ML15033A002
| ML15033A002 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/30/2015 |
| From: | Bhalchandra Vaidya Plant Licensing Branch 1 |
| To: | David Gudger, Kristensen K, Reynolds R Exelon Generation Co, Nine Mile Point |
| Vaidya B, NRR/DORL/LPL1-1, 415-3308 | |
| References | |
| TAC MF3056 | |
| Download: ML15033A002 (2) | |
Text
From:
Vaidya, Bhalchandra Sent:
Friday, January 30, 2015 3:13 PM To:
Reynolds, Ronnie J.:(GenCo-Nuc)
(Ronnie.Reynolds@exeloncorp.com); Kristensen, Kenneth J:(NMP)
(kenneth.kristensen@exeloncorp.com);
David.Gudger@exeloncorp.com Cc:
Beasley, Benjamin; Jackson, Christopher; Hardgrove, Matthew; Thomas, George; Guzzetta, Ashley
Subject:
Nine Mile Unit 2, MF3056, LAR - MELLLA+, REVISED RAI - Neutron Fluence Calculation Related Ron, Ken, and David,
Subject:
Nine Mile Unit 2, MF3056, LAR - MELLLA+, REVISED RAI - Neutron Fluence Calculation Related By letter dated November 1, 2013 (Agencywide Document Access and Management System (ADAMS) Package Accession No. ML13316B090), as supplemented by letters dated January 21, 2014 (ADAMS Accession No. ML14023A654), February 14, 2014 (ADAMS Package Accession No. ML14051A155), February 25, 2014 (ADAMS Accession No. ML14064A321), March 10, 2014 (ADAMS Accession No. ML14071A466), May 14, 2014 (ADAMS Accession No. ML14139A416), June 13, 2014 (ADAMS Accession No ML14169A034),
and September 15, 2014, Nine Mile Point Nuclear Station, LLC (the licensee) submitted a license amendment request for Nine Mile Point Nuclear Station, Unit 2. The proposed amendment would allow (1) operation in the expanded maximum extended load line limit analysis plus (MELLLA+) domain; (2) use of the Detect and Suppress Solution-Confirmation Density, DSS-CD stability solution; (3) use of the TRACG04 analysis code; (4) increase the isotopic enrichment of boron-1 0 in the sodium pentaborate solution used to prepare the neutron absorber solution in the Standby Liquid Control System (SLS); and (5) increase the Safety Limit Minimum Critical Power Ratio (SLMCPR) for two recirculation loops in operation.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in your submissions and has determined that additional information is needed to complete its review.
This email provides the Revised Request for Additional Information (RAI) subsequent to a clarification telephone discussion between the NRC staff and your staff on January 29, 2015, on the RAI that was previously sent to you by email dated January 26, 2015.
The revised RAI is provided below.
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REQUEST FOR ADDITIONAL INFORMATION NINE MILE POINT NUCLEAR STATION UNIT 2 LICENSE AMENDMENT REQUEST PURSUANT TO 10 CFR 50.90:
MAXIMUM EXTENDED LOAD LINE LIMIT ANALYSIS PLUS NINE MILE POINT NUCLEAR STATION, LLC DOCKET NO. 50-410 TAC NO. MF3056 By letter dated November 1, 2013, Nine Mile Point Nuclear Station, LLC (NMPNS, the licensee),
submitted a license amendment request for Nine Mile Point Nuclear Station, Unit 2 (NMP2) for Maximum
Extended Load Line Limit Analysis Plus (MELLLA+) (Agencywide Document Access and Management System (ADAMS) Accession Numbers ML13316B107).
Based on its review of the amendment request, the Reactor Systems Branch (SRXB) has determined that additional information is required regarding the neutron fluence calculation.
SRXB - Fluence - RAI 1 By application dated November 21, 2012, NMPNS requested changes to the facility Technical Specifications as necessary to implement a Pressure Temperature Limits Report (PTLR) using a plant-specific method performed by MPM Technologies, Inc. (MPM). This application was approved by the NRC staff in its safety evaluation, Nine Mile Point Nuclear Station, Unit No. 2 - Issuance of Amendment Regarding Relocation of Pressure and Temperature Limit Curves to the Pressure and Temperature Limits Report, dated May 29, 2014 (ML14057A554).
Fluence is identified in the MELLLA+ topical report as an item to be dispositioned. NEDC-33576NP, Safety Analysis Report for Nine Mile Point Unit 2 Maximum Extended Load Line Limit Analysis Plus (ML13316B109) attached with the application states that MELLLA+ flux is calculated using the GEH flux evaluation methodology contained in NEDO-32983-A, Revision 2, General Electric Methodology for Reactor Pressure Vessel Fast Neutron Flux Evaluations, (ML072480121).
A clarification call on Tuesday, December 16, 2014, took place to discuss the NMP2 MELLLA+ GEH method for fluence evaluation. The licensee stated, in part, that the PTLR approved by the NRC staff uses the MPM plant-specific calculation and that the fluence evaluation for MELLLA+ conditions was performed using the GEH method contained in NEDO-32983-A, Revision 2. The final outcome of this call was for the licensee to submit the neutron fluence calculation notes and data for MELLLA+ conditions for audit.
The NRC staff audited the provided material from the licensee for neutron fluence calculations using the GEH method. While auditing the provided calculations, the NRC staff observed that the fluence estimation and flux/fluence data documented in the plant-specific MPM method are used as the basis for all pre-EPU cycles. The NRC staff also observed that the fluence estimation is based on a combination of (1) End-of-Cycle (EOC) 10 fluence at 14.08 Effective Full Power Years (EFPY) documented in the plant-specific MPM method, (2) Cycle 10 flux derived from 22-EFPY fluence and EOC 10 fluence in the plant-specific MPM method, and (3) M+ flux calculated in this task.
The combination of multiple fluence methods is not in accordance with Regulatory Guide (RG) 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence. Nor is it, in the staffs view, accordant with NEDO-32983-A, Revision 2, since the NEDO document is limited only to GEHs calculational approach, and it does not provide for fluence inputs from other methods.
Furthermore, the NRC did not identify any information in the M+SAR justifying the combination of multiple fluence methods.
The NRC staff requests the licensee to provide a RG 1.190 compliant disposition of fluence calculations that is in accordance with the MELLLA+ topical report. Alternatively, provide a comparison of EPU flux and MELLLA+ flux to show that the effects of MELLLA+ operation are appropriately addressed. Provide information to show that (1) the comparative flux evaluation is conservative relative to recent plant operation, (2) the comparative flux evaluation is based on RG 1.190-adherent transport methods, and (3) the comparative flux evaluation accounts for the increased coolant void conditions associated with MELLLA+ operation.
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Subsequent to the clarification discussion mentioned above, Ken Kristensen of your staff in communicated to us the licensees firm commitment to provide the response to this RAI by February 20, 2015.
Please contact me, if you have any questions.
Thanks, Bhalchandra K. Vaidya Licensing Project Manager NRC/NRR/DORL/LPL1-1 (301)-415-3308 (O) bhalchandra.vaidya@nrc.gov