ML110310390

E-mail, Request for Additional Information, Vessels and Internal Integrity Review, Amendment Request for Extended Power Uprate to Increase the Maximum Reactor Core Power Operating Limit from 3898 to 4408 Mwt

ML110310390
Person / Time
Site:	Grand Gulf
Issue date:	01/31/2011
From:	Wang A Plant Licensing Branch IV
To:	Burford F, Millar D Entergy Operations
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC ME4679
Download: ML110310390 (3)

Text

From:

Wang, Alan Sent:

Monday, January 31, 2011 11:30 AM To:

BURFORD, FRANCIS G; MILLAR, DANA Cc:

BROADBENT, GREGORY E; THORNTON, THOMAS W; DAVANT, GUY H

Subject:

RE: GG EPU Request for Additional Information Related to Vessel and Internals Integrtity (ME4679)

Dana an Jerry, By letter dated September 8, 2010 (Agencywide Documents Access and Management System, Accession No. ML1002660403), Entergy Operations, Inc. (Entergy, the licensee), submitted a request to amend the Facility Operating License No. NPF-29 for Grand Gulf Nuclear Station, Unit 1 (GGNS). The licensee proposed a license amendment request (LAR) for an extended power uprate (EPU) to increase the maximum reactor core power operating limit from 3898 megawatts thermal (MWt) to 4408 MWt.

The U.S. Nuclear Regulatory Commission (NRC) staff has determined that the following additional information is needed for the NRC staff to complete our review of this amendment.

This request for additional information (RAI) was discussed with Mr. Jerry Burford of your staff on January 31, 2011, and it was agreed that a response would be provided within 30 days of receipt of this E-mail. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1445 or via e-mail at Alan.Wang@nrc.gov.

These RAIs have been divided into two areas: (1) Irradiation-Assisted Stress Corrosion Cracking (IASCC) management for reactor internal and core support components and (2)

Pressure Temperature (P-T) limits.

IASCC Management for Reactor Internal and Core Support Components To verify the acceptability of the proposed GGNS IASCC management plan for reactor internal and core support components described in Section 2 of Attachment 5A to GNRO-2010/0056 Safety Analysis Report for Grand Gulf Nuclear Station Constant Pressure Power Uprate, dated September 8, 2010, the NRC staff requests the following information:

(1) The top guide, core shroud, and core plate were identified as potentially susceptible to IASCC at end-of-life. Provide the following details regarding inspection of these components:

Core Plate

a. Are lateral-restraint wedges installed or has an analysis of the hold down bolts been conducted for the GGNS core plate?

b. If an analysis of the hold down bolts has been conducted, provide details of the analysis.

c. If lateral-restraint wedges are installed or an analysis of hold down bolts has been conducted are inspections following BWRVIP-25 BWR Core Plate Inspection and Flaw Evaluation Guideline still planned?

Top Guide

a. Have BWRVIP-26-A BWR Top Guide Inspection and Flaw Evaluation Guidelines inspections conducted to date identified any cracking in top guide grid beams at GGNS?

b. In addition confirm GGNS is following the inspection schedules outline in BWRVIP-183 Top Guide Grid Beam Inspection and Flaw Evaluation Guidelines or describe the inspection program implemented to address multiple top guide grid beam failures.

Core Shroud

a. Note that BWRVIP-76 BWR Core Shroud Inspection and Flaw Evaluation Guidelines has been approved by the NRC as BWRVIP-76-A and should be referenced in the submittal.

b. Provide the current shroud classification and inspection schedule per BWRVIP-76-A.

(2) The GGNS application states that to mitigate the potential for IGSCC and IASCC, GGNS utilizes hydrogen water chemistry (HWC). Reactor vessel water chemistry conditions are also maintained consistent with the EPRI and established industry guidelines.

a. Confirm that GGNS is following the water chemistry guidelines outlined in BWRVIP-130 BWR Water Chemistry Guidelines.

b. Is noble metal chemical addition used in addition to the HWC described in the GGNS application?

P-T Limits To verify that the acceptability of the proposed GGNS Reactor Pressure Vessel (RPV) P-T limits in Attachment 7 to GNRO-2010/00056 Pressure-Temperature Limits Report (PTLR) correctly implement the methodology of NEDC-33178P-A General Electric Methodology for Development of Reactor Pressure Vessel Pressure-Temperate Curves, the NRC staff requests the following information:

(3) Confirm that the proposed PTLR will take effect prior to or concurrent with the proposed EPU, replacing the P-T limits currently in the GGNS Technical Specifications (TS). If the previous statement is correct the NRC staff will not review the P-T limits in the GGNS TS, as only the PTLR is applicable to the EPU.

(4) Do the P-T limit curves provided include a hydrostatic pressure adjustment for the column of water in a full RPV? If so, provide the pressure head used in the P-T limit curve analysis.

(5) Address inconsistencies between the statement that the P-T curves are beltline (A1224-1 plate) limited above 1330 psig for Curve A for 35 EFPY and the NRC staff determination that the P-T curves are beltline (A1224-1 plate) limited above ~1360 psig from data in Table 1 of GNRO-2010/00056.

(6) Provide the surveillance data and the analysis of the surveillance data used to determine ART from reference 6.3 (BWRVIP-135, Revision 1 BWR Vessel and Internals Project Integrated Surveillance Program (ISP) Data Source Book and Plant Evaluations), as required by NEDC-33178P-A.

(7) Provide additional detail for the non-beltline analysis conducted in the following areas in order for the NRC staff to complete independent verification of the proposed P-T limits:

a. Identify limiting materials for the Reference Temperature for Nil Ductility Transition (RTNDT) values used to shift the generic Bottom Head and Upper Vessel P-T curves when applying NEDC-33178P-A.

b. The NRC staff identified a limiting RTNDT of 10 °F for the Bottom Head Torus Plates, while GGNS assumed a RTNDT of 24.6 °F for Bottom Head Curve B.

Support all RTNDT values reported by providing details of any plant-specific analysis conducted.

c. Explain minor differences in assumed RTNDT values for the Bottom Head.

Specifically Curves A and C assume a limiting RTNDT of 19 °F, while Curve B assumes a limiting RTNDT of 24.6 °F.

d. Which region of the RPV is limiting for Curve C < 312 psig?

(8) Attachment 7 identifies nozzle N12 as a beltline water level instrument nozzle and notes that an evaluation was conducted using the limiting material properties for the adjoining shell ring, which appears to be appropriate as nozzle N12 is identified as austenitic.

Provide details of this evaluation which demonstrates that the drill hole for the beltline water level instrument nozzle is not limiting.

(9) Provide details on any plant-specific feedwater nozzle evaluation conducted in support of the proposed P-T limits or explain why plant-specific evaluation was not required.