ML20112B844

Forwards Braidwood Unit 1 Cycle Length Assessment Rept Suppl

ML20112B844
Person / Time
Site:	Braidwood
Issue date:	05/17/1996
From:	Kaup K COMMONWEALTH EDISON CO.
To:	NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20112B848	List: ML20112B844 ML20112B852
References
NUDOCS 9605240029
Download: ML20112B844 (3)

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Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission  !

Washington, DC 20555 l Attn: Document Control Desk l'

Subject:

Braidwood Station Unit 1 NRC Docket Number: 50-456 Operating Interval Between Eddy Current inspections for Circumferential Indications in the Braidwood Unit 1 Steam Generators )

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References:

1. K. Kaup letter to the Nuclear Regulatory Commission dated February 23,1996

2. J. Roe letter to D. Farrar dated May 2,1996

3. May 6th and May 14th Meetings between the Commonwealth Edison Company and the Nuclear Regulatory Commission Regarding the Circumferential ,

Indication Update  !

3. K. Kaup letter to the Nuclear Regulatory Commission dated May 7,1996 j l

In the Reference letter 1, the Commonwealth Edison Company (Comed) submitted to the Nuclear Regulatory Commission (NRC) the results of the Byron Unit 1 tube pull analysis and the Braidwood Unit 1 Cycle Length Assessment  ;

Report. The report concluded that Braidwood Unit 1 should be able to operate for a period equivalent to the Byron Unit 1 operating interval (342 days) period between the 1994 refueling outage (B1R06) and the Byron Unit 1 midcycle outage. The technical basis for the conclusion that Byron Unit 1 bounds Braidwood Unit 1 consists of :

Byron Unit 1 tubes had structural integrity after the 342 day period of operation as demonstrated by tube pull results, A conservative leakage analysis for Braidwood Unit 1 demonstrates margin to the site allowable leakage limits, 9605240029 960517 PDR ADUCK 05000456 P PDR K:nla%bwd\stgen\bylkbk L fl

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l NRC Document Control May 17,1996 j 4 1 l

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Braidwood Unit i fall refueling outage inspection improvements over the j Byron Unit 1 B1R06 inspection, ard i

The number and size of the Braidwood Unit 1 indications is significantly

. smaller than those found at Byron Unit 1. '

1 We understand from your May 2nd letter (Reference 2) that the Staff found this

, cycle length proposal unacceptable due to the recent Byron Unit 1 steam l' generator inspection results.

At the Reference meetings Comed discussed the results of the studies to j evaluate the most recent inspection of the Byron Unit 1 steam generators. !t was l our belief that this review would conclude that Byron Unit i had experienced an 1 i inspection transient, and that our original conclusion that Byron bounds

} Braidwood was still valid. To confirm this belief Comed embarked on a series of

} initiatives : insitu pressure testing, Byron 1 Look Back Program, and Byron 1 i Blind Test Program. These initiatives are discussed in more detail in the l j attachment.

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Based upon a review of the data obtained from these initiatives, Comed 1 concludes that

_ inspection transients occurred at Byron Unit 1 in 1995 and 1996, and j -

there was slow growth of circumferential indications; after one full cycle of operation the maximum voltage grew from 0.55 to 1.11 volts, structural integrity of the steam generator tubes is not threatened.

i Comed believes that these conclusions, along with those presented in our ,

February 23rd submittal, support that it is safe to operate Braidwood Unit 1 until '

the Fall of 1996. 1 Comed requests the Staff's concurrence of our proposal to allow Braidwood Unit 1 to operate an additional 90 days beyond the current mid-cycle date until October 15,1996. This is a change in Comed's previous commitment (Reference 4). In addition to performing the outage at this time Braidwood, will conduct insitu testing. Additionally, Braidwood will perform tube pulls for circumferential indications during the Spring 1997 outage.

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1 NRC Document Control May 17,1996 Comed requests that the NRC review this information and inform us of their conclusions as soon as possible. We are currently planning to remove Unit 1 from service in order to conduct a midcycle inspection on May 25th per our earlier commitment, and will continue doing so until we receive the Staff concurrence on this revised commitment.

If you have any questions conceming this correspondence please contact Denise Saccomando, Senior PWR Licensing Administrator at (708) 663-7283.

Sincerely, rlKaup ite Vice President Braidwood Station i Attachments cc: ,

D. Lynch, Senior Project Manager- NRR R. Assa, Braidwood Project Manager-NRR C. Phillips, Senior Resident inspector-Braidwood l H. Miller, Regional Administrator-Rill Office of Nuclear Safety-IDNS K:nla%ybwd\stgen%ylkbk

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