ML20117M807
| ML20117M807 | |
| Person / Time | |
|---|---|
| Site: | 05000000, LaSalle |
| Issue date: | 11/25/1983 |
| From: | Spessard R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20114G054 | List:
|
| References | |
| FOIA-84-616 NUDOCS 8505170218 | |
| Download: ML20117M807 (5) | |
Text
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- 2neCu UNITED STATES
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NUCLEAR REGULATORY COMMISSION P-S REGloN Ill
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GLEN ELLYN, ILLINOIS 40137
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NOV 2 51983 MEMORANDUM FOR:
.E. L. J'ordan, Director, Division of Emergency Preparedness and Engineering Response, Office of Inspection and Enforcement FROM:
R. L. Spessard, Director, Division of Engineering, Region III
SUBJECT:
PROPOSED IE INFORMATION NOTICE: FAILURES OF SOFT SEAT SEALS ON VALVES
, Enclosed for your consideration is a proposed IE Information Notice regarding recent failures of soft seat seals of dual seated check valves at
-the-LaSaIIe County Nuclear Station.
s If you have any questions regarding the proposed notice, please contact Dorwin Hunter (FTS 388-5555) or Ned Choules (FTS 388-5561) of my staff.
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R. L. Spessard, Director Division of Engineering, Region III
Enclosure:
As Stated cc:
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,4q UNITED STATES.
NUCLEAR REGULATORY COMMISSION
~ OFFICE 0F INSPECTION AND' ENFORCEMENT
. ASHINGTON,' D.C.
20555-W DATE s
a IE INFORMATION NOTICE--NO.'83- -: FAILURES OF SOFT SEAT SEALS ON VALVES i.
[ Addressees:
J "A11'au'elear power reactor facilities holding an operating license (OL)
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or construction permit;(CP).
i jPurpose:
T is information'is provided to inform licensees of an event at a boiling
' water reactorD(BWR)lwhere the soft. seat seals on feedwater check valves-failed. Addressees are expected to-review this information for applicability to their. facilities.
- P Description of Circumstances:
~
?In, September:1983 Commonwealth Edison Company notified the.NRC that the.
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" inboard feedwater check : valves at the LaSalle County Nuclear' Station had failed:theirclocal leak rate tests. These check valves had been modified
~~prio'r to initial plant' operation from a.hard seat valve to a combination soft
,and hard' seat by modifying the. valve. discs to allow installation of the additional soft seat seals. 1The failure mode of these' soft-valve seals-
- which' were of a molded design has not been definitely determined. However,.
there appears'to.be three.possible causes. First, sharp edges around the ~
l pressure equalizing-ports located in the discs had' cut the soft seal material ~
'in multiple locations. 'The sharp edges apparently had.not been properly
? removed-whenfthe valve discs'were: modified.
It is possible the: local: leak
~rate test j air bypassed.the seal completely through those cuts. Second, a
.possible cause is,that'when:the faces of the soft seals were machined for
'properifit -the~ machining.may.have affected their-sealing capability. Third, P( t Ethe service ' conditions encountered by the valves during plant-startup and
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ishutdown-may have damaged.the soft seals. The original soft seals were
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q ethylene propylene rubber obtained through Anchor / Darling Valve ' Company from the:Stillman~ Rubber Company..
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e The damaged molded seals were replaced in September with new seals of an
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estruded-vulcanized design obtained through Anchor / Darling Valve Company from Stevens Associates. Grinding was performed on these seals at the site to obtain proper fit and the valves passed local leak rate tests.
Since the cause of failure of the original molded seals had not definitely been deter-mined, the licensee agreed to perform a local leak rate test on the valves during a subsequent outage. On November 16, 1983, Commonwealth Edison Company informed the NRC.that the check valves had failed the local leak rate tests.
Disassembly of the valves showed the soft seals had failed at the vulcanized
. joints resulting in gaps. The licensee plans to return to seals of the molded design and conduct augmented leak rate testing to assure continued seal operability.
Anchor / Darling indicated that the failure of the extruded-vulcanized seals resulted from improper vulcanizing of the seal joints. Anchor / Darling is also of the opinion that the problem is probably limited to one batch of seals and only affects the LaSalle Nuclear Power Station. Attached is an Anchor /
Darling document listing those nuclear plants which the company has provided valve seals and showing the dates delivered. All soft seals, initial and replacement, furnished by Anchor / Darling after October 1981 were the extruded-
, vulcanized type.
It is not known which of the valves listed in the attachment may have applications important to safety or which have the molded or extruded-vulcanized sof t seat material at this time.
Attachment:
Anchor / Darling Experience L
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Anchor /Dar ing
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EXPERIENCEW
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- g. i CHECK VALVES, WITH DUAL SEAT DESIGN Valve Description UTILITY - Installation ANSI Oty.
Size Pressure Design Class (#)
COSTON EDISON 3-77 Pilgrim 1 4
18" 900 TDC CAROLINA POWER & LIGHT 9-79 Brunswick 1 & 2 2
J8" 900 TDC 3-80 Brunswick 1 & 2 2
18" 900 TDC COMMONWEALTH EDISON 6-80 La Salle 1 & 2 4
24" 1500 TDC NORTHEAST UTILITIES 9 80 Millstone 1 4
18" 1500 Swing Check NEBRASKA'PUBLIC POWER 1-81 Cooper Nuclear 4
18" 900 TDC LORIDA POWER & LIGHT 1-81 Turkey Point 2
2W 150 Swing Check DUKE POWER 6-81 Oconee 6
24" 900 TDC PENNSYLVANIA POWER & LIGHT 6-81 Susquehanna 4
24" 900 TDC COMMONWEALTH EDISON 6-81 La Salle 1 & 2 2
10" 150 T-Globe VERMONT YANKEE NUCLEAR POWER 8-81 Verrnont Yankee 4
16" 900 Swing Check TAlWAN POWER 10-81 Kuosheng 1 & 2 2
12" 150 Y-Globe TVA 1 0-81 Sequoyah 1 & 2 4
8" 150 TDC 4
6" 150 TDC TVA 10-81 Watts Bar 1 & 2 4
8" 150 TDC 4
6" 150 TDC TAlWAN POWER 6-82 Kuosheng 1 & 2 2
3" 900 Swing Check
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et.LINOIS POWER 7 82 Chnton 2 I 18" 1500 TDC 8 83
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, f;,6TILITY Installation l
l Przssura ANSI I Oty.
Sin Design Class (#)
':AROLINA POWER & LIGHT 7-82 Brunswick 1 & 2 2
8-150 Angle Globe GEORGIA POWER 9-82 Hatch 1 & 2 2
20* x 16" x 20-150 Y-Globe 2
10 x 8 x 10-150-Y-Globe BOSTON EDISON 9-82 Pilgrim 1 1
20" 150 YGlobe Stop 1
8-150 Y-Globe Stop SOUTHERN CALIFORNIA EDISON 9-82 San Onofre 1
2%~
150 T-Globe ARKANSAS POWER & LIGHT 11-82 Arkansas Nuclear One 2
4-600 T-Globe PENNSYLVANIA POWER & LIGHT 12-82 Susquehanna 1
20-150 T-Globe 1
10-150 T-Globe LONG ISLAND LIGHTING 1-83 Shoreham 2
18-150 Y-Globe 2
8-150 Y-Globe WASHINGTON PUBLIC POWER SUPPLY SYSTEM 1-83 WNP-2 4
24-900 Swing Check CONSUMERS POWER 1 83 Big Rock Point 1
10-1500 Swing Check DETROIT EDISON 2-83 Enrico Fermi 2 1
20-150 Y-Globe 1
10-150 Y-Globe DUKE POWER 2-83 Oconee 3
6-630 Swing Check TVA 3-83 Browns Ferry 12 1500 Swing Check WASHINGTON PUBLIC POWER
- SUPPLY SYSTEM 4-83 WNP-2 1
10-150 T-Globe DETROIT EDISON 5-83 Enrico Fermi 2 2
24-900 Swing Check 4
20-900 Swing Check 2
12-900 Swing Check CINCINATTI GAS & ELECTRIC 6 83 W. H. Zimmer 1
8-150 TGlobe
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B-83 W. H. Zimmer 1
6-1500 TDC
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'. ut TROIT EDISON
- 83-Enrico Fermi 2 1
4-900 Swing Check 2
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900 Swing Check p
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