SBK-L-12204, Clarification to Relief Request for Service Water Piping
| ML12270A369 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 09/25/2012 |
| From: | O'Keefe M NextEra Energy Seabrook |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SBK-L-12204 | |
| Download: ML12270A369 (5) | |
Text
NEXTera EN ERGY7L-A September 25, 2012 SBK-L-12204 Docket No. 50-443 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Clarification to Relief Request for Service Water Piping
References:
- 1. NextEra Energy Seabrook, LLC letter SBK-L-12137, "Relief Request - Proposed Alternative in Accordance with 10 CFR 50.55a (a)(3)(ii)," August 1, 2012.
- 2. NRC Letter "Seabrook Station Unit No. 1 - Request for Additional Information Regarding Relief Request for Service Water Piping (TAC No. ME9187)," September 4, 2012. (ML12226A462)
- 3. NextEra Energy Seabrook, LLC letter SBK-L-12176, "Response to Additional Information Regarding Relief Request for Service Water Piping (TAC No. ME9187),"
September 7, 2012 In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted a request to use a proposed alternative in accordance with 10 CFR 50.55a (a)(3)(ii). NextEra requested relief from the ASME Code requirement that defective portions of components be removed prior to performing a repair/replacement activity by welding for buried piping in the service water system. In Reference 2, the NRC staff requested additional information to complete its review of the request, and Reference 3 responded to the information request.
The NRC staff had several questions on NextEra's response to the request for additional information, which were discussed during a conference call on September 20, 2012. In follow-up to the conference call, the Enclosure to this letter provides additional clarification to the relief request submitted in Reference I and to the responses in Reference 3.
Should you have any questions regarding this submittal, please contact Mr. Michael O'Keefe, Licensing Manager, at (603) 773-7745.
NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874
Wh.S Nuclear Regulatory Commission SBK-L-12204 / Page 2 Sincerely, NextEra Energy Seabrook, LLC 1~65; Michael O'Keefe Licensing Manager
/
Enclosure cc:
NRC Region I Administrator NRC Project Manager, Project Directorate 1-2 NRC Resident Inspector
Enclosure to SBK-L-12204 Clarification to Relief Request for Service Water Piping
NRC Question 1 In response to Question 4(c), the licensee stated that it will inspect the following pipe lines: SW-1801-003-153-24", SW-1810-003-153-24" and SW-1818-003-153-24". However, Section 1 of the relief request dated August 1, 2012, mentions only the 1801-3 and 1818-3 pipe lines. It appears that the relief request does not cover the SW-1810 pipe line. If the licensee wants to apply the proposed repair technique to the SW-1810 pipe line, the licensee needs to update the relief request.
NextEra Response The proposed repair technique will also be applied to the SW-1810 line. Therefore, section 1 of the relief request, ASME Code Component Affected, includes the portion of piping SW-1810-003-153-24" in the service water system and is revised as shown below:
- 1.
ASME Code Component Affected The affected piping is the A train 24-inch diameter service water pipes, line numbers 1801-003, 1810-003, and 1818-003.
These lines service the Primary Component Cooling Water (PCCW) Heat Exchanger CC-E-I7-A. These lines supply and return seawater to and from the PCCW Heat Exchanger, which is used to remove heat from systems and components during normal plant operation and emergency plant evolutions.
NRC Question 2 The licensee's RAI response contains many numerical values. For example, response to Question 9(a) and 9 (b) provides the thickness of the encapsulation. Is the thickness of the encapsulation proprietary infornation? Is there any proprietary information in the response (besides those that have already been identified in Attachment 3 of the September 7, 2012 submittal)? If there is proprietary information in the RAI response, please identify them so that the NRC staff will not use the proprietary information in its safety evaluation.
NextEra Response There is no proprietary information in the RAI response besides that which has already been identified.
NRC Question 3 Response to Question 9(a) and 9(b) implies that there are two sizes of encapsulations: 4-inch and 6-inch. However, Section 5 of the relief request (page 2, second paragraph) discusses only the 6-inch device. The 4-inch device is not mentioned in the relief request. The licensee should revise the relief request to include the 4-inch encapsulation if the 4-inch device will be used; otherwise, only the 6-inch encapsulation can be applied to the service water piping in accordance with the relief request.
NextEra Response NextEra will use either a four-inch or six-inch encapsulation device as appropriate for the area that requires repair. Therefore, paragraph 2 in section 5 of the relief request is revised to the following:
- 5.
Proposed Alternative and Basis for Use The structural repair consists of either a 4"or 6" diameter circular encapsulation device designed to accommodate the design pressure as well as mechanical loading. Since welding of the cap will impact the capability of the exterior wrap to preclude outer diameter (OD) corrosion due to contact with ground water, no credit will be taken for the localized external wrap in determining the service life of the repair. The encapsulation cap ID will be such that the inside diameter is greater than the maximum diameter of the defective area plus a minimum of twice the nominal thickness of the pipe.
NRC Question 4 Response to Question 18 states that a minimum of a distance of 5.262 inches will be imposed between two adjacent encapsulations. However, Attachment 3, PMC Engineering calculation, Section 9.2 (page 28 of 29) specifies a distance of 6.12 inches between the two adjacent encapsulation devices. Clarify the discrepancy.
NextEra Response:
NextEra will use the PMC Engineering value for minimum distance between two adjacent encapsulation devices. Therefore, the answer to Question 18 to the relief request is revised to the following:
PMC Engineering determined the minimum distance between two adjacent encapsulation devices from ASME Code ND-3643.3 criteria for "Special Requirements for Extruded Outlets" and, therefore, obtained a minimum distance of 6.120 inches. NextEra determined this value utilizing ASME Section XI Code Case N-661-1 criteria for "Alternative Requirements for Wall Thickness Restoration of Class 2 and 3 Carbon Steel Piping for Raw Water Service" and obtained a value of 5.262 inches. Both methods are acceptable for calculating the minimum distance between two adjacent encapsulation devices; however, because of the discrepancy, the conservative distance of 6.120 inches will be used should the installation of an adjacent encapsulation device be required.