ML15035A680

Request for Additional Information

ML15035A680
Person / Time
Site:	Hatch
Issue date:	02/05/2015
From:	Martin R Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Martin R
References
TAC MF4860
Download: ML15035A680 (6)

Text

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 5, 2015 Mr. C. R'. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.

P. 0. Box 1295/Bin- 038 Birmingham, AL 35201-1295

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNIT 2- REQUEST FOR ADDITIONAL INFORMATION (TAC NO. MF4860)

Dear Mr. Pierce:

By letter dated September 19, 2014, the Southern Nuclear Operating Company, Inc. (SNC),

submitted request for relief HNP-ISI-ALT-HDPE-01, which requests authorization to replace buried steel Plant Service Water piping with High Density Polyethylene piping for the duration of the license at Hatch Nuclear Plant, Unit 2.

The U.S. Nuclear Regulatory Commission staff has determined that additional information in the mechanical engineering area is needed as discussed in the Enclosure. We request that SNC respond by February 20, 2015.

• Sincerely,

~~~~

~obert Martin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No.: 50-366 cc: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION PROPOSED INSERVICE INSPECTION ALTERNATIVE HNP-ISI-ALT-HDPE-01, REV. 2 HATCH NUCLEAR PLANT, UNIT 2 SOUTHERN NUCLEAR OPERATING COMPANY, INC.

DOCKET NO. 50-366 The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the Southern Nuclear Operating Company, Inc. (SNC), relief request HNP-ISI-ALT-HDPE-01, dated September 19, 2014, as supplemented on November 14, and November 24, 2014 (References 1, 2 and 3 below)

(Agencywide Documents Access and Management System (ADAMS) Accession Nos.

ML14266A183, ML14317A261 and ML15028A518), which requests authorization to replace buried steel Plant Service Water (PSW) piping with High Density Polyethylene (HOPE) piping for the duration of the license at Hatch Nuclear Plant, Unit 2. The NRC staff has reviewed the request and determined that additional information is necessary in the mechanical engineering area to continue the review.

References:

1. Letter No. NL-14-1250, From C. R. Pierce, Regulatory Affairs Director, Southern Nuclear Operating Company (SNC), to U. S. Nuclear Regulatory Commission, Document Control Desk, "Edwin I. Hatch Nuclear Plant Unit 2 Proposed lnservice Inspection Alternative HNP-ISI-ALT-HDPE-01 Version 2.0," September 19, 2014.

(ML14266A183)

2. Letter No. NL-14-1821, From C. R. Pierce, Regulatory Affairs Director, Southern Nuclear Operating Company (SNC), to U. S. Nuclear Regulatory Commission, Document Control Desk, "Edwin I. Hatch Nuclear Plant Unit 2 Proposed lnservice Inspection Alternative HNP-ISI-ALT-HDPE-01 Version 2.0 Supplementary Information," November 14, 2014.

(ML14317A261t

3. Letter No. NL-14-1876, From C. R. Pierce, Regulatory Affairs Director, Southern Nuclear Operating Company (SNC), to U. S. Nuclear Regulatory Commission, Document Control Desk, "Edwin I. Hatch Nuclear Plant Unit 2 Proposed lnservice Inspection Alternative HNP-ISI-ALT-HDPE-01 Version 2.0 Conceptual Design Information Package,"

November 24, 2014. (ML15028A518)

-1. Section 1.0, Calculation SMNH-14-013, Enclosure 3 (Calculation of Minimum Wall Thickness for PSW HOPE Piping) to NL-14-1876 (Conceptual Design information Package, Reference 3):

It was noted that minimum wall thickness calculation does not apply to fittings and components. However, the PSW replacement by HOPE includes some fittings, e.g.

90 degree mitered elbows, 45 degree mitered elbows, and flange adaptors. The licensee is requested to address minimum required wall thickness for these components.

Enclosure

2. Section 1.0, Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Conceptual Design information Package, Reference 3):

Section 3.1 of Enclosure 3 of Reference 3 includes design pressure and design temperature for PSW Header HOPE pipe but does not provide normal and maximum operating pressures and temperatures. It was not identified whether the design values are for PSW supply or PSW return system. The licensee is requested to provide a table showing normal operating, and maximum operating pressures and temperatures for the HOPE piping (PSW Supply, and PSW Return portions as applicable).

3.a In Section 6220 of Enclosure 2 to NL-14-1250 (Reference 1) it was stated that the system will be hydrostatically tested at not less than 1.5times the design pressure

+ 10 psi. Please supplement Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE) to NL-14-1876 (Conceptual Design information Package, Reference 3) to include stresses in HOPE piping for the initial hydrotest based on 1.5 times design pressure+ 10 psi, along with allowable stress limit.

3.b In Supplement 5 (Section XI In-service Inspection) of Enclosure 2 to NL-14-1250 (Reference 1), it was mentioned that the periodic pressure test will be performed using a test pressure of maximum normal operating pressure. Please provide the value for maximum normal operating pressure. *

4. In Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE) to NL-14-1876 (Conceptual Design information Package, Reference 3),

(a) Include exerpts from the stress analysis computer program .(i) input, and (ii) output corresponding to the maximum reported stress locations.

(b) Provide a description of the stress analysis model termination boundaries; hour much of the piping and supports beyond the buried HOPE piping is included.

(c) Include a summary of stresses, and loadings (forces and moments) at the interface (metallic pip to HOPE pipe) adapter flange from all applicable load cases, and discuss the acceptability of these loadings.

5. On page 1 of 2 of Enclosure 1 (Conceptual Design Scope description) to NL-14-1876 (Conceptual Design information Package, Reference 3), it was mentioned that Valve 2P41-F380B and its operator are relocated in the existing Unit 2 Division II vault, and new stainless steel piping is added. Additional pipe supports will be added to the metallic piping. The licensee is requested to:

(a) Provide loads on metallic piping supports included in the buried HOPE piping model.

(b) Also include valve accelearations for any valves included in the stress analysis model along with their acceptance limits.

(c) Address the impact of these changes on above ground piping stress analysis models, and the qualification of valves and pipe supports in the vicinity of the metallic and HOPE piping interface.

6. Page E2-22, Section 3312 of Enclosure 2 to NL-14-1250 (Reference 1) provides allowable stress limit as 2S for c6mputed stresses from non-repeated anchor movements, where Sis Long-Term Allowable Stress for Polyethylene listed in Table 3131-1 (Page E2-22).

7 Page 3 of Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Reference 3) computed non-repeated anchor movement stress based on % inch assumed building settlement and used allowable stress limit of 1S only in margin factor calculation. Please provide the following information.

(a) Technical basis or a justification for% inch settlement used in conceptual design.

(b) Explain if 1S limit instead of 2S limit is used for conservatism only.

7. Page 2 of Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Reference 3) provides a tai;Jie containing computed longitudinal stresses for service levels A, B, and D. Please include the load cases and load combinations used for the above three service levels.

8. Page 3 of Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Reference 3) provides a table containing seismically induced stresses for straight pipe and miter elbow. Please include the seismic input values used such as soil strains caused by seismic wave passage, seismic soil movement, and seismic anchor motion. Briefly describe the applicable load cases and load combinations used.

9. Page 3 of Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Reference 3) provides a table containing stresses from thermal expansion and thermal contraction and combined stress. Please include the corresponding temperatures for all of the thermal modes applicable to the PSW system.

10. Page 3 of Section 2.0 of Enclosure 5 (Summary Report on Stress Analysis for PSW Buried HOPE Piping) to NL-14-1876 (Reference 3) provides a table containing stresses

• from alternative thermal expansion and contraction evaluation. Please describe if these stresses are thermal range stresses and include the corresponding temperatures for the applicable thermal cases used in this evaluation.

11. Item (e) Page E2-34, Section 4520 of Enclosure 2 to NL-14-1250 (Reference 1) discusses flanged joints at the transition flange. It is mentioned here that in assembling flanged joints, the gaskets, if used, will be uniformly compressed to the proper design loading.

The licensee is requested to clarify whether the transition flanged joints in Hatch, Unit 2, existing service water sub-grade vault 2B and in new service water sub-grade vault

. (page 1 of 2 of Enclosure 1 to NL-14-1876 (Reference 3) contain gaskets or not. Please discuss if leak tight joints can be achieved without a gasket, citing any precedents or operating experience. If gaskets will be used, please provide applicable gasket details (Gasket Material, Gasket Factor, Seating Stress, and Seating Width) .

12. As discussed in Enclosure 1 to NL-14-1876 (Reference 3) the majority of the HOPE.

piping is buried with some non-buried portions in an existing vault and in a new vault, which contain transition flanged joints and some valves. The licensee's submittal does not address moderate energy crack postulation assessments for non-buried sections of

HOPE piping. The licensee is requested to address the Moderate Energy Crack postulation assessments for non-buried sections of moderate energy piping and any impact on safety-related commodities in the vicinity. The evaluations should include computed stresses and crack postulation threshold limits to determine if moderate energy cracks need to be postulated or can be excluded.

13. Provide a brief discussion related to the fire hazard of the non-buried sections of the HOPE piping located in the existing service water vault 28 and the new service water vault and the impact on any safety-related commodities in the vicinity from the fire hazard. Please also address fire resistance characteristics of the insulation and any.

wrapping used on the HOPE piping.

ML15035A680 OFFICE NRR/LPLII-1/PM NRR/LPLII-1/LA NRR/LPLII-1/BC NRR/LPLII-1/PM NAME RMartin SFigueroa RPascarelli RMartin DATE 01/30/15 02/05/15 02/05/15 02/05/15