ML112790460

Email, Request for Additional Information, Nrr/Dci/Emcb Review, Round 4, Amendment Request for Extended Power Uprate to Increase the Maximum Reactor Core Power Operating Limit from 3898 to 4408 Mwt

ML112790460
Person / Time
Site:	Grand Gulf
Issue date:	10/06/2011
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: ML112790460 (2)

Text

From:

Wang, Alan Sent:

Thursday, October 06, 2011 2:18 PM To:

'BURFORD, FRANCIS G'; 'MILLAR, DANA' Cc:

Lent, Susan; Burkhardt, Janet

Subject:

RE: Grand Gulf Extended Power Uprate Mechanical and Civil Engineering Branch Request for Information (ME4679)

Dana and 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 October 6, 2011, and it was agreed that a response would be provided within 7 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.

The following are additional RAIs related to the EPU LAR:

RAI 1

Page 2-266 of the power uprate safety analysis report (PUSAR), which was submitted as part of Reference 1 in support of the proposed extended power uprate (EPU) at the Grand Gulf Nuclear Station, Unit 1 (GGNS), states that the GGNS annulus pressurization (AP) loads were reconciled for original licensed thermal power (OLTP), current licensed thermal power (CLTP) and EPU conditions, in response to General Electric-Hitachi (GEH) Safety Communication (SC) 09-01. Additionally, page 2-266 of the PUSAR states that evaluations were performed to determine the effect of revising the AP loads on the dynamic structural response of the reactor pressure vessel (RPV), reactor internals, piping and containment structures. With respect to the impact of the revision of the aforementioned AP loads on the EPU evaluations, please address the following:

a) Page 2-269 of the PUSAR indicates that the jet impingement (JI) and jet reaction (JR) loads on the RPV and the bioshield wall (BSW) were recalculated to address the issues identified in GEH SC 09-01. Section 2.2.1.2.3 of the PUSAR states that the dynamic effects loadings at EPU conditions, resulting from existing postulated HELBs in the aforementioned affected piping, are bounded by the current licensing basis. Please confirm that the conclusion reached in Section 2.2.1.2.3 of the PUSAR extends to the evaluations performed in Section 2.6.2 of the PUSAR, i.e., confirm that the dynamic effects loads calculated for the RPV and BSW, using the revised AP loads, remain bounded by those used in the current licensing basis requirements related to the protection of SSCs important to safety from dynamic effects loadings.

RAI 2

Section 2.2.2.1.3 of the PUSAR states that safety-related thermowells and probes in the main steam (MS) and feedwater (FW) systems were evaluated in support of EPU implementation to demonstrate that failure of these components due to flow-induced vibration (FIV) will not occur at EPU conditions. Page 2-47 of the PUSAR provides the results of the evaluations demonstrating that the MS, FW and reactor recirculation system (RRS) thermowells are structurally adequate at EPU conditions. Please provide a quantitative summary of the results of the evaluations performed for the safety-related probes. This summary should identify the safety-related probes evaluated and the corresponding stresses and stress limits resulting from the analyses performed for each probe. Additionally, please confirm that the lock-in condition, associated with the synchronization of vortex shedding frequency associated with the MS and FW flows, does not occur for any safety-related thermowell or probe at EPU conditions.

References

1)

Letter from M. A. Krupa, Entergy Operations, Inc., to NRC Document Control Desk, License Amendment Request - Extended Power Uprate - Grand Gulf Nuclear Station, Unit 1 - Docket No. 50-416 - License No. NPF-29, dated September 8, 2010. (ADAMS Accession No.: ML102660403)

Alan Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation