ML073321304

Request for Additional Information (RAI) Regarding the Measurement Uncertainty Recapture Power Uprate Amendment

ML073321304
Person / Time
Site:	Vogtle
Issue date:	11/29/2007
From:	Siva Lingam NRC/NRR/ADRO/DORL/LPLII-1
To:	Tynan T Southern Nuclear Operating Co
Lingam, Siva NRR/DORL 415-1564
References
TAC MD6625, TAC MD6626
Download: ML073321304 (6)

Text

November 29, 2007 Mr. Tom E. Tynan Vice President - Vogtle Vogtle Electric Generating Plant 7821 River Road Waynesboro, GA 30830

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2, REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING THE MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE AMENDMENT (TAC NOS.

MD6625 AND MD6626)

Dear Mr. Tynan:

By letter dated August 28, 2007, and supplemented by letter dated October 9, 2007, Southern Nuclear Operating Company, Inc. (the licensee), submitted an application requesting to increase the licensed core power level by 1.7 percent with the installation of the Caldon Check-Plus ultrasonic feedwater flow element for the Vogtle Electric Generating Plant, Units 1 and 2. The Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has determined that additional information is required to complete its evaluation.

The NRC staffs RAI is enclosed. The licensee is required to provide a response to the RAI within 30 days.

Sincerely,

/RA/

Siva P. Lingam, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425

Enclosure:

RAI cc w/encl: See next page

ML073321304 *transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/SRXB/BC NRR/LPL2-1/BC NAME SLingam MO=Brien GCranston EMarinos DATE 11/29/07 11/29/07 11/26/07* 11/29/07 REQUEST FOR ADDITIONAL INFORMATION REGARDING THE MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-424 AND 50-425 By letter dated August 28, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072470691), as supplemented by letter dated October 9, 2007 (ADAMS Accession No. ML072850108), Southern Nuclear Operating Company, Inc., (the licensee), submitted a request for changes to the Vogtle Electric Generating Plant, Units 1 and 2 (Vogtle 1 and 2) Technical Specifications. The requested changes are to obtain a measurement uncertainty recapture (MUR) power uprate on the basis of a plant modification that would result in improved accuracy of feedwater flow measurement, which is used to calculate reactor thermal power. Installation of a Caldon Check-Plus ultrasonic flow meter (UFM) system to measure feedwater flow will allow the licensee to operate the plant with a reduced margin of 0.3% for instrumentation uncertainty and an increased power level of 1.7% of the licensed thermal power.

In order to complete its review, the Nuclear Regulatory Commission (NRC) staff needs the following additional information:

Reactor Systems Branch and Nuclear Performance and Code Review Branch (1) Confirm that VIPRE-W (the version of VIPRE used for this MUR power uprate) is identical to the version of VIPRE approved in WCAP-14565 with no changes except those stated and approved in the WCAP.

(2) Confirm that VIPRE is being used under an accepted quality assurance program with adequately trained users per Appendix B to Title 10 of the Code of Federal Regulations (10 CFR), Part 50.

(3) Confirm that there is a 5-percent reduction factor to the flow entering the hot channel (per safety evaluation report for WCAP-14565).

(4) Demonstrate that the plant parameters at the uprated conditions are still within the ranges of the correlations in VIPRE.

(5) In WCAP-16736-P, Section 7.3.1 (p.7-5) states that the over-temperature-delta-T and over-power-delta-T setpoint evaluation are discussed in subsection 7.13. However, subsection 7.13 does not exist. Please provide or clarify where the evaluation is located.

Enclosure

(6) The justification, that sufficient departure from nucleate boiling (DNB) and DNB ratio (DNBR) margin exists for the non-loss-of-coolant (non-LOCA)/transient analyses, was stated in many incidents in WCAP-16736-P. For example, page 7-7, states that DNB margin is allocated to specifically address the 1.7-percent power uprate. Page 7-4 states DNB margin in Updated Final Safety Analysis Report (UFSAR) 15.0.6 has been allocated such that the core thermal limits do not change. Page 7-6 states, 34-percent margin to the DNBR limit. Based on the known DNB sensitivity to changes in power, the amount of margin is more than sufficient to offset the penalty associated with a 1.7 percent power uprate. However, insufficient detail was provided to make a determination on the adequacy of the statements. Provide a detailed evaluation of DNB/DNBR margin that demonstrates the allocation specifically addressing each non-LOCA event that utilizes the DNB or DNBR margin justification, given the uprated conditions.

(7) In WCAP-16736-P, Section 7.3.1 states that for non-LOCA evaluations it is assumed that the reload-related inputs will not be impacted and will be verified as part of the standard reload process. Confirm the two parts of this statement are true or provide an explanation.

(8) Further explanation is necessary for a comparison of the current licensing basis in UFSAR Table 15.0.3-2 and WCAP-16736-P Table 7.3-1. For approximately 10 events, the power level listed in parentheses in WCAP-16736 is the same as the UFSAR table. However, for approximately six events, the power level in parentheses is different than the UFSAR table.

Vogtle Electric Generating Plant, Units 1 & 2 cc:

Mr. Tom E. Tynan Arthur H. Domby, Esquire Vice President - Vogtle Troutman Sanders Vogtle Electric Generating Plant Nations Bank Plaza 7821 River Road 600 Peachtree Street, NE Waynesboro, GA 30830 Suite 5200 Atlanta, GA 30308-2216 Mr. N. J. Stringfellow Manager, Licensing Resident Inspector Southern Nuclear Operating Company, Inc. Vogtle Plant P.O. Box 1295 8805 River Road Birmingham, AL 35201-1295 Waynesboro, GA 30830 Mr. Jeffrey T. Gasser Office of the County Commissioner Executive Vice President Burke County Commission Southern Nuclear Operating Company, Inc. Waynesboro, GA 30830 P.O. Box 1295 Birmingham, AL 35201-1295 Mr. Steven M. Jackson Senior Engineer - Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, GA 30328-4684 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission 244 Washington St., SW Atlanta, GA 30334 Mr. Harold Reheis, Director Department of Natural Resources 205 Butler Street, SE, Suite 1252 Atlanta, GA 30334 Attorney General Law Department 132 Judicial Building Atlanta, GA 30334 Mr. Laurence Bergen Oglethorpe Power Corporation 2100 East Exchange Place P.O. Box 1349 Tucker, GA 30085-1349