Information Notice 1988-59, Main Steam Isolation Valve Guide Rail Failure at Waterford Unit 3
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C.
20555
August 9, 1988
NRC INFORMATION NOTICE NO. 88-59:
MAIN STEAM ISOLATION VALVE GUIDE RAIL
FAILURE AT WATERFORD UNIT 3
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
This information notice discusses a main steam isolation valve (MSIV) guide
rail failure at Waterford 3 and its possible generic implications. The MSIV
is a D-2 Power Seal type, manufactured by ACF Industries, WKM Valve Division.
It is expected that recipients will review the information for applicability
to their facilities and consider actions, as appropriate, to avoid similar
problems. However, suggestions contained in this information notice do not
constitute NRC requirements; therefore, no specific action or written response
is required.
Description of Circumstances
On April 11,
1988, during a routine inspection at Waterford 3, MSIV debris was
found in the strainer for the main turbine throttle valve. The disassembly and
inspection of the two MSIVs at the plant revealed that the downstream guide
rails in one of the valves (see attached drawing) had become completely dis- lodged, and several bolt heads on the still-attached upstream rails in the same
valve had been completely severed. The other MSIV had several separated bolt
heads on both upstream and downstream rails, but the guide rails were in place.
There were also galling marks on the chamfer of the guide rail and on the shoe
attached to the lever lock arm.
Discussion:
An analysis by the licensee indicates that the guide rail failure was caused by
the force of the lever lock arm assembly contacting the rail.
The valve, however, passed the inservice test requirements.
The analysis concludes that
even without the rails the valve could still perform its function, albeit at a
closure time that is slower by about a second, under the worst-case condition.
However, there is a possibility that a detached rail could jam the MSIV in a
partially open position. The failure of one MSIV is accounted for in the
utility's Safety Analysis Report.
8808030112 ZA
IN 88-59 August 9, 1988 After the failure at Waterford 3, a fiberscope examination of the WKM power
seal MSIVs at San Onofre Unit 3 revealed a broken bolt lying in the bottom
section of the body of one MSIV. Disassembly and inspection of this valve
revealed three failed bolts, galling marks on the shoe and the chamfer, and
an upstream rail slightly detached from the skirt plate.
At the same plant, a shutdown cooling isolation valve of a similar design was also damaged.
How- ever, the licensee believes that this damage occurred during maintenance. The
damage was similar to that found on the MSIVs, that is, galling marks, failed
bolts, and detached rails, but, in addition, the skirt plate was fractured and
the shoe was wedged into the lever arm pivot slot.
The NRC believes this type of failure could be generic to other plants.
Valves
of this type are also reported to be in use at San Onofre 2, South Texas 1 and 2, and Washington Nuclear Power Unit 2. Valves of similar design could exist at
other plants.
The preliminary indications suggest that the failures are
attributable to deficiencies in fabrication, engineering, and materials. The
corrective actions considered at Waterford and San Onofre 3 include
(1) stelliting the shoes and the chamfer on the rails
(2) verifying the bolt alignments
_doingnondestructive examinations of all new bolts
__ _ _ _-1--
'
.
t
-.-------
-
-. ,
__ ._
__ ___ __
(4) changing the angles of the rails and of the shoes
(5) increasing the valve closure time (within system performance constraints)
(6) periodically making fiberscope examinations of the valve internals
to detect excessive galling, severed guide rail bolts, and separated
guide ra'ls
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Kenneth Dempsey, NRR
(301) 492-0918 Attachments:
1. Figure of Valve
2. List of Recently Issued NRC Information Notices
Attachment
IN 88-59 August 9, Page I of
1988
GATE S SEGMENT
ASSEMBLY
GUIDE RAIL BOLT
LOCATIONS (9 PER
GUIDE RAIL).
TYPICAI
OF 4 GUIDE RAILS
1-'
Atti
nt
2 in 88-59
August 9. 1988
Page 1 of I
LIST oF RECEaIMT ISSUED
NRC INFOidATION NOTICES
_AA---
n-.-
rreson"At1nr
iaiWowb
Notice No.
88-57 de-Sd
88-55
88-54
88-52 SubJect
Potential Problems with
AScA 8rown toverl ITE-s1L
Time-Overcurrent Relays
Potential Loss of Safe
Shutdown Equipment Due to
Preesture Silicon Controlled
Rectifier Failure
Potential Problems with
Silicone Foas Fire Barrier
Penetration Seals
Potential Problem Caused
by Single Failure of an
Engineered Safety Feature
Swing tus
Failure of Circuit Breaker
Following Installation of
Amptector Direct Trip
AttacJment
Licensee Violations of NRC
Regulations, Which Led to
ledical Diagnostic
Misadvinistrations
Failure of Intrauterine
Tandem of Fletcher
Applicator Irachytherapy
Deuces During Patient
Treatment
UtU UT
Issuance
8/8/88
8/3/88
8/4/88 WM/8
7/28/88
7/28/88
7/27/88 Issued to
All holders of uLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPS for nuclear
power reactors.
All holders of OLs
or CPS for nuclear
power reactors.
All manufacture
and
distributors of radio- pharmaceuticals for
hum use. nuclear
pharmacies, and
medical licensees.
Medical licensees.
81-46. --
ticense- Report of
-
Supplement 1
Cefective Refurbished
Circuit Breakers
- 7/26/88-
-
All hol40dsof-Ls
or CPs for nuclear
power reactors.
- Op rating License
- Construction Permit
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE. $300
FIRST CLSSMAIL1
IPOSTAGE & FEES PAIDI
IUSNRCI
IN 88-59 August 9, 1988 After the failure at Waterford 3, a fiberscope examination of the WKM power
seal MSIVs at San Onofre Unit 3 revealed a broken bolt lying in the bottom
section of the body of one MSIV. Disassembly and inspection of this valve
revealed three failed bolts, galling marks on the shoe and the chamfer, and
an upstream rail slightly detached from the skirt plate. At the same plant, a shutdown cooling isolation valve of a similar design was also damaged.
How- ever, the licensee believes that this damage occurred during maintenance. The
damage was similar to that found on the MSIVs, that is, galling marks, failed
bolts, and detached rails, but, in addition, the skirt plate was fractured and
the shoe was wedged into the lever arm pivot slot.
The NRC believes this type of failure could be generic to other plants.
Valves
of this type are also reported to be in use at San Onofre 2, South Texas 1 and 2, and Washington Nuclear Power Unit 2. Valves of similar design could exist at
other plants. The preliminary indications suggest that the failures are
attributable to deficiencies in fabrication, engineering, and materials. The
corrective actions considered at Waterford and San Onofre 3 include
(1) stelliting the shoes and the chamfer on the rails
(2) verifying the bolt alignments
(3) doing nondestructive examinations of all new bolts
(4) changing the angles of the rails and of the shoes
(5) increasing the valve closure time (within system performance constraints)
(6) periodically making fiberscope examinations of the valve internals
to detect excessive galling, severed guide rail bolts, and separated
guide rails
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Kenneth Dempsey, NRR
(301) 492-0918 Attachments:
1. Figure of Valve
2. List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
- C/OGCB:DOEA:NRR *RPB:ARM
Rossi i
CHBerlinger
TechEd
08/3 /88
08/01/88
07/27/88
- OGCB:DOEA:NRR *EMEB:DEST:NRR *C/EMEB:DEST:NRR
- EAD/DEST:NRR
- D/DEST:NRR
DCKirkpatrick KDempsey
LBMarsh
JRichardson
LCShao
07/26/88
07/28/88
07/29/88
07/29/88
07/29/88
IN 88-XX
July xx, 1988 After the failure at Waterford 3, a fiberscope examination of the WKM power
seal MSIVs at San Onofre Unit 3 revealed a broken bolt lying in the bottom
section of the body of one MSIV. Disassembly and inspection of this valve
revealed three failed bolts, galling marks on the shoe and the chamfer, and an
upstream rail slightly detached from the skirt plate.
At the same plant, a
shutdown cooling isolation valve of a similar design was also damaged.
How- ever, the licensee believes that this damage occurred during maintenance.
The
damage was similar to that found on the MSIVs, that is, galling marks, failed
bolts, and detached rails, but, in addition, the skirt plate was fractured and
the shoe was wedged into the lever arm pivot slot.
NRC believes this type of failure to be generic to other plants.
Valves of
this type are also reported to be in use at San Onofre 2, South Texas 1 and 2, and Washington Nuclear Power Unit 2. Valves of similar design could exist at
other plants. The preliminary indications suggest that the failures are
attributable to deficiencies in fabrication, engineering, and materials.
The
corrective actions considered at Waterford and San Onofre 3 include
(1) stelliting the shoes and the chamfer on the rails
(2) verifying the bolt alignments
(3) doing nondestructive examinations of all new bolts
(4) changing the angles of the rails and of the shoes
(5) increasing the valve closure time (within system constraints)
(6) periodically making fiberscope examinations of the valve internals to
detect excessive galling, severed guide rail bolts, and separated
guide rails
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Kenneth Dempsey, NRR
(301) 492-0918 Attachments:
1. Figure
2. List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
C021 D/DOEA:NRR
C/OGCB:DOEA:NRR
- RPB:ARM
CERossi
CVBerlinger
TechEd
07/ /88
0 6) /88
07/27/fM'tA
- OGCB:DOEA:NRR EMEB4REST:NRR C/EMEB:DEST:NRR
EAD/DEST:
D/DES
h
DCKirkpatrick KD f y
LBMarsh
JRichards nr/zn LCShao
07/26/88
07/..2/88 v j
7/88
07/J '/88
07, /88
IN 88-XX
July xx, 1988 Subsequent-to the failure at Waterford 3, a fiberscope examination of the WKM
h
power seal MSIVsit
-an
Onofre9Jnit 3 revealed a roken bolt lying in the
bottom section of the body of one MSIV. 4umiang/i assembly and inspection of
-was-foUlU-te-hes
e three failed bt5, galling marks on the shoe
and the c imfer, and an upstream rail slightly detached from the skirt plate.
At the same plant, a shutdown cooltng isolation valve of a similar design was
also fewnd-te-be9damaged. However, the licensee believes that this damage
J
c ncurred during maintenance. The damage was similar to that found on the
/
MSI1iV4%e4_galling marks, failed bolts, and detached rails, but, in addition,
,Ythe skirt plate was fractured and the shoe was wedged into the lever arm pivot
S g slot. t
a PL
Cjhis type of failure
44-be+eved to be generic to other plants. Valves-of
n
this type are also eported to be in use at San Onofre 2, South Texas 1 and 2,
'nkdesign
could exist at other plants. The pr~imi- cat ons
that the failures are attributable to deficien
sn
t fabricaton, en I eering, and materials. The corrective actions
t-have-ten"er
considered at Waterford and San Onofre 3 includeiL,/
qQS8x;A F-J(1,V Xtelliting the shoes and the chamfer on the rai
,-r
,*
~ (2,)
.erifying
the bolt alignmentsa--
=LT73-) 4Voing nondestructive examinations of all ne bolts,-
u(4j)
4hanglng the angles of the rails and of t
shoes,.
//It"
fl
75i) .ncreasing the valve closure time (withi system constraints),.->
i !U..'6)Ieriodically
making fiberscope examina ions of the valve internals to
J,
e- detect excessive galling, severed gu e rail bolts, and separated
'3/4.
8 Sguide
rails.---
i
by
No specific action or written response sequired by thia/i nformation notice.
-
If you have any questions about this mat er, please ci&fiet-the technical
contact listed below or the,,,egional
inistrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Kenne
Dempsey, NRR
(30
492-0918 Attachments:
1. Figure
2. List of Recentl Issued NRC Information Notices
D/DOEA:NRR
C/OGCB:DOEA:NRR
RFA':
CERossi
CHBerlinger
WchO1fW/88
07/ /88
07/ /88
07/o77/88 OGCB:DOEA:NRR EM BDB T:NRR C/EMEB:DEST:NRR
EAD/DEST:NRR
D/DEST:NRR
DCKirkpatjjjl
KDipb6j'
LBMarsh
JRichardson
LCShao
07/g;/88 AJW# 07/ 7~f88
07/ /88
07/ /88
07/ /88
IN 88-XX
July xx,
1988 Subsequent to the failure at Waterford 3, a fiberscope examination of the WKM
power seal MSIVs at San Onofre'Unit 3 revealed a broken bolt lying in the
bottom section of the body of one MSIV. During disassembly and inspection of
this valve, it was found to have three failed bolts, galling marks on the shoe
and the chamfer, and an upstream rail slightly detached from the skirt plate.
At the same plant, a shutdown cooling isolation valve of a similar design was
also found to be damaged.
However, the licensee believes that this damage
occurred during maintenance.
The damage was similar to that found on the
MSIVs, i.e., galling marks, failed bolts, and detached rails, but, in addition, the skirt plate was fractured and the shoe was wedged into the lever arm pivot
slot.
This type of failure is believed to be generic to other plants.
Valves of
this type are also reported to be in use at San Onofre 2, South Texas 1 and 2, and WPPS. Valves similar in design could exist at other plants. The prelimi- nary indications are that the failures are attributable to deficiencies in
fabrication, engineering, and materials.
The corrective actions that have been
considered at Waterford and San Onofre 3 include:
1. Stelliting the shoes and the chamfer on the rails,
2. Verifying the bolt alignments,
3. Doing nondestructive examinations of all new bolts,
4. Changing the angles of the rails and of the shoes,
5.
Increasing the valve closure time (within system cons raints),
6. Periodically making fiberscope examinations of the alve internals to
detect excessive galling, severed guide rail bolt, and separated
guide rails.
No specific action or written response is required by
is information notice.
If you have any questions about this matter, please ontact the technical
contact listed below or the Regional Administrator f the appropriate regional
office.
Charl
E. Rossi, Director
Div ion of Operational Events Assessment
Of ce of Nuclear Reactor Regulation
Technical Contact:
Kenneth Dempse
(301) 492-09 Attachments:
1. Figure
2. List of Recently Issue NRC Information Notices
D/DOEA:NRR
C/OGCB:DOEA:NRR
RPB:ARM
CERossi
CHBerlinger
TechEd
OGCB:DOEA:NRR
DCKirkpaty4gI
07/;I$/88 AJw
EMEBL:DIST:NRR
KDOW%~y
07D-8/88
07/ /88 C/EMEB:DEST:NRR
LBMarsh
07/ /88
07/
/88 EAD/DEST:NRR
JRichardson
07/ /88
07/ /88 D/DEST:NRR
LCShao
07/ /88