GNRO-2013/00088, Supplemental Response to Request for Additional Information Regarding 18 to 24 Month Fuel Cycle License Amendment Request (TAC ME9764), Dated May 1, 2013

Supplemental Response to Request for Additional Information Regarding 18 to 24 Month Fuel Cycle License Amendment Request (TAC ME9764), Dated May 1, 2013

ML13323A549
Person / Time
Site:	Grand Gulf
Issue date:	11/12/2013
From:	Kevin Mulligan Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2013/00088, TAC ME9764
Download: ML13323A549 (3)

Text

Entergy Entergy Operations, Inc.

P.O. Box 756 Port Gibson, Mississippi 39150 Kevin J. Mulligan Site Vice President Grand Gulf Nuclear Station Tel: 601-437-7500 GNRO-2013/00088 November 12, 2013 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Supplemental Response to Request for Additional Information Regarding 18 to 24 Month Fuel Cycle License Amendment Request (TAC ME9764),

dated May 1, 2013.

Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29

REFERENCES:

1. License Amendment Request for Implementing a 24-Month Fuel Cycle, GNRO-2012/00096, dated October 2, 2012.

(ADAMS Accession No. ML122770130)

2. Electronic Request for Additional Information Regarding 18 to 24 Month Fuel Cycle License Amendment Request (TAC ME9764),

dated May 1, 2013 (GNRI-2013/00089)

3. Response to Request for Additional Information Regarding 18 to 24 Month Fuel Cycle License Amendment Request (TAC ME9764), GNRO-2013/00038, dated June 4, 2013.

(ADAMS Accession No. ML13162A201)

Dear Sir or Madam:

On November 5, 2013, NRR staff members from the Instrumentation and Controls Branch performed an audit of calculations and procedures necessary for implementation of a 24 month fuel cycle. Items needing clarification were identified by the staff members. Grand Gulf hereby provides the associated responses:

NRR staff members inquired as to why various instrument setpoint and drift calculations do not account for dynamic effects from seismic events with magnitude less than the Operating Basis Earthquake (OBE).

Response

The OBE for Grand Gulf Nuclear Station is defined as a seismic event with peak ground acceleration of 0.075g. Instrument seismic effect errors for seismic events below the

GNRO-2013/00088 Page 2 of 3 OBE threshold do not need to be addressed because the Grand Gulf OBE is very low.

Any additional error due to seismic effects below OBE magnitude would be bounded by the conservatism of the setpoint calculations. For example, use of drift values determined by statistical analysis of historical as-found/as-left calibration data is actually a combination of reference accuracy, M&TE uncertainty, temperature drift, and time drift because there is no deterministic method to separate the individual components.

NRR staff members requested identification of all calculations related to the objectives of Grand Gulf Engineering Standard EN-IC-S-022-G Rev. 0 "Instrument Performance Monitoring and Drift Trending Analysis."

Response

A copy of EN-IC-S-022-G Rev. 0 is provided with this letter as Attachment 5. Setpoint calculations are cross-referenced with their drift calculations on pages 35 through 38.

Additionally, NRR staff members requested that certain calculations be submitted for further review once finalized by the Entergy staff. Those calculations identified during the audit are provided with this letter as Attachments 1 through 4.

This letter contains no new commitments. If you have any questions, please contact Mr.

Christopher Robinson at (601) 437-7326.

Sincerely, KJM/crr Attachments:

(1) JC-Q1P81-90024 Rev 3 "Division III Degraded Bus Voltage Setpoint Calculation" (2) JC-Q1B21-N678-1 Rev 2 "Reactor Steam Dome Pressure Scram Setpoint Calculation" (3) JC-Q1B21-N681-1 Rev 1 "Reactor Pressure Vessel Level One Setpoint Calculation" (4) JC-QIB21-N694-1 Rev 1 "Drywell High Pressure RCIC Isolation Setpoint Calculation" (5) EN-IC-S-022-G Rev 0 "Instrument Performance Monitoring and Drift Trending Analysis" cc: U.S. Nuclear Regulatory Commission ATTN: Mr. Marc Dapas Regional Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511

GNRO-2013/00088 Page 3 of 3 U.S. Nuclear Regulatory Commission ATTN: Mr. Alan Wang, NRR/DORL Mail Stop OWFN/8 B1 Washington, DC 20555-0001 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150