NG-11-0289, 10 CFR 50.46 30-Day Special Report of Changes in Peak Cladding Temperature for the Duane Arnold Energy Center

10 CFR 50.46 30-Day Special Report of Changes in Peak Cladding Temperature for the Duane Arnold Energy Center

ML112301480
Person / Time
Site:	Duane Arnold
Issue date:	08/18/2011
From:	Wells P NextEra Energy Duane Arnold
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NG-11-0289
Download: ML112301480 (3)

Text

- .I NEXTera M ENERGV~

~ DUANE """"

ARNOLD August 18, 2011 NG-11-0289 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 C. Costanzo (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-10-0480, dated September 30,2010.

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 fuel design currently utilized at the Duane Arnold Energy Center (DAEC).

Our fuel vendor has notified NextEra Energy Duane Arnold of two newly-identified errors in the current Loss-of-Coolant Accident analysis methodology and application that have occurred subsequent to the referenced report. Enclosed is a historical summary of previously reported errors, as well as the addition of these new errors.

These new changes, when combined (sum of the absolute magnitudes) with all the applicable PCT changes previously reported, result in a cumulative PCT change for the DAEC of greater than the 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 OF PCT in §50.46(b)(1). Thus, a re-analysis is not currently scheduled for the DAEC as a result of these cumulative errors.

This letter contains no new commitments.

Sincerely,

,51~~

Peter Wells Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324

U.S. Nuclear Regulatory Commission NG-11-0289 August 18, 2011 Enclosure

Enclosure to NG-11-0289 August 18, 2011 10 CFR 50.46 30-Day Report for the DAEC Peak Cladding Temperature(1)

Last Acceptable Model Results(2): 1510°F Previously Reported Errors and Changes:

2001 - 2010: + 65°F New Errors and Changes:

1. Impact of over/under prediction of energy deposited in the channel/fuel + 45 °F from gamma radiation

2. Impact of minimizing the contribution of heat from gamma absorption by + 5 °F the channel Analysis of Record Results: 1625 °F (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.