BSEP 14-0056, Response to Request for Additional Information Regarding License Renewal Commitment Completion, Evaluation of Operating Experience at Extended Power Uprate Conditions

Response to Request for Additional Information Regarding License Renewal Commitment Completion, Evaluation of Operating Experience at Extended Power Uprate Conditions

ML14163A007
Person / Time
Site:	Brunswick
Issue date:	05/21/2014
From:	Pope A Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BSEP 14-0056
Download: ML14163A007 (5)

Text

Brunswick Nuclear Plant P.O. Box 10429 ENERGY, Southport, NC 28461 MAY 2 1 2014 Serial: BSEP 14-0056 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324 Response to Request for Additional Information License Renewal Commitment Completion Evaluation of Operating Experience at Extended Power Uprate Conditions

References:

1. Letter from Annnette H. Pope (Duke Energy Progress, Inc.) to U.S. Nuclear Regulatory Commission (Serial: BSEP 13-0137), License Renewal Commitment Completion Evaluation of OperatingExperience at Extended Power Uprate Conditions,dated December 17, 2013, ADAMS Accession No. ML14023A594

2. Electronic Mail from Siva Lingam (U.S. Nuclear Regulatory Commission) to William R.

Murray (Duke Energy Progress, Inc.), Brunswick I and 2 - Request for Additional Information (RAI) Regarding License Renewal Commitment Completion of Evaluation of OperatingExperience at Extended Power Uprate Conditions, dated April 25, 2014, ADAMS Accession No. ML14115A443

3. NUREG-1 856, Safety Evaluation Report Related to the License Renewal of the Brunswick Steam Electric Plant, Units I & 2, published June 2006, ADAMS Accession Nos. ML061730123 and ML061730129 Ladies and Gentlemen:

On December 17, 2013 (i.e., Reference 1) Duke Energy Progress, Inc., informed the NRC of the completion of a license renewal commitment (i.e., Commitment Number 31 in Appendix A of NUREG-1856), for the Brunswick Steam Electric Plant (BSEP), Units 1 and 2. The commitment was to perform an evaluation of plant and industry operating experience to assure that relevant aging effects caused by operation at power uprate conditions are adequately addressed by aging management programs. Subsequently, on April 25, 2014 (i.e., Reference 2), the NRC provided an electronic version of a Request for Additional Information (RAI) concerning closure of this commitment. The response to this RAI is enclosed.

This document contains no new regulatory commitments.

Sja4.

U.S. Nuclear Regulatory Commission Page 2 of 2 Please refer questions regarding this submittal to Mr. Lee Grzeck, Manager - Regulatory Affairs, at (910) 457-2487.

Sincerely, Annette H. Pope Director - Organizational Effectiveness Brunswick Steam Electric Plant MAT/mat

Enclosure:

Response to Request for Additional Information cc:

U. S. Nuclear Regulatory Commission, Region II ATTN: Mr. Victor M. McCree, Regional Administrator 245 Peachtree Center Ave, NE, Suite 1200 Atlanta, GA 30303-1257 U. S. Nuclear Regulatory Commission ATTN: Mr. Andrew Hon (Mail Stop OWFN 8G9A) (Electronic Copy Only) 11555 Rockville Pike Rockville, MD 20852-2738 U. S. Nuclear Regulatory Commission ATTN: Ms. Michelle P. Catts, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 Chair - North Carolina Utilities Commission P.O. Box 29510 Raleigh, NC 27626-0510

Enclosure Page 1 of 3 Response to Request for Additional Information

Background

On December 17, 2013 (i.e., Serial: BSEP 13-0137) Duke Energy Progress, Inc., informed the NRC of the completion of a license renewal commitment (i.e., Commitment Number 31 in Appendix A of NUREG-1856), for the Brunswick Steam Electric Plant (BSEP), Units 1 and 2.

Commitment 31 states:

An evaluation of plant and industry operating experience will be submitted for NRC review at least one year prior to the period of extended operation. The purpose of the evaluation will be to assure that relevant aging effects caused by operation at power uprate conditions are adequately addressed by aging management programs.

Subsequently, on April 25, 2014, the NRC provided an electronic version of a Request for Additional Information (RAI) concerning closure of this commitment. The response to this RAI follows.

NRC RAI The commitment states that the licensee would evaluate both plant-specific and industry operating experience. However, the review methodology described in the licensee's submittal only discusses consideration of industry operating experience. As such, the scope of the licensee's review does not fully address the intent of the commitment.

Describe the evaluation of plant-specific operating experience to ensure that the aging management programs adequately address aging effects caused by operation at extended power uprate conditions. In this description, address:

(a) the specific sources of information that were reviewed, (b) the evaluation methodology and rationale for attributing the operating experience to operation at power uprate conditions, (c) the results of the review including any relevant items that were found and the actions that were or will be taken in response.

Response

Plant-specific operating experience (OE) to ensure that the appropriate aging management programs adequately address aging effects potentially caused by operation at extended power uprate (EPU) conditions was included in a 2013 detailed evaluation performed by BSEP plant personnel. That is, BSEP events were not excluded from the OE generated from multiple sources for this evaluation. The following describes, in more detail, some plant-specific examples in response to items (a), (b) and (c) above:

(a) The specific sources of information reviewed for plant-specific events were primarily from a review of the Institute for Nuclear Power Operations (INPO) Operating Experience (OE), Electric Power Research Institute (EPRI) Power Plant Uprate Database, and the Boiling Water Reactor Vessel Internals Project (BWRVIP) Uprate database, which included OE from BSEP. These searches did not exclude BSEP from the population. Plant-specific events that require an extent of condition between BSEP

Enclosure Page 2 of 3 Units 1 and 2, and/or a determination of internal and external OE is included in the BSEP Corrective Action Program. From a plant-specific perspective, this adequately addresses aging effects potentially caused by operation at EPU conditions due to newly discovered events since EPU was implemented at BSEP. For example, a feedwater (FW) corrosion sampling probe was found in a FW sparger at BSEP Unit 2 during the March 2011 in-vessel visual inspection. A potential contributing cause of the FW sampling probe breaking and transporting to the FW sparger was higher FW flow rate due to EPU. Damage to the FW sparger was evaluated by engineering and actions were taken to find and remove the sampling probe in BSEP Unit 1 during the next refuel outage in March 2012. The Unit 1 probe was also found to be broken. Although the FW sampling probes are not within the scope of License Renewal, the failure of these components impacted the downstream FW spargers, which are within the scope of License Renewal.

Another source of information for plant-specific OE was based on plant-specific BWRVIP Review Visit recommendations by INPO for relevant aging caused by operation at EPU.

BWRVIP review visits by INPO were conducted during October 2006 and November 2010. Plant-specific actions were entered into the Corrective Action Program based on these INPO review visits for any items related to EPU. For example, in the 2006 INPO final report, the only EPU-related recommendation for improvement was cited as follows:

Steam dryer locations that have experienced flaws in the industry should be inspected or dispositioned by the station. BWRVIP-139 outlines high-stress locations and locations that have experienced flaws. General Electric (GE)

Service Information Letter (SIL)-644 recommends that after a power uprate, both of these types of susceptible locations be inspected for two refueling outages following uprate. BWRVIP-139 does not give re-inspection or uprate guidance but suggests that the guidance of SIL-644 be followed. The station has done extensive inspections of the high-stress welds but has not re-inspected the locations that have failed in the industry after power uprates.

The detailed evaluation discusses plant-specific actions taken, including re-inspection plans, with regards to steam dryer inspections and monitoring and enhancements to the applicable aging management program.

In the 2010 INPO final report, the only EPU-related recommendation for improvement was cited as follows:

Since implementation of extended power uprates (EPUs) in 2003 and 2004, Units 1 and 2 have not met BWRVIP monitoring guidance to ensure sufficient chemical mitigation. Units 1 and 2 had previously used a sister plant as the primary mitigation parameter, but when EPU was implemented, the sister plant concept was invalidated. Without a sister plant, an [electrochemical corrosion potential] ECP probe is the only primary parameter that can be used to correlate secondary parameters.

BSEP is currently implementing the INPO recommendations for improvement to install ECP probes in the reactor vessel's lower plenum region. In March 2014, the ECP probes were installed in BSEP Unit 1 and will be installed in BSEP Unit 2 in March 2015.

Enclosure Page 3 of 3 (b) The evaluation methodology consisted of a determination of which EPU-related OE had components within the scope of License Renewal, which again included BSEP plant-specific OE. It was determined that the plant-specific components at BSEP within the scope of License Renewal with EPU-related OE were the steam dryer, core shroud head assembly/steam separator, jet pumps, and FW sparger end brackets. The rationale for attributing the OE to operation at EPU conditions, as described in the 2013 detailed evaluation, is as follows:

Keywords "FLY", "fatigue", "vibration", "EPU", "Uprate", "Dryer" and "Jet Pump" were used to assist in screening the OE events. Not all of the events tabulated were attributed to post-EPU; however, these were determined to be applicable to those components within the scope of License Renewal that are susceptible to potential increases in flow induced vibration and wear due to EPU. Thus, they were considered as applicable OE for the purposes of the evaluation.

(c) The results of the review performed in support of this RAI response did not add any relevant items not already included in the detailed evaluation completed by BSEP in August 2013, which was summarized in the letter submitted to NRC in December 2013 (i.e., Serial: BSEP 13-0137). There were no BSEP-specific events that impact the results and conclusions of the original BSEP detailed evaluation. Therefore, BSEP concludes that the commitment to perform an evaluation of plant and industry operating experience, to assure that relevant aging effects caused by operation at power uprate conditions are adequately addressed by aging management programs, has been satisfactorily met.