NG-07-0367, Relief Request for Drywell Stabilizer Examinations

Relief Request for Drywell Stabilizer Examinations

ML071430227
Person / Time
Site:	Duane Arnold
Issue date:	05/15/2007
From:	Vanmiddlesworth G Duane Arnold
To:	Document Control Desk, NRC/NRR/ADRO
References
NG-07-0367
Download: ML071430227 (6)

Text

FPL Energy Duane Arnold, LLC 3277 DAEC Road Palo, Iowa 52324 FPL [

Duan~e oDndJ Energy Center May 15, 2007 NG-07-0367 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Relief Request for DrDwell Stabilizer Examinations Pursuant to 10CFR 50.55a(a)(3)(ii), FPL Energy Duane Arnold, LLC, (hereafter, FPL Energy Duane Arnold) hereby requests relief from IWE-2500 from performing the VT-3 visual examinations of the reinforcing structure and integral attachment of Drywell Stabilizers X-58C and*X758G. This relief is requested for the first ten year interval of the Containment Inspection Program for the Duane Arnold Energy Center (DAEC), which will end onMay,21., 2008.

FPL Energy Duane Arnold requests approval of this request by the end of May 2008.

This letter contains no new commitments nor revises any previous commitments.

If you have any questions, please contact Steve Catron at (319) 851-7234.

Gary Van Middlesworth Site Vice President, Duane Arnold Energy Center FPL Energy Duane Arnold, LLC EnclIsu're' r cc: '..Administrator, Region)II, USNRC Project Manager, DAEQC, USNRC SeniorResident Inspector, DAEC, USNC

Enclosure to NG-07-0367 Page 1 of 5 10 CFR 50.55a REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(a)(3)(ii)

INSERVICE INSPECTION HARDSHIP Component Identification Code Class: MC

References:

ASME Code,Section XI, Table IWE-2500-1 Examination Categories: E-A Item Numbers: E1.12

Description:

Drywell Stabilizer Man Hole Cover Frames and Welded Attachments behind the Covers.

Component Numbers: Drywell Stabilizers X-58C and X-58G

Applicable Code Edition and Addenda

ASME Section XI 1992 Edition, 1992 Addenda Code Requirement Section Xl (1992 Edition, 1992 Addenda) Subarticle IWE-2500 states, in part, "The method of examination for components... shall comply with those tabulated in Table IWE-2500-1." Table IWE-2500-1 Category E-A, Item E1.12 notes 2 and 5 require VT-3 visual examinations of manhole frames and attachment welds between structural attachments and the pressure retaining boundary.

Reason For Request The DAEC construction permit was issued in 1970 and the operating license was issued in 1974. The ASME Code Section III, Class B, 1968 Edition with the Summer 1968 Addenda and Code Cases 1177, 1330, and 1413 were used for the design, fabrication, and testing of the DAEC Primary Containment. The upper elevation drywell coolers were installed in the drywell in 1987. In the Federal Register dated August 8, 1996 (61 FR 41303), the NRC amended its regulations (rule) to incorporate by reference the 1992 Edition and Addenda of Subsection IWE of Section Xl of the ASME Boiler and Pressure Vessel Code.

The parameters for accessibility for Inservice Inspection were not requirements at the time the drywell coolers were installed, and therefore not necessarily factored into component and system configurations, thereby creating conditions where ASME Section XI Code required examination coverage for containment components became impractical.

Enclosure to NG-07-0367 Page 2 of 5 10 CFR 50.55a recognizes the limitations to in-service inspection of components in accordance with Section XI of the ASME Code that are imposed due to early plants' design and construction, as follows:

10 CFR 50.55a(a)(3)(ii): Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

To examine the manhole frame and to examine the drywell stabilizer attachment welds, the drywell stabilizer manhole covers have to be removed. The upper elevation drywell coolers were installed prior to these VT-3 exam requirements. As shown in the attached images, the upper elevation drywell coolers prohibit the removal of the bolting and the manhole covers for Drywell Stabilizers X-58C and X-58G. The manholes are 16 inches in diameter with 23.5 inch diameter manhole covers bolted to 16 studs. The studs are one inch in diameter and 6 inches in length. Without removal of the bolting, the integral attachment and the associated reinforcing structure cannot be examined. In order to perform the VT-3 visual examination, the drywell coolers would have to be moved. This removal would require extensive modification in the drywell.

Examination of the Drywell Stabilizers X-58C and X-58G, which includes the reinforcing structural and the integral attachment to the outside diameter of the drywell, has only a small potential of increasing plant safety margins and a very disproportionate impact on expenditures of plant manpower and radiation exposure.

Proposed Alternative and Basis for Use Pursuant to 10 CFR 50.55a(a)(3)(ii), the DAEC requests relief from performing the VT-3 visual examinations of the reinforcing structure and integral attachment of Drywell Stabilizers X-58C and X-58G.

There are a total of eight Drywell Stabilizers and associated manhole covers (X-58A through X-58H). X-58A is documented on a previous relief request (Precedent 1).

The remaining five Drywell Stabilizers have been examined with acceptable results.

Duration of Proposed Alternative Relief is requested for the first ten year interval of the Containment Inspection Program for the DAEC, which will end on May 21, 2008.

Enclosure to NG-07-0367 Page 3 of 5 Precedent

1) NRC Letter dated December 13, 2000, Safety Evaluation for the Proposed Alternatives to the ASME Section XI Requirements for Containment Inservice Inspection for the Duane Arnold Energy Center (TAC No. MA8523)

(ML003777130)

Enclosure to NG-07-0367 Page 4 of 5 X-58G (inaccessible) 904)

STABILIZER 9-1

Enclosure to NG-07-0367 Page 5 of 5

(.-TAR 11 17FV1D :U7 ,)-ya 0