ML13247A709

Seabrook Station Response to NRC Draft RAIs on the Seabrook Station Relief Request RA-13-001

ML13247A709
Person / Time
Site:	Seabrook
Issue date:	08/30/2013
From:	Ossing M NextEra Energy Seabrook
To:	Lamb J G Division of Operating Reactor Licensing
Lamb J G
Shared Package
ML13247A702	List: ML13247A709 ML13247A715 RA-13-001, C-S-1-45893-CALC 000 4
References
RA-13-001
Download: ML13247A709 (3)

Text

1 Lee, Erika From: Ossing, Michael <Michael.Ossing@nexteraenergy.com>

Sent: Friday, August 30, 2013 11:35 PM To: Lamb, John Cc:Connolly, James

Subject:

Seabrook Station Response to NRC Draft RA Is on the Seabrook Station Relief Request RA-13-001 Attachments:

C-S-1-45893-CALC_000_4.pdfJohn Below are the Seabrook Station responses to the Draft RAI questions discussed at 2200 on August 30, 2013.

1. The licensee submitted the proposed relief request pursuant to 10 CFR 50.55a(a)(3)(i). The NRC staff finds this is not appropriate because 10 CFR 50.55a(a)(3)(i) is for the alternative that provides equivalent level of quality and safety as the ASME Code requirement. The NRC does not believe the proposed repair could achieve the equivalent quality and safety. The NRC staff finds that the relief request should be submitted under 10 CFR 50.55a(a)(3)(ii).

Response: Seabrook concurs that the appropriate basis for this relief request is 10 CFR 50.55a(a)(3)(ii). Change Section 5 header to "hardship".

2 (a) Provide the pressure rating of the weldolet and blind flange. (b) Provide the design and normal operation pressure and temperature.

Response:

(a) The pressure rating of the weldolet and blind flange is 150 psi and 200 degrees F. (b) Design - 150 psi and 200 degrees F. Normal operating pressure is 75 psi and Normal operating temperature is 65 degrees F maximum and 35 degrees F minimum.

3. (a) Discuss whether the weldolet is an ASME Code component (satisfies the ASME Code). (b) Discuss whether the welding of the weldolet on the degraded pipe satisfies the ASME Code,Section III or Construction Code.

Response a) The weldolet is ASME SA material and meets the ASME Section III ND requirement for branch connections.

b) The welding will be performed using a qualified procedure that meets the ASME Section IX requirements for an open root, full penetration weld. The branch connection will meet the ASME Section III ND requirements for fabrication.

4. (a) Discuss the pre-installation and post-installation (pre-service) nondestructive examinations (NDE) for the weldolet. (b) Discuss the acceptance criteria for the welding of the weldolet (c) Discuss whether the NDE method is based on the ASME Code,Section XI.

Response:

a) The pre-installation NDE requirements for the weldolet consists of the verification of ASME material, the verification of proper weld joint fit-up and a final Visual and Magnetic Particle exam of the final weld. The post installation NDE requirements consist of a VT-2 for leakage in accordance Section XI, IWA-5000.

b) The acceptance criteria are in accordance with the original construction code, ASME Section III ND, requirements.

2c) The NDE examination methods performed will meet the ASME Section XI, IWA-4500 requirements.

5. Provide Reference 2-- Seabrook Station Calculation C-S-1-45893-CALC Rev. 000 "Code Case N-513-3 Pipe Wall Flaw Evaluation for: SW-1802-004-153-24"

Response: Calculation C-S-1-45893 Rev 000 is attached.

6. (a) Provide calculations to demonstrate that the pipe wall thickness underneath the weldolet and associated weldment will not be reduced by the corrosion during the effective duration of the relief request. (b) Discuss the minimum pipe wall thickness underneath the weldolet and its weldment that is required to maintain the structural integrity of the repair. (c) Discuss what is the wall thickness of the pipe that the weldolet will be weld on.

Response: The sizing of the weldolet (6 inch nominal) was based upon the identified wall thickness of the piping and it's installation position with respect to the bounded flaw size (2.327 by 1.5 inch). The weldolet will be welded to pipe wall thickness verified to be of a thickness of 0.375 inch or better. The typical corrosion rate used by Seabrook is 30 mils per year. To address the unknown corrosion rate within the bounded area, a factor of 4 is applied resulting in a rate of 120 mils per year. Although the installation duration is less than a year (next refueling outage is April 2014) 120 m ils is used. The resulting pipe wall under the weldolet and weldment will therefore be reduced from to 0.375 - 0.120 = 0.255 inch. The ASME Section III Code requirement for minimum pipe wall is 0.105 inch, calculated in calculation C-S-1-45893. As the pipe wall with future metal loss, calculated to be 0.255inch, exceeds the Code minimum of 0.105 inch, structural integrity of the repair will be maintained. The 6.6875 inside diameter of the weldolet in relationship with the major axis dimension of the bounded flaw (2.327) provides sufficient metal such that further corrosion will not affect the integrity of the repair.

7. Describe the pipe supports (hangers or lateral restraints?) that are located to the defective area. How far these pipe supports are from the defect area?

Response: The weight of the repair components is determined as follows: 14.20 lbs (weldolet) + 27 lbs (weld neck flange with bolting) + 26 lbs (blind flange) + 10 lbs (water content) = 77.2 lbs. The pipe supports adjacent to the defective area are:

1802-SG Vertical support (+) approx imately three feet downstream of th e defect area (providing strainer anchorage) 1802-RG Lateral support (+) approximately 1.5 feet downstream of the defect area on the strainer bypass piping 1802-SG Vertical support (+) appr oximately 9.0 feet downstream of the defect area on the strainer bypass piping. 1802-SG Vertical and lateral support (+) approximately 19 feet upstream of the defect area. A review of the pipe support design documentation has concluded that the existing pipe support scheme canaccommodate the weight addition of 77.2 lbs.

Additionally, Seabrook understands the following:

1. Seabrook will not install the blind flange prior to NRC verbal authorization. 2. Seabrook will remove IWA 4340 references in the relief request.

Michael Ossing Licensing Manager 3Seabrook Station 603-773-7512