

REGULATORY BASIS Title 10 of the Code of Federal Regulations (10 CFR) 50.36, Technical Specifications, requires, in part, that the TS shall be included by applicants for a license authorizing operation of a production or utilization facility. 10 CFR 50.36(c) requires, in part, that Technical Specifications include items in the following categories: (1) Safety limits, limiting safety system settings, and limiting control settings, (2) Limiting conditions for operation (3) Surveillance requirements [SRs], (4) Design features, and (5) Administrative controls. The proposed LAR involves changes under the SR category.

ISSUE Section 2.1, System Design and Operation of the LAR stated, in part:

The 480 V Emergency bus 1 is normally powered from the 115 kV switchyard through the dedicated 115 kV SUT, 4.160 kV bus 6 and station service transformer (SST) 2FThe 4.160 kV buses 1, 2, 4 and 5 are normally powered from the main generator via the UAT Section 2.3, Reason for the Proposed Change of the LAR stated, in part:

The current SR 3.8.1.16 requires automatic transfer capability of both the 4.160 kV bus 2 and 480 V Emergency bus 1 from the UAT to a SUT. However, normal electrical lineups exist such that 480 V Emergency bus 1 is already aligned to a SUT when 4.160 kV bus 2 is not. In this configuration, if equipment is taken out of service for maintenance that removes automatic transfer capability of 4.160 kV bus 2, the current SR 3.8.1.16 would not be met.

The NRC staff understands that based on the above statements in Section 2.3 of the LAR, additional normal electrical lineups exist in addition to the normal lineup described in Section 2.1 of the LAR. These additional normal electrical alignments were not described in the LAR, Robinsons Updated Final Safety Analysis Report (UFSAR, ADAMS Accession No. ML21147A414), or Robinsons TS Bases.

Enclosure RA-22-0245 Page 2 of 2 INFORMATION REQUESTED Describe any/all additional normal electrical lineups that exist besides the lineup described in Section 2.1 of the LAR, preferably supported by markups (highlights) of these lineups on the one-line electrical diagram in Robinsons UFSAR, Figure 8.1.2-1A (post-Robinson License Amendment No. 261), in which the current SR 3.8.1.16 would not be met if certain equipment is taken out of service. Also, explain how the proposed revised SR 3.8.1.16 would be met in these additional normal electrical lineups.

Duke Energy Response to NRC RAI There are no additional normal (i.e. 100% reactor power, no equipment out of service, offsite power provided via both SUTs, no diesel generator testing being performed) electrical lineups that exist besides the lineup described in the RAI citation of Section 2.1 of the LAR. Section 2.3 of the LAR intended to recognize that there are additional non-normal (but allowed by procedure) electrical lineups such that 480 V Emergency bus 1 is already aligned to a SUT when 4.160 kV bus 2 is not. As with the normal electrical lineup, these non-normal electrical lineups would not be required to meet the proposed SR 3.8.1.16, per the proposed SR 3.8.1.16 Note 2: SR 3.8.1.16 is not required to be met if the 480 V Emergency bus 1 power supply is from a start up transformer. This is acceptable because the automatic transfer capability function that is being verified by SR 3.8.1.16 has been satisfied in this condition.