ML20214U929

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Rev 0 to TVA Employee Concerns Special Program:Piping & Valve Design
ML20214U929
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 10/28/1986
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20214T770 List:
References
232.6-(B), 232.6-(B)-R, 232.6-(B)-R00, NUDOCS 8612090459
Download: ML20214U929 (9)
v • d • e


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1 TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)

SPECIAL PROGRAM REPORT TYPE: SEQUOYAH ELEMENT REVISION NUMBER: 0 TITLE: PIPING AND VALVE DESIGN Rubt'er Gasket Deterioration PAGE 1 0F 9 REASON FOR REVISION:

PREPARATION PREPARED B N /0//7/RS

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// SIGNATURE 'DATE REVIEWS M644 REVIEW COMMITTEE f

/0//7/df

/ DATE V

TAS:

SIGNATURE DATE CONCURRENCES V) / /0 lll CEG-H: NW / O'2 7- 14 SRP:

SIGNATURE DATE SIGNATURE DATE APPROVED BY:

ECSP MANAGER DATE MANAGER OF NUCLEAR POWER DATE 8612090459 861120 7 CONCURRENCE (FINAL REPORT ONLY)

DR ADOCK 0500

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TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (8)

SPECIAL PROGRAM REVISION NUMBER: O PAGE 2 0F 9

1. CHARACTERIZATION OF ISSUE (S):

Concern: Issue:

IN-85-400-002 Rubber gaskets, used in flange

" Rubber gaskets used in the ERCW, joints, installed in safety-related RCW, and other unspecified raw water piping systems such as systems, exhibit deterioration Essential Raw Cooling Water (ERCW),

over short periods of time: exhibit rapid deterioration and could which could adversely impact impact plant nuclear safety, plant nuclear safety due to '

gasket failure. No further specifics or other details are available."

2. HAS ISSUE BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? YES X NO Identified by TVA Generic Concern Task Force Report Date 05/19/86 Documentation Identifiers:

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GOR-23-23, Rev. 1

3. DOCUMENT NOS.. TAG NOS.. LOCATIONS. OR OTHER SPECIFIC DESCRIPTIVE IDENTIFICATIONS STATED IN ELEMENT:

The element identifies rubber gaskets installed in flanged joints used in ERCW and Raw Cooling Water (RCW).

4. INTERVIEW FILES REVIEWED:

File No. IN-85-400-002

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:

See Appendix A.

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (8)

SPECIAL PROGRAM REVISION NUMBER: O PAGE 3 0F 9

6. WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN REQQlREMENTS. OR OTHER APPLY OR CONTROL IN THIS AREA?

See Appendix A.

7. REQUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER DISCUSSIONS RELATED TO ELEMENT:

See Appendix A.

8. EVALUATION PROCESS:
a. Reviewed with site personnel maintenance history of rubber gaskets at SQN and WBN plants.
b. Established historical validity of the concern from a search of maintenance records.
c. Identified material presently used for rubber gaskets and reviewed code requirements.
d. Reviewed TVA Generic Concern Task Force Report, GOR-23-23 for this element and assess / verify findings.
e. Determined safety impact of rubber gasket deterioration if it were presumed to occur.
9. DISCUSSION. FINDINGS. AND CONCLUSIONS:

Discussion:

The concern relates to short-term deterioration of rubber gaskets installed in flanged piping joints in the ERCW, the RCW and other unspecified systems at WBN plant. The CI postulates that such a condition may have a possible adverse impact on plant nuclear safety.

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (8)

SPECIAL PROGRAM REVISION NUMBER: 0 PAGE 4 0F 9 Initially this concern was investigated on WBN. Interviews with WBN maintenance personnel could not establish a historical problem with rubber gaskets in either safety or non-safety related systems. One isolated instance suggested that about six years ago some unidentified rubber gasket material installed in non-safety related systems did not perform satisfactorily and required replacement. No further action was considered necessary at that time, and no further problems of this nature have been noted.

Based on the WBN concern the TVA SQN Generic Concern Task Force identified " rubber gasket deterioration" as a potential generic

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issue. An investigation was initiated to determine if a similar problem existed at SQN plant. The Task Force interviewed responsible SQN mechanical maintenance personnel, but none were aware of any rubber gasket deterioration problem. Additionally, the Task Force examined 1555 maintenance requests (MR) on the ERCW system covering a six year period through April 17, 1986. Five of these MRs identified system leakage; however, none involved rubber gaskets. The Generic Task Force Report GOR-23-23 appropriately concluded that while rubber gaskets are used in cerisin mechanical systems in both the reactor and auxiliary buildings, there has been no verifiable adverse impact on operation.

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1069d - 10/17/86 I

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (8)

SPECIAL PROGRAM REVISION NUMBER: 0

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i PAGE 5 0F 9 The economy of using a gasket in a flanged joint results from ,

avoiding the expense of grinding and lapping the joint faces to obtain fluid tight joints. The gasket in a flanged piping joint provides a seal and is not associated with the pressure retaining function of the flanges and bolting. The presence of a deteriorated or imperfectly sealing gasket may risult in a leaking joint but is not considered a failure of the system pressure boundary.

A leaking flanged joint is a plant maintenance item without impact on plant nuclear safety. The failure of a gasket is not a sudden event. The amount of system inventory that would be lost through joint leakage is not sufficient to diminish a safety system's ability to meet its intended purpose.

Leaktight integrity of the ERCW system is assured by periodic pressure tests and inspections required by SQN design criteria No.

SQN-DC-V-7.4, " Essential Raw Cooling Water System (67)." The required tests and inspections are implemented at SQN Plant by preventive maintenance program procedures PM-168'6-067 and PM-1685-067 for units 1 and 2 respectively.

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 0

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\ PAGE 6 0F 9 Section III of the ASME B&PV code requires only that gaskets be made of materials that are not injuriously affected by the fluid in the pipe or by temperature within the piping design temperature range. In accordance with the code, if the expected normal service pressure does not exceed 720 psi or the temperature does not exceed 750*F (which is the case for all SQN systems wher'e rubber gaskets are used), the selection of a suitable gasket material is the owner's responsibility and not an issue.

Rubber gasket material (1/16 inch thick red rubber, Garlock ring type #122) is specified on relevant SQN design drawings, as reported in App. A, 5.a. The Garlock #122 ring type rubber gasket is manufactured to meet the requirements of ASTM D 1330. This gasket material is typically used in low temperature / pressure water services. All rubber gaskets now used in both safety and non-safety related systems at SQN Plant are procured to ASTM Standard Specification for Rubber-Sheet Gaskets, D1330.

Findings:

a. The rubber gasket material specified and installed in certain systems at SQN plant complies with Section III of the ASME B&PV code for class 2 and 3 piping systems.

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 0 t

PAGE 7 0F 9

b. The rubber gasket material installed at SQN plant is typical of the best industrial standard rubber gasket material commercially available.
c. There is no evidence of rubber gasket failure (premature or otherwise) at SQN Plant.
d. Deterioration of gasket material does not present a safety issue.

Conclusions:

a. The concern is not valid for the rubber gasket material used at SQN Plant.
b. There is no adverse impact on plant nuclear safety as a consequence of the rubber gasket material used at SQN Plant.

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 0

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PAGE 8 0F 9 APPENDIX A

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
a. TVA Generic Concern Task Force Report, GOR-23-23, Rev.1, (05/19/86)
b. TVA Design Criteria SQN-DC-V-7.4, Essential Raw Cooling Water System (67) ,
c. Drawings 47BM450,17BM302, and 47BM915; Bill of Materials for ERCW and High Pressure Fire Protection (HPFP) systems
d. ASTM Standard Specification for Rubber-Sheet Gaskets, D 1330
e. ASME Code,Section III, Division 1, Subsection NC-Class 2 Components, and Subsection ND-Class 3 Components
6. WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN REQUIREMENTS. OR OTHER APPLY OR CONTROL IN THIS AREA?

a Design Criteria }0N-DC-V-30, " Classification of Piping, 25(PIV-E*d -V 3* 0 Valves, and Vessels" Pumps,

b. ANSI-B16.21-1978, " Nonmetallic Flat Gaskets for Pipe and Flanges"
c. Drawings 47BM450,17BM302, and 47BM915; Bill of Materials for ERCW and HPFPS
d. ASTM Standard Specification for Rubber-Sheet Gaskets, D 1330
e. ASME Code,Section III, Divisinn 1, Subsection NC-Class 2 Components, and Subsection ND-Class 3 Components e

1069d - 10/17/86

TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)

SPECIAL PROGRAM REVISION NUMBER: 0 j

[ PAGE 9 0F 9

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7. REQUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER DISCUSSIONS RELATED TO ELEMENT:
a. RFI #SQN-506
b. Telephone calls from S. Presser, Bechtel, to J. Casey, TVA, SQN, and H. Mahlman, TVA, Knoxville, (09/15/86 and 09/24/86)
c. Telephone call from S. Presser, Bechtel, to K. Lewis, TVA, WBN, and H. Mahlman, TVA, Knoxville, (09/15/86)
d. Telephone call from S. Presser, Bechtel, to T. E. Cook, Garlock Area Representative, (09/24/86)
e. Response to RFI SQN-508, TVA Transmittal No. 100(4) 1069d - 10/17/86

ENCLOSURE 2 l

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