ML042860514

E-Mail to Ken Nicely, Exelon Dresden ILRT Amendment Request

ML042860514
Person / Time
Site:	Dresden
Issue date:	05/18/2004
From:	Banerjee M NRC/NRR/DLPM/LPD3
To:	Nicely K Exelon Corp
Banerjee, M. NRR/DLPM/LPD3-2, 415-2277
References
Download: ML042860514 (4)

Text

Maitri Banerjee - Re: Dresden ILRT Amendment Request Page 1I From: Maitri Banerjee To: ken.nicely@exeloncorp.com Date: 5/18/04 11:21 AM

Subject:

Re: Dresden ILRT Amendment Request Our review of your January 15, 2004 application requesting an amendment to the Dresden Units 2 and 3 technical specification 5.5.12, "Primary Containment Leakage Rate Testing Program," has identified the following questions. These questions are attached. Please let me know if you will need a phone call with the staff for clarifications before you can respond to these questions.

Maitri Banerjee, PE Dresden PM DLPM/NRR CC: Lawrence Rossbach

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Re: Dresden ILRT Amendment Request Creation Date: 5/1 0D4 11:21 AM From: I Maitri Banerjee Created By: MXEianrc.aov Recipients exeloncorp.com ken.nicely (ken.nicelyeexeloncorp.com) nrc.gov owf4_po.OWFNDO LWR CC (Lawrence Rossbach)

Post Office Route exeloncorp.com owf4_po. OWFN-DO nrc.gov Files Size Date & Time RAXILRT0504.wpd 6573 05/18A04 11:20AM MESSAGE 1056 05118104 11:21AM Options Expiration Date: None Priority. Standard Reply Requested: No Return Notification: None Concealed

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- age1 I Maitri Banerjee - RAI-ILRT0504.wpd Page _111 SPSB Request for Additional Information Regarding ILRT Interval Extension for Dresden, Units 2 and 3

1. It is our understanding that many of the two-ply containment penetration bellows have been replaced at Dresden because of degradation, but that several potentially-degraded bellows remain in service. Leakage through these bellows was not considered in the risk assessment submitted in support of the license amendment request. In this regard, please provide the following information related to potential leakage through the bellows:

a. The estimated probability of a leak to the environment via a degraded bellows, and the basis for this estimate. This should consider the number of degraded bellows that has been identified out of the total population of bellows (classified in terms of type and general location, if appropriate), the number of potentially degraded bellows that are still in service in each Unit, and the frequency and results of periodic local leak rate testing performed on the bellows.

b. A characterization of the potential leak rate from the containment airspace to the environment for a degraded bellow, and the conditional probability that the leak would be classified as small versus large. This should consider the range of leak rates observed for degraded bellows, and whether the leakage represents leakage through one or both plies of the bellows.

c. An assessment of (or sensitivity case exploring) the impact on risk results if the potential for leakage via degraded bellows was included in the risk model.

2. As part of license renewal, Exelon made a number of commitments related to corrosion of the steel shell. This includes commitments to monitor the cylindrical and upper spherical area of the drywell through augmented UT inspections and to inspect the sand pocket drains. Please confirm whether these inspections will be performed at Dresden during the current operating license term. If not, please provide an assessment of the impact on risk results if the potential for corrosion-induced leakage of the steel shell in the sand pocket areas and any other affected regions was included in the risk model.

EMEB Request for Additional Information Regarding ILRT Interval Extension for Dresden. Units 2 and 3

1. IWE-1 240 requires licensees to identify the containment surface areas requiring augmented inspections. The fourth paragraph of Page 7 of 16 of Attachment 1, states that "... No areas of the containment liner surfaces require augmented examination, and no loss of structural integrity of primary containment was observed." Please provide the basis for not requiring any augmented inspections, addressing the license renewal commitments discussed in SPSB question no. 2 above.

2. Has any relief to the requirements of the Code related to the examination of the penetration seals and gaskets, and examination and testing of bolted connections associated with the primary containment pressure boundary (Examination Categories E-D and E-G) been granted?