ML042670371

E-mail from T. Alexion to G. Davant pre-application for Use of MNSA-2 on Vessel Bottom Nozzles

ML042670371
Person / Time
Site:	Arkansas Nuclear
Issue date:	03/26/2004
From:	Alexion T NRC/NRR/DLPM/LPD4
To:	Davant G Entergy Operations
Alexion T W, NRR/DLPM, 415-1326
Shared Package
ML043570180	List: ML042670312 ML042670319 ML042670327 ML042670335 ML042670338 ML042670341 ML042670344 ML042670370 ML042670371 ML042670375 ML042670381 ML042670384 ML042670389 ML042670395 ML042670485 ML042670489 ML043570163
References
CNRO-2004-00010
Download: ML042670371 (4)

Text

Thomas Alexion - PRE-APPLICATION FOR USE OF MNSA-2 ON VESSEL BOTTOM NOZZLES Page 1 .1 From: Thomas Alexion To: DAVANT, GUY H Date: 3/26/04 8:50AM

Subject:

PRE-APPLICATION FOR USE OF MNSA-2 ON VESSEL BOTTOM NOZZLES Guy, Attached is NRC staff feedback on your 02/05/04 pre-application submittal (CNRO-2004-0001 0).

I can arrange for a phone call with the NRC staff reviewers if you want to discuss it.

Tom CC: SBENNE2@entergy.com o A 1S

I CiW1IN D0WS\TEMP\GW)00001 .TMP Pagie 1 Paae 1 I.1 I CAWINDOWS\TEMP\GW}00001 .TMP Mail Envelope Properties (40643522.CA3: 0: 20628)

Subject:

PRE-APPLICATION FOR USE OF MNSA-2 ON VESSEL BOTTOM NOZZLES Creation Date: 3/26/04 8:50AM From: Thomas Alexion Created By: TWA@nrc.gov Recipients Action Date & Time entergy.com Transferred 03/26/04 08:50AM GDAVANT (DAVANT, GUY H)

SBENNE2 CC (SBENNE2@enterzy.com)

Post Office Delivered Route entergy.com Files Size Date & Time MNSA2RAI.wpd 6435 03/26/04 08:44AM MESSAGE 880 03/26/04 08:50AM Options Auto Delete: No Expiration Date: None Notify Recipients: Yes Priority: Standard Reply Requested: No Return Notification: None Concealed

Subject:

No Security: Standard To Be Delivered: Immediate Status Tracking: Delivered & Opened

STAFF FEEDBACK ON THE ANO-1 PRE-APPLICATION SUBMITTAL ON USE OF MNSA-2 CLAMPS ON THE BOTTOM MOUNTED INSTRUMENTATION NOZZLES

1. The application needs to have an expanded justification (the 2nd paragraph in Section III of the submittal is not sufficient) why MNSAs are the appropriate repair technique to be applied in this area, when there are other permanent repair techniques available.

2. By proposing a temporary MNSA repair, followed by a permanent half-nozzle repair, ANO-1 will incur higher worker radiation exposures than if the permanent repair were performed at the outset. This deviation from ALARA principles needs to be further justified.

3. If the MNSAs are the appropriate repair technique, then the application needs to discuss how this can be considered a temporary repair since drilling holes into the reactor vessel is not reversible. How would the reactor vessel be returned to its original condition when a permanent repair is completed in the future?

4. Since the use of MNSAs on the vessel bottom may not be considered a temporary repair, your application should discuss the concerns identified in the NRC's letter of December 8, 2003.

5. You will need to submit a separate relief request for leaving flaws in service and not reinspecting them in accordance with IWB-2420(b) of Section Xl of the ASME Code.

6. If nozzle leakage is identified, you will need to off load the core and perform extensive NDE to fully characterize the flaws. The staff would need for you to describe the NDE and flaw characterization results in detail.

7. NRC staff approval on the use of MNSAs on the vessel bottom will likely involve an extensive review. A general comment here would be that you provide as complete and thorough a design and test package as possible, and not wait for the staff to ask for it.

The design package should include a Section III fatigue evaluation of the region adjacent to the MNSA as well as a Section Xl fatigue crack propagation analysis, based on postulating a detectable crack within the wall adjacent to the MNSA. Note that the statement in the relief request that the staff previously reviewed and approved the methodology used to evaluate the installation of the MNSA-2s is not consistent with the referenced letters.

8. In addition, the request should be as accurate as possible. For example, the cover letter says relief is requested under 10 CFR 50.55a(a)(3)(ii); however, the Enclosure requests relief under 10 CFR 50.55a(a)(3)(i). You need to determine upon what basis you are requesting relief.

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9. The staff believes that before authorizing the use of MNSAs on the bottom of the vessel, it is prudent to await the finalization of the ASME Code deliberations on the use of this type of repair technique.

10. A first-of-a-kind staff approval to use the MNSAs to repair nozzle leakage on the bottom of the vessel is not envisioned to be a straightforward, nor short duration, review. The staff recommends pursuing a proven permanent repair technique (half-nozzle) for the upcoming outage and for the industry to seek approval to use MNSAs for this application on a longer term.

11. At a minimum, visual inspection requirements should be consistent with past applications; e.g., insulation removal and treating all leaks as pressure boundary leaks (since the design of the original installation did not permit any leakage).

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