ML112800214

Email, Request for Additional Information, Nrr/Dss/Srxb, Long-Term Stability Option, Amendment Request for Extended Power Uprate to Increase the Maximum Reactor Core Power Operating Limit from 3898 to 4408 Mwt

ML112800214
Person / Time
Site:	Grand Gulf
Issue date:	10/07/2011
From:	Wang A Plant Licensing Branch IV
To:	Burford F, Millar D Entergy Operations
Wang A, NRR/DORL/LPL4, 301-415-1445
References
TAC ME4679
Download: ML112800214 (2)

Text

From:

Wang, Alan Sent:

Friday, October 07, 2011 10:50 AM To:

BURFORD, FRANCIS G; MILLAR, DANA Cc:

Lent, Susan; Burkhardt, Janet

Subject:

Grand Gulf Extended Power Uprate Audit Regarding the Implementation of the Long Term Stability Option (ME4679)

Jerry and Dana, By letter dated September 8, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML1002660403), Entergy Operations, Inc. (Entergy, the licensee),

proposed an amendment to increase the maximum reactor power operating limit authorized in the Operating License from 3,898 MWt to 4,408 MWt for the Grand Gulf Nuclear Station, Unit 1 (GGNS). In support of the proposed extended power uprate (EPU) amendment, Entergy will implement a new Long Term (L/T) Stability Option. The U.S. Nuclear Regulatory Commission (NRC) staff has requested an audit to: (1) determine and understand the status of the GGNS L/

T Stability Option implementation, and (2) review the implementation of the anticipated transients without scram (ATWS) emergency operating procedures (EOPs), including the ATWS/Stability mitigation actions, as it relates to the EPU upgrade. The NRC expects that the audit would only take one day and proposed that the audit be held on either October 26, 27 or 28, 2011. This was discussed with Mr. Jerry Burford of your staff and he noted he needed to confirm with the plant the availability of the simulator and training crews for those dates.

The NRC proposes that Entergy provide a presentation of these issues (cover list of items) in the morning and have a hardware demonstration (control room, testing lab, plant simulator )

in the afternoon, if appropriate. The NRC staff proposes to cover the following items during the GGNS audit.

Questions related to Implementation of L/T Stability Solutions:

1. Describe the process followed by GGNS to implement L/T Solutions

2. Where is GGNS today in the implementation schedule and what is its implementation status?

3. Describe the GGNS Technical Specifications (TSs) affected by the L/T Solution implementation

4. What is the GGNS experience with the PBDA? Noise, false positives ect

5. Describe the acceptance testing process. Include a description of PBDA results where false alarms were detected

6. What are the TS operability requirements?

7. Describe the backup stability implementation (e.g. ICA) in GGNS for EPU as well as MELLLA+, if known.

8. Describe any Solution-III hardware implementation issues such as: location of the new hardware, periodic testing procedures, cable ringing for verification. Describe any future implications with MELLLA+

9. Describe the implications for operator training. How are false alarms handled?

Questions related to ATWS, ATWS/Stability, and EOPs:

1. Provide a short summary of the EOPs that apply during ATWS (e.g. level control).

2. Provide plant specific information related to ATWS performance. Specifically: (1) location of boron injection (stand pipe or core spray) (2) turbine bypass valve capacity, (3) percent of steam/motor-driven feedwater pumps, (4) location of extraction steam for feedwater heaters and pumps, and availability of steam after a turbine trip, (5) Standby Liquid Control (SLC) injection time, (6) how many SLC pumps are required per TS.

3. Describe how are the ATWS/Stability Mitigation Actions implemented in GGNS EOPs

4. Past ATWS analysis have shown that the suppression pool may reach high temperatures during ATWS. What is the effect on plant equipment (e.g. net positive suction head (NPSH))?

5. Describe the effects, if any, of the EPU upgrade on ATWS and EOPs.

6. Please, provide an ATWS demonstration in the plant simulator. Provide special emphasis on:

a. Mitigation of instabilities during ATWS. For this purpose, set up a turbine trip with bypass available ATWS from EPU conditions. The operator will need to reduce water level and insert SLC and/or alternate rods to terminate the event

b. Effect of EPU. Provide a comparison of two MSIV isolation ATWS scenarios starting from (1) pre-EPU power and (2) EPU power.

c. If the simulator can handle it, provide a MSIV isolation ATWS from MELLLA+ (full EPU power and reduced core flow) conditions.