ML11178A034

Categorization of Risk-Informed Piping

ML11178A034
Person / Time
Site:	South Texas
Issue date:	06/20/2010
From:	Ruvalcaba M South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-11002684
Download: ML11178A034 (4)

Text

Nuclear Operating Company South Texas Pro/eel Elecric Generating Station PO. Box 289 Wadsworth. Texas 774S3 June 20, 2011 NOC-AE-1 1002684 File No.: G25 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2746 South Texas Project Units 1 and 2 Docket Nos. STN-498, STN 50-499 Categorization of Risk-Informed Piping To facilitate NRC review of STP Nuclear Operating Company submittals involving risk-based assessments, Table 3.3.1 of the South Texas Project Electric Generating Station (STPEGS)

Inservice Inspection Program Plan is attached. This table lists the risk-informed category/item number designations of Class 1 and Class 2 piping. Application of these designators aids in classification of risk-informed piping.

The attached table is from Revision 6 of the current program plan which became effective November 17, 2010. Categorization using these criteria was also applied during the second 10-year inspection interval ending September 24, 2010 (Unit 1) and October 18, 2010 (Unit 2). The table is provided for information.

There are no commitments in this letter.

If there are any questions, please contact either Mr. P. L. Walker at (361) 972-8392 or me at (361) 972-7904.

Marco Ruvacaba

Manager, Testing and Programs Engineering PLW

Attachment:

STPEGS Units 1 and 2 Inservice Inspection Program Plan, Cover Sheet and Table 3.3.1, "Risk Informed Category/Item Number Designations," Revision 6 STI: 32886888

NOC-AE-1 1002684 Page 2 of 2 cc:

(paper copy)

(electronic copy)

Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 612 East Lamar Blvd., Suite 400 Arlington, Texas 76011-8064 Balwant K. Singal Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (MS 8 B1) 11555 Rockville Pike Rockville, MD 20852 Senior Resident Inspector U. S. Nuclear Regulatory Commission P.O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 John Ragan Catherine Callaway Jim von Suskil NRG South Texas LP A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Balwant K. Singal U. S. Nuclear Regulatory Commission Kevin Polio Richard Pena E. Alarcon City Public Service C. Mele City of Austin Peter Nemeth Crain Caton & James, P.C.

Richard A. Ratliff Texas Department of State Health Services Alice Rogers Texas Department of State Health Services STI: 32886888

STPEGS Units 1 and 2 Inservice Inspection Program Plan INSERVICE INSPECTION PROGRAM PLAN FOR THE SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION UNITS 1 AND 2 Commercial Operation Dates Unit 1 - August 25, 1988 Unit 2 - June 19, 1989 STP NUCLEAR OPERATING COMPANY Effective Date 11/17/2010 Revision 6

STPEGS Units 1 and 2 Inservice Inspection.Program plan Table 3.3.1 Risk Informed Category/Item Number Designations Risk Informed Categories R-A-1 Class I Risk Informed Piping R-A-2 Class 2 Risk Informed Piping Risk Informed Item Numbers R #. ##.

1. R 1

Class 1 2

Class 2 R

Risk-Informed 1,

High Risk

2.

Medium Risk

3.

Low Risk

11.

Thermal Fatigue

11.

1 Thermal Stratification Cycling and Striping (TASCS)

11.

2 Thermal Transient (TT)

11.

3 TASCS-TT

11.

4 TASCS-TT-PWSCC

11.

5 TT-IGSCC

11.

6 TT-PWSCC

11.

7 TASCS-PWSCC

12.

High Cycle Mechanical Fatigue

13.

Erosion-Cavitation

14.

Crevice Corrosion Cracking is-Primary Water Stress Corrosion Cracking(PWSCC)

16.

IGSCC/TGSCC ( Intergranular/Transgranular SCC)

17.

Microbiologically Influenced Corrosion (MIC) or Pitting

18.

Flow Accelerated Corrosion (FAC)

19.

External Ch]oride (ECSCC)

20.

No Degradation Mechanism 3.3.2 Examination Method The column lists the examination method(s) required by Code Tables 1W3B-2500-I, IWC-2500-1, IWD-2500-1, IWE-2500-1, IWF-2500-1, and IWL-2500-1 or alternative examination method based on a referenced Relief Request or Code Case.

3-3 Revision 6