ML13310A817

MF2462, Draft Rais, MF2462, LAR Standby Liquid Control System - Increase in Isotopic Enrichment of Boron-10

ML13310A817
Person / Time
Site:	Nine Mile Point
Issue date:	11/06/2013
From:	Bhalchandra Vaidya Plant Licensing Branch 1
To:	Darling T, Kristensen K, Perkins E Constellation Energy Nuclear Group, Nine Mile Point
Vaidya B, NRR/DORL/LPL1-1, 415-33-8
References
TAC MF2462
Download: ML13310A817 (2)

Text

From:

Vaidya, Bhalchandra Sent:

Wednesday, November 06, 2013 12:52 PM To:

'Darling, Theresa H'; 'Kristensen, Kenneth J';

everett.perkins@cengllc.com Cc:

Huang, Tai; Jackson, Christopher; Beall, Robert; Elliott, Robert; Panicker, Mathew; Bucholtz, Kristy; Dean, Jeremy

Subject:

DRAFT RAIS, MF2462, LAR Re: STANDBY LIQUID CONTROL SYSTEM -

INCREASE IN ISOTOPIC ENRICHMENT OF BORON-10

SUBJECT:

NINE MILE POINT NUCLEAR STATION, UNIT NO. 2; DOCKET NO. 50-410, LICENSE AMENDMENT REQUEST PURSUANT TO 10 CFR 50.90: STANDBY LIQUID CONTROL SYSTEM -

INCREASE IN ISOTOPIC ENRICHMENT OF BORON-10 (TAC NO. MF2462)

By letter dated July 5, 2013, (ADAMS Accession No. ML13197A221) Nine Mile Point Nuclear Station, LLC (NMPNS) submitted a license amendment request (LAR) for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2). The proposed amendment would increase the isotopic enrichment of boron-10 in the sodium pentaborate solution used to prepare the neutron absorber solution in the Standby Liquid Control (SLC) System. This request includes the supporting changes to the NMP2 Technical Specification (TS) 3.1.7, "Standby Liquid Control (SLC) System," to increase the boron-10 isotopic enrichment in the sodium pentaborate solution utilized in the SLC System and to decrease the SLC System tank volume.

The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in your LAR and has determined that additional information is needed to complete its review. The NRC staffs DRAFT request for additional information (RAI) is provided below.

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DRAFT REQUEST FOR ADDITIONAL INFORMATION RELATING TO LICENSE AMENDMENT REQUEST REGARDING TS 3.1.7 STANDBY LIQUID CONTROL SYSTEM NINE MILE POINT NUCLEAR STATION UNIT 2 TAC NUMBER MF2462 The staff has reviewed Nine Mile Point Nuclear Station, LLC (NMPNS) request for an amendment to Nine Mile Point Unit 2 (NMP2) Renewed Operating License (OL) NPF-69 to increase the isotopic enrichment of boron-10 in sodium pentaborate solution used to prepare the neutron absorber solution in the Standby Liquid Control (SLC) System. As the results of our review, the staff identified the areas to be clarified by the NMPNS are given below.

1. The application describes the changes to the volumes, concentrations and enrichments but does not describe physical plant changes to the SLC System. Is the system being physically changed? Describe the system (storage tank size, pumps location and its actuation mechanism during ATWS), provide a schematic of the systems, and describe the functionality of the proposed SLC System for NMP2 including the operator actions necessary during an ATWS.

2. Please provide a design rationale for the assumptions regarding SLC System Performances listed in Table 1 of the July 5, 2013 submittal. Specifically explain why the range of values was chosen for minimum boron-10 enrichment for ATWS analysis and SLC System pump flow rate to support:

a. The application states the required minimum volumes for the 13.6 wt% and 14.4 wt%

solution volumes were derived by determining the minimum solution volume and then increasing the volume to account for: 1) the dead volume not pumped in the reactor that remains in the SLC System and HPCS piping; and 2) instrument accuracy.

Please explain how these volumes were derived. Please include the methodologies and the basis for the criteria used.

3 With respect to maintaining suppression pool pH 7.0, please provide the methodologies used to generate the minimum sodium pentaborate solution volume required for injection post-LOCA for adequate pH control at the limiting concentration as given in the submittal as 1,065 gallon for a sodium pentaborate concentration of 13.6%. Also provide an explanation regarding how the maximum time available to add boron is determined.

4 With respect to Net Positive Suction Head Available (NPSHA) for SLC System pumps, the proposed a reduction in the minimum volume for SLC System storage tank results in a reduction in the static head available to provide NPSHA and the calculation that determines the SLC System pump NPSHA did not take any credit for the static head above the SLC System storage tank zero level. Please describe any difference in the SLC System pump specifications between the current ones and the ones to be used for proposed change of the minimum SLC System storage tank and justify that the proposed NPSHA for the SLC System pumps adequate.

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The NRC staff would like to receive the responses to the RAIs within 30 days from the date of this communication. Please contact me, ASAP, to schedule a tele-conference between the licensee and the NRC staff to ensure that the licensee clearly understands the RAIs and also, to obtain a firm commitment/

confirmation from the licensee for the Responses to these RAIs.

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