ML14183B705

NRR E-mail Capture - Grand Gulf Nuclear Station Maximum Extended Load Line Limit Plus Amendment (MF2798)

ML14183B705
Person / Time
Site:	Grand Gulf
Issue date:	07/02/2014
From:	Wang A Division of Operating Reactor Licensing
To:	Scarbrough R Entergy Nuclear Operations
References
MF2798
Download: ML14183B705 (4)

Text

NRR-PMDAPEm Resource From: Wang, Alan Sent: Wednesday, July 02, 2014 2:20 PM To: 'SCARBROUGH, RICHARD A (RSCARBR@entergy.com)'

Cc: Burkhardt, Janet

Subject:

Grand Gulf Nuclear Station Maximum Extended Load Line LImit Plus Amendment (MF2798)

Richard:

by letter dated September 25, 2013 (Agencywide Document Access and Management System (ADAMS)

Accession No. ML13269A140), Entergy (the licensee) submitted a License Amendment Request (LAR) for Maximum Extended Load Line Limit Analysis plus (MELLLA+) for Grand Gulf Nuclear Station (GGNS). The proposed amendment request would allow operation in the expanded MELLLA+ domain.

Upon review of the Attachment 4 to the LAR titled 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 the review:

RAI-1

Reference 2, Table 4-1 indicates the wetwell airspace volume in the proposed analysis is increased by13,192 ft3 (149,978 ft3 minus 136,786 ft3) from the current analysis. Please provide the following information:

(a) Is the change in wetwell air space volume correction of an error?

(b) In case the change is not correction of an error, please describe the changes in the containment configuration that provides additional air space volume in the wetwell.

RAI-2

The proposed revised wetwell airspace volume (as a part of the overall wetwell volume) is an input parameter to the following analyses:

(a) Long term containment pressure and temperature response, (b) Long term suppression pool temperature response for net positive suction head (NPSH), and (c) NPSH analysis for residual heat removal (RHR) and core spray (CS) pumps which is impacted by (b). Please describe the impact of the increase in the wetwell air space volume on these analyses, and provide results.

RAI-3

Assuming the overall containment volume is the same as in the current analysis; the proposed increase in the wetwell air space volume by 13,192 ft3 should result in one or both of the following:

(a) Decrease in the suppression pool volume by 13,192 ft3 or less, which would impact its heights at low and high level and vent submergence.

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(b) Decrease in the containment volume above hydraulic control unit (HCU) floor level by 13,192 ft3 or less.

Please describe the impact of the changes in above parameters on the containment analyses which use them as inputs, and provide results.

In case the overall containment volume has increased, please provide reasons and its impact on the analyses which uses it as input and provide results.

RAI-4

It appears that the current short term containment pressure and temperature response are impacted by (i) revised M&E release under MELLLA+ operation, and (ii) the increase in the wetwell air space volume which is not related with MELLLA+ operation.

(a) What are the parameters other than (i) and (ii) that have impacted the short term containment pressure and temperature response?

(b) Provide containment pressure and temperature response results (peak values and profiles) assuming revised M&E release under MELLLA+

operation and with all other assumptions and input parameters including wetwell air space volume same as in AOR.

RAI-5

Reference 2, Section 3.9.3 states:

Consequently, suppression pool suction is more limiting for RCIC NPSH. GGNS calculations demonstrate that the RCIC pump would have adequate NPSH and low suction pressure trip margins given a suppression pool water temperature of 140°F.

(a) What is the RCIC pump NPSH margin when the suppression pool temperature is 140°F?

(b) What happens when the RCIC pump trips on a low suction pressure or inadequate NPSH margin, i.e., is the pump allowed to trip or suction is transferred to a different source before the suction pressure reaches the trip setpoint?

RAI-6

Refer to Reference 2, Section 4.1.2, since the increase in the wetwell air space volume is not MELLLA+ related, please provide the following information (a) Section 4.1.2.1; does the LOCA loads remain bounding under MELLLA+ operation without the change in the wetwell air space volume?

(b) Section 4.1.2.4; does the SRV containment dynamic loads remain bounding under MELLLA+ operation without the change in the wetwell air space volume?

This request was discussed with Mr. Richard Scarbrough of your staff on July 2, 2014, and it was agreed that a response would be provided within 45 days from the issuance 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.

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Alan B. Wang Project Manager (Grand Gulf Nuclear Station)

Nuclear Regulatory Commission Division of Operating Reactor Licensing 3

Hearing Identifier: NRR_PMDA Email Number: 1411 Mail Envelope Properties (C0A338EE37A11447B136119705BF9A3F02108CE2C158)

Subject:

Grand Gulf Nuclear Station Maximum Extended Load Line LImit Plus Amendment (MF2798)

Sent Date: 7/2/2014 2:19:39 PM Received Date: 7/2/2014 2:19:00 PM From: Wang, Alan Created By: Alan.Wang@nrc.gov Recipients:

"Burkhardt, Janet" <Janet.Burkhardt@nrc.gov>

Tracking Status: None

"'SCARBROUGH, RICHARD A (RSCARBR@entergy.com)'" <RSCARBR@entergy.com>

Tracking Status: None Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 4948 7/2/2014 2:19:00 PM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: