NG-14-0155, 10 CFR 50.46 30-Day Special Report of Changes in Peak Cladding Temperature

10 CFR 50.46 30-Day Special Report of Changes in Peak Cladding Temperature

ML14174B093
Person / Time
Site:	Duane Arnold
Issue date:	06/19/2014
From:	Richard Anderson NextEra Energy Duane Arnold
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NG-14-0155
Download: ML14174B093 (4)

Text

NEXTera ENERGY7 DUAN June 19, 2014 NG-14-0155 10 CFR 50.46(a)(3)(ii)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 10 CFR 50.46 30-Day Special Report of Changes in Peak Cladding Temperature for the Duane Arnold Energy Center

Reference:

Letter from R. Anderson (NextEra Energy Duane Arnold) to USNRC, "10 CFR 50.46 Annual Report of Changes in Peak Cladding Temperature for the Duane Arnold Energy Center," NG-1 3-0382, dated September 30, 2013.

In accordance with 10 CFR 50.46(a)(3)(ii), NextEra Energy Duane Arnold, LLC (hereafter NextEra Energy Duane Arnold) hereby provides this 30-day special report regarding changes in the calculated peak cladding temperature (PCT) of the GE14 and GNF2 fuel designs currently utilized at the Duane Arnold Energy Center (DAEC).

Our fuel vendor, Global Nuclear Fuels (GNF), has notified NextEra Energy Duane Arnold of the potential impact of four newly-identified changes or errors in the current Loss-of-Coolant Accident analysis methodology and its application that have occurred subsequent to the referenced annual report. Enclosed is a historical summary of previously reported changes or errors, as well as the potential impact of these new changes or errors on the GE14 and GNF2 fuel designs currently utilized at DAEC.

These new changes or errors, when combined (sum of the absolute magnitudes) with all the applicable PCT changes previously reported for the GE14 fuel design, result in a cumulative PCT change for the DAEC of greater than 50 OF reporting threshold under §50.46(a)(3)(i). Although this is defined as a "significant change" under §50.46, the actual impact on nuclear safety is negligible, as the DAEC has significant margin, over 500 OF, to the regulatory limit of 2200 °F PCT in §50.46(b)(1). Thus, a full re-analysis for GE14 fuel design is not currently scheduled for the DAEC as a result of these cumulative changes.

NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA52324

U.S. Nuclear Regulatory Commission NG-14-0155 June 19, 2014 These new changes or errors, when combined (sum of the absolute magnitudes) with all the applicable PCT changes previously reported for the GNF2 fuel design, result in a cumulative PCT change for the DAEC of exactly 50 OF. The cumulative change is less than the reporting requirements of 10 CFR 50.46 (greater than 50 OF). The impact on nuclear safety is negligible, as the DAEC has significant margin, over 450 OF, to the regulatory limit of 2200 OF PCT in §50.46(b)(1). Thus, a full re-analysis for GNF2 fuel design is not currently scheduled for the DAEC as a result of these cumulative changes.

This letter contains no new commitments or changes to any previous commitments.

Sincerely, Richard L. Anderson Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC Enclosures cc: Administrator, Region III, USNRC Project Manager, Duane Arnold Energy Center, USNRC Resident Inspector, Duane Arnold Energy Center, USNRC

Enclosure 1 to NG-14-0155 June 19, 2014 10 CFR 50.46 30-Day Report DAEC - 2014 GE14 Fuel Peak Cladding Temperature°')

Last Acceptable Model Results.2 ): 151 0°F Previously Reported Errors and Changes:

2001 - 2013-13: + 125 0 F New Errors and Changes(3 ):

1. Impact of several SAFER maintenance O updates

2. Impact of SAFER logic error in system + 10 OF mass calculation

3. Impact of SAFER non-conservative + 20 OF minimum core Ap

4. Impact of inconsistency in SAFER iteration scheme for counter current - 20 OF flow limitation (CCFL)

Analysis of Record Results: 1645 OF (1) Licensing Basis PCT (LBPCT), as defined in NEDE-23785-1-P-A, "The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident:

Volume III - SAFER/GESTR Application Methodology," February 1985.

(2) General Electric Report, "Safety Analysis Report for Duane Arnold Energy Center Extended Power Uprate," NEDC-32980P, Revision 1, April 2001.

(3) Evaluations of each reported error have concluded that re-analysis was not required.

Enclosure 2 to NG-14-0155 June 19, 2014 10 CFR 50.46 30-Day Report DAEC - 2014 GNF2 Fuel Peak Cladding Temperature (l)(2)

Last Acceptable Model ResultsC3 ): 1730 OF Previously Reported Errors and Changes: None New Errors and Changes:

1. Impact of several SAFER maintenance 0 OF updates

2. Impact of SAFER logic error in system + 10 OF mass calculation

3. Impact of SAFER non-conservative + 20 OF minimum core Ap

4. Impact of inconsistency in SAFER iteration scheme for counter current - 20 OF flow limitation (CCFL)

Analysis of Record Results: 1740 OF (1) Licensing Basis PCT (LBPCT), as defined in NEDE-23785-1-P-A, "The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident:

Volume III - SAFERIGESTR Application Methodology," February 1985.

(2) Licensing Topical Report, Global Nuclear Fuel, "The PRIME Model for Analysis of Fuel Rod Thennal-Mechanical Performance", Technical Bases - NEDC-33256P-A, Qualification - NEDC-33257P-A, and Application Methodology - NEDC-33258P-A, September 2010.

(3) General Electric-Hitachi (GEH) Engineering Report # 0000-0133-690 1-RO, "Duane Arnold Energy Center GNF2 ECCS-LOCA Evaluation," August 2012.