ML20209G135

Forwards Relief Request Re Repair Welding on SA-351 Matl to Be Installed in Seabrook Station SW Pumps & SW Cooling Tower Pumps

ML20209G135
Person / Time
Site:	Seabrook
Issue date:	07/09/1999
From:	Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AR#99010008, NYN-99061, NUDOCS 9907190032
Download: ML20209G135 (7)

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i North North Atlantic Energy Service Corporation P.O. Box 300

',sg Atlantic H

seehrook, Nii O3874 ,

(603) 474-952t )

I The Northeast Utilities System l July 9,1999 Docket No. 50-443 NYN-99061 AR#99010008

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United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Seabrook Station ASME Section III Relief Request for the Service Water and Service Water Cooling Tower Pumps Enclosed is a relief request pertaining to repair welding on SA-351 material (grade CD4MCu) to be installed in the Seabrook Station Service Water Pumps and the Service Water Cooling Tower Pumps. North Atlantic Energy Service Corporation (North Atlantic) requests to utilize an c alternative to the requirements of the 1989 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code pursuant to 10 CFR 50.55a(a)(3)(i). North Atlantic requests NRC review and approval of this relief request by September 15,1999 to support the planning and scheduling of work activities for the Service Water Pumps.

Should . you require further information regarding this matter, plcase contact Mr. James M. Peschel, Regulatory Compliance Manager at (603) 773-7194.

Very truly yours, NORTH ATLANTIC ENERGY SERVICE CORP.

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Ted C. Feigenbaun'i Executive Vice President and ChiefNuclear Officer l

l cc: H. J. Miller, NRC Regional Administrator W. T. Harrison, NRC Project Manager, Project Directorate 1-3 i R. K. Lorson, NRC Senior Resident Inspector I

^ 9907190032 990709 f\v PDR ADOCK 05000443 p PDR L

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9 ENCLOSURE 1 TO NYN-99061 l

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Enclosure 1

/' NYN-99061/ Page 1 of 3 North Atlantic Energy Service Corporation Seabrook Station Unit 1 Relief Request

1. Components For Which Reliefis Requested: ,

Service Water Pumps Service Water Cooling Tower Pumps

2. Component ID No's:

SW-P-41 A SW-P-41B SW-P-41C SW-P-41D SW-P-110A SW-P-Il0B

3. - ASME III r' ode Class:

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4. ASME Section III Code Requirement:

Note (5) of ASME Boiler and Pressure Vessel, Code Section Ill,1989 Edition, Table I-7.2, "M!owable Stress Values S for Austenitic Steels, High Nickel Alloys, and Copper Alloys for Class 2 and 3 Components" prohibits the use of welding processes on SA-351, Grade CD4MCu material. Note (5) states that "No welding is permitted on these materials."

ASME Section II Code Requirement:

ASME Section II,1989 Edition, Specification SA-351/SA-351M, Section 10, " Repair by Welding," allows weld repairs to Grade CD4MCu material provided, the repairs are made i l

using procedures and welders qualified under Section IX of the ASME Code.

S. Basis for the Relief Request:

Reliefis being requested from the requirements of Note (5) on Table I-7.2 for SA-351, Grade CD4MCu for the Service Water pumps pursuant to 10CFR50.55a(a)(3)(i) on the basis that the proposed altemative will provide an acceptable level of quality and safety.

Enclosure 1

. NYN-99061/ Page 2 of 3 The function of the station Service Water system is to transfer the heat loads from various i sources in both the primary and secondary portions of the plant to the ultimate heat sink. The i ultimate heat sink for all operating and accident cooling loads is normally the Atlantic Ocean.

The Service Water pumps normally supply the Service Water system heat loads. The design conditions for the service water system piping, valves and pumps (Service Water and Cooling Tower Pumps) are 150 psig and 200 'F.

In the unlikely event that the seawater flow to the Service Water pumps is restricted, a mechanical draft evaporative cooling tower is available to dissipate shutdown and accident 4 heat loads. The Service Water Cooling Tower Pumps are used to circulate water through the l

required Service Water system loads and the cooling towers. The design of the Service Water Pumps and the Service Water Cooling Tower Pumps are similar. Both are vertical line shaft pumps with two stage impellers and bowl assemblies. The present design for the pump l impeller and bowl assemblies utilizes SA-351 (grade CF3M) as the material. In order to improve the reliability of the pumps, the pump vendor has recommended that Seabrook Station install impellers and bowl assemblies utilizing SA-351 (Grade CD4MCu) as the material.

Certain material conditiens may require that weld repairs be made to components made from SA-351 (Grade CD4MCu). The ASME Boiler and Pressure Vessel Code Section II,1989 j Edition Specification SA-351/SA-351M, Section 10. " Repair by Welding," allows weld repairs for all grades of SA-351 materials, provided the repairs are made using procedures and welders qualified under Section IX of the ASME Code. Note (5) of ASME Boiler and Pressure Vessel, Code Section III,1989 Edition, Table I-7.2, is in conflict with the Section II, 1989 Edition requirements because it prohibits the use of welding processes for repairs SA-351, (Grade CD4MCu) material. This conflict was resolved by the ASME in the 1995 Edition of Section II, Part D, Table 1 A (which replaces Table I-7.2 in the 1995 Edition of Section III) by removing the footnote (5) for SA-351 (Grade CD4MCu).

The NRC published a proposed rule (6? FR 63892) dated December 3,1997 which would i amend 10 CFR 50.55a to permit the use of Section III, Division 1, of the ASME Boiler and l Pressure Vessel Code,1989 Addenda through the 1996 Addenda. However, the NRC has not issued the final rule.

t This alterriative request is similar to a relief request approved by the NRC in a safety evaluation dated May 5,1995 for the Salem Nuclear Generating Station, Units I and 2 and the Hope Creek Nuclear Generating Station (Docket Nos. 50-272/311/354).

6. Alternative Requirements:

Repairs made to components utilizing SA-351 (Grade CD4MCu) materials in the Service Water and Service Water Cooling Tower Pumps will be performed using procedures and

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Enclosure 1 NYN-99061/ Page 3 of 3 6

welders qualified under Section IX of the ASME Boiler and Pressure Vessel Code. Weld repairs shall be mspected to the same quality standards that are used to inspect the castings.

When castings are produced with Supplementary Requirement S5 specified, weld repairs on castings that have 16aked on hydrostatic test, or on castings in which the depth of any cavity prepared for welding exceeds 20% of the weld thickness or 1 in. [25 mm], whichever is smaller, or on castings in which any cavity prepc. ed for welding is greater than 2

approximately 10 in [65 cm ], shall be radiographed to the same standards that are used to inspect the castings. When castings are produced with Supplementary Requirement S6 specified, weld repairs shall be inspected by liquid penetrant examination to the same standards that are used to inspect the castings. These requirements are consistent with the requirements of ASME Section II,1989 Edition, Specification SA-351/SA-351M, Section 10," Repair by Welding."

In addition to the above, no weld repairs will be performed on-site at Seabrook Station. All repairs to the SA-351 (Grade CD4MCu) material will be performed in accordance with a 10 CFR 50 Appendix B Quality Assurance Program by an ASME Certificate Holder at the Certificate Holder's facility where the material can be solution heat-treated after the weld repair. The ferrite content of the repairs will be controlled utilizing procedures and administrative controls approved by North Atlantic.

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ENCLOSURE 2 TO NYN-99061 l

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Enclosure 2

, , . NYN-99061/ Page 1 of 1 NRC Commitments Contained in NYN-99061 AR#99010008 Description of Commitment Assignment 02 Upon approval of this relief request by the NRC, North Atlantic will develop controls to ensure that repairs mede to components utilizing SA-351 (Grade CD4MCu) materials in the Service Water and Service Water Cooling Tower Pumps will be performed in accordance with the requirements outlined in NYN-99061.

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