05000266/LER-1990-001, :on 900402,containment Isolation Valve Leakage Found in Excess of Tech Spec Limits.Suspected That Two Intermediate Attempts May Have Partially Cycled Valve.Valve Reassembled & Tested Satisfactorily
| ML20034C722 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 04/30/1990 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-90-001, LER-90-1, VPNPD-90-204, NUDOCS 9005070088 | |
| Download: ML20034C722 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(1) |
| 2661990001R00 - NRC Website | |
text
-
~
v.-
' Electnc 1
POWER COMPANY 231 W Michigan Po. Box 2046. Mboakee, WI 53201 (414)221 2345 VPNPD-90-204 10 CFR 50.73 NRC-90-038 April 30, 1990 U.
S. NUCLEAR REGULATORY COMMISSION I
Document Control Desk Mail Station P1-13*/
Washington, D.
C.
20555 Gentlemen:
DOCKET 50-266 LICENSEE EVENT REPORT 90-001-00
'l CONTAINMENT LEAKAGE IN EXCESS OF l
TECHNICAL SPECIFICATIONS l
POINT BEACH NUCLEAR PLANT, UNIT 1 Enclosed is Licensee Event Report 90-001-00 for Point Beach Nuclear Plant, Unit 1.
This report is provided in accordance with 10 CFR 50.73 (a) (2) (i), "Any-Operation or Condition.
j Prohibited by the Plant's Technical Specifications."
j This report details the failure of a containment isolation valve i
to pass its Type "B" leak rate test.
l If any further information is required, please contact us, j
Very trul
- yours, 0-(?6L/
tky/
C.
W.
Fay i
Vice President l
Nuclear Power Enclosure Copies to NRC Regional Administrator, Region III NRC Resident Inspector i
i 9005070088 900430 PDR ADOCK 05000266 4
S PDC I.
AlhSkS9/)*OfN AUllShi NN*W(Ol] WINE lUU '
c eo a see U.S. Nuct 22 to evLaf omT ComuassioN APexovtD out No 3160c104 ixmi..,wn
,'SaA%',f3'"J'T J'A'??vi'.T t*?T# !!'.".'a'!
LICENSEE EVENT REPORT (LER) g u,ty,1,8,a4o,A,a,o;= g t g f4uA,t g T,5a g ag y
Ri",,%".'Jt"tNJ8%*~^%",il!"#d"& tifilf Of MANAGtutNT AND DVDOET,W ASHINGTON. DC 20603.
8 ACILITY e:Aut,116 DOCElf NuttDE R (2)
F'GE 4 i
Point Beach Nuclear Plant o i s I o I o I o 121616 1lOFIO14 l
Containment Isolation Valve Leakage in Excess of Tech Spec Limits IVtWT DAf t ill Lim NUMeth 161 REPORT DAf t (Tl OTHE R F ACILITill INVOLVED tal MONT M Day vtam vtan 5(Qg ' A h yf,*,$
woNTM CAv vtam PaciLaT e h& Mas DocalT NuwstRisi 015101010 12 16 16 0l4 0\\ 2 90 9l0 0l 0l1 0l 0 0l 4 3 !0 9l0 0 1 51 0 1 0 1 0 1 1 I TMis af ront is iveueTTio eva uANT To THE aiovialutNrs o, a Con i
<C,
..,..,,,,,,.u...,, nu "o08
N
,,,,,, n, n,,,
,1, n,,
n.asi.ninn ftfu i y
w w.im un.ntn.i nos l 10 so mmn'n">
'o *' ns '
?l,"l W lllllyg',,,
mo 's=nt""*'
- so T3.imna un n2HvennAl M A/
n mainnoi u m.in n.,
.on.nen i wn ian..n.,
n.06.in net u T36 alt 2ndal to T3 entual LICEPs485 CONT ACT FOR TMil LER (12)
NAME TELEPMONE NvMSIR C.
W.
Fay, Vice President - Nuclear Power 4 il l4 2 l2 ill-12l8l111 COMPLlit ONE LINT 70m ( ACM CotePONENT f AILVal DiaCaistD IN TMis REPORT tt3e CAv$t Sv8tiv COMPONENT "i g$C yo,TAf n
caust systtu COMPONENT gC-y0mtA LE pp g X
BD II I SlV P 3 015 Y
i ii t i i I
l I
I I I I I I I
I I I I I I SUPPLEMENT AL REPORT EXPECTED llei MONTH Dev veAR SutMr$$10%
v t$ <H v.s toepme, f M*ECTED SUOM:SSION OATil No l
l l
tut a ACT to-,,,, em -u,
....-.<,,,,.....a,,.,,,,,,,nel On April 2, 1990, during Appendix J, " Type C" containment leak rate testing, service air system check valve 1SA-17 was discovered with leakage in excess of limits cited in Technical Specifications 15.4.4.II.B and 15.4.4.III.B.
The required test pressure could not be achieved during two attempts utilizing the low volume " leak rate test rig," (leakage off scale-high; greater than two liters per minute).
Two intermediate attempts to quantify leakage with the high volume " mass flow rate test rig" resulted with no detectable leakage.
In this case, the required test pressure could not be achieved during the first two attempts with the low volume " leak rate test rig"; therefore, a leak rate for the design basis conditions could not be quantified.
Investigations by Maintenance identified no anomalies with the valve or the valve internals.
It is suspected that the two intermediate attempts may have partially cycled the valve and properly aligned / seated the valve disc.
The valve was reassembled, tested satisfactorily, and restored to operation.
This report is filed pursuant to 10 CFR 50.73(a)(2)(1), "Any operation or condition prohibited by the plant's Technical Specifications."
fAC P.,m 384 i649i
C FAM 3e6A U.S.tuCLEAR Lt1ULATORY COMMstet04 g
p t KPilt8:4/30/92 LICENSEE EVENT REPORT (LER) f,Us%'!40'N @tM?o0M,nT'..cfW,T".h
- - 1 u
TEXT CONTINUATION in't45,h',MT!"ous?',*dfCn,!37N,".'$$R T,'A,'t9"Mf""d'U7C,a'.=W A$MINGTON. DC 20 OF MANAGEMENT AND DVDGIT f ACILITV NAME tu DOCKET NUMSSR (2)
LIR NUMSIR ($1 PA0613) vsAm
. SQ,8 N,[,A4
- - gy*,y, J
Point Beach Nuclear Plant o ls lo lo j o l2 l6 l6 9l0 0 l0 l1 0 l0 0l 2 oF 0l4
-]
TEXT (# more asoce a revunen use esecons/ N4C,orm M4's)(17) i
EVENT DESCRIPTION
On March 31, 1990, Unit 1 shut down for annual refueling and maintenance Outage 17.
On April 2, operators commenced Refueling Test 49, " Leak Check of the Service Air-Containment Penetration."
This test-is completed annually to satisfy the requiremente of 10 CFR 50,-Appendix J and plant Technical Specifications.
The low volume leak rate test equipment was installed, but the operator was unable to pressurize the penetration, The~ test meter read ="off scale-high" which indicated air leakage greater than two liters-per minute.
This was confirmed as.the operator witnessed significant air passage via the leak test discharge path.
At this point in time, service air check valve 1SA-17 was sus?ected to have backleakage.
In order to quantify the backleakage, tae operator connected the high volume-leak rate test equipment.
The penetration pressurized in approximately 30 seconds, and no appreciable leakage was noted.
The low-volume leak-rate test equipment was installed a second time, and again'the operator was unable to pressurize the penetration.
The high volume leak rate test equipment was reattached, and the penetration pressurized in approximately 10 seconds.
The low volume leak rate test equipment was attached a third time.
This time the' penetration pressurized-and maintained an acceptable leak rate of 1280 standard cubic-centimeters per second (secm).
Maintenance Work Request 901575 was initiated to investigate the problem.
No hardware anomalies were found. 'It is suspected that the two intermediate attempts to quantify leakage with the high volume test equipment may have partially cycled the valve and seated the valve disc.
The valve was reassembled, tested satisfactorily, j
and restored to operation.
COMPONENT AND SYSTEM DESCRIPTIONS Valve 1SA-17 is a 4-inch, 150 pound class, carbon steel (A-216 GR WCB), swing check valve.
(Figure No. 1561-A weld end, Drawing 034963, manufactured by the William Powell Company, Cincinnati, Ohio)
It is located outside of containment, on the supply side of the containment service air header.
It-has been in service since commercial operation begancin December 1970.
Piping on either side of the check valve is a Schedule 40 carbon steel ASTM A-106, Grade B, with a design rating of 120 psig at-100 F.
Penetration piping and check valve 1SA-17 are normally.
isolated while the unit is at power.
Additional isolation capability for this piping is provided by manually-operated valve 1SA-15 outside of containment.
NT.C f orm 304A (6 89)
If WRC FIT 4A 3es&
U.S. 8:UCLt1R h80pLATMY COMill10Sloh p
g EXTilt$ 4/30/92 UCENSEE EVENT REPORT (LER) 5RE'Ao'ush"leWofi'U$1'sTI.0Ts*,7"wl"RS TEXT CONTINUATION
!J"R't",'O'R f"M!0"oi MO" '!d'UldN"' UEEdl e
PAPERwo R$ U TOON R J (3 604 O I Of MANAGEMtNT AND SUDGET, WASHINGTON DC 20603-j f ACitlTV hAMt til DOCKtT WVMBER (2)
LtR NUMeta (el
- AOS (3)
[,^ 4 q"y j,y, l
88 vtaR Point Beach Nuclear Plant a p;o;o;o 2;6 6 9;0 0 ;0 l1 0 ;0 0l 3 or 0l4 j
l TEXT f# mwe since e eageren use seweow NAC Fenn M W (17) l REPORTABILITY-L This licensee event report is filed pursuant to 10 CFR 50.73(a)(2)(i), "any operation or condition prohibited by l
the plant's Technical Specifications."
The NRC resident ~ inspector was notified.
The Energy Industry Identification System component function l
identifier and system name of the valve and system referred to.in i
this LER are:
Valve No.
ISA-17 System BD Component ISV
SAFETY ASSESSMENT
Operation of Unit 1 during the last fuel-cycle posed no significant safety hazard to the general public or to the employees of the Point Beach Nuclear Plant.
Alternate means of manually isolating the piping system outside of containment tested satisfactorily and was available to the operators.
In addition, no event in the Final Safety Analysis Report _ considers.
a need for service air supplies to containment.
SIMILAR OCCURRENCES AND GENERIC IMPLICATIONS Check valve 1SA-17 has a history of corrective maintenance.
In March 1974 and December 1975 (Abnormal-Occurrences74-057 and 76-003), the valve exhibited excessive leakage and was repaired.
Because of the incidence of repair, the check valve was' modified with a new composition disc in October 1977.. Valve performance remained acceptable until October 1979 when the valve' disc was again replaced.
Since that date, valve repairs included:
1.
Removal of debris scale in October 1981 (LER 81-014).
2.
Disc adjustments and debris scale removal in April 1986.
3.
Disc adjustments and debris scale removal in May 1987.
4.
Disc adjustments in May 1988.
In 1989, leakage past valve 1SA-17 was at an acceptable value of-approximately 1 secm.
a 6tCC Penn as4A (649}
unucum.mAmv c-loN gc,,,oo u IXPl%18 U30'92 -
LICENSEE EVENT REPORT (LER)
'Ss**MA,%',fiOt'cWo0'M" liv'.0 f?/ 70f"-/J'!
TEXT CONTINUATION
$"*n't,'o'.%"M2"oie'ifM'e'O,'!d 'u".'#MNf!
PAPERwo Al 7 N J
d 50
[
l 0F MANAGEMENT AND SVDGET.W A&MINGTON. DC 20503.
f ACittiv NAME 06 DOCKEY NUMeta t2l gg n,yugg R (66 PA04 (31 64 mt vlam ep qyeIN n
l Point Beach Nuclear Plant o p jo lolol2l6l6 9l0 0 l0 l1 0 l0 0l4 OF 0l4 TEXT (J more anew 4 mownsif. use esistorier NRC Femi JI5d 'sJ (17)
Corrective maintenance to the identical valve installed in Unit 2 l
(2SA-17) occurred on the following dates:
-)
i 1.
Modified valve with a composition disc in May 1977, 2.
Disc adjustments and debris scale removal in October 1985 (LER 85-002).
3.
Dice and disc holder hanger adjustments in September 1986.
Considerable maintenance has been completed on these two valves.
The nuclear plant reliability data system was consulted for failure data with regard to Powell check valves, Model 1561-A, and no significant trends could be developed.
The problems identified appear to be unique to Point Beach Nuclear Plant, and no industry generic concerns are evident.
CAUSES AND CORRECTIVE ACTIONS Past maintenance assessments identified the disc in need of minor adjustment.
Part of the valves inherent design provides some allowance for the valve to self-adjust to establish proper seating (leak tight condition).
The fact that the valve has problems i
self-adjusting at low differential pressures characterizes many of the past failures.
Two items abet the failures of 1SA-17.
1.
The size of the disc, which is 4.03 inches.
The size of the I
disc is directly proportional to the weight and the differential pressure necessary to seat it.
At lower I
differential pressures (such as these exerted by the low l
volume leak rate test equipment), the valve is less likely to seat properly.
2.
The valve design causes the disc to seat at a slight incline.
If self-adjustment is necessary, the entire disc must shift upwards slightly, against the forces of gravity and the friction of the seats.
Corrective actions will include:
1.
A successful leak test of the penetration will be conducted before returning the unit to operation.
2.
Manual isolation valves on either side of 1SA-17 will be admi:.istratively controlled " shut" unless unit is in cold shutdown to prevent any use of the penetration.
3.
The penetration will be modified with a suitable replacement for valve ISA-17 by the end of Unit 1 Refueling Outage 18 (June 1991).
]
N7.C Form 306A (&491