CNL-14-198, Response to NRC Request for Additional Information on the Proposed License Amendment Request to Modify P/T Limits (BFN TS-491)

Response to NRC Request for Additional Information on the Proposed License Amendment Request to Modify P/T Limits (BFN TS-491)

ML14336A691
Person / Time
Site:	Browns Ferry
Issue date:	12/02/2014
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-14-198, TAC MF4303
Download: ML14336A691 (6)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-14-198 December 2, 2014 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 2 Renewed Facility Operating License No. DPR-52 NRC Docket No. 50-260

Subject:

Response to NRC Request for Additional Information on the Proposed License Amendment Request to Modify Browns Ferry Nuclear Plant, Unit 2 P/T Limits (BFN TS-491) (TAC No. MF4303)

References:

1. Letter from TVA to NRC, Browns Ferry Nuclear Plant (BFN), Unit 2 -

Application to Modify Technical Specification 3.4.9, RCS Pressure and Temperature (P/T) Limits (BFN TS-491), dated June 19, 2014 (ADAMS Accession No. ML14175A307)

2. Electronic Mail from NRC to TVA, RAIs Regarding Browns Ferry Nuclear Plant, Unit 2, Pressure Temperature Limits Amendment Docket No.

50-260 (TAC No. MF4303), dated October 23, 2014 (ADAMS Accession No. ML14296A770)

By letter dated June 19, 2014 (Reference 1), the Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) to revise the Browns Ferry Nuclear Plant, Unit 2, Technical Specifications (TS) for Limiting Condition for Operation (LCO) 3.4.9, RCS Pressure and Temperature (P/T) Limits.

By electronic mail dated October 23, 2014 (Reference 2), the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI) to support the review of the LAR. The due date for the response is December 2, 2014. The Enclosure to this letter provides TVAs response to the NRC RAI.

Consistent with the standards set forth in Title 10 of the Code of Federal Regulations (10 CFR), Part 50.92(c), TVA has determined that the additional information, as provided in this letter, does not affect the no significant hazards consideration associated with the proposed application previously provided in Reference 1.

There are no new regulatory commitments contained in this submittal. Please address any questions regarding this submittal to Mr. Edward D. Schrull at (423) 751-3850.

U.S. Nuclear Regulatory Commission Page 2 December 2, 2014 I declare under penalty of perjury that the foregoing is true and correct. Executed on this 2nd day of December 2014.

Enclosure:

Response to NRC Request for Additional Information on the Proposed License Amendment Request for Browns Ferry Nuclear Plant, Unit 2 (TAC No. MF4303) cc (Enclosure):

NRC Regional Administrator- Region II NRC Senior Resident Inspector- Browns Ferry Nuclear Plant State Health Officer, Alabama State Department of Health

ENCLOSURE Response to NRC Request for Additional Information on the Proposed License Amendment Request for Browns Ferry Nuclear Plant, Unit 2 (TAC No. MF4303)

NRC RAI No. 1 Clarify why the modified P/T limits curves required Note 1 of TS SR 3.4.9.1 and associated values to cite >313 psig rather than >312 psig.

TVA Response The change from 312 psig to 313 psig was based on the pre-service hydrotest pressure that was previously stated as 1563 psig, but was later found to be 1565 psig per the BFN Unit 2 Form N-1A Manufacturers Data Report for Nuclear Vessels. The P/T curve notch pressure is defined as 20% of pre-service hydrotest pressure (1565 psig), or 313 psig.

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NRC RAI No. 2 The staff requests that sample calculations for Curves A, B, and C be provided for the 48 Effective Full-Power Year (EFPY) P/T limits curves representing the 313 psig notch in said curves. Specifically clarify the relationship between the notches and the controlling material property from which the notches are derived.

TVA Response The 313 psig notch is a direct result of 10 CFR 50 Appendix G requirements, which are based on the initial Reference Temperature of the Nil-Ductility Transition (RTNDT) of the limiting material in the closure flange region. For BFN Unit 2, the limiting material is the electroslag weld (ESW), which has a chemistry factor of 141 (based upon 0.24% copper and 0.37% nickel) and an initial RTNDT of 23.1°F. Using Table 1 of 10 CFR 50 Appendix G, this results in a minimum temperature requirement as follows:

Curve A (Hydrostatic Pressure Test and Leak Test)

Pressures less than or equal to 20% pre-service hydrotest:

Larger of ASME Limits or highest closure flange region Initial RTNDT + 60°F = 83.1°F Pressures greater than 20% pre-service hydrotest:

Larger of ASME Limits or highest closure flange region Initial RTNDT + 90°F = 113.1°F (notch temperature at 313 psig)

NOTE: Upper vessel / beltline curve becomes limiting at 510 psig for the 48 EFPY curve (using equation (T-RTNDT) = ln [(KI - 33.2)/20.734]/0.02, where T-RTNDT is the Temperature relative to the Reference Temperature and the stress intensity factor (KI) includes a safety factor of 1.5).

Curve B (Core Not Critical)

Pressures less than or equal to 20% pre-service hydrotest:

Larger of ASME Limits (137.8°F) or highest closure flange region Initial RTNDT + 60°F

[83.1°F] = 137.8°F NOTE: Upper vessel / beltline curve becomes limiting at 150 psig for the 48 EFPY curve (using equation (T-RTNDT) = ln [(KI - 33.2)/20.734]/0.02, where KI includes a safety factor of 2.0).

Pressures greater than 20% pre-service hydrotest:

Larger of ASME Limits or highest closure flange region Initial RTNDT + 120°F = 143.1°F (notch temperature at 313 psig)

NOTE: Upper vessel / beltline curve becomes limiting at 330 psig for the 48 EFPY curve (using equation (T-RTNDT) = ln [(KI - 33.2)/20.734]/0.02, where KI includes a safety factor of 2.0).

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Curve C (Core Critical)

Pressures less than or equal to 20% pre-service hydrotest:

ASME limiting values of Curve B + 40°F [177.8°F] or highest closure flange region Initial RTNDT + 60°F [83.1°F] = 177.8°F Pressures greater than 20% pre-service hydrotest:

ASME limiting values of Curve B + 40°F [177.8°F] or highest closure flange region Initial RTNDT + 160°F [183.1°F] or minimum permissible temperature for inservice system hydrostatic pressure test at 1070 psig = 214.6°F NOTE: Notch temperature at 313 psig of 214.6°F for the 48 EFPY curve obtained from Inservice System Pressure Test Rule; Upper vessel / beltline curve becomes limiting at 430 psig.

Summary:

Notch temperature of 113.1°F for Curve A at 313 psig obtained from Initial RTNDT + 90°F Notch temperature of 143.1°F for Curve B at 313 psig obtained from Initial RTNDT + 120°F Notch temperature of 214.6°F for Curve C at 313 psig obtained from Inservice System Pressure Test Rule (Hydrostatic Pressure Test temperature at 1070 psig)

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NRC RAI No. 3 represents a Pressure and Temperature Limits Report (PTLR), including text such as, Changes to the curves, limits, or parameters within this PTLR, based upon new irradiation fluence data of the reactor pressure vessel, or other plant design assumptions in the Updated Final Safety Analysis Report, can be made pursuant to Section 50.59 of Title 10 of Code of Federal Regulations, provided the above methodologies are utilized. The revised PTLR shall be submitted to the NRC upon issuance.

However, the application does not request implementation of a PTLR. Confirm that it is not the intent of the application to implement a PTLR.

TVA Response The PTLR for BFN Unit 2 (Reference 1) was provided to TVA as part of the GE Hitachi Nuclear Energy (GEH) contract deliverables for generation of new BFN, Unit 2, P/T curves.

The subject statement in the GEH PTLR is not applicable to BFN. TVA is requesting the change to BFN Unit 2 Technical Specifications. TVA is not requesting implementation of a PTLR in lieu of a change to the plants Technical Specifications.

Reference:

1. GE Hitachi Nuclear Energy, Tennessee Valley Authority Browns Ferry Nuclear Plant Unit 2 Pressure and Temperature Limits Report (PTLR) up to 38 and 48 Effective Full Power Years, NEDC-33854P, dated April 2014.

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