ML20214U308
| ML20214U308 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/20/1986 |
| From: | Mason P, Parkinson J, Wiedner K TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20214G966 | List:
|
| References | |
| 232.6(B), 232.6(B)-R, 232.6(B)-R00, NUDOCS 8612090222 | |
| Download: ML20214U308 (9) | |
Text
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.s TVA EMPLOYEE CONCERNS REPORT NUM8ER: 232.6 (B)
SPECIAL PROGRAM
[i$1 ff-REPORT TYPE:
SEQUOYAH ELENENT REVISION NUMBER: 0 N
TITLE:
PIPING AND VALVE DESIGN Rubber Gasket Deterioration PAGE 1 0F 9 REASON FOR REVISION:
PREPARATION PREPARED 5
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'DATE REVIEWS SE6k REVIEW COMITTEE f
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SIGNATURE DATE CONCURRENCES 8612090222 861124 W
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APPROVED BY:
Y ll~$O'Eb n/A ECSP MAN AER DATE MANAGER OF NUCLEAR POWER DATE
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TVA ENPLOYEE CONCERNS REPORT NUN 8ER: 232.6 (8)
SPECIAL PROGRAN REVISION NUNBER: 0
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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.
NAS ISSUE BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? YES X NO Identified by TVA Generic Concern Task Force Report
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Date 05/19/86 Mfi Documentation Identifiers:
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 ELENENT:
See Appendix A.
.?,l 2 4m 1069d - 10/17/86
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)
SPECIAL PROGRAM REVISION NUMBER: 0 PAGE 3 0F 9 V
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WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN REQUIREMENTS. OR OTHER F
APPLY OR CONTROL IN THIS AREA?
See Appendix A.
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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 W8N 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:
j The concern relates to short-tenn deterioration of rubber gaskets r
4 installed in flanged piping joints in the ERCW, the RCW and other unspecified systems at W8N plant. The CI postulates that such a condition may have a possible adverse impact on plant nuclear safety.
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TVA EMPLOYEE CONCERNS REPORT NUM8ER: 232.6 (8)
SPECIAL PROGRAM
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REVISION NUM8ER: 0 g
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Initially this concern was investigated on W8N.
Interviews with f
WBN maintenance personnel could not establish a historical problem t:
g with rubber gaskets in either safety or non-safety related b
systems. One isolated instance suggested that about six years ago j.
some unidentified rubber gasket material installed in non-safety '
related systems did not perform satisfactorily and required I'
replacement. No furt'her action was considered necessary at that l
time, and no further problems of this nature have been noted.
Based on the W8N concern the TVA SQN Generic Concern Task Force identified " rubber gasket deterioration" as a potential generic issue. An investigation was initiated to determine if a siellar 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 f
j concluded that while rubber gaskets are used in certain mechanical i
l systems in both the reactor and auxiliary buildings, there has been no verifiable adverse impact on operation.
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l 1069d - 10/17/86 i
TVA EMPLOYEE CONCERNS REPORT NUM8ER: 232.6 (8)
SPECIAL PROGRAM
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REVISION NUMBER: 10 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 result 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.
1 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 i
required tests and inspections are implemented at SQN Plant by preventive maintenance program procedures PN-1686-067 and 4
PM-1685-067 for units 1 and 2 respectively.
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TVA EMPLOYEE CONCERNS REPORT NUM8ER: 232.6 (B)
SPECIAL PROGRAM REVISION NUM8ER: O S
PAGE 6 0F 9-Section Ill 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 where 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 0 1330. This gasket material is typically used in low temperature / pressure water services.
All rubber gaskets used in both safety and non-safety related systems at SQN Plant are procured to ASTM Standard Specification for Rubber-Sheet Gaskets, D1330.
I.
fintings:
a.
The rubber gasket material specified and installed in certain systems at SQN plant complies with Section III of the ASME h,
B&PV code for class 2 and 3 piping systems.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (B)
SPECIAL PROGRAM REVISION NUMBER:
0
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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.
Ov Conclu;j.ons:
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.
- 10. CORRECTIVE ACTION:
No corrective action is required.
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1069d - 11/18/86
TVA EMPLOYEE CONCERNS REPORT NUMBER: 232.6 (8)
SPECIAL PROGRAM REVISION NUMBER: 0 PAGE 8 0F 9 A_P_P.ENDIX A 5.
DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
a.
TVA SQN Plant 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; Bills of Material for ERCW and High Pressure Fire Protection (HPFP) systems d.
AS7M 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 COMITMENTS. DESIGN REQUIREMENTS. OR OTHER h
APPLY OR CONTROL IN THIS AREA?
a.
Design Criteria SQN-DC-V-3.0, " Classification of Piping, Pumps, Valves, and Vessels" b.
ANSI-816.21-1978, " Nonmetallic Flat Gaskets for Pipe and Flanges" c.
Drawings 47BM450,17BM302, and 47BM915; Bills of Material for ERCW and HPFPS d.
AS7M Standard Specification for Rubber-Sheet Gaskets, D 1330 e.
ASME Codw.Section III, Division 1. Subsection NC-Class 2 Components, and Subsection ND-Class 3 Components for items initially procured af ter April 2,1973 l
t 1069d - 11/18/06 l
TVA EMPLOYEE CONCERNS
< REPORT NUM8ER:
232.6 (8)
SPECIAL PROGRAM REVISION NUMBER: 0 PAGE 9 0F 9 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, W8N, and H. Mahlman, TVA, Knoxville, (09/15/06) 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. 103(4)
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