ML15110A098

E-Mail Peach Bottom Unit 2 - Power Ascension Hold at 104% of 3514 Mwt

ML15110A098
Person / Time
Site:	Peach Bottom
Issue date:	04/10/2015
From:	Doug Broaddus Plant Licensing Branch 1
To:	Greenlee S Exelon Generation Co
Ennis R, NRR/DORL/LPLI-2, 415-1420
References
TAC MF4792
Download: ML15110A098 (2)

Text

From: Broaddus, Doug Sent: Friday, April 10, 2015 7:05 PM To: 'Scot.Greenlee@exeloncorp.com' Cc: Uhle, Jennifer; Evans, Michele; Lund, Louise; Wilson, George; Lubinski, John; Li, Yong; Manoly, Kamal; Basavaraju, Chakrapani; Bower, Fred; Barber, Scott; Hansell, Samuel; Smith, Brian; Modes, Michael; Ken Ainger; Ennis, Rick

Subject:

RE: Peach Bottom Unit 2 - Power Ascension Hold at 104% of 3514 MWt Mr. Greenlee, This email is a follow-up to the April 9, 2015, email from Mr. Rick Ennis (attached) which conveyed the results of NRCs review of the Peach Bottom Unit 2 steam dryer performance evaluations at 104% of 3514 MWt in accordance with license condition 2.C(15)(a).4.g, and our conference call with you this evening concerning our review of the additional performance information provided to the NRC earlier today.

As we discussed with you on the call, the NRC staff has determined that the additional performance information provides reasonable assurance regarding the structural integrity of the steam dryer up to 108% of 3514 MWt. Therefore, the NRC staff has no objection to the resumption of power ascension for PBAPS Unit 2 to the next hold point specified in license condition 2.C(15) (i.e., 108% of 3514 MWt). Further power ascension of PBAPS Unit 2 beyond 108% of 3514 MWt will be contingent upon continued demonstration of the structural integrity of the replacement steam dryer in accordance with the provisions in license condition 2.C(15).

In addition, during the call you agreed that Exelon will provide the following additional information no later than the date that the steam dryer evaluation, performed based on data collected at 108% of 3514 MWt, is provided to the NRC in accordance with license condition 2.C(15):

1. Exelon will provide the measured strain trending data for the non-MSLA frequency range (0-50 Hz), and MSLA frequency range (50-250 Hz) at 108% of 3514 MWt, analogous to the data provided in response to the NRC staff question #9 regarding the steam dryer evaluation performed based on data collected at 104% of 3514 MWt.

2. To provide further indication into the level of conservatism in Exelons revised methodology for the non-MSLA evaluation, Exelon will apply the approach discussed in RAI 10-S1 to a narrow frequency band (35 to 40 Hz) in the NMSL frequency range, and compare it with the corresponding results for the same narrow frequency range extracted from the response to RAI 10.

As we also discussed in the call, Rick Ennis will schedule an additional call with your staff early next week concerning RAI 10-S1.

Please let me know if you have any questions.

Doug Douglas A. Broaddus Chief, Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: 301-415-8124; email: Doug.Broaddus@nrc.gov From: Ennis, Rick Sent: Thursday, April 09, 2015 4:14 PM To: Ken Ainger Cc: Uhle, Jennifer; Evans, Michele; Lund, Louise; Wilson, George; Broaddus, Doug; Lubinski, John; Ross-Lee, MaryJane; Li, Yong; Manoly, Kamal; Breach, Michael; Basavaraju, Chakrapani; Vik Shah; Stephen Hambric; Samir Ziada; Bower, Fred; Barber, Scott; Hansell, Samuel; Smith, Brian; Modes, Michael; David Neff; Rommel, John C.:(GenCo-Nuc); Kevin Borton (kevin.borton@exeloncorp.com)

Subject:

Peach Bottom Unit 2 - Power Ascension Hold at 104% of 3514 MWt Importance: High

Ken, The NRCs letter dated March 27, 2015 (ADAMS Accession No. ML15033A489), approved the power ascension of Peach Bottom Unit 2 from 100% of 3514 MWt to 104% of 3514 MWt. As discussed in that letter, further power ascension beyond 104% of 3514 MWt will be contingent upon continued demonstration of the structural integrity of the steam dryer in accordance with the provisions in license condition 2.C(15). In addition, the staffs letter stated that additional information (detailed in the enclosure to the letter) needs to be provided to help inform the staffs decision on the acceptability of power ascension beyond 104% of 3514 MWt. This request for additional information (RAI-10) was provided in draft form to Exelon on March 19, 2015. In addition, the RAI was discussed during a meeting between Exelon and the NRC on March 26, 2015. The RAI pertained to Exelons request for NRC approval of a proposed change in the steam dryer analysis methodology as described in Exelons letter February 3, 2015, as supplemented by letter dated March 24, 2015 (ADAMS Accession Nos. ML15034A573 and ML15083A559, respectively). The request for NRC approval of the change in methodology is required in accordance with license condition 2.C(15)(d).

In my email dated April 6, 2015, at 8:02 am, I confirmed receipt of Exelons evaluations for the 104% of 3514 MWt hold point for the Peach Bottom Unit 2 power ascension. That email also confirmed receipt of Exelons letter dated April 5, 2015 (ADAMS Accession No. ML15096A007),

which provided a response to RAI-10 associated with the proposed change in the steam dryer analysis methodology dated February 3, 2015. The April 6, 2015 email started a 96 hour0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> period for NRC review of the 104% evaluations in accordance with license condition 2.C(15)(a).4.g.

On April 7, 2015, the NRC staff sent Exelon questions regarding the steam dryer evaluation at 104% as well as on the response to RAI-10 contained in Exelons April 5, 2015, letter. A call to clarify the staffs questions was held with Exelon on April 8, 2015. During the call, the staff expressed concerns regarding the response to RAI-10. These concerns relate to issues discussed in detail during the meeting with Exelon on March 26, 2015. In order to address

these concerns, the staff indicated that it needed Exelon to formally docket a response to a supplemental RAI question designated as RAI 10-S1.

Given that Exelons response to RAI-10 did not provide sufficient information to provide the NRC with reasonable assurance regarding the structural integrity of the steam dryer at higher power levels, the staff has determined that power ascension above 104% of 3514 MWt is not warranted at this time. The staff will reconsider this determination following submittal of the response to RAI 10-S1.

Please let me know if you have any questions.

Thanks, Rick