ML14037A149

Request for Additional Information Regarding Maximun Extended Load Line Limit Plus Amendment Request

ML14037A149
Person / Time
Site:	Grand Gulf
Issue date:	02/06/2014
From:	Wang A Division of Operating Reactor Licensing
To:	Seiter J A Entergy Nuclear Operations
References
MF2798
Download: ML14037A149 (3)

Text

1 NRR-PMDAPEm Resource From: Wang, Alan Sent: Thursday, February 06, 2014 8:29 AM To:SEITER, JEFFERY ALAN Cc: Burkhardt, Janet

Subject:

Grand Gulf Nuclear Station Request for Addi tional Information Regarding Maximun Extended Load Line Limit Plus Amendment Request (TAC MF2798)

Jeff, By letter dated September 25, 2013 (Agencywide Document Access and Management System (ADAMS) Accession No. ML13269A140), Entergy Operations Inc. (Entergy, the licensee) submitted a license amendment request (LAR) to allow plant operation in the expanded maximum extended load line limit analysis plus (MELLLA+) domain.

Upon review of Attachment 4 to the submittal ti tled "Safety Analysis Report for Grand Gulf Nuclear Station- Maximum Extended Load Line Limit Analysis Plus" (ADAMS Accession No. ML13269A139), the US Nuclear Regulatory Commission (NRC) staff has determined that the following additional information is needed to complete our review:

1. Section 9.3.3 of Attachment 4 states that zirconium credit will be used in the Shumway correlation. The NRC staff has reviewed the zirconium data described in letter dated September 9, 2013 (ADAMS Accession No. ML13253A105), from GE Hitachi Nuclear Energy and has the following questions

a. Fresh fuel that has little or no oxide at the start of the transient and the fresh fuel is often in the more reactive part of the core; therefore, it is the data of interest. Figure 6 of the September 9, 2013, letter has many data sets provided together on it. Provide a plot showing clean zirconium separate from all the other data including SS, Inconel, zirconium oxide and any data that would be expected to have oxidized zirconium.

b. In the September 9, 2013 letter, much of the Hoffman (FKZ) data that has a rapid cooling rate early in the experiment that may have been incorrectly interpreted as quench. A closer examination of the data shows this initial cooling was due to startup of the test and that quench occurred much later at significantly lower temperatures. In addition, because of high temperatures during the tests and pre-conditioning of the rods, the rods are likely have thick oxide layer thicknesses that are not representative of fuel in a commercial reactor undergoing an Anticipated Transient without Scram with Instability (ATWS-I) event. Provide a plot showing the data considered valid by the licensee for justifying Shumway as implemented in TRACG for the intended application (e.g. ATWS-I under MELLLA+). Textual justification to support the choice of the selected data and exclusion of the other data should be provided focusing on comparing the applicable test conditions to the plant application conditions to support a conclusion that the data is applicable.

2. Section 9.3.3 of Attachment 10 states:

The plant-specific ATWS stability calculation was performed using the NRC-approved neutronic and thermal-hydraulic codes - TRACG04.

2 An error in the code was corrected by letter from GE Hitachi Nuclear Energy to the staff dated October 15, 2013 titled "Updated TRACG Quench Front Model Description and Qualification", which is currently under staff review. In the October 15, 2013 letter, GE noted:

The quench front model has been updated to correct an error in the quench front heat transfer coefficient for bottom reflooding, and to better capture the heat transfer ahead of and behind the quench front.

Please clarify which quench model is being used in the application.

This RAI was discussed with Mr.

Jeff Seiter on February 4 , 201 4, and it was agreed that a response would be provided within 30 days of receipt of this email. 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.

Alan Wang Project Manager (Grand Gulf Nuclear Station)

Nuclear Regulatory Commission Division of Operating Reactor Licensing Alan.Wang@NRC.gov Tel: (301) 415-1445 Fax: (301) 415-1222

Hearing Identifier: NRR_PMDA Email Number: 1069 Mail Envelope Properties (Alan.Wang@nrc.gov20140206082800)

Subject:

Grand Gulf Nuclear Station Request for Additional Information Regarding Maximun Extended Load Line Limit Plus Amendment Request (TAC MF2798) Sent Date: 2/6/2014 8:28:36 AM Received Date: 2/6/2014 8:28:00 AM From: Wang, Alan Created By: Alan.Wang@nrc.gov Recipients: "Burkhardt, Janet" <Janet.Burkhardt@nrc.gov> Tracking Status: None "SEITER, JEFFERY ALAN" <jseiter@entergy.com> Tracking Status: None Post Office: Files Size Date & Time MESSAGE 3888 2/6/2014 8:28:00 AM

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